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#26 2020-03-05 07:17:13

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 10,835

Re: electromagnetic launch with microwave propulsion

For kbd512 re #25

It's good to see new details coming into focus!

Thanks for helping SpaceNut with the 400 mile confusion.

Thanks for clarifying that your design would incorporate a small angle of inclination.

As I read your earlier post about the launch angle, it appeared (to me at least) you were planning a laser beam trajectory straight out over the surface of the Earth.  It was that concept that lead to the 400 mile computation.  Due to the curvature of the Earth, a flat trajectory would reach 20 miles of altitude after a horizontal run of 400 miles.

The tradeoff is simplicity of construction at the launch site, versus time spent by the vehicle in the atmosphere.

On the other hand, if your design for the vehicle includes sufficient strength for the airframe, you can bend the flight path gently upward, in order to decrease the time spent in the lower part of the atmosphere.

There are several aspects of the plan that will be of interest to investors, whether military (for the Space Force for example) or civilian.

1) it will be helpful to find political actors who understand the concept and see the benefits so will spend political capital to support it
2) It will be helpful to find land owners who will support this use of their land, and will accept the long wait until profits materialize
3) it will be helpful to find vendors who are willing to at least discuss the potential of their technology to be used for this purpose
  In the case of the energy storage and dump technology used for US Navy, there may be security concerns, so a military sponsor may be helpful

The NewMars forum is a friendly environment in which to bring ideas from conception to the point of presentation.

I am hoping other members with appropriate backgrounds and interests will pitch in to help you along.  This is potentially a very nice consulting gig, but it's not one you (or any single person) can pull off alone.   This is going to require cooperative support by a number of folks, and this forum is as good a place as any for cooperation on the needed scale to take place.

I think that design of the airframe for the first stage vehicle ought to be of interest to folks with related experience, whether currently members of the forum or not.  It is easy enough to register.  What is difficult is solving the design problem kbd512 has posed.

(th)

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#27 2020-03-05 09:19:23

kbd512
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Registered: 2015-01-02
Posts: 5,868

Re: electromagnetic launch with microwave propulsion

tahanson43206,

Yes, the initial trajectory is going to be rather straight out of necessity, but it turns out that lift and CG are real tangible "things" and as a consequence this vehicle will be ascending like a F-22 in full afterburner.  If you pull up too sharply at max gross in any fighter jet, then no matter who made it or what it's made from, you can rip the wings right off without too much difficulty.  The control laws that govern how the software responds to pilot input are what prevent that from happening in modern fighters like the F-16, F/A-18, F-22, and F-35.  In older airframes like the F-4, you actually had to understand and respect the design limitations or it just might be your last flight.  This is not meant to suggest that these airframes weren't tough customers, but absolutely everything in aviation comes with limitations attached to it.  None of what I've stated about that would come as a surprise to any structural engineer who has designed a jet of any kind.  Airliners have spectacular takeoff and climb performance when they're lightly loaded, for example, but load it up with passengers and fuel and the kinds of stunts you see pilots pull in company propaganda would be fatal mistakes.

1. Political actors only need to understand that the project will bring jobs and smart young people to their districts.  They don't understand technology, nor do they care to understand, but that's okay.  Some people were meant to be engineers and others were meant to be basket weavers.  One is not necessarily any more valuable than the other.  It all depends upon what you're trying to accomplish.  I want a technology-rich, education-rich, and energy-rich future.  This is one way to bring about that goal.

2. You probably won't find many people who want a military air base by their home, but that air base also brings many employment opportunities with it.  Eventually, most of them realize that their kids need jobs that permit them to use those fancy (and expensive) educations they received in college if they ever hope to get them out of the house and gainfully employed so that they can retire.

3. There are always vendors willing to supply the government what it asks for.  The only question is whether or not it's a good deal for the tax payer.  As a tax payer who pays lots of taxes, I'm keen to maximize the use of my tax dollars.  There are many ways in which we could simply employ the maximum number of people possible and run the cost of a given project into the stratosphere, but this project is intended to pay us back in terms of reduced launch costs and more efficient use of our tax dollars.

There's no military technology used here because the military doesn't really have anything comparable to it.  We're not going to build a whiz-bang solution to this problem because it's just not needed.  We don't need a super duper conducting electro-flinger made with Unobtanium.  A simple stainless steel guide rail, electrical steel and copper electromagnet system, and steel reinforced concrete (same stuff we use in roadways and bridges and buildings) is sufficient to make this project work.  The flywheel energy storage system will be made using low(er) steel flywheels because it's a reasonably good low-maintenance compromise that will still be usable decades from now and for many thousands of launches.

