Quote from: RanulfC on 02/24/2015 06:49 pmWhich dates from the mid-60s hence the "needle" nose instead of the more common "shovel" nose you'd see today.Given the advances in supersonic and hypersonic flow heating analysis is the "needle nose" even plausible today?
Which dates from the mid-60s hence the "needle" nose instead of the more common "shovel" nose you'd see today.
Quote from: RanulfC on 02/24/2015 03:38 pmand in fact does not require Liquid Hydrogen [...]Exhaust IR mitigation IS a possible use but again mitigation doesn't "require" the use of liquid hydrogenNeither does Bond's heat exchanger. Indeed the major testing has not been with LH on the cold-side of the He-loop. LH is a requirement for Skylon because of the hypersonic operating environment where they need around 1000°C cooling (as would most hypersonic applications, for the same reason.) Outside of that operating environment, you pick the coolant to suit the application.
and in fact does not require Liquid Hydrogen [...]Exhaust IR mitigation IS a possible use but again mitigation doesn't "require" the use of liquid hydrogen
The key to Bond's idea is a) that it's frostless, b) that it's fast, and c) that it's both hot- and cold-side agnostic. The first lets you use where you can't use other heat-exchanges, the second means it acts almost like a thermal-superconductor (it will near-instantly cool the hot-side close to the temp of whatever is on the cold-side), the last means it's flexible for more applications. A bonus is that it's ridiculously light as a side-effect of (b).[I do like how now I'm arguing that REL understands their pre-cooler well enough to model applications, while you're arguing that they've been a little premature/overenthusiastic...]
@Moe GrillsThey're building a full-size SABRE. Not a scaled down version. The costs and difficulties involved in the engineering of the engine mean that a full-sized engine makes more sense.
Quote from: Citizen Wolf on 02/25/2015 04:48 pm@Moe GrillsThey're building a full-size SABRE. Not a scaled down version. The costs and difficulties involved in the engineering of the engine mean that a full-sized engine makes more sense.I guess size matters, maybe.BTAIM, If it works, bully to Mr. Bond and his engineering disciples; a spaceflight revolution can then begin sometime next decade. If it doesn't work, alas, humanity will have to plod along with conventional boosters for another century perhaps.Fingers crossed that it may work as advertised.
Well for one thing it will cut down a small bit on the people who will still refuse to believe the engine will work because "it's ONLY a scale-model"
IIRC the plan for SCEPTRE is a full size prototypes/demonstrator rengine but it will not be laid out to fit inside the cowling - more like a breadboard than something you could fly. Anyone know if that's correct? I'm also not sure if SCEPTRE will include thrust chambers and/or nozzles, but I'm going to guess not.If it is not tightly packaged as it will be in the cowling then that will make it easier to troubleshoot and tweak. But doesn't a lot hinge on the plumbing/flow properties and thermal cycles that are influenced by layout? If so, will that necessitate a SCEPTRE 2.0?
LH is a requirement for Skylon because of the hypersonic operating environment where they need around 1000°C cooling (as would most hypersonic applications, for the same reason.) Outside of that operating environment, you pick the coolant to suit the application.
Building a full size engine with no restrictions on fitting into a cowling is sensible, just prove it works and leave a R/R type company to carry out the design needed to fit into the cowling and any further work needed to produce a flight ready engine.
Interesting - I missed the change away from the 'dissected rabbit'. Hopefully that's indicative of confidence in all the theoretical and simulation work they've done, rather than impatience.Any idea if what they're building includes everything, i.e. combustion chambers, nozzles, bypass burners, etc?And does this match up with the phasing they mentioned in 2013 - where 3a included SCEPTRE? A near-flight-worthy engine is much more ambitious (expensive) than what I was expecting.
Phases 3 & 4 of the £10bn project now stretch over 10.5 years, of which £3.64bn is for SABRE. Phase 3 (£0.36bn) commenced April 2014 and approximately £100m has been secured, with approx £250m to secure in the next few years. Phase 4 is due to commence October 2018, with a (new) Skylon in-service date of October 2024.Valkyrie? - "Could not possibly comment on that". Phase 3 WILL however involve a flying SABRE engine (not Skylon).
My impression was a single full-size SABRE with wings and tank
Valkyrie? - "Could not possibly comment on that". Phase 3 WILL however involve a flying SABRE engine (not Skylon).
Quote from: SICA Design on 02/26/2015 08:51 amMy impression was a single full-size SABRE with wings and tankIf you're not going with something looking like a Skylon you loose pretty much any benefits from getting early test data you can apply to the full vehicle
My impression could (of-course) be completely wrong, but it would advance REL's position (as engine mfg) and separate the issues of Skylon from SABRE.Successful testing of SABRE through air and vacuum would surely encourage airframers to get onboard with Skylon development. It would be one further huge landmark in RELs track record of delivering what they claim.
I'm sure this is ridiculous for many reasons but: Could SABRE be tested by bolting it on to or into some existing airframe as is done with new jet engines? I presume full power would not be possible unless perhaps for fractions of a second and the maximum speed would have to be very low compared to SABRE's potential hence perhaps it's completely nonsensical? Would there be anything to gain from this? e.g. behaviour at various altitudes, ability to restart ...
what existing aircraft uses lh2?
Quote from: aga on 02/26/2015 02:41 pmwhat existing aircraft uses lh2?I've now got silly visions of a large airliner with one engine replaced with a SABRE, and another replaced with an aerodynamic LH2 tank...