X-36 drone - Weapons Systems - Offense/Defense

kbd512 · 2022-04-25 14:56:20

I found a new weapon being developed by MBDA for UK's F-35B models that will add a new dimension to the A-36's attack capabilities:

SPEAR-3 is a combination general purpose air-to-surface miniature cruise missile capable of attacking the radar systems associated with IADS, as well as ships. It carries a rather small warhead, so it won't be sinking any ships, but it doesn't need to. We will use SPEAR-3 in combination with SDB-II / Stormbreaker glide bombs, in order to attack ships. The SPEAR-3 will first blind their radar systems, and then the SDB-IIs will be used to seriously damage the ships using their much larger warheads.

UK F-35B will carry up to 8 SPEAR-3 internally. A-36 would carry 2 SPEAR-3 or 2 SDB-II internally. A squadron of microfighters could therefore attack an individual ship with up to 24 weapons. The first wave would fire their SPEAR-3 at the target ship from low-altitude. The second wave would drop their winged SDB-II glide bombs from altitude, which would dive on the target ship during the terminal phase of the attack.

Side Note:
It seems that AGM-176A was designed for aft-eject only, which means AGM-176B will be carried instead. It has apparently been dropped from drones during testing as a standalone munition, meaning not aft-ejected, but the fins don't appear to "fold" to quite the same degree as the tube-launched AGM-176B model.

The weapons bays will be long enough to accommodate up to 2 of the precision attack munitions or 8 of the AGM-176B missiles for ground attack.

I've also been thinking about a centerline 30mm M230 gun pod, similar to what the F-35B and F-35C carry for strafing runs. It won't carry a lot of ammo, but 100 rounds should be enough for 5 passes using 20 round bursts. Burst length can be user-selected with chain guns. The AH-64s have had their magazine capacity reduced to 300 rounds and the space previously taken up by the other 900 rounds was replaced with 100 gallons of additional fuel in a combination ammo bin / fuel tank sometimes called a "Robby Tank" after the company that makes it, Robertson Fuel Systems.

Oddly enough, the AH-64's standard internal fuel capacity plus the "Robby Tank" comes to around 459 gallons, which is pretty close to the intended 470 gallon internal fuel capacity of the A-36. AH-64s can remain in the air for 3 hours at most. A-36s can remain in the air for 4.5 hours at most, including 30 minutes of reserve fuel. Combat radius will be very similar to the F-35, although it won't be quite as fast. Anyway, it's a good indicator of just how thirsty helicopter gunships are.

kbd512 · 2022-09-21 01:26:55

As more information about the Kratos XQ-58A "Valkyrie" and Boeing MQ-28A "Ghost Bat" trickles out, I'm starting to see how my crewed A-36A concept compares with these other supposedly "attritable" platforms in the same weight class. These drones cost somewhere between $2M and $5M each, before mission sensors or weapons are added. Kratos said their XQ-58A will cost about $2M per copy and I think Boeing stated that their more capable MQ-28A is closer to $5M, so my $5M flyaway cost projection seems pretty reasonable.

The XQ-58A, with its almost identical MTOW to my A-36A concept, at around 6,000lbs, has roughly half as much thrust. XQ-58A cruises near 550mph, so even with half as much thrust it still qualifies as a "fast jet". The range of the XQ-58A is stated as up to 3,500 miles. My FJ-44-4M powered A-36A is also crewed and landing gear-equipped, whereas the XQ-58A is a drone that lands via parachute and airbags. No crew or landing gear and rocket-assisted takeoff does provide significant mass savings to Kratos' Valkyrie, even as it limits how it can be used and complicates recovery if the airframe will be reused. Since it must be reused in order for the Valkyrie to be anything more than a very expensive, if highly capable, expendable munitions dispenser. Tomahawk cruise missiles already deploy munitions for far less cost. That means extra weight must be allocated to crew and aircraft recovery in my design. A-36 range or combat radius will be significantly reduced, as compared to the XQ-58A as a result. A-36 will also be a thirstier machine due to its much more powerful engine, but there are positive aspects to that trade-off. A-36 should easily match the kinematics of the F-8 (climb rate) or A-4 (roll rate) and F-16 (instantaneous turn rate).

Skyhawks are still used for DACT by both the USAF and USN to this day, specifically because those jets are so small, nimble, and difficult to maneuver with in clean or nearly-clean configurations. Acting as a very low cost but stealthy and maneuverable DACT opponent for F-22s and F-35s is a bonus feature that will improve overall readiness levels. My primary goals is to make these jets useful for attack to prosecute all targets that don't merit the payload capacity of a F-22 or F-35, which accounts for most missions if we're honest about how tactical fighters are actually used to support ground forces. Pure thrust and therefore speed was never a key performance metric, because it's not an end unto itself in practical air warfare, most of which is now directed towards attacking ground mobile systems and smaller naval vessels, with attacking enemy aircraft in the air being a secondary mission objective for which truly excellent mission-specific aircraft already exist. Even so, normal A-36 cruise speeds will match any other tactical fighter jet, to include the F-22 / Su-27 / Su-57 / J-20.

In terms of climb rate and speed, an A-36's closest match for thrust-to-weight class is the F-8 Crusader. In terms of snap-roll and turn performance, it will easily equal or exceed the A-4s and F-16s, which the original X-36 drone aptly demonstrated with its spectacular roll rates and turning performance, all done without a vertical tail. A-36 cannot keep up with a F-22 / F-35 / Su-27 / Su-57 / J-20 in a vertical fight. All A-36 pilots will be admonished not to attempt something so foolish. However, any attempt by those far more powerful jets to enter into a horizontal turning fight with an A-36 would result in a swift loss. None of them can haul their nose around as sharply, better known as instantaneous turn and roll rate performance. Those larger jets with twice as much thrust can maintain greater sustained turn rates using afterburner, especially at higher altitudes where they typically operate, but most dogfights do not involve two planes endlessly circling each other until one or the other winds up on the tail of the other plane. At the lower altitudes where the A-36 will typically operate at, the greater lifting surface area necessary for high altitude turning performance penalizes those larger jets by more rapidly bleeding energy due to drag.

None of this is intended to suggest that a smaller jet with significantly less thrust should press an attack against larger fighter jets with twice as much thrust on tap. However, it aptly illustrates the very significant limitations imposed by the physics of flight. The greater the surface area, the more your airframe behaves like a speedbrake if you try to maneuver with a smaller jet, especially at low altitude. You either use afterburner to keep turning with the smaller and more maneuverable jet or you fall out of the sky. Plenty of F-14 pilots have learned that lesson in DACT at lower altitudes with A-4s. On paper, it appears as if the the F-14s should win that fight every time. In practice, F-14 pilots were taught to use their greater speed and thrust to avoid a horizontal turning engagements where they were all but guaranteed to lose against an A-4 flown by a competent pilot.

The same was true of F-16 vs A-10 engagements. The F-16 wins on paper every time, but not by trying to turn with the A-10, where it will lose every time. The F-16, when compared to all other contemporary fighter jets, was a lot more nimble. It was designed to be and had a lot of thrust available to recover energy quickly. The moment you loaded it up with fuel tanks and weapons, handling was quite similar to other similarly loaded fighter jets with more lift and less thrust. Once again, this excludes vertical maneuvering where more thrust wins every time. All Cessna 172s ever made will easily turn inside of all modern fighter jets at the altitudes they typically operate at. That doesn't make 172s suitable F-16 or F-35 replacements. For starters, both of those jets carry individual stores under their wings that weigh more than a 172. In reality, the F-16 or F-35 would use it's vastly superior speed to initiate a high speed attack run against the 172. The 172 could only respond in a purely defensive manner, with no ability to pursue the much faster fighter jets. If the 172s were single seat and equipped with a pair of Sidewinders, along with appropriate sensors to detect approaching enemy aircraft, essentially making them entirely different aircraft, then yes, at close range they'd pose a serious threat to the F-16 or F-35. However, fighter jets are so much faster that they could avoid engagement altogether or snipe at them with longer range missiles.

I estimate you'd need 600hp of cruise power, or more, to carry the sensor systems and pair of missiles, so now your fuel burn rate is remarkably similar to a much faster jet's fuel burn rate at lower power settings, but your piston engine is also a lot less reliable than a jet engine, so your pilots will get to use their ejection seats with greater frequency, and the millions spent on the sensors and weapons will be lost with greater frequency. The T-28 Trojan trainer that the US Air Force and US Navy historically used for advanced basic training and eventually for carrier qualification was a good example. T-28 was also used in light attack roles during the Viet Nam War, and has the power required to carry a modern AESA radar and other EO sensors, along with 1,200 pounds of stores under its wings, much like the new XQ-58A, which carries an identical maximum weapons payload, albeit internally for stealth.

The T-28's massive Wright R-1820 radial engine has a cruise fuel burn rate of around 100 gallons per hour, which is remarkably similar to what the FJ-44-4M burns at cruise power settings, which would burn less fuel at lower power settings while delivering equivalent or greater speed. XQ-58A's engine develops about half as much thrust as the FJ-44-4M. It's probably using either a de-rated variant of the same FJ-44 family of engines since Williams International, maker of the FJ-44 series, supplies a lot of small turbofans to the US military for missiles, drones, and light aircraft. Anyway, T-28's empty weight, at 6,424 pounds, is also 424 pounds greater than a XQ-58A's MTOW, yet the XQ-58A's max range is 3.8 times greater. Basically, power-to-weight ratio combined with total weight of powerplant plus fuel supply matters greatly to flight characteristics, namely range and speed. T-28 was also equipped with ejection seats in some models, so it greatly resembles the type of aircraft required if we were to try to replace a fighter jet with "less expensive" piston-engine / propeller-driven airframe.

There is nothing stealthy about the T-28, either, in case that needs to be stated, which means operating them as light attack aircraft in airspace defended by IADS is suicidal unless those IADS operators determine that they can't afford to launch very expensive missiles to shoot down cheaply-made airframes equipped with very expensive sensors and weapons. I wouldn't count on that, though. They'll be treated as spy drones and shot down, along with any other less-than-capable non-stealthy aircraft.

If it's not apparent by now, there aren't any "good-and-cheap" solutions to be had. Everything is a significant trade-off. We can't afford to field enough F-22s or F-22 replacements and F-35s to provide 24/7 availability of on-station assets for CAS or light attack missions because those stunningly capable jets are also horrendously expensive to operate. Attritable drones are potentially ideal for relatively simple missions like penetration strikes against fixed targets, but that type of mission is most plausible after air supremacy has been established and the EW environment is relatively benign, which will not be the case against Russia or China. In other words, "Week 1" penetration strikes would be conducted using faster missiles or longer-ranged cruise missiles. The entire concept of an attritable drone aircraft, such as XQ-58A or MQ-28A, presumes there are high value targets (IADS radars or missiles, parked aircraft, or communications equipment) that can only be attacked at great peril to the weapons delivery platform and from relatively close ranges that droppable munitions (small guided glide bombs) allow for, but somehow a stealthy cruise missile would not be the ideal weapon to take out such targets. That set of preconditions for use, makes no real sense. It's paying millions of additional dollars for the ability to use small glide bombs dropped from an aircraft that you anticipate and accept has a high probability of loss. That use case best describes a cruise missile, but the missile costs less because it's intentionally expendable. If a cruise missile could also be recovered in mid-air, as DARPA is doing with actual cruise missile drones launched from C-130s, then the use case for attritable drones, or "loyal wingmen" as some now call them, is almost non-existent. You'd be much better off purchasing in-flight recoverable cruise missiles and using much smaller / less expensive / less capable (compared to a F-35) crewed attack jets that you don't send after targets they should stay away from until after more capable jets (F-35s) or stealthy missiles (NSM, JASSM, LRASM) have destroyed them.

