Starship is Go...

GW Johnson · 2021-07-18 09:09:47

Re TH 1322: UPDATED 7-25-21 AS NOTED UPDATE2 7-26-21 AS NOTED

There are a lot of stories about the rocket plane testing. Folks who saw "The Right Stuff" would be aware of the competition between Chuck Yeager in the various versions of the X-1 and Scotty Crossfield in the D-558-2 to be the "fastest man alive". That was less a competition than most would think from the movie.

Douglas Aircraft built the D-558-2. Their company test pilot for it was Bill Bridgeman, who went directly from testing propeller-driven A-1 Skyraiders to rocket plane flight, via a few hours with Tony Levier in a subsonic two-seat F-80 jet (now known as a T-33). Bridgeman flew the D-558-2 to Mach 1.98 [UPDATE 1.88] before Douglas ever turned it over to NACA and Crossfield, who trained himself to fly it, eventually breaking Mach 2.

It was Bridgeman who identified the necessity of controlling pitch with the trim control that moved the horizontal stabilizer, because the elevator was "washed out" in the wake created by the shock waves at its hinge line. That's how both he and Crossfield were forced to fly the craft on its missions. [UPDATE: early missions. Later missions were flown with the bird refitted with an all-moving horizontal tail.]

Yeager's near-death experience in the X-1 was not in the original X-1, but in the larger X-1A with the bubble canopy. He tumbled out of the sky at almost Mach 2.5 [UPDATE 2.44] in it. Later versions addressed the [UPDATE some] problems, with Mach 2.5 [UPDATE 2.24] safely reached in the X-1E.

The original X-1 had both elevators and a large-motion pitch trim that moved the stabilizer. It did not break the sound barrier using elevators for pitch control, it used the trim. The later versions had the "all moving tail" horizontal stabilizer design typical of all supersonic jets today.

In 1947, the all-moving tail concept was a military secret that went into the design of the F-86, which gave it supersonic dive capability that its opponent in Korea, the Mig-15, did not have. Yeager nearly got himself killed flight-testing a captured Mig-15 over Okinawa about 1951 or 1952, reaching Mach 0.94 in the dive. About 1960, he was part of a tour of aviation types in Russia. The Russians were astonished he survived a near-sonic dive in the Mig-15. None of their test pilots had survived it.

It was the X-2 that finally reached above 70,000 feet [UPDATE highest was 126,000 feet] and above Mach 3. The original version had too small a vertical fin for adequate supersonic stability in the thin air. Mel Apt died because of that, attempting a Mach 3 turn at about 70,000 feet. I've seen the cockpit camera footage of that. Later versions had a larger fin, and could do the missions without losing control. [UPDATE: there were only two birds and they did not make very many flights. There were no later versions. Apt's fatal crash ended the X-2 flights.]

That's the rocket plane work that fed into the X-15 program. It rolled out in 1958, I remember the Walter Cronkite news story on the TV about that roll-out. They got started with 4 little engines [UPDATE two of the same 4-chamber non-throttleable XLR-11's that powered the X-1 and the X-2 and the D-558-2] [UPDATE2: the X-2 was powered by a two-chamber, throttleable Curtis-Wright XLR 25 rocket engine], then the big XLR-99 engine became available about 1960 or 1961 [UPDATE: throttleable, restartable XLR-99 started in 1960]. That's when it busted past Mach 4 and past 50 miles altitude. With the drop tanks, it busted past Mach 6. There were 199 flights of the 3 birds, with one fatal crash. Several X-15 pilots took the bird above 50 miles, earning astronaut wings in it. Neil Armstrong was one of them.

UPDATE: the XLR-11 was a 4-chamber engine unit burning ethyl alcohol and liquid oxygen (the V-2 propellant). You could turn off individual chambers to "throttle" it. It was uprated a bit to push the D-558-2. Some of these were pressure-fed, others were turbo-pump fed, using hydrogen peroxide decomposition to drive the turbopump. The XLR-99 was a throttleable single chamber engine fed ammonia and liquid oxygen by the same separate hydrogen peroxide decomposition cycle. It was throttleable from 50% to 100% of max thrust.

