7 ms·
F-1 Thrust Chamber
- WalterBright 8y agoUsing the fuel to both cool the nozzle and pre-heat the fuel is just genius. (The method first appeared on the V2.)
- benj111 8y agoConcorde used fuel as a coolant also, not to cool the jet nozzle, but ancillary things. http://www.concordesst.com/fuelsys.html http://www.concordesst.com/fuelsys.html
- lultimouomo 8y agoThe SR-71 used it to cool its skin and keep it around 300°C during Mach-3 flight. It also used it to cool its engines.
- benj111 8y agoIsn't it also the SR-71 that has to expand to become fuel tight, and so leaks fuel all over the runway at takeoff.
- enriquto 8y agoI wonder how do this kind of crazy engineering ideas happen. What is gained by not making the thing fuel tight unconditionally? Leaking fuel at takeoff sounds extremely dangerous!
- benj111 8y agoExpansion due to heat, the GP mentions a temperature of 300c. Edit to add: Different materials expand by different amounts due to heat, and different parts of the aircraft are reaching different temperatures. If you know all the bits are going to expand x amount in normal flight, then you work back to what size they are when cold, if the shrinkage/expansion is too great you possibly could go with a different material (with various tradeoffs) or you just accept the shrinkage as they did here.
- sitharus 8y agoIt also helps that the SR-71 fuel was almost impossible to ignite. It couldn’t be spark ignited, instead they used triethylborane, an pyrophoric liquid that burns in contact with air. It’s also used to ignite rocket engines as its reactive enough to burn on contact with liquid oxygen.
- benj111 8y ago"almost impossible to ignite" .... "pyrophoric liquid that burns in contact with air" Those seem mutually exclusive? Do you mean that triethylborane ignites the fuel?
- benj111 8y agoI don't know why I'm getting down votes for this, its a reasonable question. To answer my own question triethylborane is indeed used to ignite the main fuel. https://www.quora.com/Why-was-Triethylborane-used-as-a-starter-fuel-for-the-SR-71-Blackbirds https://www.quora.com/Why-was-Triethylborane-used-as-a-start...
- refurb 8y agoYou’re getting downvoted because you’re calling out an inconsistency that doesn’t exist. The fuel that doesn’t burn is separate from the pyrophoroc stuff used to start it.
- wtallis 8y ago> Leaking fuel at takeoff sounds extremely dangerous! The fuel that was used had to withstand fairly extreme conditions before reaching the engine to be burned, which also made it pretty hard to ignite under ordinary conditions. https://en.wikipedia.org/wiki/JP-7 https://en.wikipedia.org/wiki/JP-7
- deleted 8y ago[deleted]
- frostburg 8y agoIt's lighter and you're inherently accommodating for thermal expansion that would happen anyway and possibly cause issues.
- hyperbovine 8y ago> I wonder how do this kind of crazy engineering ideas happen Three words: the Cold War. See also: Project Sunshine, the Oak Ridge Experiments, SDI, etc. Once you start writing blank checks to the military-industrial complex the crazy ideas start pouring forth.
- refurb 8y agoIf you know everything is going to expand significantly due to heating, I’m sure making it fuel tight at room temperature would involve significant engineering trade offs.
- avmich 8y agoIt's interesting that at the dawn of rocket engines the regenerative cooling was thought to be a bad idea. The reasoning was the hot side will expand too much and disconnect from cool side because of stresses. It's good von Braun actually used one...
- throwaway77384 8y agoIt is!
- twic 8y agoI suppose on a supersonic aircraft, you can't reject heat into the surrounding air, because that's already been heated up too far by your passage through it. Is this technique still in use in supersonic aircraft?
- DuskStar 8y agoThe use of a fuel as a coolant is pretty common in modern high performance aircraft.
- shereadsthenews 8y agoAnd motorcycle engines. Evaporating fuel happens to be a great coolant.
- imglorp 8y agoCool. Any examples or details?
- shereadsthenews 8y agoMost “v” block engines even if they are liquid-cooled direct more fuel to the rear cylinder(s) to cool the head, either with larger carburetor jets in older engines or with software in newer ones. If you think about it all ICE are cooled by fuel; if you fed them with boiled fuel they would overheat.
- benj111 8y ago"if you fed them with boiled fuel they would overheat" It isn't clear to me that they would. I suppose if your cooling system was highly optimised the extra energy could tip the balance, or is that what you're saying? But then all ic engines would be cooled by their fuel, its kind of inherent to the process.
- mrfusion 8y agoThe new raptor engine actually passes all the fuel and o2 through preburners to vaporize it. Pretty ingenious.
- ncmncm 8y agoI am finding it astonishing that they could construct them at all, never mind get them to work and not explode. There is a great deal of this in modern life that we successfully ignore until management failure makes it unmaintainable any more.
- enriquto 8y ago> ... and not explode. But it does explode! It's just that the all the explosion power is arranged to go in the same direction
- deflagrate 8y agoUh, well, more to the point, the propellant does not instantaneously go off as a single, entire quantity, expending all potential energy in the blink of an eye. Does a person need to clarify this point, in order to convey intended meaning in this context?
- amelius 8y agoThings explode in a car engine all the time, so it's not really anything special.
- dsfyu404ed 8y agoIt's more of a gradual thwump that progresses through the combustion area than an explosion, unless it's a diesel.
- bumby 8y agoDetonation in a car engine is bad. What's actually happening in a normally operating engine is deflagration. Deflagration = subsonic combustion Detonation = supersonic combustion When people say "explode" they tend to mean detonation.