A small stealthy attack jet is the greatest bargain that America and her allies will get for every mission that doesn't require a F-22 or F-35. To be perfectly blunt, the F-22 was developed to intercept and shoot down enemy aircraft. All other considerations were secondary. F-35 was developed for penetration strikes against IADS-defended targets. Whatever replaces the F-22 should be very long range and specialize in destruction of enemy air defenses, rather than solely designed to dogfight similar stealthy interceptor-type aircraft that will likely never find each other until they're so close that human eyes become the primary sensor system employed, whereupon any modern IR-guided weapon is sufficient to fight with.

The bottom line is that the A-36 should be developed for all those other battlefield missions that don't rate high-demand / low-density F-22 or NGAD and F-35 assets. Throwing money at a dozen different drone concepts that all replicate the capabilities of existing drones or cruise missiles do is increasingly bizarre and absurd. They're assigning new mission roles and inventing new terminology to describe what strike missions and missiles have been doing for decades. Knowing what I know about attack missions, it's silly. An attritable drone is not an attack jet replacement, nor is it a cruise missile replacement.

If you must attack an IADS-defended target or if the IADS itself is the target, when the mission is SEAD / DEAD, then you launch a dozen or more cruise missiles at it. Some missiles make it through, even though some won't. Either way, the target is destroyed. The vaunted S-400 can, apparently, only start engaging cruise missiles at about 40km as a function of how the missile and radar system works. It's doubtful that stealthy cruise missiles would even be detected against background clutter. Cruise missiles with modest stealth features (basic airframe shape optimization and an engine inlet masked from direct view) are so difficult to detect that they do not become trackable by most types of search radars until they're so close that taking all of them out is nearly impossible. The IADS would need its own EO / IR-guided point-defense system, sort of like a warship.

We're now talking about very serious money to defend individual targets from air attack. Russia quoted a price of $200M USD for 8 mobile launchers with 4 missiles, so $6.25M a pop. A non-stealthy Tomahawk cruise missile costs about $2M per copy, so launching a dozen missiles at a single radar control set is well worth the cost. If half are shot down, then the rest destroy the radars and some number of launchers.

Will you expend your limited supply of $6.25M S-400 interceptor missiles, that could feasibly take out satellites or ballistic missile warheads or stealth bombers, assuming they can be successfully tracked and engaged at reduced ranges, at $5M attack jets or $2M Tomahawks?

Something tells me that the math of this exchange, even if it's 1-for-1, doesn't work in favor of our enemies. They'll use such missiles against F-22s or F-35s or B-1s / B-2s / B-21s because the reward is so great if they succeed, whereas launching a missile that expensive against an A-36 engaging tanks or artillery, even if successful, still represents a losing proposition. We can afford to replace our lost A-36. They can't afford to manufacture enough missiles of that capability class for the use case against a stealthy low-cost attack jet to be worth the expense involved, especially if said attack jet is not behaving as a threat to their air defense radars and missile launchers. There's also an opportunity cost involved in spending very large sums of money to counter F-35s and B-2s or B-21s while plentiful stealthy attack jets are crippling your land forces and sinking smaller naval vessels. War is ultimately a logistics game for the professionals.

kbd512 · 2023-05-11 00:31:36

I've had some second thoughts about smaller aircraft carriers, assuming that Liquid Plutonium Reactor (LPR) Calliban mentioned is a feasible Pressurized Water Reactor (PWR) substitute. LPRs would be drastically smaller and lighter than PWRs. We can have 60,000t class nuclear powered super carriers if we drop most of the other combat systems that make them so costly to purchase and operate. This notional ship would be the same size as the boiler-powered Forrestal class super carriers, which were very close in physical size to the later Nimitz and Ford classes, but at lower displacement. Without the requirement for diesel fuel to power the ship itself, 60,000t sounds about right, since that was the standard load displacement of a Forrestal class ship.

Per-ship purchase cost could still end up near $2B, if the sonar array, 3D air / surface radar systems, RAM point defense missile system and ESSM medium range missile system, and the carrier's island superstructure were eliminated. If these ships solely operate much smaller / lighter attack jet, so as to allow many more to be carried, then we can put all four catapults in the bow of the ship, as well as have two sets of arresting gear instead one (because the island superstructure is no longer in the way). The additional combat systems add serious tonnage and cost to purchase and personnel requirements to maintain that equipment. This new carrier still needs radar and point defenses, but the radar suite needs to be based upon something similar to what the F-35s carriers, rather than the gigantic billboard-sized AESA arrays affixed to the island of the Ford class.

If possible, I'd like to eliminate the giant weapon sponsons used to mount CIWS or RAM and ESSM launchers on Nimitz and Ford, replacing those systems with M230 chain guns and Stingers for point defense. If we're down to using those more expensive defensive systems to protect the carrier, then in all probability many other defensive measures have already failed spectacularly, so one more similar system to those mounted on the escort ships is highly unlikely to change the outcome of an engagement. Maybe the argument for greater onboard protection systems is academic if all the escorts failed to intercept inbound missiles using the same types of weapons and sensors. The destroyers have Standard missiles and AEGIS, in addition to CIWS / RAM / ESSM. Whatever the carrier has in terms of defensive capability will always be a minor fraction of what those guided missile destroyers have.

During WWII, all types of carriers were hit by aircraft or weapons, regardless of defensive systems capabilities. Reality says that if enough anti-ship missiles are fired at the carrier, then eventually the carrier will be hit. That means the loss of a carrier simply has to be absorbed, as painful as that will be. We can't do that if each carrier costs $13B and takes years to construct. Beyond that, the aircraft are an aircraft carrier's primary armament and its best defense against enemy action. WWII experience also indicated that the carriers with the largest air wings tended to be the most destructive to a similarly-equipped enemy, despite losses. The theoretical sortie rate of Nimitz and Ford classes comes with important caveats that are at odds with how the Navy wishes to use them. All the jets had to fly very short range missions that imply our carrier is close to its intended target, thus the carrier can also be hit. The Navy will never get close enough to use most of their aircraft because their carriers are too expensive to lose. In turn, my attack jet concept could realistically sustain the sortie rate that the Navy would like the Ford class to be capable of.

Anyway, think of this as a refinement of the sea control ship concept. The Navy gets to keep its super carriers, but it has to reduce the per-hull purchase price to something that allows the Navy to operate enough of them to matter in a shooting war.

kbd512 · 2023-05-11 13:12:11

For those who have never seen a Forrestal class aircraft carrier, here's a photo taken of the ship from 1955 during sea trials:

US_Navy_80-G-682046_USS_Forrestal_%28CVA-59%29_underway_on_trials_1955.jpg

USS CV-59 Forrestal
Length: 990ft at waterline; 1,067ft overall
Beam: 129ft 4in at waterline; 238ft across the flight deck at the widest point
Draft: 37ft
Displacement: 60,610t standard load; 82,402t full load
Cost (1952 dollars adjusted to 2023 dollars): $2.4B

Note #1:
USS CV-60 Saratoga (next ship of the USS CV-59 Forrestal class), had a 253ft extreme beam
Note #2:
Saratoga had a displacement of 62,218t, with a deadweight of 20,185t (the ship's load carrying capacity, above and beyond standard / light displacement, meaning ready for service, but without any crew, personal belongings, food, water, fuel oil or aviation fuel, or munitions)
Note #3:
USN's naval vessel register measures ship displacement in long tons (2,240lbs) and they call metric tons 2,204.9lbs, whereas I use 2,204.62lbs per metric ton, so my numbers (provided in metric tons) could be slightly off from what they state.

USS CVN-78 Gerald R. Ford
Length: 1,040ft at waterline; 1,092ft overall
Beam: 134ft at waterline; 256ft across the flight deck at the widest point
Draft: 39ft
Displacement: 100,000t full load
Cost (2013 dollars adjusted to 2023 dollars): $16.7B

The 5 inch guns on Forrestal's weapons sponsons were subsequently removed because they were very heavy and never used for their intended purpose, namely shooting down incoming aircraft or firing at small gun / torpedo / missile boats. They were a carryover from WWII that served no practical purpose by the mid-1950s. Photos taken of the ship in the early 1960s show the weapon sponsons removed.

As previously stated, we need to downsize aircraft carrier defensive sensors and armaments to use newer / smaller / lighter / cheaper radars and weapons that can be carried in greater quantities useful for stopping mass attacks from low-cost drones and cruise missiles. I've seen little in the way of supersonic or hypersonic weaponry that has been as consistenly effective as stealthy subsonic sea-skimming weapons. There are various armaments that have the potential to provide this capability at reduced weight and cost and maintenance requirements. In practice, these weapons won't be any less effective in their intended roles, but will reinforce the carrier's point protection using sheer numbers.

IR / UV / laser-guided 70mm high-velocity folding-fin rockets (~$22,000 per weapon), the new radar-guided Peregrine missiles intended to arm the F-22 and F-35 and double their weapons loadout as compared to larger / heavier missiles like the AIM-120 (same range as the AIM-120, but with half the length and weight at 6ft long and 150lbs per missile- smaller and lighter than the AIM-9 Sidewinder or RIM-116 rolling airframe missile now paired with the 20mm CIWS), but with much greater range than any variant of the Sidewinder.

We can use the new-ish 30mm M230LF chain guns for chewing up small attack boats. This option provides weapon and/or ammunition commonality with the US Army's AH-64 Apache gunships, as well as their JLTV tactical vehicles and Stryker APCs. The "LF" stands for "linked-feed", meaning the cost and complexities of a linkless feed system are not required. These weapons use standard ammo boxes loaded with belted 30mm cartridges of the same variety that the Apaches use. The entire M230LF cannon weighs about 160lbs with the long barrel and ammo de-linker. The extended barrel adds muzzle velocity over the shorter barrel cannons carried by Apaches. M230LF is much lighter and physically much smaller than either the 20mm M61 / CIWS gatling cannon or 25mm M242 Bushmaster chain guns currently installed on surface combatants. The barrel and receiver can be separated and each carried to the mount by a single sailor, in much the same way that we hand-carry M2 Browning heavy machine guns to their pedestal mounts during General Quarters drills or while traversing dangerous waterways and in overseas ports-of-call. A single operator can aim the cannon by hand like the M2 Browning heavy machine gun, meaning a powered mount is not required. Each weapon can mount a large red dot zero-magnification optical sight for aiming. It's chunkier than the M2 but still very manageable.

The M242s we used?... good luck with that. I tried it once during a fam-fire event. You need power to move something that big and heavy. They're just very awkward to use, not really uncomfortable since you don't feel much recoil (plenty of muzzle blast with that enormous muzzle brake, though) but clumsy and slow to aim. Maybe I simply didn't have the practice that our gunner's mates had, but I think a smaller weapon would be more manageable. M2s are easy to use because they're much smaller, but .50cal is not a substitute for a small caliber cannon. I saw them change barrels on those Bushmasters, too. It was an involved process and required some equipment to steady the barrel in rough seas. The M230 is easier to work with and has enough of the punch of the more powerful Bushmaster to tear apart any small vessel. M242s are also the guns that the US Army's M2 Bradley IFVs mount in their turrets. They work great in that role. As a close-in shipboard defensive weapon they leave something to be desired in every department except stopping power (against small / fast vessels, in case that needs to be said). Anything the size of a motor torpedo boat, the Bushmaster will wreck or sink in short order.