UPDATE2: the two-chamber Curtis-Wright XLR 25 that powered X-2 burned ethyl alcohol and liquid oxygen, and could be throttled from 50% to 100% thrust. Reaction Motors built the non-throttled XLR-11 4-chamber engine for X-1 and D-558-2, and also the throttleable XLR-99 for X-15.

UPDATE: the hydrogen peroxide decomposition attitude-control thrusters used on the X-15 were pioneered on the X-1.

UPDATE: there are some very good articles on Wikipedia about all of these birds, plus the cancelled X-20 Dyna-Soar that this rocket plane program was leading to. X-20 would have been the first spaceplane, had it flown. It was to be launched by a Titan-3 booster rocket out of Canaveral. The other big USAF space effort was toward a manned spy satellite call "Manned Orbiting Laboratory" or "MOL". That one had a big spy satellite module plus a hab module, fitted with a Gemini-B crew delivery capsule that had a hatch through the heat shield. The station and Gemini-B flew (successfully) once unmanned before the program was cancelled by Nixon in 1969. The Russian equivalent was called Almaz, and flew under the name Salyut as manned spy satellites, early in the Salyut series. Wikipedia has some good articles about MOL and Almaz, too.

GW

Last edited by GW Johnson (2021-07-26 08:26:01)

tahanson43206 · 2021-07-18 10:39:18

For GW Johnson re #1326

SearchTerm:History of mach flight testing
SearchTerm:Mach flight testing history of
SearchTerm:X15 X-15 X-1 X-2

Note highlight of "all moving tail" design for supersonic flight

(th)

louis · 2021-07-19 18:33:43

First successful static fire of the booster. No major issues.

https://www.youtube.com/watch?v=_Cl5wrUffk0

louis · 2021-07-20 13:29:12

Felix's latest outlining Space X's recent stunning successes with the Booster and various developments at Boca Chica.

https://www.youtube.com/watch?v=uG0PcWpDb7E

Last edited by louis (2021-07-20 13:33:31)

SpaceNut · 2021-07-20 22:18:02

The raptor engine for stage 1 will need to run for more than 10 minutes as it pushes starship on the path towards orbit. These engines after many attempts may need longer test stand testing before selecting the units to go into the stage assembly.
There is not going to be much room for error or for a bad engine since the mass being moved to orbit is so great.

louis · 2021-07-21 16:40:17

Presumably the first orbital test would have only a very light "payload"?

SpaceNut wrote:

The raptor engine for stage 1 will need to run for more than 10 minutes as it pushes starship on the path towards orbit. These engines after many attempts may need longer test stand testing before selecting the units to go into the stage assembly.
There is not going to be much room for error or for a bad engine since the mass being moved to orbit is so great.

tahanson43206 · 2021-07-21 17:51:22

We're in Starship is Go... topic, so I'll toss out a request for anyone who might come across a report on how the "great tower" controversy is playing out.

If Elon could be trusted not to launch from the tower, I'd be in favor of letting him try stacking. However, I would NOT be surprised if no one trusts Elon to restrain himself if he gets the tower built. Besides, his engineers can use computer modeling to test stacking, so the need for physical testing is less than it might have been in the early days of rocket development.

(th)

louis · 2021-07-21 18:30:28

Not sure I am following your train of thought there.

As far as I understand it, the choice is between a launch from Boca Chica (ie from the tower) and a launch from a sea platform. The FAA has not yet approved a launch from Boca Chica.

That's my understanding as of now.

What do you mean by "stacking".

I may well have this wrong but I understand there is a test platform for static fire tests.

tahanson43206 wrote:

We're in Starship is Go... topic, so I'll toss out a request for anyone who might come across a report on how the "great tower" controversy is playing out.
If Elon could be trusted not to launch from the tower, I'd be in favor of letting him try stacking. However, I would NOT be surprised if no one trusts Elon to restrain himself if he gets the tower built. Besides, his engineers can use computer modeling to test stacking, so the need for physical testing is less than it might have been in the early days of rocket development.
(th)

tahanson43206 · 2021-07-21 19:40:03

For Louis re #1333

Thanks for your question ... In a post a few days back, it was reported that a request had been given to SpaceX to delay completion of the launch tower at the Texas onshore location, pending completion of an environmental impact review. Someone (and at this point I no longer recall who) suggested the problem might have to to with doubt that Mr. Musk would restrain himself from launching if he had a tower available.

