The TBE (DeLong) Spaceplane presentation. Weights are in the middle of the document.
Quote from: HMXHMX on 04/18/2018 05:27 amThe TBE (DeLong) Spaceplane presentation. Weights are in the middle of the document.Thanks! That does seem like the most plausible large space-plane that would fit what we are told about "Black Ice". But a project that size requires a lot of funding and work...
Quote from: HMXHMX on 04/18/2018 05:27 amThe TBE (DeLong) Spaceplane presentation. Weights are in the middle of the document.Thanks, very interesting. So takeoff weight of Spaceplane is 380klb, or 1/4 of Shuttle.They estimated close to $1billion for DDT&E of one test vehicle and two flight units. I didn't see a date on the presentation, but it looks like late 1980's.
Just completed our monthly program review at Mojave and the Stratolaunch aircraft remains on-track for first flight later this summer. Three more taxi tests and we will be ready to “slip the surly bonds”.
Note that this was before the discovery (by the HOTOL) team of how much forebody lift increases while the engine mass (at the back) stays the same, need a very large down force on the front to stop the design "flipping" upward. In practice probably an issue for any vehicle that follows this sort of layout. There's a reason REL went with engines on the wing tips and split both LO2 and LH2 around the payload bay. Those reasons have not changed.
Looking at the GLOW for the vehicle in this document (~170,000kg), I think that the version developed for Roc could be about 50% larger with an increased payload, since Roc can carry up to 250,000 kg.
I think that the payload would have to be compared to the "first flights" version of the spaceplane, though, which only was expected to have a payload of 3200 pounds to 28 degrees,
...since I doubt that Stratolaunch would do any of the modifications to Roc that were assumed for the B747 in the paper.
OTOH, the spaceplane could probably be built a lot lighter today. Also wonder whether other engine/fuel options could improve payload.
Swapping an RS-68 for the SSME is possible of course though replacing the RL-10s is a bit of an issue atm.
Quote from: RanulfC on 04/28/2018 08:55 pmSwapping an RS-68 for the SSME is possible of course though replacing the RL-10s is a bit of an issue atm.Why would you swap RS-68 in?
Its twice the mass, much lower ISP, and most importantly not reusable (and still a decent chunk of the cost of a new RS-25). Loses all around, and for an almost-SSTO you really can't afford to throw away performance. The only gain it has is being in production, but theres plenty of RS-25 spare parts (see: AR-22 for Phantom Express), especially if SLS ends and a bunch of RS-25Ds are made available. And with RS-25E being a thing soon, Aerojet could probably make a reusable variant for a commercial user without quite as high startup costs.
Keep in mind in aerospace vehicles 'bigger' is also vastly more expensive so it might make more sense to start with a smaller vehicle such as this with an obviously useful payload and go from there once you have a proven flight system.
Eh, the description on page 29 has 14,000lbs, (6300kg) to a 216nm orbit, page 39 has the "Initial Spaceplane" version with 3200lbs and no thrust augmentation to the 747 but keep in mind this is LIGHT for the Roc payload so performance should be better even without augmentation. "Baseline" and "Growth-1" with "H2 afterburners" which I suppose is 'duct-burning' for the bypass turbofans and/or a "lightweight" Spaceplane is between 3100lbs to 11,700lbs to LEO. "Growth-2" adds an SSME to the 747's tail and tankage to support a short burn to increase speed and altitude before separation while "Growth-3" is a new carrier aircraft with 8 J58 engines. Those two options move the payload range up to between 7,600lbs and 28,500lbs. Which I'm not sure you really need.(Page 42 says 7 (metric) tonnes which is 15,432 pounds just FYI)
The biggie is the engine augmentation system which I don't recall it has and which could either be duct-burning in the bypass fan duct or possibly mass injection to boost the performance temporarily as needed. Putting a couple of SSME (RS25E's) in the tails of the Roc is probably not workable but it also depends on how much payload you NEED rather than competition with existing launchers.
Liquid Methane is going to reduce vehicle size with a very similar ISP to LH2 but you need engines. Kerolox might work but again you need engines. Swapping an RS-68 for the SSME is possible of course though replacing the RL-10s is a bit of an issue atm.
@Stratolaunch aircraft was outside yesterday for our annual Scaled/Stratolaunch employee family day event. Next event is taxi Test #3.
After reaching new heights WhiteKnightTwo taxies past the Stratolaunch. Just another day at Mojave Airport. #envelopeexpansion #flighttest #virgingalactic #stratolaunch
Eh John? The "reasons" don't apply here as this only 'flies' using lift for a few seconds till it finishes a pull up to high-AOA, (separates at about 30 degrees and increases' till outside the effective atmosphere) and like other LV's pushes it's way "uphill" to orbit. IF you have an air-breathing engine system then it will require a re-design but one of "MY" points was it was out there and in fact doesn't need a lot of work to be used as a basis for "Black Ice"...
Keep in mind in aerospace vehicles 'bigger' is also vastly more expensive so it might make more sense to start with a smaller vehicle such as this with an obviously useful payload and go from there once you have a proven flight system.IIRC, (and frankly I'm pretty sure I don't) it was something like "50% bigger costs about 150% more) and so on.
I'm still a bit fuzzy on the whole air launch thing specifically as it relates to Stratolaunch. I have read a few articles about pros and cons of air launch. The more specific of these suggest that air launch is of questionable benefit for orbital flight. Could someone point me to a reliable source for information on drag and gravity losses? Thanks!
We are rolling out this morning for Taxi Test #3. We plan to conduct 5 Taxi Tests prior to First Flight.
Weekend aircraft testing continues as we wrap up a full day of fueling operations and engine runs. All engines successfully tested to max power settings.