On that note, I'm not sure I'd be the right person to do any consulting work on this project.  I know enough about the technologies involved to know that it's feasible, but I'm not the right kind of engineer for a project like this.  Between my own work, raising my kids, and designing and building my own aircraft for my own personal knowledge and enjoyment, I have enough going on to keep me reasonably busy.

GW is retired.  I don't believe building cactus killers is a very good use of a rocket scientist's time, though he may differ with me on that point.  So, we'd need some electrical engineers with experience designing and building large motors and flywheel energy storage systems, some civil structural engineers to work out the facilities and infrastructure requirements, and some aerodynamicists and airframe structures engineers to work on the flying bits.  I expect that designing the launch vehicle to withstand launch conditions will be a more significant task than anything related to the electromagnetic catapult design.

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#28 2020-03-05 10:13:23

tahanson43206
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Registered: 2018-04-27
Posts: 10,835

Re: electromagnetic launch with microwave propulsion

For kbd512 re #27

Thank you for advancing the ball here.  If this were an American football game, I'd evaluate this post as a good solid three yard gain, which follows a series of similar solid but modest advances.  The key addition is what I am quoting below:

GW is retired.  I don't believe building cactus killers is a very good use of a rocket scientist's time, though he may differ with me on that point.  So, we'd need some electrical engineers with experience designing and building large motors and flywheel energy storage systems, some civil structural engineers to work out the facilities and infrastructure requirements, and some aerodynamicists and airframe structures engineers to work on the flying bits.  I expect that designing the launch vehicle to withstand launch conditions will be a more significant task than anything related to the electromagnetic catapult design.

With good reason, persons with reputations to lose are unwilling to participate in this forum.

For SpaceNut ... your management of the rambunctious crowd on this site is key to any hope there might be of attracting people with PhD's in fields related to the project under discussion.  However, in addition to your management of the site, outreach to the desired audience is needed.

I have observed that there is a way for serious people to co-exist on this site along with individuals who are free to (and encouraged to) let their imaginations run free.  It is the continuous brain storming aspect of this site that I find encouraging and even occasionally inspiring.

The key for success with an open site such as this is to select the ID's to read.

This concept is tested, however, by individual contributors who are dramatically uneven in their performance.

Upon occasion, I will allow myself to open a post from someone of variable performance.  Sometimes I am rewarded, and sometimes I am disappointed.

Cross-posting between regulated sites and this one is a possible technique that might allow collaboration without putting reputation at risk.

Even that has proven risky, because a cross-site post can lead to a post from someone of uneven performance which drives the cross-site originator away permanently.

(th)

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#29 2020-03-05 10:13:25

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,974

Re: electromagnetic launch with microwave propulsion

Kbd, excellent post.  It would appear that the lower stage is about 80% of the wet launch mass of the Falcon 9 and should therefore account for a similar proportion of capital and operating cost.  If the electromagnetic launcher is used heavily, it does not seem unreasonable for launch costs to be reduced by 70%.  And that is before consideration of microwave power.

There are other advantages that may reduce launch costs further.  We would be concentrating production on a much larger number of identical and smaller, reusable launch vehicles.  That allows scale economies that will be more difficult for the full size Starship.  As a general rule of thumb, doubling production volumes reduces unit cost by 10%.  So launching in 5t batches instead of 100t batches should reduce capital costs by 40% compared to the full size Starship, all else being equal. 

Small modular nuclear reactors have similar advantages over big reactors for the same reasons, although in their case poorer neutron economy will be a drag.


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#30 2020-03-05 12:19:44

tahanson43206
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Registered: 2018-04-27
Posts: 10,835

Re: electromagnetic launch with microwave propulsion

For Calliban re #29

Thanks for the 80% figure for the Falcon 9!

There ** is ** a way to bring the "microwave" part of kbd512's vision into play sooner rather than later, and that is by deploying an SPS to feed the launcher.

The cost of building the SPS would then be blended into the overall cost structure for the launch complex, and once in place, it would slowly but surely pay for itself as the high volume of launches you have proposed unfolds.

Everything about the project would become more feasible (from a social standpoint) if the vehicle size is reduced.