The same post (if I'm remembering ir correctly) stated that SpaceX claimed they only wanted the tower to practice stacking the Starship on top of the Super Heavy booster. According to the report (that I am vaguely remembering) US officials did not believe the claims by SpaceX because they were reported to have in their possession copies of documents (electronic?) indicating that a launch was to be attempted.

You're right that the off shore location has fewer risks, but (as I remember the situation) those two platforms will not be ready any time soon, and Mr. Musk had already announced plans to launch a Starship to Hawaii. That could ** only ** have happened if the Texas onshore tower were ready.

If you run across any additional details, I'd definitely be interested in seeing them.

(th)

SpaceNut · 2021-07-21 20:40:48

here is the BFR starship booster stage topic

louis · 2021-07-22 04:58:39

I remember as a child collecting bubble gum cards with the X-15 series being one of the featured craft and my favourite. They looked sooo cool.

Looking back, I'm not sure what the point of the development programme was, except to keep the Air Force in the space race! It didn't lead anywhere did it?

GW Johnson wrote:

Re TH 1322:
There are a lot of stories about the rocket plane testing. Folks who saw "The Right Stuff" would be aware of the competition between Chuck Yeager in the various versions of the X-1 and Scotty Crossfield in the D-558-2 to be the "fastest man alive". That was less a competition than most would think from the movie.
Douglas Aircraft built the D-558-2. Their company test pilot for it was Bill Bridgeman, who went directly from testing propeller-driven A-1 Skyraiders to rocket plane flight, via a few hours with Tony Levier in a subsonic two-seat F-80 jet (now known as a T-33). Bridgeman flew the D-558-2 to Mach 1.98 before Douglas ever turned it over to NACA and Crossfield, who trained himself to fly it, eventually breaking Mach 2.
It was Bridgeman who identified the necessity of controlling pitch with the trim control that moved the horizontal stabilizer, because the elevator was "washed out" in the wake created by the shock waves at its hinge line. That's how both he and Crossfield were forced to fly the craft on its missions.
Yeager's near-death experience in the X-1 was not in the original X-1, but in the larger X-1A with the bubble canopy. He tumbled out of the sky at almost Mach 2.5 in it. Later versions addressed the problems, with Mach 2.5 safely reached in the X-1E.
The original X-1 had both elevators and a large-motion pitch trim that moved the stabilizer. It did not break the sound barrier using elevators for pitch control, it used the trim. The later versions had the "all moving tail" horizontal stabilizer design typical of all supersonic jets today.
In 1947, the all-moving tail concept was a military secret that went into the design of the F-86, which gave it supersonic dive capability that its opponent in Korea, the Mig-15, did not have. Yeager nearly got himself killed flight-testing a captured Mig-15 over Okinawa about 1951 or 1952, reaching Mach 0.94 in the dive. About 1960, he was part of a tour of aviation types in Russia. The Russians were astonished he survived a near-sonic dive in the Mig-15. None of their test pilots had survived it.
It was the X-2 that finally reached above 70,000 feet and above Mach 3. The original version had too small a vertical fin for adequate supersonic stability in the thin air. Mel Apt died because of that, attempting a Mach 3 turn at about 70,000 feet. I've seen the cockpit camera footage of that. Later versions had a larger fin, and could do the missions without losing control.
That's the rocket plane work that fed into the X-15 program. It rolled out in 1958, I remember the Walter Cronkite news story on the TV about that roll-out. They got started with 4 little engines, then the big XLR-99 engine became available about 1960 or 1961. That's when it busted past Mach 4 and past 50 miles altitude. With the drop tanks, it busted past Mach 6. There were 199 flights of the 3 birds, with one fatal crash. Several X-15 pilots took the bird above 50 miles, earning astronaut wings in it. Neil Armstrong was one of them.
GW

GW Johnson · 2021-07-22 08:28:46

Louis:

Actually, the X-15 tests gave us most of what we now know of hypersonic heat transfer and heat transfer in very thin air. That enabled the SR-71 Mach 3 spy plane, and fed directly into the heat shields of Apollo and the Space Shuttle, and now into Musk's Starship. And it helped enable the X-43A and X-51A scramjet tests.