M230s can also fire light-jacketed specialty projectiles with more explosive and higher muzzle velocities (around 1,000m/s), but the primary reason for using them is their light armor penetrating capabilities from the standard HEDP shaped charge shells which have been in service for decades now. Both the gun and ammunition are thoroughly proven at this point. There is no question about how well they work.

I'll go over how I think we could use very small reactors as plug-and-play power plants for additional carrier hulls in another post, meaning we build the entire ship so we have spare hulls in case one ship is damaged, but we leave the otherwise complete spare hulls in the ship yard and transplant reactor cores into the hulls so fewer cruises / deployments per hull are accumulated over time, thus extending the life and maintenance periods for these ready-to-use spares.

Calliban · 2023-05-11 15:42:13

The molten plutonium reactor was developed under LAMPRE at Los Alamos. One of the reports is linked below.
https://digital.library.unt.edu/ark:/67 … adc876429/

This is in some ways comparable to the molten salt reactor in that the fuel is liquid. There are some significant differences. One obvious difference is that virtually all nuclei in the core are fissile plutonium atoms. This allows for a very compact core as there are few parasitic neutron absorptions and the neutron spectrum is extremely hard, allowing a large number of neutrons yielded by fission. This also allows for a high breeding ratio. As liquid sodium mixes with liquid plutonium, heat transfer is very efficient allowing high heat transfer rate into the sodium droplets. It was also noted that sodium would carry fission products out of the fuel zone. So waste removal can be carried out by periodically removing some fraction of the sodium.

kbd512 · 2023-05-12 17:30:59

Calliban,

My thought process on this is to use small repairable / maintainable reactors that are periodically removed from service for repair work or upgrades, and that the reactors are small enough to be craned off the aircraft carriers, without cutting them out of the ship. Trying to design a reactor to last for 25 years without refueling or significant maintenance has proven to be very expensive and has prevented more widespread use of naval nuclear power. An aircraft carrier in the same tonnage class as the Forrestal would use 4 reactors producing 50MWe per reactor, for a total power output of 200MWe, which is sufficient to run a ship with smaller / lower capacity steam catapults and arresting gear suitable for launching great numbers of micro fighters.

If the new carrier has 2 hangar decks, then carrying 200 attack jets is well within the realm of feasibility. The deck footprint of a single F-35C is approximately equal to 4 micro fighters. The US won the Pacific War against the Imperial Japanese Navy by overwhelming them with sheer numbers of aircraft and smaller ships with smaller caliber fast-firing 5 inch guns. Barrage fire was how a handful of destroyers were able to maul an entire line of cruisers and battleships. Despite our losses, the damage dealt to the Japanese surface action group by Taffy 3 could only be seen as verification that the entire concept of large caliber gun battlecruisers and battleships was a dead-on-arrival operational concept. The cruisers that escaped looked like Swiss cheese- still floating, unlike our destroyers, but no longer fightable warships. We had certain types of technical superiority in aviation over the IJN, mostly limited to speed or dive speed, both of which mean very little against guided missiles with double to triple the speed of any fighter jet. Future naval battles won't be won or lost by super weapons. Death from above will come via the "thousand paper cuts" route, where a combination of stealthy attack jets, sensor and munition precision enabling the use of great numbers of smaller munitions, with sheer numbers determining which side wins or loses.

All the hypersonic missiles fired into Ukraine have had zero measurable effect on the outcome of the war. Unless such weapons are nuclear-tipped or able to hit moving targets, then they're about as destructive as the "Grand Slam" bombs dropped during WWII by the British- nothing to sneeze at, but not a "game changer". No battles in Ukraine have been won or lost because of supersonic or hypersonic missile attacks or integrated air defenses or fighter-bomber jets the size of F-15E Strike Eagles. If anything, small but precise loitering munitions and drones employed by the thousands have had an outsized impact on the course of the war. Training and experience, basically sound tactics, and surprise have played key roles, as they have since the dawn of warfare.

Technology has an important role to play, and always will, but Ukraine's use of tanks and infantry fighting vehicles has yielded results where Russia's utter failure to plan an invasion or train its people demonstrates what a difference training and tactics makes. No matter how technically superior Russia is to Ukraine, and Russia beats Ukraine on every military measure except training and tactics, it's won nothing by using super weapon attacks, whilst losing some of its most powerful weapons (Moskva, Su-27s, Su-34s) in the process, and for the same reason.

More aircraft carriers equipped with greater numbers of attack jets means more damage inflicted upon a potential enemy in a shorter period of time by simultaneously attacking more targets by virtue of simply "being present" in greater numbers than a similarly equipped enemy, which is ultimately what deters aggression. It also means having more trained pilots who can prosecute attacks. Losses are going to occur no matter what we do, so the best course of action is to be able to absorb whatever punishment our enemies can dish out. The faster we reduce their military capabilities, the faster the and more certain the end of any future war.

The nazis thought that their superior weapons and superior soldiers would win the wars they waged. America proved that amateurs think about war in terms of who has the fastest planes or the biggest artillery guns. Professionals know that logistics and numbers win wars. As time went on, our professionals were replaced by amateurs who lusted after faster planes and bigger guns. Evidence of effectiveness was ignored, because an effective counter-attack by our enemies was functionally impossible. The Chinese are rapidly building out a Navy and Air Force capable of generating an effective counter-attack, so that paradigm no longer holds true.

If we start the process of developing, building, and employing effective alternative weapons now, even though they're not necessarily the absolute best on paper by all conceivable measures, then future victories in a truly contested battlespace are far more probable. China has a basically competent and well-equipped military with a force structure broadly similar to the one employed by America, which the Chinese military emulates. China also has an enormous industrial base and vast numbers of people who can be recruited into their military. That combination of factors makes them a real military threat, far more serious than the one-dimensional nuclear threat that Russia poses. If America keeps doing what we've done for so long now, with respect to Gold-plated military procurement, then America will eventually subject itself to Chinese military power and find that what worked so well against poorly led and/or equipped third-world military forces doesn't work so well against a peer-level opponent with broadly similar military capabilities and ability to fight.

I'm trying to plant the ideas for practical and affordable military weapons that present credible threats to our enemies, rather than smaller and smaller numbers of "super weapons" / wunderwaffe for them to concoct economical methods of defeating. Germany had jets during WWII when everyone else had propeller-driven fighters. It turns out that jets still have to take off and land. The answer to a particularly threatening weapon system is often asymmetric in nature. We had no chance of touching the Me-262 when it was already at altitude and attacking our bombers. None of that mattered because we had so many planes that we could afford to follow the small numbers of jets all the way back to their airfields and strafe or bomb them where they had no hope of effectively fighting back.

We need aircraft carriers to project power abroad, but also to establish local numerical superiority over enemy forces. If we can afford to have 3 carriers on station with 600 attack jets between them, then unless the Chinese intend to send everything with a pair of wings to that one location to counter the threat our carriers pose, then they're going to be badly outnumbered. At best, they manage to fight to a stalemate. The most plausible scenario is that they suffer significant losses. This is how you dissuade invasions of our allies. If they know they'll be facing massive numbers of our naval air forces, then they'll refrain from giving battle or pull back to reduce losses. They cannot be seen to suffer significant military defeats at home, else they lose prestige, and power shortly thereafter.

In the same way that putting ships on the bottom was less impactful to the IJN's war effort than mauling an entire battle fleet the way Taffy 3's destroyer squadron did during the Battle of Samar, forcing them to withdraw to make repairs, we're better off badly damaging most of the PLAN's ships than outright sinking them, which favors the use of smaller but highly destructive weapons like the small diameter bombs. Outright sinking their ships means no efforts will be expended to recover or repair those ships, so then we'll face a new generation of ships, probably better armed and equipped to counter the way we intend to fight them. Beyond that, sinking lots of PLAN ships will only invoke the ire of the Chinese people and fuel a desire for revenge. No doubt some ships will be sunk in these mauling attacks, but if we wreck the radars on their superstructures or damage their guns and VLS tubes, then breaking the ships in half is not required. A ship that still floats has to be repaired or salvaged.

Calliban · 2023-05-15 12:29:54

For aircraft carriers and other naval ship propulsion, pressurised water reactors are a long established technology with high power density and a lot of operational history. Power density is high, around 60MWth/m3 in comnercial reactors and they have the convenient characteristic of being load following. If you need more power in a hurry, you open the throttle valve on the turbine inlet. The accumulated steam in the steam generators floods into the turbine, leading to a pressure drop in the SG. This increases the rate of boiling, lowering the temperature of water in the SG boiler side. The dT across the SG tubes increases, increasing heat transfer across the tubes. This reduces moderator temperature, which reduces average neutron energy, which increases the rate of fission. So naturally load following. That makes PWRs pretty ideal for naval ship propulsion. And if naval ship propulsion is what you have in mind, then developing anything other than a PWR would be unnecessarily expensive.

I think a better design solution for what you have in mind, is a small, compact and easily modular reactor that is cheap and easy to build and install. We want a nuclear steam supply system that can be factory made, transported by rail and craned into the ship as a single self contained module. It would be ideal if it could use low enriched uranium oxide fuel as well. Having to use HEU in naval reactors really pushes up cost and security concerns. One way of getting around the problem of lower reactivity is to make SGs larger, so that they can function as steam drums. That allows power transients to be smoother and provides a lot of safety benefits as well. Some commercial designs have attempted to build the steam generators into the reactor vessels, which provides a very compact arrangement. The downside with that idea is that damaged or corroded steam generators cannot easily be replaced. But that might not matter if your nuclear steam supply system is a self-contained modular system that is flanged onto secondary steam pipes. If the reactor develops problems, you call into port, unbolt it, crane it out as a single piece and replace it. Problem solved.

To keep costs down and ensure a readily available supply of replacement units, we should develop a single modular unit that can be used for naval and commercial ships and as small modular reactors for power grids. For commercial and supply ships, a single 50MWe unit would suffice. A Type 45 destroyer has 43MW shaft power provided by 2GTs. A single 170MWth reactor would suffice for a destroyer. For an air craft carrier, four units would be employed. The navy would always get first call of stockpiled units. Within hours of any reported problem, the factory would have a replacement unit loaded onto a railway carriage and on its way to whatever port the naval ship will be docking at.

Last edited by Calliban (2023-05-15 12:49:35)

kbd512 · 2023-05-15 12:58:14

Calliban,

I need a reactor design that doesn't have to be cut out of the ship to cross-deck the reactor to another ship of the same class. I intend to build more hulls than reactors or weapons, halving the number of deployment cycles each hull experiences in a given period of time, hopefully doubling service life in the process. Each ship must have plug-and-play reactors, self-defense weapons, and sensor systems that can be moved between hulls, either by hand or dockyard crane. I intend to use F-35 radar systems and Stinger / Peregrine / 30mm chain guns for point defense, which is also what the carrier's combat planes will carry.

I must have 4 miniature bow-mounted catapults and 2 sets of arresting gear (remember, no island superstructure) for launching / recovering the miniature attack jets and smaller single-engine turboprops (AWACS / COD / ASW planes) for support roles. The largest plane I intend on launching is around 10t. I need a shipboard propulsion system capable of providing 30 knots of wind over the deck for launching aircraft, so that means 190MW of power for an 80,000t carrier. I don't want or need giant reactors to do that.

The total number of people aboard will also be considerably less- somewhere between 3,500 and 4,000.

