You CAN after all make a "SABRE" cycle LIKE engine with any cry-fluid but the deep cooling of the air pretty much takes LH2 to accomplish so using something else how accurate is the result? Randy
Quote from: RanulfC on 04/15/2015 07:31 pmYou CAN after all make a "SABRE" cycle LIKE engine with any cry-fluid but the deep cooling of the air pretty much takes LH2 to accomplish so using something else how accurate is the result? So I don't realy understand. Is the SABRE cycle even possible with other cryogenic fuel or not?Strictly theoretically, is it possible with deep cooled methane for instance, or is it not cold enogh to "liquify" the air?
You CAN after all make a "SABRE" cycle LIKE engine with any cry-fluid but the deep cooling of the air pretty much takes LH2 to accomplish so using something else how accurate is the result?
indicating interest by the USAF, will SABRE technology get snared in ITAR problems. I am delighted that SABRE has received the endorsement, but would hate to see Reaction Engine's IP inadvertently sequestered.
Quote from: SteveKelsey on 04/16/2015 05:38 pm indicating interest by the USAF, will SABRE technology get snared in ITAR problems. I am delighted that SABRE has received the endorsement, but would hate to see Reaction Engine's IP inadvertently sequestered.An excellent point.The Official UK position on ITAR was described in the BSA's report on UK spaceports. It makes depressing reading and you'd have to be very careful to ensure that any SABRE/Skylon IP is not "contaminated" by USAF work, effectively making the USG a business partner and giving it power of veto over your decisions. That might not be a position the British government is too bothered by but it should scare the hell out of any British company that wants to be predominately a supplier to the world in aerospace.
May I at this point out that for the second time that 20 billion dollars (my random, but somewhat educated guess at current cost now) is not a lot of money in terms of US govt spending...I am slightly concerned about IP having been already handed over in this CRADA process however...
It probably should be pointed out that the USAF is formulating proposals for a next generation bomber and a 6th generation fighter, with hypersonic.on the wish list for the latter.
Honestly, the press release makes my previous gut feel that much stronger - it's Scimitar the USAF really want.Could REL develop the two engines in parallel? I'm going to say no. Regardless of the similarities, I would expect the detailed engineering on either one would consume their entire energies.
Actually I've always thought that too. The CRADA might have specified SABRE, but it seems extremely unlikely that the investigations didn't involve all types of uses they were interested in.
$20Bn is about a 66% rise on the last REL estimate I'm aware of ($12Bn.) That last rise was caused by including the Skylon Upper Stage to take payloads to GTO as part of the baseline development.
Quote from: momerathe on 04/17/2015 02:59 pmHonestly, the press release makes my previous gut feel that much stronger - it's Scimitar the USAF really want.Could REL develop the two engines in parallel? I'm going to say no. Regardless of the similarities, I would expect the detailed engineering on either one would consume their entire energies.It's clear what the CRADA studied. It's equally clear that SABRE's focus is single stage to orbit launch and if the USAF chose to ignore that point that's their decision. I will note that SABRE and Skylon are separate designs. If the USAF were so minded they could look at a more conservative airframe that traded payload for more traditional aerospace materials. How small I don't know. Part of it would depend on wheather they wanted orbit from a CONUS site, rather than an equatorial site. It would be an option. Quote from: flymetothemoon on 04/17/2015 05:17 pmActually I've always thought that too. The CRADA might have specified SABRE, but it seems extremely unlikely that the investigations didn't involve all types of uses they were interested in.It's not the use. LAPCAT's internals are completely different, with the turbine outside the core. IIRC it trades higher weight for better LH2 economy and of course eliminates all the air sealing system as it runs in atmosphere all the time.
Quote from: flymetothemoon on 04/16/2015 07:59 pmMay I at this point out that for the second time that 20 billion dollars (my random, but somewhat educated guess at current cost now) is not a lot of money in terms of US govt spending...I am slightly concerned about IP having been already handed over in this CRADA process however...The cargo transport contract to the ISS is about $18Bn$20Bn is about a 66% rise on the last REL estimate I'm aware of ($12Bn.) That last rise was caused by including the Skylon Upper Stage to take payloads to GTO as part of the baseline development. That's a lot of inflation compared to REL's estimate.
Is that Skylon Upper Stage planned to be reusable and return to the Skylon befor reentry or expendable?
Quote from: momerathe on 04/17/2015 02:59 pmHonestly, the press release makes my previous gut feel that much stronger - it's Scimitar the USAF really want.Could REL develop the two engines in parallel? I'm going to say no. Regardless of the similarities, I would expect the detailed engineering on either one would consume their entire energies.It's clear what the CRADA studied. It's equally clear that SABRE's focus is single stage to orbit launch and if the USAF chose to ignore that point that's their decision. I will note that SABRE and Skylon are separate designs. If the USAF were so minded they could look at a more conservative airframe that traded payload for more traditional aerospace materials. How small I don't know. Part of it would depend on wheather they wanted orbit from a CONUS site, rather than an equatorial site. It would be an option. Quote from: flymetothemoon on 04/17/2015 05:17 pmActually I've always thought that too. The CRADA might have specified SABRE, but it seems extremely unlikely that the investigations didn't involve all types of uses they were interested in.It's not the use. LAPCAT's internals are completely different, with the turbine outside the core. IIRC it trades higher weight for better LH2 economy and of course eliminates all the air sealing system as it runs in atmosphere all the time. Quote from: flymetothemoon on 04/16/2015 07:59 pmMay I at this point out that for the second time that 20 billion dollars (my random, but somewhat educated guess at current cost now) is not a lot of money in terms of US govt spending...I am slightly concerned about IP having been already handed over in this CRADA process however...The cargo transport contract to the ISS is about $18Bn$20Bn is about a 66% rise on the last REL estimate I'm aware of ($12Bn.) That last rise was caused by including the Skylon Upper Stage to take payloads to GTO as part of the baseline development. That's a lot of inflation compared to REL's estimate.