I'm not concerned about the technical issues here.  Everything under discussion has been studied or actually accomplished decades ago.  The challenge for those who might become involved in moving this along is finding the presentation elements that will convince the people of Texas in particular, and in regions around the Gulf of Mexico, to support it.

A sufficient level of wealth generated, which finds it's way into the pockets of the entire population around the Gulf, would help!

There's a big "if" in that statement.  The American capitalist system contains structural elements that would allow for distribution of wealth on that scale, but we don't see a lot of examples of successful implementation.

Never-the-less, there ** are ** some examples.   There is a lot of discussion in print, on radio and (I'm sure) on television and cable, about Jack Welsh.  Without taking sides in the pros and cons about his life, it seems clear (to me at least) that Mr. Welsh understood the capitalist system as it existed in his time, and managed his people and assets effectively.

A person like that could take the electronic launcher idea and develop it into a successful business, with bases both in the US and at suitable locations elsewhere in the world.

(th)

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#31 2020-03-05 17:16:43

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 25,992

Re: electromagnetic launch with microwave propulsion

The problem is creep for any item being designed as to the features and perameters which are the required values which keep changing such as to not have a solid concept of how we will perform this miracle of flight to orbit in an unknown ship with unknown size or mass let alone a fixed payload capacity to what level of altitude above earth.
Its a problem where you need to work the design from both orbit back towards earth and from earth towards orbit to get the numbers to firm up for a design.

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#32 2020-03-06 05:36:38

tahanson43206
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Registered: 2018-04-27
Posts: 10,835

Re: electromagnetic launch with microwave propulsion

For SpaceNut re #31

Thanks for your call for focus!  Here is a concept for a stretch goal which can be achieved by this group, within one year:

Develop a proposal to:

Launch X37 from the coast of Texas over the Gulf of Mexico and achieve LEO.  Employ electromagnetic acceleration to provide first stage impulse.  Employ a lifting body as second stage using chemical fuel.  Allow X37 to top off the orbit if necessary, but perform as much orbit shaping as possible using second stage.

In order to accomplish this, begin an active campaign of email and physical letter outreach to attract needed talent to participate in the project.

Declare the project as Open Source.  Anyone who participates has the same chance as anyone else to form a local team to bid for the project.

Request military department guidance for procurement requirements specific to X-37 launch.

Invite participation by political leadership in Texas to see if there is any interest in taking on the responsibility of managing land use.

Invite participation by the Republic of Indonesia to evaluate whether the concept would work in their situation.

(th)

Last edited by tahanson43206 (2020-03-06 05:37:07)

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#33 2020-03-06 09:50:49

kbd512
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Registered: 2015-01-02
Posts: 5,868

Re: electromagnetic launch with microwave propulsion

SpaceNut,

We could certainly design the launch system to handle payloads up to 5t, but start with sub-scale models.  I think we should have 500kg, 1t, and finally, 5t payloads.  There are specific markets that can be served by each of these payload classes and the advantage of electromagnetic launch is the ability to deliver a wide mass range of payloads using appropriate force for acceleration.  The general concept of operations is that we deliver all payloads to a staging location where a miniature space station with robotic manipulator arms can capture, sort, store, and/or redeploy the payloads using upper stages, as is appropriate.

As far as the technology for the orbital vehicle is concerned, these vehicles are excellent candidates to showcase the use of high specific impulse and high density impulse hybrid rocket technology, such as the paraffin wax solid rocket motor technology.  This could provide very similar specific impulses to our RP-1 or LCH4 fuels, but with improved density impulse for smaller propellant tanks and it could reduce some of the cleanliness requirements to prevent unwanted interactions between LOX and liquid fuels / fuel vapors.  Unlike conventional solid rockets, these can be throttled as required.  This is also done to improve the total cost of the propellant, as paraffin wax is more economical to produce and store than RP-1 or LCH4 or LH2.  A paraffin wax fuel is ~$1/kg, which is right in line with RP-1.  Jet-A may be cheaper than RP-1, but it's not suitable for rocketry.  If there's a paraffin wax "fuel spill", then you walk over to the spill and "pick it up" with your bare hands.  The RCS propellant will utilize the new HAN / AF-M315E (so-called "green" monopropellant) due to drastically reduced toxicity hazard over Hydrazines (you can't drink HAN, but if you spill it on your skin you won't immediately have a horrific chemical and thermal burn; HAN is mildly acidic but not wildly reactive with nearly everything naturally present, which includes our most important asset- people).  HAN also has a fantastic density impulse increase over Hydrazine.  You can't have all of that with RP-1 or LCH4 or LH2 and/or Hydrazine.  The manpower and infrastructure requirements for handling of propellants needs to be taken into account.  In the real world, a room temperature solid you can move around with your bare hands beats most liquid fuels that require special tanks, especially cryogens.  This minimizes infrastructure costs (ongoing maintenance costs that are never going away).