Calliban · 2023-05-15 14:49:15

Kbd512, this link gives data on the volume of primary circuit components for a 3000MWth Russian VVER. This is basically a rip off of Westinghouse PWR technology.
https://www.nuclear-power.com/nuclear-p … nt-system/

A 3000MWth nuclear steam supply system has wetted volume 285m3. That is 0.095m3 per MWth. Light water reactors really do have excellent power density! I am going to make the (almost certainly) erroneous assumption that volume scales with power. That is a safe assumption for heat transfer surfaces and pipework. But not for shielding and thermal insulation. I am also going to further assume we can pack our reactor into a volume that is twice the volume of its wetted volume.

For our relatively small steam powerplant, I am going to assume a 30% efficiency. To produce 47.5MWe at full power, our reactor must produce 160MWth. If we assume the same primary circuit power density as VVER, total wetted volume would be 15.2m3. If the reactor compartment has twice the wetted volume, we end up with a total volume of 30.4m3 per reactor. That is equivelent to a cube some 3.12m aside. If we do go for a design with heat exchangers built into the RPV, we can achieve volume savings that would make this more achievable. We could probably put the pressuriser in the vessel as well. The main coolant pumps and MIVs need to be accessible for maintenance. But a single cylindrical module with volume 30m3 is probably doable for a 160MWth steam supply system.

To minimise neutron leakage, the core would ideally be spherical. But practical cooling solutions tend to favour a cylindrical core. A right circular cylinder with H = 2R, is the best compromise between neutron economy and cooling. A core power density of 60MWth per cubic metre is typical for civil PWRs. For a 160MWth of power, this implies a fuel volume of 2.7m3. Which gives us a height and diameter of 1.5m. Around that you need the core barrel. This is relatively thin stainless steel. Water flows down the outside of the barrel from the inlet nozzles, and then up through the core. The several cm (3") thickness of water that flows down the outside of the core barrel also functions as a neutron reflector. After that, there are steel baffle plates whose job it is to mop up stray neutrons and gamma rays that make it past the reflector. Their job is really to protect the pressure vessel from radiation induced dislocations which cause embrittlement. These can be low alloy steel and would need to be a couple of inches thick. Then we have the wall of the RPV which will be low alloy steel about 6" thick. So I think we could build a naval reactor whose RPV is 2m in diameter with external SGs. Putting the entire nuclear steam supply system in vertical cylinder that 3m wide and 5m tall should be possible. We want to be able to lower these units into sleeves through the deck, and then bolt them into place. Secondary steam connections can be flanged.

In the UK, a 6-axle railroad car can carry 115.8 metric tonnes.
https://en.m.wikipedia.org/wiki/Axle_load

That gives us a practical weight limit for a fuelled (not wetted) nuclear steam supply module. Let us assume a design with inbuilt heat exchangers and pressuriser, with a spherical RPV with diameter of 3m. Pressure is 200bar and shell stress is 100MPa, giving a design factor of about 5 for a low alloy steel with tensile strength 500MPa. Wall thickness would be 15cm. The mass of the pressure vessel would be 33.9 tonnes, taking steel density at 8000kg/m3. This is our heaviest component, as steam generators are internal. So I think it is realistic to meet a weight limit of 115.8 tonnes.

Last edited by Calliban (2023-05-15 15:46:37)

kbd512 · 2023-06-25 23:36:37

Calliban,

116t is something completely immobile that must be cut out of the ship, at fantastic cost. How about I bring the total power requirement way down to something easier to accomplish?

The GAO issued a report on the cost-effectiveness of nuclear powered aircraft carriers around the turn of the century. Compared to the nuclear powered ships, the 50 year lifetime operational cost of each nuclear powered aircraft carrier was $7B USD higher, and that was about 25 years ago. Before the idiocy of the Ford class, which involved rolling out 20+ new technologies onto a single new class of ship, none of which were properly tested prior to integration, we used to purchase brand new nuclear powered Nimitz class aircraft carriers for that amount of money.

The working theory was that the new Ford class aircraft carriers would enable us to launch and recover smaller drone aircraft, for which there were no defense dollars remaining after the Ford / Zumwalt / LCS debacles, and no such small drone aircraft ever materialized as a result. In point of fact, the Navy's idea of "smaller drone aircraft", such as Boeing's new drone tanker, were in the same weight class as the F-4 Phantom II and A-7 Corsair II heavy fighter-bombers of the Viet Nam War era.

If we had continued building Forrestal / Kitty Hawk class aircraft carriers, constructing three of them would cost less than a single copy of the Ford class. Does a single Ford class carrier provide 3X the utility of a Forrestal class carrier? That's highly debatable. A Ford class theoretically has a higher sortie rate, mostly due to deck layout, but I sincerely doubt it could sustain flight operations at a higher optempo than 3 carriers of almost identical size and carrying capacity, because 2 carriers could be on station and the third undergoing maintenance for the same money spent. In today's money, the Forrestal / Kitty Hawk class would cost $4B each. Both then and now, a great deal of the cost of the Forrestal / Kitty Hawk class, the first of the super carriers that the US Navy built and operated, was the weaponry and sensors fitted to those ships, rather than the cost of building the ship itself.

In light of how history turned out, which was rather unlike Admiral Rickover's portrayal of how nuclear power would revolutionize carrier battle group operations, there must be a compromise solution to be had that opts for smaller reactors able to maintain typical cruising speeds.

How much would a nuclear reactor weigh that can propel an aircraft carrier at 15 knots?

It turns out that none of the conventionally powered escort ships can sustain speeds much beyond 15 knots, on account of how much fuel they burn to do it. Gas burners are the only kind of escort ship that the US Navy has today because all of the various nuclear powered cruisers were grossly uneconomical to operate. Moving at speeds much faster than 15 knots could feasibly be handled by some kind of conventional engine, such as a gas turbine.

The important point is that the reactor must be easily and rapidly removable from the carrier, so that reactor servicing can take place when the ship is in port, but then the ship can still operate as a conventional ship using its gas turbines for power and propulsion. The maintenance requirements and refueling costs are what made naval nuclear reactors so uneconomical to operate. The nuclear powered ships required less underway replenishment of fuel oil / diesel, but 50 year lifetime operating cost of a super carrier went from $14B to $22B by using nuclear reactors as the sole source of power and propulsion.

A 6 month deployment of Kitty Hawk in 1999, when I was both in the Navy and part of 7th Fleet (she was forward deployed to the home port of Yokosuka, where my ship was also forward deployed to), for example, consumed about 105,000t of fuel oil to power the ship, traveling a distance of 48,330 nautical miles, or about 2,173kg per nautical mile. That's about $101.32M in 2019 US DoD F-76 prices, or $596K per day, and in peacetime there is only 1 deployment per year. A Nimitz class cost about $1.5M per day of operation and $90K in maintenance costs, for comparison. I served aboard 2 Nimitz class carriers, but as part of the air wing. Most of the time was spent at cruising speeds so that the escorts could keep up. This seems to indicate that a nuclear reactor would do its best work maintaining cruising speeds and supplying fresh water, which requires far less power than flanking speed. Power requirement to go 30 knots is 8 times the power to go 15 knots. A Forrestal or Kitty Hawk class requires about 30,000hp to go 15 knots. 6 Caterpillar C280-16 marine diesel engines would consume 138t of F-76 fuel per day to maintain 15 knots, so $129,473.23 in terms of F-76 at 2019 prices, in order to maintain that speed.

22.37MW worth of output horsepower from F-76's heat energy content of about 68.7MW being burned every hour. If we use the heat from the engine to flash evaporate water, then at 2.72kWh of heat per gallon of flash evaporated drinking water equates to about 8,224 gallons of water per hour, so 197,382 gallons per day. That's near the maximum that the nuclear powered carriers produce per day. That's also near the extent of what we can get out of our 138t of diesel fuel consumed per day. Maybe we can use some of the hot exhaust to generate some electrical power or additional fresh water. I can't recall how much electricity a Forrestal / Kitty Hawk class consumed, but the Nimitz class can generate about 64MW of electrical power. I would hope that LED lighting can reduce power requirements. I know that most of the electrical power is for lights, radars, and air conditioning. I suspect most of the electrical power is used for the air conditioning, so maybe there's a way around that problem.

Anyway, there needs to be some kind of "escape clause" that allows us, and now you guys as well, to operate our carriers, with or without the availability of a working reactor. I envision this working like so:

1. During peacetime and for air wing training purposes, we primarily run our carriers using a pool of available reactors, thereby easing the replenishment at sea burden on our oilers. Since our microfighter combat jets are so much smaller and subsonic, you can carry more of them, they burn a lot less fuel than the F-35 or Super Hornet, and the catapult alone, with zero wind speed over the deck, can generate enough force to bring said jets up to flying speed by the time they reach the end of the cat's run.

2. During wartime, to preclude the loss of nuclear reactors at sea, we crane the reactor(s) off the ship and operate purely on conventional power. That could be plain old marine diesel engines, gas turbines, or advanced sCO2 gas turbines. A caterpillar C280-16 marine diesel engine costs about a million dollars brand new, and it weighs 28.5t without lube (279 US gallons) or coolant (485 US gallons) or an electric generator (18t) attached to it. I'm talking about a war with a peer-level adversary that's mostly over with inside of a few months, in case that point isn't clear, not the pointless "forever wars" fighting people who can't write their own name in their own language.

I'm operating in the real world where I expect a shooting war with a peer-level adversary to result in the loss of a couple of carriers, regardless of how well-prepared we may think we are. I'm not sticking my head in the sand and pretending that such a thing will never happen, either. I view this as an acceptable compromise between the fuel efficiency of nuclear reactors and the very real threat of loss during a conventional war with a peer-level adversary.

Let's say we only need 32MW of electrical power and 24MW of propulsive power for a super carrier to cruise around. How small can that kind of reactor be?

kbd512 · 2023-06-26 01:35:13

It seems that there's a RAND report that came up with the exact same concept that I have:

Future Aircraft Carrier Options by Bradley Martin and Michael E. McMahon

A 70,000ton USS Forrestal–size carrier with an updated flight deck and hybrid nuclear-powered integrated propulsion plant with capability to embark the current large integrated air wing but with reduced sortie generation capability, survivability, and endurance compared with the Ford-class (referred to as CVN LX)

So, apparently I'm not the only person who has thought this to be a viable option. I just discovered the report. Clearly, none of my ideas are all that original. Other people have already thought of this before I have, I simply wasn't aware that other people were thinking along the same lines as I've been thinking.

Something needs to be done to start containing costs and providing more actual combat capability.

kbd512 · 2023-06-26 02:41:30

We're going to need some Japanese-style mini-subs that our super carriers can bring to the party as well:

Said vessels carried a crew of 2, were 42t to 50t in displacement, 72ft to 81ft in length / 6ft in diameter, about 10ft in height from the bottom of the keel to the top of the sail, were capable of top speeds up to 25 knots submerged, test depth was 100m, and could sail 500 nautical miles at 6 knots. Modern engine tech could easily triple their cruising range. The originals carried a pair of 772 pound 17.7in diameter torpedoes that were derivatives of the Long Lance, but modern 12.75in Mk54 torpedoes seem more appropriate. I think 4 of the Mk54s could be carried for approximately the same weight. We're developing some new 10in diameter mini torpedoes that would also work acceptably well against submarines, but would be less effective against ships. Modern HY100 steel would easily triple the diving depth these mini-subs could reach. We can build vacuum chambers large enough to electron-beam weld the hulls. In point of fact, much larger-than-necessary pressure and vacuum chambers already exist.

