Reaction Engines SABRE engine (Skylon Spaceplane)

Byeman said:
Additionally, the premise that "space launcher with aircraft-like operations will be cheaper and safer than vertical takeoff rockets due to their simpler ground facilities, lesser environmental impact and abort capabilities." is not a fact, it is an opinion that doesn't have much support behind it
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The available evidence suggests quite the opposite on all those points. The main issue is that a spaceplane simply won't have "aircraft-like" operations - it's much more like a vertical take-off rocket with wings than an aircraft. And those wings eat payload fraction and hence costs.
 
red admiral said:
The available evidence suggests quite the opposite on all those points. The main issue is that a spaceplane simply won't have "aircraft-like" operations - it's much more like a vertical take-off rocket with wings than an aircraft. And those wings eat payload fraction and hence costs.
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And wings needed for HT are much different than those for HL.
 
publiusr said:
An orbiter is not a 'payload fairing"...feelings hearsay and bias are New Space attributes. I asked you before which you would rather fly in--something that can glide--or something that can't. When the red light comes on--I'd rather my astronauts have options Starship doesn't offer.
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Another aspect that is typically overlooked is that powered vertical landings literally burn engine life and thus impact reusability. A passive structure like a wing typically also poses far fewer failure modes and risks than an active one like a rocket engine.
 
publiusr said:
An orbiter is not a 'payload fairing".
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Yes, orbiters (Shuttle and Buran) with large bays are payload fairings. Crews are not needed for them
publiusr said:
I asked you before which you would rather fly in--something that can glide--or something that can't. When the red light comes on--I'd rather my astronauts have options Starship doesn't offer.
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Starship isn't going to be flying crew for several years and many scores of flights and will be proven. I have flown in helicopters, they don't have wings and gliding is not a given. I rather fly in a capsule than Shuttle or Buran,

publiusr said:
.feelings hearsay and bias are New Space attributes.
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Wrong, look in the mirror. And here:

 
All systems I supported flew better than Starship—it stayed intact (after orbital shots) upon landing…how many times?

At any rate—this is about Skylon—-and the fact remains that air-breathing’s utility in a spaceplane is a more complicated project than an all rocket system that—at most-could have simpler jets so as to not land dead-stick.

Now, we can disagree about whether an Orbiter really needs jets—but they at least are simpler affairs than LACE and such.
 
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publiusr said:
All systems I supported flew better than Starship—it stayed intact (after orbital shots) upon landing…how many times?
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Starships uses flight testing vs ground tests. Starship is doing the same thing as the N1, just cheaper. Don't have to build expensive test stands.

publiusr said:
At any rate—this is about Skylon—-and the fact remains that air-breathing’s utility in a spaceplane is a more complicated project than an all rocket system that—at most-could have simpler jets so as to not land dead-stick.

Now, we can disagree about whether an Orbiter really needs jets—but they at least are simpler affairs than LACE and such.
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With modern avionics, there is no situation where jet engines would help. A go around is just not feasible.
 