The heat shield would be a combination of NASA's TUFROC and UHTC technologies to enable sharp leading edges required for low altitude hypersonic flight.  Perhaps we could also experiment with ejectable motor cores to save the vehicle and payload in the event of an ignition or motor failure.  The motor is essentially a candle and LOX can simply be released into the atmosphere.  Neither are particularly toxic nor troublesome to recover, either.

So, we spend our money on the orbital vehicle in terms of better heat shield and propellant technologies to enable ease of manufacture / handling / storage / ultimate durability.  I haven't broached the subject of structural materials for the airframe yet, but I'll get to that later.

I'm still mulling over our options for avionics and how that would affect cost.  I'm inclined to believe that SpaceX has the right idea using COTS hardware / software plus redundancy over specialized radiation hardened chips and arcane programming languages known only to a handful of aerospace engineers.  If the entire avionics package can be written in C and Assembly, then there are plenty of talented developers the world over who can provide their services.

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#34 2020-03-06 18:27:34

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 25,992

Re: electromagnetic launch with microwave propulsion

The Pegasus is an air-launched rocket released from its carrier aircraft at approximately 40,000 ft, and its first stage has a wing and a tail to provide lift and attitude control while in the atmosphere. Capable of carrying small payloads of up to 443 kilograms into low Earth orbit. The drop is considered to be the actual launch, although the first stage is not fired until five seconds later at an altitude of 11,470 meters.

The rocket employs an inertial guidance system to pitch it upward after first stage ignition. The first stage burns out 77 seconds after launch, and is jettisoned. The second stage is fired 95 seconds after launch, followed by separation of the payload fairing at 111 seconds after launch. The second stage burns out 168 seconds after launch, at which time the second and third stage combination begin an unpowered coast period. During this coast period, the second stage remains attached to provide aerodynamic stability.

Ultimately, the spent second stage is jettisoned and the third stage is fired 592 seconds after launch. The third stage burns out 657 seconds after launch and is jettisoned from the payload, having successfully inserted it into orbit. The Pegasus XL can deliver a payload of 450 kilograms to low Earth orbit, or place 125 kilograms on an Earth-escape trajectory.

https://snebulos.mit.edu/projects/refer … _Guide.pdf

https://www.northropgrumman.com/space/pegasus-rocket/

The original vehicle, now referred to as the Pegasus Standard, has been superceded by the Pegasus XL which is available in three- or four-stage versions. There are two fourth-stage options. The Hydrazine Auxiliary Propulsion System (HAPS), which burns hydrazine liquid fuel, provides precision orbital insertion capability for the payload. Alternatively, the fourth stage can be powered by a Thiokol Star 27 solid rocket motor, which burns HTPB solid fuel and can provide Earth-escape trajectory capability for the payload. The Pegasus XL employs a standard payload fairing, 2.1 meters long with a diameter of 1.1 meter.

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#35 2020-03-06 18:33:44

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 25,992

Re: electromagnetic launch with microwave propulsion

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#36 2020-03-07 07:34:42

tahanson43206
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Registered: 2018-04-27
Posts: 10,835

Re: electromagnetic launch with microwave propulsion

For SpaceNut re #34 and #35

Thank you for both of those reminders of proven technology which might be adaptable to the extreme conditions kbd512 has posed in this topic.

Today, I'd like to start a follow up on the (very) important subtopic of the electromagnetic launch system.

While the launch system is proven for heavily laden fighter aircraft, it must be extended both in distance and in mass capacity to deliver the results needed for a repeatable, reliable space launch system.

Here is a response from Google that may help to start a deep dive into this subtopic:

patent electromagnetic catapult

About 56,400 results (0.57 seconds)
Search Results
Web results

CN103231808A - Electromagnetic catapult for carrier-based ...patents.google.com › patent
The invention discloses an electromagnetic catapult for a carrier-based aircraft. The electromagnetic catapult comprises a dragging rack, a dragging rack track, ...