Anyway, subs this small could literally be strapped to the sides of the hulls of our carriers and amphibious ships, to be released on-station and deployed to create a protective screen around our ships in littoral waters. The entire sub would cost around $4M and carry approximately $4M worth of torpedo armaments. For $4M, you can afford to purchase quite a few submarines. Heck, we could have subs everywhere for that cost. We'd need submarine tenders without mini-reactors like KiloPower, but assuming we can use HALEU-fueled KiloPower reactors, these subs would pose a mortal danger to other submarines and most surface ships. Again, the entire notion of hot-swap reactors is key to an affordable and practical implementation of nuclear power.

Calliban · 2023-06-27 07:47:24

If the reactor system can be bolted and flanged into a sleeve within the RC, then unbolting it and lifting it out with an EOT crane, is entirely possible. We have cranes that can lift several hundred tonnes. A 116te lift is certainly possible. We would need a dedicated low level lift facility to do it. The reactor unit needs to be safe from dropped load. That is probably the biggest challenge. A lower power output would reduce size and mass, but not linearly, because neutron laekage becomes more problematic as you scale down. A liquid metal cooled reactor would have 3-5× the power density, but that is an entirely new technology. Light water reactors are a fully developed and old technology.

Last edited by Calliban (2023-06-27 07:49:08)

kbd512 · 2023-09-19 01:05:06

In another perfect example of how the US military takes a good concept and turns it to dirt through excessive cost and lack of suitability to the intended role, the US Army's M10 Booker "Mobile Protected Firepower" (MPF), which is a not-so-light tank pretending not to be a tank, weighs in at 42t, combat loaded. It's only air transportable via the C-17 because it can't fit in the cargo compartment of the C-130, our most numerous air mobility asset and the only one truly intended to land in austere field conditions.

The entire concept of operations behind MPF was to provide direct-fire infantry support for our airborne divisions. The thing is slightly heavier than the WWII Era M26 Pershing, which was eventually transformed into the M46 / M47 / M48 / M60 series of main battle tanks (MBTs). MPF mounts a 105mm main gun, intended to destroy field fortifications and armored personnel carriers or infantry fighting vehicles, but not other MBTs. The M119 105mm towed howitzer will destroy any of the targets that MPF was intended to destroy.

Much to the shock of the US Army, which previously thought artillery was ineffective at engaging their MBTs, if you land a hit on or even near a MBT (with 10m to 30m) with either caliber of artillery shell, the result is a highly probable mobility and/or mission kill, no matter how well the tank is armored. The MBTs frontal armor, and even the side armor of certain tanks these days, will resist penetration from a direct hit or near miss from 105mm or 155mm HE artillery shells, but that does not mean the target MBT will remain usable as a tank afterwards. In most cases, the main gun's sighting equipment and radio antenna were completely destroyed (mission kill- unable to acquire targets), the unarmored main gun barrel was damaged (also a mission kill- unable to fire at targets), and in certain cases the tracks and suspension components were completely removed from the vehicle (mobility kill- vehicle unable to move), even when side armor over the top of the track was present. Airburst rather than direct hits did to the most damage to the various MBTs tested. The photos I've seen of the test results show that HE shells are fully capable of disabling any MBT. Blowing a hole through both sides of an opposing MBT was simply not required to render the vehicle combat ineffective from the first hit or near-miss. While not an absolute guarantee of destruction the way a penetration of the hull or turret armor would be, airbursts frequently would penetrate the upper turret roof or engine compartment.

All of this would seem to indicate that a much lighter 105mm howitzer is entirely sufficient to cripple any modern MBT. The desire to punch through the armor, while admirable, also tends to be superfluous to the objective of rendering the opposing MBT inoperable as a tank.

Where does that leave us?

A vehicle half as heavy and physically large as the M10 Booker, which is almost as large as the M1 Abrams MBT, would probably provide inordinately more bang-for-the-buck. This doesn't mean the lighter vehicle is invulnerable to fire from opposing MBTs, but neither is the M10 Booker, even in up-armored configuration. Does the US Army really need to spend $12M on a vehicle that remains vulnerable to most modern anti-tank weapons, whether ATGMs, MBT guns, or artillery?

This seems like another colossal waste of money for a specialist infantry support vehicle that's not supposed to attempt to fight real MBTs, because it lacks the armor and main gun penetrating power to do so. The M10 Booker is almost identical in weight and size to the ill-fated MBT-70 program that eventually led to the development of the M1 Abrams MBT. This project looks like more "wheel reinvention".

What would be the advantages of a much lighter vehicle?

1. Mobility, both on land in a combat environment and also the ability to bring the vehicle to the fight to begin with, using C-130s.
2. The ability to use much lighter and less costly vehicle engines, such as the GM L5P DuraMax diesel that powers some of our light vehicles like the Hummer and J-LTV. This is a domestically-produced truck diesel engine that can make 500hp very reliably. The M10 Booker uses a specialist MTU diesel tank engine that produces over 1,000hp. In other words, a very expensive engine sourced from a company that proved to be an unreliable business partner for the US Navy's LCS engines, when it came to providing timely spare parts replacements.
3. A greatly reduced logistical burden through the use of common gun barrels with our M119 howitzers, which are themselves a copy of the British L118 light field howitzer. The barrel life of these howitzers is listed as 7,500 effective full charge rounds. That is a considerably greater barrel life than the very high wear 105mm and 120mm main guns used by MBTs. The 120mm, for example, is replaced after 1,500 rounds due to accuracy issues, but rarely makes it to 75% of the stated barrel life.
4. Lower cost training and combat ammunition, therefore more ability to fire the main gun during training, because it shares ammunition commonality with our M119 light howitzers.
5. There's at least a chance to restore vehicle acquisition and operating costs to the realm of sanity. Any not-a-tank "tank" which costs substantially more than our existing MBTs, yet is meaningfully less well-armored and capable than our M1 Abrams, is straining credulity as a practical infantry support vehicle that the US Army states is not intended to engage and destroy enemy MBTs.

I wish I could rationalize the decision making behind nonsense like this, but I can't, because putting checks in boxes next to contradictory design requirements is downright silly. The air mobile division of the US Army still doesn't have an air mobile light tank, because the M-10 Booker is an M1 Abrams MBT before the real armoring was applied to it. It's pretending to fulfill a role it clearly wasn't designed to fill. I'm starting to think that whatever combination of procurement officers and defense contractors are involved in coming up with stuff like this, they seem to be hellbent on ensuring that our military is less combat capable than it should be.

tahanson43206 · 2023-09-19 07:30:28

For kbd512 re Fair Fight vs Unfair Fight

Thanks for your analysis of the M-10 Booker ....

What comes across to me is that if you (or anyone else) were issued an M-10 Booker for deployment in field operations, you would want to deploy the vehicle where it is an overwhelming force against a weaker but annoying force you've been ordered to take out. You would NOT want to engage in a fair fight.

Since it appears that your interests may lie along these lines, please consider the range of operations where the Booker would be far superior to a vulnerable truck towing a howitzer, for example.

It seems to me that in modern warfare, as it is evolving, the ability to fire and immediately move to another location is a capability that will increase chances of your personnel surviving the engagement. A truck towed howitzer is NOT going to be moving around rapidly, under the best of circumstances.

If your opposition is infantry hiding behind boulders, and your mission is to insure that NONE of your infantry are injured or even inconvenienced by the opposition, I would imagine you might like to have assets available which can rapidly and efficiently remove the threats when they are identified.

Criticism is one thing. Engagement with the enemy is quite another. In their ** infinite wisdom ** Congress has provided you with this weapons system. How can you use it most effectively?

(th)

kbd512 · 2023-09-19 12:50:11

tahanson43206,

I'm not suggesting that we tow the M119 howitzer behind a truck. A towed howitzer is not mobile in a practical sense, where it can shoot and then immediately move to a new position. I'm suggesting that we could build a tracked vehicle with about half the weight of the existing M10 Booker. I base that assertion upon existing tracked light self-propelled gun designs, any of which better fit the description of "Mobile Protected Firepower" than a not-so-light tank that weighs as much as the MBT-70 or early Soviet-built T-72s.

I am stating that a 20t tracked 105mm howitzer bearing vehicle could use existing off-the-shelf diesel truck engines from GM and still provide 25hp per ton of vehicle weight. 25hp/ton is identical to hp/ton for the early M1 Abrams models before we started adding a bunch of armor (M1A1HA / M1A2 / M1A2SEPv3). If less than 25hp/ton is acceptable for M1 Abrams and M10 Booker mobility, then 500hp to 600hp diesel engines are viable for 20t to 25t MPF vehicles.

Rather than fixate on penetrating the frontal armor of a real MBT, we will instead fixate on wrecking the aiming sight for its main gun and vision blocks, removing its ability to communicate with other vehicles by stripping the radio antenna, punching holes in the main gun barrel, and blowing its tracks off. An airburst 105mm HE shell does all of those things astonishingly well. Artillery is called the "King of Battle" for a reason. Despite the fact that a 105 shell won't outright kill the vehicle by penetrating its armor and killing everyone inside, that really doesn't matter too much if the targeted MBT in question can't move or hit anything its main gun. The turret doesn't have to be launched into the air for the vehicle to be useless to the enemy without a trip back to the factory for major repairs.

MBTs with no ability to move, aim their main gun, or communicate with other units, are static field fortifications with machine guns- the very type of target MPF was intended to deal with. Friendly infantry can outright kill any disabled MBTs at closer ranges, if so desired. The MBT's crew are left with their coaxial machine gun, assuming the artillery shell didn't damage or destroy its barrel. Much like the tracks, the roof-mounted heavy machine guns will be completely removed from the tank. If any hatches are left open when a 105 detonates overhead or even nearby, then the crew will be killed as well. The desire to see immediate catastrophic destruction of the target is an American "requirement" that doesn't correlate well with practical military requirements. Enemy tank turrets joining their airborne divisions is a crowd pleaser, but dead is dead. Another American axiom is that anything worth shooting once is worth shooting twice. Well, if you fire a pair of 105s at an enemy MBT and they burst overhead, that vehicle is well and truly disabled. Any lesser vehicle will be outright destroyed. Any nearby enemy troops will be injured or killed. That's good enough for government work.

The design choices of the M10 Booker are what caused it to weigh as much as the MBT-70, which is an absurdity, unless we're designing a light tank to engage other light tanks (Russia and China have very few of these) while being dishonest about what we're really attempting to do (duel with other light tanks). If they were honest about their intent, I would take no issue with the M10 design. The entire concept of "over-match" can only be taken so far before it becomes absurd and absurdly expensive for what you get. We need large numbers of infantry support vehicles with serious firepower for taking apart field fortifications, light armored vehicles, and opposing infantry. A light tank that you choose to not call a tank, doesn't change what it will encounter on a battlefield, nor how its crew will be forced to use the vehicle if it encounters a real MBT (APFSDS won't penetrate, because we tested this against real T-72s). Since the M10 Booker won't win a slugging match with a real MBT without a bigger gun and much heavier armor, I see little point to pretending that the M10 is a suitable replacement for light tracked self-propelled howitzers intended to provide infantry support by eliminating field fortifications.