red admiral said:
And even if it worked they'd soon go out of business because existing rockets have multiple times cheaper cost /kg to orbit
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Byeman said:
You blindly champion it because you don't understand the business aspect of spaceflight. It is no longer performance based or coolness faction. Launch vehicle systems that make it is because they are cheaper or more efficient than others. It is already proven that there is no reason to fly a crew on a payload deployment missions. There is no reason to use an uncrewed orbiter type vehicle as a payload fairing. For the foreseeable future, there is no need to return large volume payloads back to earth or to fly large amounts of people into orbit. Capsule or small spaceplanes like Dreamchaser will suffice. Starships with large compliments of passengers is years and years away if ever.
Also, it has been shown that spaceplanes returning from space do not need jet engines. They only add mass and complexity and do not increase safety. If something go wrong during a return, jet engines aren't going to help.
Additionally, the premise that "space launcher with aircraft-like operations will be cheaper and safer than vertical takeoff rockets due to their simpler ground facilities, lesser environmental impact and abort capabilities." is not a fact, it is an opinion that doesn't have much support behind it.
You need to provided data to back up your claims instead of hearsay, feelings and bias,
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red admiral said:
The available evidence suggests quite the opposite on all those points. The main issue is that a spaceplane simply won't have "aircraft-like" operations - it's much more like a vertical take-off rocket with wings than an aircraft. And those wings eat payload fraction and hence costs.
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That a horizontal-takeoff-and-landing, partially-air-breathing SSTO spaceplane will be impractical into the indefinite future is indeed today's conventional wisdom, Red admiral and Byeman. But as you will remember, it was just a few years ago that conventional wisdom told us a reusable VTOL rocket launcher is impractical, because "the dead mass of landing gear and extra propellant means that this will never be competitive with expendable launchers—and a reusable rocket motor would mean that only one would be constructed every year or two: unrealistic!" The Ariane 6 design team and their political masters smirked in the early 2010s. They are not smirking today. Yes, the X-30 was a bridge too far for late-20th-century technology; and the Skylon spaceplane might not have worked, even with a lavish budget. But I suggest you and others join the chastened Ariane staff in having more humility about "it has been shown" and "available evidence", and have a greater openness to what tomorrow might bring, especially from minds not beholden to conventional wisdom. Details are of course arguable, but for myself, and while wishing SpaceX all the best, I stand with Richard Varvill's overall vision. We'll see.
 
Owens Z said:
That a horizontal-takeoff-and-landing, partially-air-breathing SSTO spaceplane will be impractical into the indefinite future is indeed today's conventional wisdom, Red admiral and Byeman. But as you will remember, it was just a few years ago that conventional wisdom told us a reusable VTOL rocket launcher is impractical, because "the dead mass of landing gear and extra propellant means that this will never be competitive with expendable launchers—and a reusable rocket motor would mean that only one would be constructed every year or two: unrealistic!" The Ariane 6 design team and their political masters smirked in the early 2010s. They are not smirking today. Yes, the X-30 was a bridge too far for late-20th-century technology; and the Skylon spaceplane might not have worked, even with a lavish budget. But I suggest you and others join the chastened Ariane staff in having more humility about "it has been shown" and "available evidence", and have a greater openness to what tomorrow might bring, especially from minds not beholden to conventional wisdom. Details are of course arguable, but for myself, and while wishing SpaceX all the best, I stand with Richard Varvill's overall vision. We'll see.
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Even if X-30 or Skylon worked, it doesn't mean that they would have aircraft-like operations or would be cheaper and safer.
 
Bizarre

At about the same time as HOTOL or early Skylon then the USA was demonstrating reusable rocket vertical landing with DC-X at a reasonable scale. The next new US rockets incorporated reusability and VL. And now the rest of the world is following.

Simple thing with HL is that wings eat payload mass. The technical challenge is isn't particularly "new" as it's "simply" about making light enough structure. But this technology hasn't developed much further since the 80s. And if it did, you can likely apply it to a VL rocket as well to get similar gains...

If we want to think about technology that doesn't exist then I'll have a space elevator instead
 
Regardless of whether HL or VL is theoretically best, the ideal solution has to involve some form of SSTO for cost and simplicity purposes. Once an appropriate cycle of technology evolution and maturity has passed of course.

Unless someone invents a viable material to build an orbital elevator...
 
scautomoton said:
Regardless of whether HL or VL is theoretically best, the ideal solution has to involve some form of SSTO for cost and simplicity purposes. Once an appropriate cycle of technology evolution and maturity has passed of course.
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It sounds obvious that SSTO will be lower cost and simpler but it's actually the opposite. TSTO is much simpler which drives lower up front development costs in particular. Then the higher payload fraction to orbit drives lower costs per kg.