CN103057722B - Active maglev electromagnetic catapult ...patents.google.com › patent
Jump to Patent citations (2) - ... 2012-05-11 2012-09-26 Permanent magnet suspension electromagnetic ejection platform for airplane. Family To ...

SpaceNut re this topic and others ... In order to make progress on this topic and others in the forum archive, it would seem (to me at least) helpful to add to the group of already highly qualified participants who contribute here.  I remain hopeful that individuals with PhD level standing will be willing to take the risk of helping to move this topic (and others like Calliban's Spider) along, but the feedback I am getting is not encouraging.  This forum is not regarded (at present) as a venue where a hard earned reputation can be justifiably put at risk.

The most promising avenue for pulling in PhD level people is ** before ** they've earned that standing!  A college student, and even a person working on a thesis, has some leeway in the kinds of venues they can join.

This topic needs lots of assistance from people with skills, education and experience that are NOT academic in nature.  I am thinking here of those who would help locate land for a launch facility, as well as those who would explore with US Military departments the potential funding opportunity that would arise from an highly efficient, very reliable and high performance electromagnetic launch facility.

In Louis we ** may ** have the nucleus of a finance branch of the effort, although even Louis might appreciate assistance from suitably qualified and experienced individuals.

(th)

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#37 2020-03-07 10:09:19

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 25,992

Re: electromagnetic launch with microwave propulsion

In the past we have had a few people from Nasa read from the forum and they have meantion our name when they do submit work that is based off from a topics reading. From what I remember they never interact as they are on a government computer when reading and as such could not comment on business time.

Modish is the one which was on the forum that got a job for Maven but can not comment as well for much of the same NDA I am sure prohibits it. Even I must walk a thin line for things I speak of.

So going back to the method and means from the vehicles we are trying to calculate the length of run and change in velocity as well as energy input for the duration that is required to achive the replacement of the first stage of a rock and possibly more as in the multi stage rockets of given payload targets that I listed.

We have the stage information for each and there normal burn time for mass that we can use to use to reverse calculate the needed input values for the machine that we are building.

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#38 2020-03-07 10:27:45

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,858
Website

Re: electromagnetic launch with microwave propulsion

The easy way to find out what ballpark you are playing in with EM launch is to use the old high-school physics kinematics equation V^2 = 2 a s.  In this equation,  V is the final velocity you achieve (with the initial being zero),  s is the path length over which the constant acceleration a applies.  Use consistent units. 

It's not at all accurate to design anything based on only this,  because no propulsion known maintains constant vehicle accelerations over extended intervals of speed.  But it tells you what ballpark you are playing in.  For a desired speed V,  set an acceleration a you can tolerate,  and then s = V^2/2a will be an approximation to your launcher length.  You can tell m from km this way.

Acceleration levels beyond about 40 standard gees will maim or kill,  almost regardless of the seating and protective suiting.  Anything over about 50-60 gees leaves behind only a bloody ooze for a body.

EM launch was first investigated about 1950 for flinging overweight B-36's off the runway.  Back then the supporting technologies to do it were missing.  No longer:  the latest USN aircraft carrier has an EM catapult instead of a steam catapult.  It has been having some teething problems,  but I think it may actually go to the fleet as an operational device.  That technology scaled way up is what you have available. 

GW

PS: anybody here on these forms know what a B-36 was?  (I do.)

Last edited by GW Johnson (2020-03-07 10:33:25)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#39 2020-03-07 16:48:34

kbd512
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Registered: 2015-01-02
Posts: 5,868

Re: electromagnetic launch with microwave propulsion

GW,

I've seen the B-36 on display at SAC's museum.  I've never seen one fly, though.  I love piston engined aircraft and can only imagine the symphony from six R4360's at full power.  Didn't they put jet engines on them as well?  I have seen plenty of B-52's taking off and landing.

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#40 2020-03-07 17:14:52

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,858
Website

Re: electromagnetic launch with microwave propulsion

Hi Kbd512:

Yep,  there was a jet-assisted version,  the B-36D.  B-36A-C did not have them.  D was the last model produced.  This was two two-engine pods outboard of the recips,  that made for a total of 10 engines to manage.  I think they were the same engines that were used on the Lockheed P2V-7 Neptune.  They were only used for takeoff and climbout.  "Jet assisted take off" or JATO,  it was termed. These were jets that burned the same avgas as the recips.