We learned a lot from its XLR-99 engine about burning ammonia with liquid oxygen, ammonia being a dense candidate hydrogen supply. You'll note that nobody uses that combination any more. Both kerosene and methane are better, more practical, less toxic dense sources of hydrogen.

We learned a lot about hypersonic aerodynamics and hypersonic flight vehicle mechanics from the X-15. That went directly into the SR-71 Mach 3 spy plane, the XB-70 Mach 3 bomber, the Space Shuttle, the two scramjet test vehicles, and is even now a part of the knowledge base supporting Musk's Starship.

There would be no computational fluid mechanics capability with experimentally-verified codes without the X-15 data.

Shall I go on?

GW

tahanson43206 · 2021-07-22 10:22:50

For GW Johnson re #1337

Yes, if there is more of this important history you have time to share, please do !!!

However, as a favor to future searchers, please do as you have done once before, and edit the original post.

I'll create a set of tags to help future searchers, but it would be best if they could go to a single post instead of multiple.

I've said this before ... I think that Louis' major (and significant) contribution to this forum is to create incentive for more knowledgeable members to do some of their best writing.

In doing so, Louis is serving those who will come along later, if we (members) can help with searches.

I'll try here ...

SearchTerm:X-15 history and significance
SearchTerm:X15

(th)

louis · 2021-07-23 15:02:16

Latest from Felix, informative as ever...

https://www.youtube.com/watch?v=jWn1yLYjY2w

kbd512 · 2021-07-23 15:27:31

Louis,

If memory serves, the X-15 required a rather sophisticated computer-controlled stability-augmenting adaptive flight control system above Mach 3 or so. That system was the forerunner of all modern hypersonic flight control systems, as the pilot had actual control over his vehicle, with the help of a computer, rather than simply being guided through a ballistic trajectory or arc back to Earth. Specifically, they performed reentry type maneuvers from high altitude. I consider that pretty significant. X-15 also tested how heat shield material ablation would alter vehicle aerodynamics and control responses with respect to its nominal shape-driven flight characteristics.

Have a read, it's really interesting stuff if you're into aerodynamics and control systems:

Experience with the X-15 Adaptive Flight Control System

GW Johnson · 2021-07-24 09:49:25

That was a nifty document, Kbd512! Thanks. I saved a pdf copy for myself.

The most pertinent comment was in the pilots' evaluation appendix towards the end. It said the control system freed them up to do the real work while flying into space, all of which was done at exit speeds well above Mach 4. There was a flight envelope altitude vs velocity plot in the document that showed everywhere the bird had ever flown. Remarkable plot.

This sort of self-adaptive control fed directly into the control that was developed for the Space Shuttle, I feel sure. It worked too well not to.

GW

Last edited by GW Johnson (2021-07-24 09:50:00)

GW Johnson · 2021-07-25 12:57:50

Following TH's request, I have updated my original post about the rocket plane program that culminated in the X-15. I corrected some mnor errors, and added some extra detail. That would be post 1326 above.

Back to thread topic: I have heard nothing about any progress Spacex might have made toward getting approval to fly a Superheavy out of Boca Chica.

GW

Last edited by GW Johnson (2021-07-25 12:59:32)

kbd512 · 2021-07-25 16:44:31

GW,

I thought you might like that. One of my aviation-related interests is "how it all began". For computerized control over crewed American aerospace vehicles, as near I can tell it started with the F-101 and X-15, many moons ago. There were various test systems carried about US aircraft as far back as WWII, even further back for drones. However, the F-101 and X-15, to my knowledge, were the first aerospace vehicles that absolutely required a stability augmentation system that worked both with and independently of pilot input in order to make the machine flyable, meaning if the control augmentation system didn't work, then the machine wasn't controllable. The X-15's flight control system was an important milestone for the development of stability augmentation systems.

GW Johnson · 2021-07-25 17:12:52

Kbd512:

The very first one was the stability augmentation system for the YB-49 flying wing bomber back in 1946. That was the very first one. It was less about basic controllability (although the XB-35 crash showed there were controllability issues with flying wings), and more about bomb dispersal patterns. There was a shimmy that scattered the bombs, until it was damped by the very first stability augmentation system that ever was.

The XB-35 crash killed test pilot Glenn Edwards. The test flight base Muroc Dry Lake was renamed Edwards Air Force Base in his memory.