It's difficult to see what technology advancement can only be applied to SSTO rather than TSTO.
 
red admiral said:
It sounds obvious that SSTO will be lower cost and simpler but it's actually the opposite. TSTO is much simpler which drives lower up front development costs in particular. Then the higher payload fraction to orbit drives lower costs per kg.

It's difficult to see what technology advancement can only be applied to SSTO rather than TSTO.
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The only thing that dictates multi-STO is the propulsion technology we currently have available. Imagine that some day soon someone invents something that outstrips chemical rocket propulsion significantly, both in terms of energy density, specific impulse, fuel mass required etc etc and thus making SSTO viable. At that point why would anyone choose TSTO? You can get rid of all the wastage, collection of spent stages (and all the associated costs), etc. I appreciate there's far more to it, but its just a few short steps from Concorde. Difficult to maintain, yes. Expensive, yes. Technically difficult, hell yes. A genuine step forward, yes. Will costs come down with technology maturity and development, of course.

I think ultimately, its like any new tech. Its expensive and unattainable with no viable business case until someone makes it work for the first time, Plus there's always the lobbying (and underhandedness) from the people with vested interests in the status quo who have a monopoly. Once its proven to work however, then everyone wants to jump on the bandwagon. Take Tesla and SpaceX. Everyone expected them to fail because the tech was impossible, or too expensive, with no support network. And look at them now, and look at all their competitors struggling to keep up with change (I'm not in anyway an Elon fanboy btw, I think he's a cretin).
 
In the introduction to that marvellous HOTOL book, our vey own @newsdeskdan quotes Alan Bond. Who said "Earth is just 10% too big for SSTO." Which echoes the Great DOGE a-hole past statement when he still had a brain "Earth is wrong planet for SSTO. On Mars : no problem." (indeed: 5000 m/s orbital velocity).

Orbital velocity of a celestial body is determined by its size, mass, and density (plus the atmosphere, if any). With Earth, we were gifted the biggest rocky body in the entire Solar System. Even swapping for Venus (not the atmosphere, God forbidd - just the rocky body) would help - 10% smaller and 25% less dense, makes orbital velocity in the 7200 m/s range. Of course the atmosphere completely ruins that.

A case could be made than even with hydrolox all-time record of 466 seconds specific impulse, all-rocket SSTO are on their (propellant mass fraction) knees past 7000 m/s - when Earth mandates 9000 m/s. That's the rub.
Also LOX being almost 80% of an all-rocket SSTO takeoff weight. That's another rub.

Aerospace-plane (1958-1964) identified "air collection" and scramjet as... realistic (?) ways to suck atmospheric air and burn the 21% oxygen inside.
And... we have been stuck there ever since : 70 years later.
Guess why staging is still going strongly, expendable or reusable ? its the cheapest, most efficient trick on hand. Tsiolkovsky smart trick.
 
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scautomoton said:
The only thing that dictates multi-STO is the propulsion technology we currently have available. Imagine that some day soon someone invents something that outstrips chemical rocket propulsion significantly, both in terms of energy density, specific impulse, fuel mass required etc etc and thus making SSTO viable. At that point why would anyone choose TSTO?
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Duh, nobody is arguing that. All this talk is wrt chemical propulsion. If what you state happens, then more than just space launch changes. Air vehicles in general and in space maneuvering changes drastically (short transit times).
 
Byeman said:
Duh, nobody is arguing that. All this talk is wrt chemical propulsion. If what you state happens, then more than just space launch changes. Air vehicles in general and in space maneuvering changes drastically (short transit times).
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I find that using childish language when in a discussion with your peers tends to reduce their opinion of your intelligence. And there I was thinking this forum was a place for mutual respect. I think I was about twelve the last time I belittled someone using"duh".

Nevertheless, the thread isn't entirely about the propulsive method used. There are plenty of valid comments regarding ground operations and operating costs. All of which, with mature technology on a like for like basis, should be simpler and cheaper for a single stage vehicle simply because there should be less overall work to do.