B-36 served SAC from 1947 to 1954,  so my memories of seeing them fly are dim from single-digit childhood years.  All of them were based out of what used to be called Carswell AFB in Ft. Worth;  they were built at the old Consolidated/General Dynamics/now Lockheed plant that shares the same runway with Carswell (now the "Joint Reserve Base"). 

One of them crashed in the lake just north of the base;  if you are flying over that lake and the sunlight is at just the right angle,  you can see its outline under the water. 

For most of my life,  there were only two surviving airframes of the B-36.  One was at the Air Force museum in Dayton,  near WPAFB,  the other was on public display at the old Greater Southwest airport site made obsolete by the existence of the DFW construction site in 1969-1970.  That was at the intersection of what is now highway 360 and highway 183,  north side of Grand Prairie and Arlington. 

The bird in Dayton was not restorable to flyable condition,  but the Texas bird was.  They did run the engines,  but never had enough instruments to run more than one engine at a time.  So it was trucked in pieces over to the plant where it was built in Ft. Worth,  and is now on display there.  I don't think there are any plans to ever fly it.

I believe the Grumman Bearcat uses the same R-4360 engine.  Only one,  but it's otherwise the same.

As you know,  there are several flying B-17's.  Nearly all of them are B-17G models with the chin turret.  There is one,  maybe two,  B-17F models around.  Those had no chin turret,  looking much like B-17E,  the first example of Fortress II with the power turrets and the big vertical fin,  starting 1940. 

It's my understanding that Boeing Seattle has a restorable example of Fortress I on site.  Supposedly,  it is a B-17D.  No power turrets,  no tail gun position,  small vertical fin.  I've seen no news about this,  but I surely would like to see that old bird fly.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#41 2020-03-07 18:08:52

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 10,835

Re: electromagnetic launch with microwave propulsion

For GW Johnson re #38 ...

EM launch was first investigated about 1950 for flinging overweight B-36's off the runway.  Back then the supporting technologies to do it were missing.  No longer:  the latest USN aircraft carrier has an EM catapult instead of a steam catapult.  It has been having some teething problems,  but I think it may actually go to the fleet as an operational device.  That technology scaled way up is what you have available.

EM launch research in 1950 would have been based upon the same physics in use today.  Would that research have been documented?  It was probably classified in 1950, but (hopefully) the records from that time can be released.

Edit#1: Wikipedia has an entry that includes carrier EM but it does not include reference to the B-36 EM idea.

https://en.wikipedia.org/wiki/Assisted_take-off

The United States is replacing carrier steam catapults with linear induction motors. The system is called the electromagnetic aircraft launch system (EMALS). An electromagnetic wave traveling through the motor propels the armature along its length, pulling the plane with it. With this system, it will be possible to match launch power and aircraft weight more closely than with the steam system, causing less wear on the aircraft.

This page was last edited on 15 July 2019, at 04:42 (UTC).

(th)

Last edited by tahanson43206 (2020-03-07 18:40:52)

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#42 2020-03-07 19:10:21

kbd512
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Registered: 2015-01-02
Posts: 5,868

Re: electromagnetic launch with microwave propulsion

GW,

Interesting.  I never knew we had a flyable B-36.  I was told that they cut through the wing spars on the one at SAC, so it was not flyable.  I always thought the Bearcats used R-2800's, but maybe I'm mistaken on that.  I believe Martin had a fighter with a R-4360, though.  I know the Boxcars and B-50's (super B-29's) used R-4360's.  I think Boeing and Lockheed also had some kind of transports with R-4360's.  They were used on a variety of very large aircraft from that era, the Spruce Goose being a notable example.

Any thoughts on flying a small fighter-sized vehicle at Mach 6 at tree top level, however briefly?  I know for sure that we'll need a pretty good thermal management solution and computerized guidance system.  I was thinking in terms of 10g accelerations, though, not something that would turn someone into Jello.

FYI, I was actually thinking that the track would be a circle, perhaps 20km in diameter.  At 10g, the launch vehicle would make 7 laps around the 62.8km circumference track, potentially followed by a straight-away and up a shallow ramp, whereupon it would be flung off into the stratosphere at Mach 6.  That leaves 314km^2 in the center for the solar array to power it.

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#43 2020-03-07 21:11:27

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,858
Website

Re: electromagnetic launch with microwave propulsion

Kbd512:

The Wikipedia article over-rules me on R-4360's in the Bearcat.  I honestly misremembered the Bearcat as using them. 