My over-arching point is that you do not get to pick and choose which enemy you fight, so send a real MBT to engage other real MBTs if that is a mission requirement / directive, or use light tracked self-propelled howitzers if you intend to use the main gun to blow up field fortifications, because those vehicles will be drastically lighter / more mobile / less expensive to own and operate than MBTs or "not-so-light tanks" which can't survive a slugging contest with a MBT. The entire light tank concept died during the 1950s because hordes of inexpensive Soviet-built MBTs became so pervasive on the battlefield. The M41 Walker, T92, M551 Sheridan, M8 Buford, and Stryker Mobile Gun System (Stryker MGS was a MPF precursor program) attempted to revive the concept. The powerful main guns kept breaking the much lighter M551 and Stryker vehicles. The M551 was constructed from Aluminum and the Stryker was a wheeled vehicle with a very high CG and very limited armor protection. It should be noted that 105mm M68 or similar tank cannons and 105mm M119 artillery cannons are NOT the same gun. The 105mm M68 probably has twice as much powder behind the projectile, and consequently far more recoil energy. It was designed as a high pressure / high velocity MBT main gun, though, not something for light vehicles to fire. Muzzle brakes only help so much. Both M551 and Stryker had persistent reliability problems. The Stryker MGS was not air-transportable via C-130 (wouldn't fit and too heavy). The M8 Buford was a true light tank from the 1990s, which BAE trotted back out as a contender for the M10 program, but the M8 refresh was rejected by the Army. M8 had the 105mm M68 gun of the M10, but little armor, emphasizing mobility and firepower, the hallmarks of a light tank.

Anyway...

We don't need to spend $12M on the M10 Booker when our $8M M1 Abrams MBT already has the firepower and armor protection required to engage other MBTs and win. Calling the M10 by a new meaningless buzzword (MGS vs MPF vs whatever), does not affect the threats it will encounter. You don't get to "re-imagine" what the enemy brings to the battlefield to fight against your "not-a-tank" light tank. You do need to fit the vehicle to its intended role, and then train to use it that way.

Incidentally, using Titanium alloy for the M1 Abrams hull and turret (the composite armor package is welded over the top of the hull, same as all modern MBTs, regardless of who built them, and yes, the US Army already uses welded Titanium alloy plate for some M2 Bradley components, such as the hatches, to make drastic weight changes) would instantly drop well over 20t of weight from the vehicle. I think it would make the vehicle 25t to 28t lighter, IIRC. 20t of Titanium alloy at $9,500/ton would cost $190,000- a minor fraction of the total vehicle cost.

If this were me spending tax payer money, I would design a LIGHT tracked vehicle to do what the US Army claims it wants the vehicle to do- infantry fire support with enough armor and firepower to matter. It's not a match for MBTs in gun duels, nor heavyweight ATGMs, but it doesn't need to be and the as-designed M10 Booker is equally vulnerable to 125mm MBT cannons / heavy RPGs and ATGMs. My criteria are the use of a commercial mass-manufactured diesel light truck engine for propulsion, 105mm M119 howitzer capable of direct or indirect fire support with a manually operable gun and turret, air-transportable via C-130 or CH-53 heavy lift helicopters, a high quality thermal imaging sight for direct fire, the M119's computer for indirect fire, and that's about it. It will not be festooned with other weapons and gadgets. Armor packages will depend upon the threat environment. It doesn't need to be absurdly complex / expensive / unreliable / combat ineffective in austere environments. What I have in mind might cost $1M, not $12M. Most of the money is in the electronics and weapon. Using Titanium for the hull is a minor cost for a major benefit in fuel logistics, corrosion protection, and weight. Removing an L5P DuraMax is a lot simpler and easier than a 1,000hp MTU diesel that weighs as much as a car. They put that MTU engine on rails inside the M10 for a reason. It's too heavy (about the same weight as a car) to be easily moved using hand cranes / "cherry pickers".

kbd512 · 2023-09-20 01:35:32

tahanson43206,

If this vehicle requires a secondary weapon system to provide close-range fire to suppress enemy infantry, a South African man named Tony Neophytou created a weapon that shares a mix of characteristics of our .50 caliber machine guns and 40mm automatic grenade launchers. The projectile it fires has a flatter trajectory more akin to a rifle bullet, with substantially less time-of-flight than our 40mm grenades, but with fragmentation effects on target like our 40mm. It's known as the Inkunzi Strike. The "Strike" is a belt-fed 20mm automatic grenade launcher firing the same 20mm cannon projectiles that our M61 Vulcan cannon fires, with a greatly reduced powder charge for a 310m/s muzzle velocity to create a lightweight belt-fed grenade launcher with more manageable recoil. He also designed a semi-auto 6 round magazine rifle firing the same cartridge. The Strike uses the links from the Russian 14.5x114mm KPV heavy machine gun.

These are our realistic choices for a secondary armament to deal with infantry:

FN Herstal M240B General Purpose Machine Gun
Action: gas piston, fully automatic; ROF: 650rpm; MV: 2,850fps
Caliber: 7.62x51mm; 71mm OAL; 11.8mmD max; 25.4g/ctg (M80 ball)
Weight: 26.7lbs; Length: 48.5in; Recoil Force: 4.8lb-ft (single shot), so 52lb-ft (I think)

Inkunzi Strike Automatic Grenade Launcher
Action: short recoil, fully automatic; ROF: 300rpm; MV: 1,017fps
Caliber: 20x42mmB; 104.22mm OAL; 22.83mmD max; 162g/ctg (HEI)
Weight: 28.7lbs; Length: 33.5in; Recoil Force: 75lb-ft (I think)
I remember that 77lb-ft was the limit that the designer stayed under
TOF to 300m is 1.07 seconds

The US Navy paid about $24 per linkless 20mm HEI cartridge in 2020, which has a lot more cartridge case and powder behind the projectile, as well as an electric primer, so I would expect a per-unit cost of $15 to $20 per 20x42mmB cartridge.

Air Force Armament Laboratory - Development of a Thin-Wall 20mm Explosive Projectile

In May 1975, the US Air Force issued a report about 20mm HEI projectiles intended to improve effect on target. They developed a 79g thin-wall HEI projectile vs 110g which is what the Strike uses, with a 0.256 drag coefficient at Mach 3, which packed about 34% more explosive vs metal, into a 20mm HEI projectile. This would significantly increase muzzle velocity, reduce time-of-flight to 300m to well under 1 second, and improve explosive effects on target.

M2 Browning Heavy Machine Gun
Action: short recoil, fully automatic; ROF: 450-650rpm; MV: 2,910fps
Caliber: 12.7x99mm; 137.61mm OAL; 20.42mmD max; 117g/ctg (M2 ball)
Weight: 84lbs; Length: 65.1in; Recoil Force: 150 to 250lb-ft

Mk19 Mod 3 40mm Automatic Grenade Launcher
Action: blowback, fully automatic; ROF: 325-375rpm; MV: 791fps
Caliber 40x53mm; 112.3mm OAL; 41.27mmD max; 397g/ctg (M430A1 HEDP)
Weight: 77.6lbs; Length 43.1in; Recoil Force: 500lb-ft
TOF to 300m is a bit over 5 seconds, IIRC

M430A1 HEDP cost is highly variable, but minimum would be around $50 per cartridge, and I've seen prices as high as $145 per cartridge. The Rheinmetall Mk281 ammo costs about $84 per cartridge. Rheinmetall Mk315 Mod 0 HEDP is a new type of ammo with self-destruct and insensitive munition plastic-bonded explosive. It's more expensive but safer for the operator and those downrange because the fragments are designed to lose kinetic energy much faster than M430A1. Both new types are designed to have very low velocity deviation, which is important for a comparatively low-velocity grenade launcher.

What should be immediately obvious is that the 20mm ammo weight and bulk is quite comparable with our .50 BMG ammo while gaining explosive effects on target, a much flatter trajectory than 40mm HEDP, and greatly reduced recoil than M2 or Mk19. The USAF min weight / max aero / max HE projectile would allow for an additional 31g weight reduction to 131g. A plastic casing would make the entire 20x42mmB cartridge slightly lighter than standard brass-cased .50 BMG ball ammo. Regardless, the only other weapon you can fire from the shoulder is the M240B. If you've fired the M2 from a ship like I have, then you know that the concussion from firing is substantial. Your entire body knows you just fired the M2, even if you can't hear anything. The recoil is not too bad, though. The Mk19 is simply jarring to fire, but doesn't produce the concussion of the M2. Between the M2 and Mk19, I'd much rather fire the M2 and live with the concussion than the thumping that the Mk19 delivers through your hands and upper body. If I had the option of no massive concussion or thumping, I think I'd prefer that third option delivered by the Strike.

Most of the mass distribution of the Strike is between your hands, unlike the M240B, so carrying and aiming the little beast is easier. For those who have never handled a 240, its a pain to aim from the shoulder at any appreciable distance. There's too much weight in front of your support hand, sort of like the HK21, which I thought was the bee's knees until I handled one. HK21s are lighter than the M240 or M60 or even a PKM, but the weight distribution is abhorrent for anything but prone fire, even with that heavy 200 round box attached, plus nowhere to put your support hand that doesn't result in a burn. There are some weird angle grips for the 21 so you have somewhere to put your support hand for shoulder firing, but it's impractical. Firing a HK-91 / G-3 with attached bipod and full-sized handguard from anything but the prone position was uncomfortable, even after I added the much heavier HK-21E buttstock to mine, so imagine adding another 5 pounds in front of your support hand. HK rifle recoil is atrocious compared to the M1 or M14, but that HK21 soaks up some of it. Our M60s could be fired from the shoulder with relative ease, but that 240? Not so much. Moving with the weapon in a normal carry position is fine, very little recoil because it's so gosh darn heavy, not as easy to screw up reassembly or lose parts as with the M60 ("the pig" to us), but aiming is only practical from its bipod on the ground, or secured to the pintle mounts we normally used. If it's pintle-mounted, give me the 240. If I have to carry it all day, move quickly, and fire it from the shoulder? M60, no contest, and the pig is still too heavy in my opinion, just drastically better balanced than the HK21 or M240B. I've never used or fired the lightweight M240s so I can't comment on those. I heard the newest versions of the M60 are much improved and lighter, but the only ones I've ever used were Viet Nam era guns. Both are good guns, dependent upon use case, but I can understand why our SEALs use M60s. It's hard to argue with a well-balanced gun, and that's where I think the Strike will excel, relative to the other options.

Shooting and moving aside, a light weapon firing light HEI rounds sounds like a good compromise for creating a suppressive effect against enemy infantry, splitting the difference between our M2 and Mk19, by using a higher muzzle velocity than 40mm, but far less recoil and muzzle blast than Ma Deuce. The ammo cans will be slightly heavier than .50 cal, but far less cumbersome and heavy than those 40mm ammo cans. There is no realistic use case for the M2 or Mk19 against modern jet aircraft or helicopter gunships, nor were our M2s particularly effective against adobe brick walls in Afghanistan from reports on small arms effectiveness. This light 20mm weapon is right-sized for defense against infantry wearing body armor. It can't tear up vehicles as well as a .50 cal or 40mm, but my proposed vehicle already has a 105mm howitzer for that role, and nothing but a larger howitzer holds a candle to it in that role.

The M2 can obviously shoot father and penetrate armor better, but it either hits the target or has no effect. The Mk19's 40mm HEDP packs a wallop, but rapidly loses velocity and is difficult to aim at moderate distances because the trajectory is so steep. The Inkunzi Strike provides a better balance of exterior and terminal ballistic performance. If we can pack more HE into the 20mm, increase velocity, and reduce cartridge weight to .50 BMG levels, then I think we have a winner. Cost per cartridge falls between .50 BMG and 40mm as well. You can fire 5 rounds of .50 cal or 1 round of 20mm for the same money spent. We don't presently have any light automatic grenade launcher like this, and I think we need one.

kbd512 · 2023-09-24 15:17:25

tahanson43206,

Here's a Japanese Type 60 dual 106mm recoilless rifle carrier vehicle:

JGSDF_Type60_RR%28SP%29.jpg

This JSDF vehicle is all-steel construction that weighs in at 18,000lbs, and is powered by a Komatsu 150hp diesel gives it a top speed of 34mph. If the vehicle was made from Titanium alloy, we're looking at a 10,800lbs vehicle. It first entered service in 1960 and served to 2006 when it was withdrawn from service. Our 60-years-newer Cummins R2.8 161hp / 307lb-ft of torque 4-cylinder turbo diesel weighs 503lbs and easily fits inside the Jeep engine bay. At 161hp, that 5.5 tons of vehicle weight translates to 29hp/ton, which is a higher power-to-weight ratio than any MBT. Simply put, it will have no issue moving at speed and the R2.8 is remarkably quiet compared to any tank engine. Unlike the M10 Booker, a vehicle based upon my concept would easily fit aboard a V-22, CH-47, CH-53, or C-130. That makes them tactically air mobile weapon systems that don't require strategic air lift assets like the C-17 and C-5, neither of which operate from rough fields.