If the shuttle hasn't been so manually laborious with regards the tiles then I suspect a reusable space plane would be more favourably looked upon as a launch system design choice. Similarly, if the tech used in the X-33 Venturestar hadn't been so immature it might have worked. With modern composite tech and metallurgy I suspect it could today.
 
scautomoton said:
With modern composite tech and metallurgy I suspect it could today.
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I've been thinking about this point recently with going through the HOTOL book. We're used to technology advancing as a general principle, but in some areas it doesn't change that much. e.g. I'm not sure anything has significantly changed for spacecraft structures from the 80s. Nothing like say a 20% mass reduction....
Archibald said:
Aerospace-plane (1958-1964) identified "air collection" and scramjet as... realistic (?) ways to suck atmospheric air and burn the 21% oxygen inside.
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These concepts can produce concepts with lower take-off mass than conventional rockets from reduced fuel burn. But fuel is "cheap" and the air collection and wings etc. add quite a lot extra to the empty mass - which is the expensive bit. At some point you go full rocket and have negligible drag so this extra empty mass hurts in this phase.
 
red admiral said:
. I'm not sure anything has significantly changed for spacecraft structures from the 80s. Nothing like say a 20% mass reduction....
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CFRP tech was still reasonably immature in the 90s . Certainly for the likes of lightweight pressure vessel design which is what really doomed the X-33. Now consider that the 787 has a CFRP fuselage and when that entered service. So the tech has come a long way, but has taken a long time to achieve the performance necessary. Plus think of all the myriad other small improvements to other technologies that would no doubt be used. Continued shrinking of electronic components, HMI replaced with touchscreens etc. imagine what 30 years continued high investment into aerospikes might have led to.

I know we can't say for sure without repeating all the design and development. But I strongly suspect we're at least on the cusp of being able to deliver an X-33-alike these days.
 
scautomoton said:
I know we can't say for sure without repeating all the design and development. But I strongly suspect we're at least on the cusp of being able to deliver an X-33-alike these days.
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No, not with chemical propulsion. It isn't ground operations and operating costs. The rocket equation says no. Can't get a mass fraction that makes an SSTO with a"viable" payload much less a reusable one. Once you start adding mass to allow for reusability, the mass fraction goes to crap.
 
Byeman said:
Once you start adding mass to allow for reusability, the mass fraction goes to crap.
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Thus my support for wet workshops.

Only put TPS on high value items--leave the rest of the tankage in orbit as floor space. Turn a disadvantage into an advantage.

SSTO spaceplanes are about as likely as spindizzies--Giant TSTO craft like Starship may have more tile headaches than shuttle and more plumbing than Manhattan Island.

The laws of physics seem to smile widest upon stage-and-a-half schemas.

If SSTOs ever do become real--it will likely come from a microgravity materials breakthrough that can only come from embracing space manufacturing first and more futuristic types of RLVs later.

The notion that RLVs must come before space manufacturing is nothing but an idee fixe.
 
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publiusr said:
Thus my support for wet workshops.

Only put TPS on high value items--leave the rest of the tankage in orbit as floor space. Turn a disadvantage into an advantage.
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Nope, Wet workshops are worse.
a. don't need that many
b. it doesn't work. the launcher can't do its primary mission. There is no in-between. It is either a fully functional stage or a fully functional station.