But the R-4360 was used on the KC-97 tanker,  the C-119 "Flying Boxcar",  and the C-124 "Globemaster".  I used to see a lot of those flying overhead when I was a boy.  Big loud things.

I grew up in Grand Prairie,  near the old Dallas Naval Air station/Chance Vought Aircraft and not very far from Carswell AFB/Convair in Ft. Worth.  Our house was under the pattern for Dallas NAS,  so I saw a lot of stuff.  My dad worked for ~30 years at Chance Vought.  He retired as their chief of airframe design.

The R-4360 was used in the B-377 Stratoliner,  but not in the Douglas DC-6 and DC-7 airliners.  According to the Wikipedia article,  it had incredibly-severe maintenance problems,  which pretty much precluded its use in profitable airliners.  I know there was a tunnel out into the wings of the B-36,  so that in-flight maintenance and repair could be conducted. 

I saw a bunch of overloaded P-2V Neptunes over the house.  It took two turns around the pattern before they could clear the hills at the south end of Mountain Creek lake,  and head for the Gulf.  First pass was usually way under 500 feet over our house,  sometimes only about 150-200 feet.  Second pass was nearer a proper pattern altitude in the neighborhood of 700+ feet.  Military could do all sorts of things civilians could not legally do.  I think the P-2's used the R-2800.  I know it was 2 rows of 7 cylinders each.

M6 at sea level is a really serious heat protection problem!  The recovery temperature in the boundary layer is pretty much the total temperature,  which is 3793.4 F on a standard 59 F day.  If the exposure is brief,  you can heat-sink your way through the transient,  the same as is done for orbital entry.

You want to fling it way above the stratosphere as fast as you can manage,  up high enough that the low density cuts the heat transfer rates low,  so you can cool off by radiation at a skin temperature you can tolerate (1200+ F).  Be careful of the radius of curvature getting from the horizontal circle to rising ramp.  It's the same problem as the radius of the circle:  a = V^2/R.  So it's 10 km to hold the transient acceleration to 10 gees.  Just like the circle,  except a different plane of action.

GW

Last edited by GW Johnson (2020-03-07 21:12:59)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#44 2020-03-08 06:03:11

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 10,835

Re: electromagnetic launch with microwave propulsion

For kbd512 re quote from post above ...

FYI, I was actually thinking that the track would be a circle, perhaps 20km in diameter.  At 10g, the launch vehicle would make 7 laps around the 62.8km circumference track, potentially followed by a straight-away and up a shallow ramp, whereupon it would be flung off into the stratosphere at Mach 6.  That leaves 314km^2 in the center for the solar array to power it.

An alternative I've been thinking about overnight was along the same lines ... The ability to change the azimuth of the flght path is worth considering.

Another way of achieving that is to set a straight launcher on a circular platform, with railroad tracks to support the rotation of the track to meet the customer's requirements.  If the track is a km long, then the launch pad would be a circle a km in diameter.

An aircraft carrier provides 360 degree azimuth capability.  The Earth based EML would not need that degree of capability.

The orbital inclination of the ISS is 51.6 degrees, and shipments to the ISS would seem (to me at least) to be a reasonable business use for the launcher.

Another (to me) very attractive business use is supply of fuel to Elon Musk for his Mars transit vehicles.  Whatever orbital inclination Elon decides upon for a given starship, the launcher can be rotated to match and the payloads can be shipped in 1 ton containers until the refill operation is complete.

There are (no doubt) other business uses, but one that seems likely is non-ISS orbital hotel systems.

It is even remotely possible that non-US orbital stations would be willing to buy supplies from a US based entity able to swing the launcher round to meet whatever the orbital plane inclination may be.

SearchTerm:RotateEML
SearchTerm:EMLRotation

Edit#1: If the rotating configuration is considered for engineering development, it would seem prudent to plan to deploy anchors after each move is completed, to insure the track does not move longitudinally under the stress of launching a vehicle with a mass of many tons.

For that purpose, the entire 1 km circle may be constructed of concrete of sufficient depth to be able to serve as an anchor.

(th)

Last edited by tahanson43206 (2020-03-08 06:07:23)

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#45 2020-03-08 09:31:10

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 25,992

Re: electromagnetic launch with microwave propulsion

The circular motion will mean centripical force will be at work on the payload plus ship mass as it moves around the track. With that the centrifugal force would be acting as well on the payload and ship as it goes around the track. The mass and speed forces will become quite great as it continues to achive the launch speed.
https://www.diffen.com/difference/Centr … etal_Force
Its centrifugal that we are looking to for AG for man's health control once we are on the journey to mars.