If the vehicle was substantially larger, then it's no longer air mobile. It clearly won't be capable of taking MBT rounds, but neither can the M10 Booker. In point of fact, the US Army stated that the M10 Booker was not a tank, despite its uncanny resemblance to the early M1 Abrams models in terms of size and weight, and not designed to fight MBTs like the Russian T-90. With that in mind, the real end goal is to put 105mm HE rounds on target and to operate in conjunction with the troops from our airborne divisions. For that to happen, the vehicle needs to be much smaller and lighter so its air mobile in the tactical sense of the word, and it needs to cost about as much as the Joint Light Tactical Vehicle (J-LTV). J-LTVs are substantially larger vehicles than what I had in mind, although they can still be sling-carried beneath our transport helicopters such as the CH-47.

tahanson43206 · 2023-10-01 10:29:41

For kbd512 re tanks in general, and transport of tanks to shore in particular ....

Just curious .... we know the Navy has the capability of moving tanks to shore using heavy lift helicopters.

Have you ever heard of anyone considering a rocket powered lifter for such vehicles?

I have not, but your reading list is FAR deeper and wider.

(th)

kbd512 · 2023-10-01 14:55:23

tahanson43206,

The short answer is no. There is no rocket-deployed tank capability in any military, nor has there ever been, and for good reason. The notion of rocket power was a 1930s to early 1950s fad, in much the same way that nuclear power was a 1950s to 1960s fad. We quickly learned the practical limitations of those technologies long ago.

Someone with enough money could design an air-breathing rocket-powered glider (atmospheric O2 / JP8 in a rotating detonation wave engine) to deliver armored vehicles to shore a few tens of miles away, approximately as fast as a helicopter but with more range and less fuel burn, using less mechanically complex engines with no rotors or propellers to endanger people, and then return to the amphib's flight deck a short distance away. This would be no more or less dangerous than present methods, and arguably much cheaper using aerodynamic vs powered lift. The main advantage would be a dramatic power-to-weight ratio improvement from a simplified pulse-jet style "rocket engine", but it would be crazy loud and landings would be power-off with no abort capability (and probably why this will never be done).

Pure thrust would be grossly impractical for any type of tactical military aircraft, but rocket powered thrust with glider wings is doable. Remember the "rock tornado" that Starship created? That would happen on a smaller scale, but still enough to damage a vehicle light enough to do propulsive landings with an armored vehicle, or injure friendly troops near the landing area.

The Soviets attempted this silliness:
The Soviet Union's Rocket Tank Was an Explosively Bad Idea

Remember Chrysler's 1950s-era nuclear powered tank silliness?:
Chrysler’s nuclear-powered tank was the height of Atomic Age optimism

There were a handful of attempts to transport tanks using various types of detachable powered aircraft or gliders, as well as proposals to power them using miniature nuclear reactors, between the 1930s and 1960s. None of these faddish engineering curiosities ever amounted to anything, in the same way that a flying car remains as impractical today as it always has been. They were all grossly impractical and/or wildly dangerous ideas, which is why they never made it beyond initial testing, if they made it that far.

As far back as WWII, British and German radar systems could detect aircraft leaving the ground in each others' respective countries, so the RAF and 8th USAAF expended a great deal of effort to ground the Luftwaffe's fighters and destroy their air defense radars, which is the only reason the combat gliders carrying troops and tankettes weren't entirely lost during the Normandy invasion. Maybe some gliders were sporadically used during the Korean War, but apart from combat drones, none have been used since. Helicopters have replaced gliders.

Russia had Object 279, which was another attempt at a nuclear powered tank. During or before WWII, IIRC, the Russians flight-tested a small tank (most armored vehicles were pretty small prior to WWII) with detachable wings / tail / engine, as well as glider based units. By the mid to late 1930s, aircraft engines and rocket engines were becoming powerful and reliable enough (having one without the other is not militarily useful) for these high power-to-weight ratio flight experiments to be technically feasible to perform. The tank glider testing yielded positive results. It was a reasonably stable glider that could be landed on the tank tracks. In modern times, we'd classify similarly-sized and equipped armored vehicles as "tankettes" or light tracked carriers, rather than tanks.

A powerful low-elevation main gun mounted to a turret, lots of frontal armor to protect against similar main guns, and powerful diesel or gas turbine engines are what make modern MBTs possible. However, these types of vehicles are far too heavy to transport via anything but the largest jet aircraft- Boeing 747-sized or larger.

Starship could lift off and transport a pair of M1 Abrams MBTs half-way around the world, much like the C-5 Galaxy. Anything smaller is a waste of time and money. If the M1's have Titanium alloy hulls, that instantly drops 20t of weight over the existing M1A2. If the M1's have 3 crew in the hull, a crew-less turret with an autoloader, then you drop at least another 10t. That describes the US Army's M1 TTB project from decades ago. We lacked the electronics and autoloader tech to do that during the late 1980s, but we have it now. With a modernized M1 TTB variant, we can carry a trio of M1s inside the payload bay of a Starship. On top of that, almost halving the vehicle drastically improves fuel economy and ground pressure to the point that we can delete a pair of extra road wheels and associated hull length, saving even more weight.

The all-steel M1 TTB weighed about 48t. It featured 3 crew positions in a well-protected hull compartment and an autoloader for the 120mm gun. Russia's T-14 Armata is what our M1 TTB project was.

This flying tank idea was ultimately abandoned as too expensive and too dangerous for the limited additional battlefield mobility provided. All similar designs had what amounted to a real aircraft's functional bits (all the expensive parts) attached to a light tank chassis. Your tanker had to be a good glider pilot, if not also a single-engine land plane rated pilot, in addition to a tanker. It's easy to guess at what armies thought of the idea of putting someone capable of flying a plane inside a short-lived / lightly armored tank. Oddly enough, the armored branch forces suffered the fewest casualties by far, as compared to any aviation / infantry / naval forces, so maybe putting some of your aviators inside armored vehicles was a way of killing fewer of them.

I think the US Army briefly entertained the Christie flying tank concept which pinned a rather small Christie suspension system tank to a powered biplane. It was another technically feasible idea that never went beyond basic conceptualization and perhaps very limited testing, on account of how impractical and dangerous it would be for the tank's crew.

I saw a resurgence of this silly idea from some former US Army officer who thinks the M113 can be used for everything. His website is combatreform.org. I checked out most of his other ideas as well, just to get the perspective of a cavalry officer and what he thinks should be changed to better perform combined arms warfare. Some parts of his proposals may have had merit about 20 years ago. Most of it appears to be a collection of design concepts without much thought put into the logistics and technology required to make his proposals work in combat.

Project Astron attempted to make the turret portion of a tracked vehicle fly using a podded propeller driven aircraft engine. Calling it a tank is a bit of a stretch. It was essentially a tracked land vehicle acting as a carrier for a flying machine gun turret, somewhat akin to the ball turret of a B-17, with the propeller blades mounted above the pilot / gunner. This was a silly way to make a less-capable light helicopter like the OH-6.

Overall, the problem is far too much weight for practical vehicle designs:

To demonstrate the current situation, Carter showed a graph that identified the different contributors to the weight of a 75-ton Abrams tank. Of the total, he said that 40.7 tons, or greater than 50 percent, is armor and structure, 12 tons is running gear, 11.6 tons is for the weapons including the main gun and ammunition, and the remainder is distributed among powertrain, auxiliary automotive, and crew equipment. He noted that the Army ran several simulations and came up with a “very high risk” approach that would reduce the vehicle to 35 tons, with 13.5 tons of armor, achieving this with broad material science advances and other technology improvements. But Carter posed a rhetorical question: “How do you get 40.7 tons of protection with 13.5 tons [of armor]?” National Academies of Sciences, Engineering, and Medicine. 2018. Combat Vehicle Weight Reduction by Materials Substitution: Proceedings of a Workshop. Washington, DC: The National Academies Press. https://doi.org/10.17226/23562.

General Dynamics Land Systems - Titanium in Combat Vehicles by William A. Herman, PhD, Manager, Materials Engineering & Survivability

The Design and Application of Titanium Alloys to U.S. Army Platforms by William A. Gooch, US Army Research Laboratory, Weapons and Materials Research Directorate Aberdeen Proving Ground, Maryland

Potential Applications of Titanium Alloys in Armor Systems by William A. Gooch

2019 NDIA GROUND VEHICLE SYSTEMS ENGINEERING AND TECHNOLOGY SYMPOSIUM - TITANIUM ROAD WHEELS: A COST-EFFECTIVE LOW-RISK ALTERNATIVE FOR LEGACY AND NEXT GENERATION COMBAT VEHICLES

Edit: For some reason, I keep thinking of the tensioning road wheels as being separate / different, but they're not for the M1 Abrams, all of which have 28 road wheels per side, not 24, which has been corrected below (they do carry spares in addition to the 28 on the vehicle, so more weight; also, there are another 2 guide rollers per side at the front, and although these look just like regular road wheels they may or may not be, which means there might be 32 total road wheels / guide rollers):

M1A2 Abrams MBTs have 28 steel / Aluminum alloy road wheels that weigh 103.6lbs each, and never seem to reach their design service life of 3,000 miles. Failures before 1,000 miles are most common. The all-Titanium alternative weighs 83.8lbs and costs considerably less by achieving its rated service life. It also makes the M1 Abrams 555.6lbs lighter than the current steel and Aluminum road wheels. A quarter ton here, a quarter ton there, and pretty soon we're talking about serious weight. The most dramatic weight savings will come from making the armor, hull chassis, turret chassis, and tracks from stronger and lighter materials, but we need to start somewhere, and a place that saves a lot of money over time is a good starting point.

There are a lot of "low hanging fruit" items like this, which are not massive all-encompassing platform re-development programs, where our Army can both save money, improve the actual combat capability of their vehicles by reducing maintenance, and reducing the fuel burden on their logistics tail.

The M1 is the correct tank. The M2 and the various iterative design improvements based upon it are the correct IFV / APC. The M109 is the correct SPH. Apart from increasing sensor capability to rapidly detect and classify targets, networking between platforms to share target data, reducing OODA loop time by presenting operators with concise information, and lowering total vehicle weight with stronger / lighter materials, there are no revolutionary improvements to be had. We don't need to "reimagine" a tank or a howitzer, unless imagination alone can cause an enemy tank to cease to be a tank, because new labels only wow the idiots who will believe anything. The enemy doesn't care if you "imagine" that your fancy new MBT design no longer needs armor, and the main gun rounds he'll be sending your way lack any ability to care.