publiusr said:
SGiant TSTO craft like Starship may have more tile headaches than shuttle and more plumbing than Manhattan Island.
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There is nothing that supports that claim. No engineering or data but again "hearsay, feelings and bias,"
publiusr said:
The laws of physics seem to smile widest upon stage-and-a-half schemas.
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again, no engineering or data to back that claim.
publiusr said:
If SSTOs ever do become real--it will likely come from a microgravity materials breakthrough that can only come from embracing space manufacturing first and more futuristic types of RLVs later.
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Wrong, there is no realistic material (other than unobtainium) that can help
publiusr said:
The notion that RLVs must come before space manufacturing is nothing but an idee fixe.
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That is so wrong. it is just silly to even say. it is just being a pointless contrarian.
Cost is what is preventing it. The lack of low cost transportation is the largest hinderance to space manufacturing and even research. This is a fact and not an opinion. For space manufacturing to work, it has to be able to make ROI and lower (transportation) costs will help. Falcon 9 and Starlink isn an example of what lowering transportation cost can enabling.
 
publiusr said:
At any rate—this is about Skylon—-and the fact remains that air-breathing’s utility in a spaceplane is a more complicated project than an all rocket system that—at most-could have simpler jets so as to not land dead-stick.

Now, we can disagree about whether an Orbiter really needs jets—but they at least are simpler affairs than LACE and such.
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wrong, there is no need for any propulsion upon entry. With current avionics, there is no scenario where engines are needed. It is impossible to have a velocity shortfall without an avionics failure and the same failure would prevent engines from helping. There is no capability for a go around. Wings and fuel load prevent that.

Dead stick hasn't failed.
 
scautomoton said:
CFRP tech was still reasonably immature in the 90s . Certainly for the likes of lightweight pressure vessel design which is what really doomed the X-33. Now consider that the 787 has a CFRP fuselage and when that entered service. So the tech has come a long way, but has taken a long time to achieve the performance necessary.
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I agree there's been advancement on the CFRP side, but this isn't really making it lighter. It's more been about manufacturability, repeatability, robustness etc. Reality has turned out quite different to the predicted 15-20% savings back in the 80s.

On the avionics side then the advancement is clearer, but generally people have used the increased processing power available to do more processing. The mass fraction is very low compared to structure or engines.
 
Deepstuck said:
...I'm not sure if there's been a confirmation on the engine including a pre-cooler, but that would be interesting given how both RR and BAE invested in Reaction Engines with the pre-cooler part of the SABRE engine being one of the only successes before they went bankrupt last year.
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djpowell1984 said:
...That's why i curious about pre-cooler too. be frankly, I'm not sure if it (pre-cooler) is useful as most multi-role aircraft are limited to 2.2-2.3 machs (due to skin rub fracture temperature affecting metal melt and weakening metal by heat even sonic speed pressure.
Or increase weight by pre-cooler to help the engine run better (even pre-cooler would help increase fuel effective and produce more power, as it can reduce heat and require less maintenance to the engine), yet the penalty is a weight increase and cost to build a pre-cooler...
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Yes, interesting that the UK/Japan/Italy 'Global Combat Air Programme' for a next-generation fighter plane might be considering including a precooler at the front of each jet engine. Precooled turbojets have been studied in Japan since the 1980s. The UK planned a 2019-21 ground test project to add one of Reaction Engine Ltd's helium precoolers to the intake of a EJ200 low-bypass turbofan, as used in the Eurofighter Typhoon. The project apparently was fully funded, but never happened for unknown reasons. Back in 2019 there were hints from RAF officials that, assuming the test project was successful, they would be interested in adding Reaction precoolers to many or all of the RAF's Typhoons, for higher performance. That fell through, but maybe the GCAP could benefit from Reaction Engine Ltd tech. Of course, precoolers necessarily cost money, and add mass.
 