- gmueckl 8y agoI don't have any data for the F-1, but the typical high power rocket engines of these days had an explosive temperament that needed to be tamed on the test stands. I recall that the SSME had a tendency to self-disassemble vilently on its test stand due to turbo pump failures that took a long time to solve. Other rocket engines probably were very similar in that regard.
- Todd 8y agoI had a chance to see an F-1 at the Destination Moon exhibit which just opened at the Museum of Flight in Seattle. It is astonishingly large. If you're in the area, or near one of the other (few) locations where they are on display, I would definitely recommend going. https://en.wikipedia.org/wiki/Rocketdyne_F-1#Locations_of_F-1_engines https://en.wikipedia.org/wiki/Rocketdyne_F-1#Locations_of_F-... (The Apollo 11 command module is there, too!)
- mikejb 8y ago> The Apollo 11 command module is there, too Temporarily though. Normally it's exhibited at the Smithsonian in Washington DC (Which is also absolutely worth a visit).
- marvin 8y agoThis is excellent information. I'm headed to Seattle from Norway in May, and will definitely take the opportunity to check this out :D
- mcguire 8y agoIf anyone's near Huntsville, AL, the Space and Rocket Center has stacks of stuff for your gawking pleasure. Although I think the only F-1 you can go up and rub on is outside the MSFC main building, which you wouldn't get to unless you take a MSFC tour.
- iClaudiusX 8y agoHere is 500 fps film of the Saturn V launch for Apollo 11, narrated by Mark Gray. It explains the sequence of events over the course of 8+ minutes (30 seconds real time). https://www.youtube.com/watch?v=DKtVpvzUF1Y https://www.youtube.com/watch?v=DKtVpvzUF1Y
- mywacaday 8y agoThanks for that, great video that led me to this, https://www.youtube.com/watch?v=ImoQqNyRL8Y https://www.youtube.com/watch?v=ImoQqNyRL8Y, sound recording organised by Dustin from SmarterEveryDay of the latest SpaceX launch, the sonic booms of the boosters coming into land are amazing, listen with headphones!
- tim333 8y agoCool. Shame they couldn't have a microphone by the landing site so the sound comes at the same time as the landing - maybe on a future one.
- mikejb 8y agoJust as a Side-note: that video is from the Falcon Heavy demo launch last year. The recent launch was the first commercial Falcon Heavy launch (Arabsat 6a)
- tigeba 8y agoA portion of flown engine #5 from the Apollo 11 mission on display at the Kansas Cosmosphere and Space Center. It was retrieved in 2013 put on display in 2015.
- Iv 8y agoA similar design (the space shuttle main engine) brought me some peace of mind at work one day. Nowadays, I do deep learning for a living, before that I was doing computer vision. One day I am really pissed off at some compiling issue, with a parallel code and I am like "fuck this, this is a plumbing issue! I should spend my time on algorithms and shit. Not on ordering the damn bytes of the raw pixels. I have done that for years, that should be a solved problem by now." I go on reddit for some well-deserved outrage-slacking and stumble on the shuttle engine. "Yeah, that's what I am talking about. Now that is engineering." Then I realized it is basically a maze of pipes and pumps. Uh, yeah, 95% of plumbing (and some metallurgy feats as well). Ok, back to coding my data pipelines then...
- mrec 8y ago"Aerospace is plumbing with the volume turned up" -- John Carmack
- delibes 8y agoI think somewhere in this sci.space archive of rocketry usenet wonders is a quote along the lines of "Rocket science is just extreme plumbing". Cryogenics with powerful oxidizers is hard! https://yarchive.net/space/index.html https://yarchive.net/space/index.html
- 00N8 8y ago"All engineering is plumbing - some fields just manage to avoid working on broken sinks & toilets" -anonymous
- mrec 8y agoEven the arts aren't necessarily safe. A story told by the composer Philip Glass in 2011: > While working, I suddenly heard a noise and looked up to find Robert Hughes, the art critic of Time magazine, staring at me in disbelief. ‘But you’re Philip Glass! What are you doing here?’ It was obvious that I was installing his dishwasher and I told him I would soon be finished. ‘But you are an artist,’ he protested. I explained that I was an artist but that I was sometimes a plumber as well and that he should go away and let me finish.
- sandworm101 8y agoWhat I find most amazing about these engines isn't the complexity but rather that they operated successfully despite multiple errors. We are often told that a single failure will destroy the craft, but that really wasn't the case. Shuttle make it to orbit with multiple cracked tubes in one engine. Some bits from the recovered F-1s show clear manufacturing errors. Building something that will work at these energy levels is hard, but creating something that can survive multiple random failures and still keep ticking is spectacular.
- avmich 8y agoThis engine is still outstanding - after all these years - for the thrust per single chamber it achieves. May be only the RD-270 approached similar value for the parameter. Which is not the most important parameter, but not an insignificant one as well.
- boyd 8y agoThe performance and track record of these engines is even more impressive when you realize that all of the design and modeling work was largely done by hand! This is perhaps apocryphal, but I briefly worked with a guy who’d worked on the F-1 engine, and he said they’d use surplus WW2 grenades to simulate distortions/aberrations in the combustion chamber.
- mcguire 8y agoWrapping the turbine exhaust around the fuel return manifold would seem to be counter-productive---exhaust gasses would heat the fuel, reducing its cooling efficiency as it returns to the top of the engine. ...Unless the fuel at that point was already hotter than the turbine exhaust... Rocket engines are weird.
- DuskStar 8y agoThe turbine exhaust forms a barrier between the uncooled portion of the nozzle and the chamber exhaust, which is significantly hotter. It's not colder than the unburned fuel being used for regenerative cooling, but the bottom of the nozzle isn't regeneratively cooled anyways.