The M10 is too light to be a true MBT and too heavy to be air mobile. What the US Army chooses to call it is irrelevant to how it will be dealt with by the enemy, who will use MBTs and ATGM-armed helicopter gunships (modern day "tank destroyers") to destroy it. The Stryker brigades were supposed to be C-130 air mobile, but were heavier and larger, with less volume under armor, than the M113s they were supposed to replace, but never actually did. Somehow, they cost far more money to own / operate / fuel than the M113s, which still had superior armor protection for a given weight and dramatically superior off-road mobility for less weight. Geometry and physics flipped the bird to the US Army's notion of mobility. Go figure.

The US Army shouldn't have any wheeled combat vehicles, because after you add enough armor, they're either absurdly large and heavy for the protection provided, meaning no longer light or air mobile in any tactical sense, or they no longer have much of the badly needed off-road mobility with the extra armor bolted on. All the Strykers, MRAPs, J-LTVs, and similar vehicles were a way to spend piles of money on this ridiculous "medium force" nonsense that started under Gen Shinseki, and confers none of the advantages of light or heavy forces. It was a stand-out failure against lightly armed and poorly trained insurgents. It'll be an unmitigated disaster against the Russians or Chinese. The new M10 Booker is more of the same faulty thinking that applying cool-sounding labels to your new toys somehow changes the armor / mobility / firepower equation. Just because the Russians and Chinese have light tanks, doesn't mean we need one. We should use better protected MBTs for doing "tank stuff" (direct application of cannon fire to enemy armored vehicles), and much lighter tracked vehicles for most everything else. None of those Russian or Chinese vehicles could withstand a hit from their own main gun, much less a 120mm. How do I know? None of their MBTs can withstand hits from our 120mm. Any less well protected vehicle is a guaranteed hard kill.

Why fight geometry and physics? Use it to your advantage, even if your enemy doesn't.

Last edited by kbd512 (2023-10-01 17:18:31)

kbd512 · 2023-10-03 09:50:40

The US Army started with gasoline engines because diesels were not reliable or powerful enough at the weight targets the Army needed them to hit. They switched to diesel engines after WWII because diesel fuel was less of a fire hazard and diesel engines were more efficient than gasoline engines.

By the late 1970s, the first and only broadly successful gas turbine engine was used to power the then-new M1 Abrams, which is by far the largest active fleet of gas turbine powered armored vehicles. The Soviet era T-80 also had a gas turbine engine, with about half as many made as compared to the M1 Abrams, though far fewer T-80s remain in service. Soviet experience with the T-80 was not as favorable, so all of their newer tank designs use diesel engines. However, the Swedish Strv-103, or "S-tank" as it was more commonly known, was actually the very first series production tank to use a gas turbine engine, primarily to supplement the power of its 240hp Rolls-Royce K60 opposed piston sleeve valve diesel, which was used at low speeds. The S-tank started off using 300hp Boeing T50 gas turbines that powered the US Navy's DASH anti-submarine helicopter drones of the late 1950s and 1960s. T50 engines couldn't supply enough power, so more powerful 490hp Caterpillar 553 gas turbines replaced the original T50s. Similarly, K60s didn't supply enough power for low-speed operation, so 290hp Detroit Diesel 6V53T engines that powered the US Army's M113 were fitted.

S-tanks were most famous for lacking a turret entirely, much like WWII assault guns. Its 105mm main gun was fixed inside the hull, so a large travel range hydropneumatic suspension system used to elevate and depress the gun -11/+16 degrees, with steering providing traversal. This meant its main armament had to be used defensively from static hull-down positions. This was not seen as a great loss since the ability of moving tanks to hit other moving tanks in the 1950s, was nowhere close to what it is today. Aiming, ranging, and gun stabilization devices were rather primitive back then, even though they existed. S-tanks were eventually equipped with dozer blades to rapidly create a berm in front of the vehicle to fire from behind. This type of fighting is still favored by tank crews because it provides both hull protection and sometimes partial concealment as well. A particularly peculiar feature of the S-tank was that the driver could perform all vehicle functions without assistance from the other two crew members normally present. The main gun was equipped with an autoloader and its ammo supply was separated from the crew compartment, much like our M1 Abrams. The S-tank had a forward driver / gunner, a reverse driver (also the radio operator, I think), and a vehicle commander. It could drive at top speed in forward and reverse directions, something no other tank could do. The design isn't practical for today's moving engagements, but a good example of "thinking outside the box" from the 1950s.

Photos of the Strv-103 / S-tank demonstrating gun elevation and depression using the suspension system:

Strv-103 could make one hell of an IFV if they removed the main gun, switched to pure turbine power, and added a remote turret with an automatic cannon and missiles. The hull is as well protected as many modern MBTs. All modern IFVs have very high vertical profiles and comparatively poor armor, by way of comparison. In the end, Strv-103's vertical profile was not significantly lower than the T-62s it was designed to fight against if the Soviets invaded, but the T-62 is now equally obsolete.

The US Army, therefore, did nothing particularly revolutionary with their M1 Abrams design. The AGT-1500 was selected for its tremendous off-idle torque and reliability compared to 1970s era diesels. The gas turbine was considerably more reliable than the air-cooled Continental AVDS-1790 diesel engines used to power the Patton series of tanks (M46/M47/M48/M60). The M46, IIRC, was powered by an air-cooled gasoline-fueled AV-1790, the forerunner of the AVDS-1790. Continental is better known today for their various certified gasoline-fueled piston aircraft engines, especially the O-200 and IO-550. Continental also made gas turbine engines, as did Lycoming, but most pilots will immediately think of opposed / boxer layout 4 / 6 / 8 cylinder air cooled engines.

I think this chart shows why the AGT-1500 was and is the better option for a very heavy vehicle like a MBT:

kbd512 · 2023-10-03 09:57:33

When the M1 Abrams first starts moving, I think the transmission delivers around 210,000 pound-feet of torque to the tracks. It still takes over 7 seconds to accelerate from a standing start to 20mph. Looking at how much torque that diesel gives up to a gas turbine low in the rev range, is it any wonder that the Army of the 1970s (which still believed that physics was real) went with a gas turbine for torque and reliability (relative to a large diesel), at considerably lower weight? You only get better fuel consumption from a diesel at idle, and oddly enough as the graph shows, at maximum engine output (where it matters very little to acceleration). If the US Army had prioritized development and procurement of LV100-5 engines to replace their aging AGT-1500s, rather than squandering money on blue sky tech development programs that all amounted to less than nothing, then there would be no compelling fuel consumption advantage in favor of a diesel, at idle or any other output level.Since every M1 Abrams tank in existence has been rebuilt from the ground-up multiple times over its service life, there was ample opportunity for better gas turbines, a lighter Titanium hull and turret to attach armor / engine / other components to, and an improved main gun. I don't need to "re-imagine" what a tank is to know that this was the only correct way to retain the winning combination of characteristics that make the Abrams a world-class Main Battle Tank. Apart from sensors and more reliable electronics, no other revolutionary changes have come about, from the 1970s to the 2020s, which have conspired to make MBTs obsolete for the direct fire support role that they presently fill.

The amount of money squandered on blue sky tech development over the past 20 years is more than enough to pay for modernization packages for all of our M1 Abrams and M2/M3 Bradleys (new engines, new sensors, upgraded firepower). We keep trying to replace the M113 with various wheeled vehicles, but the US Army continuously has to re-learn (sometimes in combat, which is not a testing agency amenable to failure) that larger / heavier / under-powered / poorly-armored wheeled trucks are not acceptable substitutes for tracks in off-road environments. It's fair to say that none of these trucks will ever overcome the basic physics governing off-road mobility for heavily armored vehicles.

Every 5 to 10 years the Army issues another report denoting the clear superiority of tracks vs wheels for off-road mobility, but then they pursue another pointless "physics isn't real" spending program to squander obscene amounts of money on new trucks that will never do what tracked vehicles do. I think a true M113 replacement is decades overdue, but I also think that replacement means more M2/M3 production, not more "let's re-imagine the battlefield as it never was" nonsense.

kbd512 · 2023-10-03 10:54:44

After you have a complex weapon system mastered to the degree that it mostly works, even after many things go wrong, then you refine that weapon system to the degree practical. M1 Abrams is a solid tank design that typically wins slugfests against Russian and presumably Chinese tanks. That's fantastic news, but resting on our laurels is not an option. Technology moves forward. However, there are relatively few revolutionary advancements to MBT design. Evolutionary improvement of successful designs is therefore the correct approach.

1. We should give our M1 Abrams a lower cost LV-100 gas turbine engine with even fewer parts than the existing AGT-1500 engine, even better reliability, and much greater fuel economy. Our "good tank" is now an "even better tank". The T-156 track links were already replaced with T-158 tracks, which added weight, but also greatly improved their reliability and longevity.

2. Rheinmetall's 120mm L44 (M256) smoothbore cannon is already an accurate and powerful weapon. Some variant of it equips nearly all western-designed MBTs. German Leopards use a longer barrel L55, at the expense of added weight. The US Army solved the same penetrator velocity and terminal effects problem using more efficient propellant and improved penetrator design, which was the better trade. To improve further we need to take our XM360 iterative design improvement upon Rheinmetall's hard-hitting L44 / M256, to increase reliability and reduce recoil and shorten recoil stroke length inside the fighting compartment, as well as reduced main gun weight, even as increasingly powerful propellant charges are used. The tradeoff for the new main gun design is more cost and no coaxial machine gun. The XM360's integrated fume extractor eliminates external penetrations of the barrel, which reduces cleaning / maintenance problems, and simplifies barrel manufacturing.

3. Our tank now has a much more usable engine than most others equipped with diesels and its firepower is on par with anything else fielded. To top that, we eliminate a substantial amount of weight by switching from steel to Titanium alloy for the hull and turret chassis that the armor plates are welded or bolted to. Acceleration improves dramatically, fuel consumption drops, logistics requirements decrease, and it requires fewer road wheels while producing a lower ground pressure, making our tank more mobile, so there are fewer places it cannot go. After this upgrade, in terms of usable combat capability, there are only armor and sensor improvements that can make it dramatically better.

4. As electronics improve, we refresh the electronics and software to take advantage. Our "better tank" has very few equals at this point, which boosts foreign sales and reinvestment into our MBT program. Training and tactics haven't changed all that much because a repertoire of repeatable winning combat tactics only extends so far. However, training must be commensurate with capabilities. After this series of upgrades, anyone who wishes to fight our MBT force and win either needs supporting artillery and air power combined with vastly superior numbers, or they must sink as much time / money / effort as we did into their own MBT program. Their tanks are not going to out-maneuver / out-gun / out-run / out-armor one of our machines without making significant concessions that leave their tank vulnerable in various ways.

5. We look at ways to extend our world-class engine / tracks / suspension / road wheels, sensors / electronics / software, and materials / armor programs to our other ground combat vehicle platforms, such as our IFVs and APCs and SPHs. Common platforms reduce cost and increase availability of spare parts. They also simplify operator training and repair depot activities.

Our military keeps searching for revolutionary advancements while neglecting their aging equipment, which could be kept modern / reliable / capable through routine refreshes of basic working vehicle designs. Combat experience has taught us that our equipment is getting the job done as well as or better than our adversaries in Russia and China. Attempting to totally outclass all of their hardware is a waste of time and money if the tradeoff is fewer and fewer fully functional major combat systems. War is ultimately a matter of logistics when your technology is broadly comparable. All the super weapons the Germans invented during WWII couldn't overcome their basic logistical limitations. There's no reason to believe that logistics doesn't apply to our military, either.

Mars_B4_Moon · 2024-03-29 13:58:34

Different Aircraft and Different Missiles

Ukrainian MiG-29 jets originally made in the USSR or Russian Soviet Union but employing US-made AGM-88

https://theaviationist.com/2022/08/21/u … -missiles/

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