Owens Z said:
Yes, interesting that the UK/Japan/Italy 'Global Combat Air Programme' for a next-generation fighter plane might be considering including a precooler at the front of each jet engine. Precooled turbojets have been studied in Japan since the 1980s. The UK planned a 2019-21 ground test project to add one of Reaction Engine Ltd's helium precoolers to the intake of a EJ200 low-bypass turbofan, as used in the Eurofighter Typhoon. The project apparently was fully funded, but never happened for unknown reasons. Back in 2019 there were hints from RAF officials that, assuming the test project was successful, they would be interested in adding Reaction precoolers to many or all of the RAF's Typhoons, for higher performance. That fell through, but maybe the GCAP could benefit from Reaction Engine Ltd tech. Of course, precoolers necessarily cost money, and add mass.
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I'm hear same story about success project test - but somehow not information much also news about it as I was high expectation Reaction Engine go successfully, somehow it is become suspire failed, I'm disappointed with government as they should've back it more as it is high potential for future, it is could help with Hypersonic even Ramjet, Turbofan, VCE. even Civilian and spaceplane will great with this technology Sabre will travel world fast and better cost effective could cheap that Musk Rocket and other, even British Space Program will help become independent Space not rely any other nations.

also Helium is very expensive product (also government keep lots of it) as specific Helium are rare, especial Fuel Helium is rare - that why they want go moon mine of it.

EJ200 Without Pre-cooler
  • Rate of climb: 315 m/s (62,000 ft/min) [385][386][verification needed]
  • Wing loading: 312 kg/m2 (64 lb/sq ft) [387]
  • Thrust/weight: 1.15 (interceptor configuration)[388]
  • Brakes-off to Take-off acceleration: <8 s
  • Brakes-off to supersonic acceleration: <30 s
  • Brakes-off to Mach 1.6 at 11,000 m (36,000 ft): <150 s
EJ200 with Pre-Cooler is very good combined
my estimate (but please not use my estimate as I'm not expert as rough idea figure)

Yet only possible improve if Pre-cooler is in 0-1.6 Mach at 30,000ft 150 sec< (2 mins 10 sec) would better if use Pre-Cooler will rough might save 10-20 percent of time could more, also increase KN, (but exact number i not sure? might better than EJ2x0 without pre-cooler) due engine thermal is low due Pre-Cooler.

0-supersonic 30s and 0-65,000ft/1mins

Pre-Cooler will help i think not much different maybe for example for 0-65k ft/45s and 0-30s might 0-20 or 0-25s, yet might save fuel too..

Pre-Cooler x VCE is very good option and cheap if before full production aircraft ie GCAP compare to upgrade and test before Eurofighter Service near end in 6 years start replace also refunishment all will done in 2 years so 4 years and done might waste money..

VCE can Turbofan-Turbojet, I think Turbofan off and allowed air go throw use Bypass as act as Ramjet so 3rd optional VCE to increase Speed could go up 3.5-4 MACH even save lots fuel even for big plane. That why GCAP might idea use it better performance for small two Engine (4m x 80mm) with Pre-cooler which normal maybe need big single engine plane as two engine put in big aircraft (5m x 120cm) if Pre-cooler in big and moreee powerfully yet waste space when small engine might better optional. (i suspect the GCAP estimate size engine is more around 4.5-4.7m x 90-100cm) VCE or likely 5-5.25m x 120cm as other engine like X101-X102 and X103-X104

yet that why i think pointless use powerfully engine and airframe only go to 2.2-2.5 mach ie Eurofighter already maximum power for this also Carbonfibre will worse struggle compare full metal wing, as they could cope to 800-900 oC (therefore maximum 2.0 until wartime to 2.2-2.5 Mach<) useless new Carbonfibre material could hold more that 1,600-1800 oc so once success so can increase to 2.8 Mach rough...

ie Turbofan better 1.2-1.4 Mach under and when turn to the Turbojet better from 1.4-2.5 mach compare to Turbofan and than switch Turbojet to use Ramjet over 2.5 MACH (they start better fuel effective around 2.2 mach plus much save fuel compare turbojet reheat or fuel rate in after 2.2 Mach vs Ramjet) and Ramjet effective reach to 3.5-4 Mach where Hypersonic better fuel effective. so (3.5 mach to 5-8 mach maybe more idea for Hypersonic)

So only i can see what advangte of Pre-Cooler will help cool Engine intake when heat come in so will less damage to Engine and Exhust high again..