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#46 2020-03-09 05:16:56

elderflower
Member
Registered: 2016-06-19
Posts: 1,262

Re: electromagnetic launch with microwave propulsion

You are going to put an awful lot of fuel containers into orbit at 1 te of payload each, TAH. Will you try to recover them, fire them into the sun or deorbit them for burnup/ disposal in the ocean? With 1% chance of failure something bad is very likely to happen with the number required to fuel up a starship!
I think you need to be more ambitious with your payload, which means there will be less of them and more money can be spent on each to reduce the failure probability.

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#47 2020-03-09 08:23:33

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 10,835

Re: electromagnetic launch with microwave propulsion

For elderflower re #46

Thank you for your insights and reminders of probability.  The 1 ton figure flows from design options kbd512 is considering in this topic.  The larger the payload, the larger the launcher must be (in terms of performance, not length).  The energy storage systems have to increase in size, the size of magnet wiring has to increase, and many other design factors have to be adjusted.  The market will have a LOT to say about what size launcher has the best chance of financial success. On the other hand, if the customer is the US military, then non-market forces will be at work.

To answer your question, I like the Musk mantra of expecting EVERY component (other than fuel) to be reusable.  With modern computing techniques, and advances in materials, that is (I suspect) quite achievable.

A failure rate of 1% would be on the high end of what a production facility on Earth (in any industry I can think of) would tolerate.

The engineering team working on the project could be expected to try for better performance than that.  Even Musk and his team dump a stage now and then, so your 1% estimate is definitely worth keeping in mind.

Question for you ... as I recall, you have directed or participated at some significant level of responsibility in design of a large chemical plant.  I would imagine your 1% figure comes from hard won experience, so would it be correct for me to assume that the chemical plant never achieved more that 99% success.  That may well be a high performance figure for a complex operation on that scale.  I have no way of judging, but I would not be surprised if that turned out to be the case.

(th)

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#48 2020-03-09 17:53:01

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 25,992

Re: electromagnetic launch with microwave propulsion

Well a 2% was what ended thew shuttle and that carried 7 max so a ship failure with 100 is the end.....
Cargo is what ever you can not afford to lose....

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#49 2020-03-10 04:38:02

elderflower
Member
Registered: 2016-06-19
Posts: 1,262

Re: electromagnetic launch with microwave propulsion

I was involved in large industrial facilities, TAH. These tend to be built to order, not serial production. Faults mostly get corrected in commissioning before full production commences.
I was thinking about batch production of complex equipment when I suggested 1 percent. It would only be an order of kind of number for illustration.
The bathtub curve applies.

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#50 2020-03-10 10:51:10

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 10,835

Re: electromagnetic launch with microwave propulsion

For elderflower re #49

Thanks for your reply!  There are two aspects of the situation, and your experience is helpful for both.

In the first case, kbd512 has proposed a fixed installation for launching vehicles using electromagnet force.  This is a distinct facility which must be designed and built to order.  While there may eventually be more than one on Earth, I would be surprised if there are ever more than three.

However, just about everything ELSE would be batch produced, and the flights themselves can be understood as a batch process.

Accordingly, your reminder of the inevitability of failure in any and all of the supporting processes is helpful. 

I am hoping to steer a course here that avoids imposing upon forum members, but at the same time, encourages participation by anyone who sees an opportunity to bend the direction toward realizing kdb512's vision in the real world.

I have asked a third party who lives in Texas to evaluate the Real Estate aspect of the proposal.

Mexico is an attractive location for a launcher in a number of respects, so I'm hoping someone with a connection to Mexico will pick up on the opportunity to consider a launch facility in that country.  A glance at the map of the West shore of the Gulf of Mexico will show why I am making this suggestion.

The Southernmost extremity of Texas on the West coast of the Gulf, and the Northernmost extremity of Mexico on the West coast, both have an attractive location, in that they can initiate flights that pass entirely over the waters of the Gulf toward the SouthEast, missing all land areas entirely.

However, in case of necessity (on behalf of the customer) and with the necessary approvals for overflight, it would be possible for launch facilities with azimuth flexibility to offer a fairly wide range of orbital inclinations.

In fact (the more I think about it) a healthy competition between the United States and the country of Mexico could be/would be good for both.

(th)

Last edited by tahanson43206 (2020-03-10 10:52:06)

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