I never got to see any B-49's (the jet version of the flying wing bomber). They had all been scrapped by then. But I did get to see three examples of the XB-35 (the propeller-driven version of the flying wing bomber). They looked like big bats on spindly legs, across the field at what eventually became LAX.

When I saw those, I also saw B-17's with lifeboats under their bellies, flying with the coastal rescue command. The F-100 was just entering service for the very first time. And the X-1 and D-558-2 were flying. The X-2 was yet to come.

GW

Last edited by GW Johnson (2021-07-25 17:18:13)

kbd512 · 2021-07-25 18:48:30

GW,

I would've loved to have been there to see that. I often feel as though I was born at the wrong point in time in history. I don't recognize this world I'm now living in. It's nothing like it was when I grew up in the 1980s.

louis · 2021-07-27 13:50:31

Felix says Space X is working in a frenzy to get BN4 and SN20 to the launch mount by 5 August! Brilliant news. Could indicate a realistic mid August orbital launch attempt.

https://www.youtube.com/watch?v=eawzWLelqaM

louis · 2021-08-02 14:15:07

Felix's latest explaining the incredible rate of progress at Boca Chica as Space X drives towards the first orbital launch...

https://www.youtube.com/watch?v=nP6YdTgA4FM

My interpretation of all this is that a September launch is a distinct possibility assuming Space X can get FAA permission.

RobertDyck · 2021-08-02 16:55:32

Space.com: SpaceX installs 29 engines on giant Super Heavy Mars rocket (photos)

"Installing Starship booster engines for first orbital flight," SpaceX founder and CEO Elon Musk said via Twitter yesterday (Aug. 1) in a post that included a photo of the rocket, with himself holding his young son nearby. And today (Aug. 2), Musk tweeted a close-up photo of Super Heavy's base, which is now bristling with Raptor engines.

Oldfart1939 · 2021-08-02 17:09:24

The difference between Musk and Bezos is level of commitment and being there on site.

RobertDyck · 2021-08-02 20:07:44

Excruciatingly slow real-time installation of orbital launch table:
YouTube: Lift, Part 1/5, Orbital Launch Table, SpaceX Starbase, Boca Chica, TX. July 31, 2021. Nikon P1000.
Part 2/5
Part 3/5
Part 4/5
Part 5/5

Same thing from NASASpaceFlight. Video from farther, 18 minutes
Orbital Launch Table Lifted Onto Mount - Grid Fin Installed on Super Heavy B4 | SpaceX Boca Chica

New Mars Forums

Announcement

#1326 2021-07-18 09:09:47

Re: Starship is Go...

#1327 2021-07-18 10:39:18

Re: Starship is Go...

#1328 2021-07-19 18:33:43

Re: Starship is Go...

#1329 2021-07-20 13:29:12

Re: Starship is Go...

#1330 2021-07-20 22:18:02

Re: Starship is Go...

#1331 2021-07-21 16:40:17

Re: Starship is Go...

#1332 2021-07-21 17:51:22

Re: Starship is Go...

#1333 2021-07-21 18:30:28

Re: Starship is Go...

#1334 2021-07-21 19:40:03

Re: Starship is Go...

#1335 2021-07-21 20:40:48

Re: Starship is Go...

#1336 2021-07-22 04:58:39

Re: Starship is Go...

#1337 2021-07-22 08:28:46

Re: Starship is Go...

#1338 2021-07-22 10:22:50

Re: Starship is Go...

#1339 2021-07-23 15:02:16

Re: Starship is Go...

#1340 2021-07-23 15:27:31

Re: Starship is Go...

#1341 2021-07-24 09:49:25

Re: Starship is Go...

#1342 2021-07-25 12:57:50

Re: Starship is Go...

#1343 2021-07-25 16:44:31

Re: Starship is Go...

#1344 2021-07-25 17:12:52

Re: Starship is Go...

#1345 2021-07-25 18:48:30

Re: Starship is Go...

#1346 2021-07-27 13:50:31

Re: Starship is Go...

#1347 2021-08-02 14:15:07

Re: Starship is Go...

#1348 2021-08-02 16:55:32

Re: Starship is Go...

#1349 2021-08-02 17:09:24

Re: Starship is Go...

#1350 2021-08-02 20:07:44

Re: Starship is Go...

Board footer