that why Ramjet and Hypersonic will better without Engine Turbine etc etc as just compress and expand heat and release gas of hot and lit fuel on it and burn crazy explosive more force to exhaust power thrust. it if tooo hot would damage aircraft if tear half of part will split half, that pre-cooler will help reduce heat.

yet if we go 2.2-2.5 MACH Skin fracture will increase to 700-850 oC on nose and wing. metal become soft and brittle by increase heat that why sound sonic could destroy airplane that why Titanium is prefer choice at over 2.5 Mach (ie Mig 25/Mig 31/BlackBird) of course Titanium is hard find (ukraine and russian have plenty of it) for thermal fracture skin as high temperature, light and strong also protection pressure from sonic I think i see Mach 3-3.5 will rise to 1,400 oC-1,600 oC

(which my Engineering knowledge which i learn in a colleges but figure i not sure but roughly what i remember maybe i wrong as it is lonnnnng time ago..)

where lots of metal will melt as low melt point vs Brittle soft (turn shape and crack, crumble) vs Strenght for punch and hold weight vs weight ratio strenght

ie Stainless Steel (Heavy) 1,400oC but start brittle around 1,000oC.

Aluminum (Light) they melt like 1,000oC yet start brittle 600-800 oC but best light strength

Tungsten (VERY HEAVY / 2800 oC brittle is 1,300oC <-- i not sure if i right i will double check and edit as they brittle that why they good at frag and penetrate as brittle and hot make melt other metal to penetrate that brittle frag inside of peneration ie Tank etc) as it is strong punch but shape will go brittle.

Titatium (Heavy 2400oC brittle is around 1700oC) Weak Punch but still strong as Stainless steel. also high strength and weight, melt point best.

B..............ium cant spelling will edit it later (Heavy and rare, VERY Expensive can heat 3,200 and brittle around 2,500) yet hard to make modular or mould or set shape precision)

Therefore, Titanium is the best choice.
 
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also Cystal/Carbon/metal mixed for Engine Turbine blade handle heat better than Normal that R.R. very good but somehow Japanese is better i not sure why might wholes engine where R.R. just focus on front Fans blade. handle receive heat from Intake, and no "defuct blade grow crystal or change shape due heat etc, brittle use, and wholes flush to exhaust is less thermal affect engine if heat build inside and will melt wholes engine as original engine Whittles Engine solves by better metallugy.

Pre-Cooler vs this method (i try think name) as i think cost and simple and that why this method is more better option and choice over Pre-Cooler and that why they failed. I think that why company and military, space etc prefer over Pre-cooler this other reason failed.
 
djpowell1984 said:
ie Stainless Steel (Heavy) 1,400oC but start brittle around 1,000oC.

Aluminum (Light) they melt like 1,000oC yet start brittle 600-800 oC but best light strength

Tungsten (VERY HEAVY / 2800 oC brittle is 1,300oC <-- i not sure if i right i will double check and edit as they brittle that why they good at frag and penetrate as brittle and hot make melt other metal to penetrate that brittle frag inside of peneration ie Tank etc) as it is strong punch but shape will go brittle.

Titatium (Heavy 2400oC brittle is around 1700oC) Weak Punch but still strong as Stainless steel. also high strength and weight, melt point best.
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Stainless steel at 1000°C:

soft as cheese

Aluminium at 1000 °C

like water (usable up to about 260°C, melting point 660°C)

Titanium at 1700 C:

allready a liquid (melting point 1680 °C)

You are totally overestimating the heat resistance of metals! At high temperatures, metals tend not to become brittle (steel must be hot for forging!) but they get soft and start to creep
 
If you propose a pre cooler for a fighter jet engine, what kind of cooling fluid shall be used and how shall the cooling fluid itself be cooled?? When air friction heats up the surfaces of a plane, there is simply no way to cool the cooling fluid, so only an open cycle with evaporation cooling is possible. This might work with hydrogen or ammonia as combined fuel and cooling fluid, but not with jet fuel.
 
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Nicknick said:
Stainless steel at 1000°C:

soft as cheese

Aluminium at 1000 °C

like water (usable up to about 260°C, melting point 660°C)

Titanium at 1700 C:

allready a liquid (melting point 1680 °C)

You are totally overestimating the heat resistance of metals! At high temperatures, metals tend not to become brittle (steel must be hot for forging!) but they get soft and start to creep
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as i say it is lonnnnnng time ago, but i should double check again use proper information before put up these.

yet thank for correct me ;-) and give me information.
 
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Nicknick said:
You are totally overestimating the heat resistance of metals! At high temperatures, metals tend not to become brittle (steel must be hot for forging!) but they get soft and start to creep
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Is there a way to combine transpiration cooling and boostback's burn protection?

The exhaust of Falcon and Starship both slow and protect---might there be a way to burn propellant such that...while it isn't enough as a retro--it IS enough to keep the heat of re-entry at arms length?

Perhaps Reaction's tech can be used in a different manner than intended.

A burning rocket sheds heat--where re-entry hits you in the face.
 
publiusr said:
Is there a way to combine transpiration cooling and boostback's burn protection?

The exhaust of Falcon and Starship both slow and protect---might there be a way to burn propellant such that...while it isn't enough as a retro--it IS enough to keep the heat of re-entry at arms length?
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Don't burn it, just use for cooling then

publiusr said:
Perhaps Reaction's tech can be used in a different manner than intended.

A burning rocket sheds heat--where re-entry hits you in the face.
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No. It is a heat exchanger, a radiator in reverse. Used to heat a fluid. Much of entry heating isn't from hot air but radiative.
 
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djpowell1984 said:
...also Helium is very expensive product (also government keep lots of it) as specific Helium are rare, especial Fuel Helium is rare - that why they want go moon mine of it.
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Thanks, Djpowell1984. Nicknick has some appropriate corrections to your melting point numbers. If I am understanding correctly, the prototype precoolers manufactured by Reaction Engines Ltd before its demise did not "use up" their helium-4 during operation. Although this slippery element is noted for eventually leaking out of almost anything, the annual quantity of helium-4 needed for a force of precooled GCAP fighter planes would be about the same as what a party balloon distributor needs (far less than, for example, NASA expends to pressurize propellant tanks each year). So the cost per cubic meter, which has indeed risen faster than inflation for the past few decades, would not be prohibitive. We'll see whether anything comes of these proposals.

It may be worthwhile someday to recover helium-4 from the Moon's regolith, e.g. for large-scale foamed metal production there or in orbit. The specific substance you are thinking of is the other stable isotope of helium, helium-3, which is a minuscule fraction of the helium on Earth, in the regolith, in the atmosphere of Jupiter, etc. Calculations seem to show that helium-3 would be very valuable for fusion power plants, but because nobody has yet come close to building a fusion power plant, such a market remains speculative.
 
Zoo Tycoon said:
In the presence of a high speed flow of air(a copious supply of oxygen) it can burn like magnesium.
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In the engine world, we call that a “rapid oxidation event”. Most modern turbofans are constructed from Ti alloys in the fan / LPC and the front end of the HPC, but transition to Ni construction in the back end of the HPC once the air temp reaches a critical value to minimize the risk of a Ti fire.
 
It should be clear, that even with a Titanium alloy, the usable temperature will allways be much much lower than the melting point of Titanium.

In "my" engine world, we are not so much affected with "rapid oxidation event", but I faced such an event in my CNG Car when the exhaust valve was burned...(worn out leaking valve seats)
 
The original F100 design had the entire HPC built from Ti, as was everything else besides the combustor and turbines. It worked until a HPC blade broke during altitude test cell operation. I didn’t see it, but I was told the only remaining parts of the engine were the motor mounts.
 

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