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Paul Allen's new rocket-launching plane

arstechnica.com

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Re: Paul Allen's new rocket-launching plane

#81

Post by endorphone »

kashkhan wrote: post #52
SkyMarshal wrote: post #49

This is awesome but a little bit scary. Interesting that they didn't physically connect the tail wings at all, I wonder what stresses and torques the main wing will endure under maneuvering or turbulence. I assume all the control surfaces are computer controlled to synchronize and minimize that, but from the perspective of an ignorant observer, looks a little fragile.

it's a proven design. scaled composites, which built this also built the GlobalFlyer with similar configuration. https://en.wikipedia.org/wiki/Virgin_Atlantic_GlobalFlyer

Clearly Allen and his team did the necessary engineering work, but I'm not sure the GlobalFlyer is a good example. It had a single mid-mounted engine, and had a gross, fully loaded weight of 22,000lbs. This thing has 70,000+ lbs of engines alone. The torque has to be absolutely colossal.

Again, I know that much smarter people did the math, but from the eye check this does not look like a tenable design.

Re: Paul Allen's new rocket-launching plane

#82

Post by Animats »

Scaled Composites built it. It should work. Although Rutan has retired, the company goes on. It's interesting that they didn't connect the tails, like the old Lockheed P-38, but there's probably some good reason for that.

Launching a Pegasus XL has to be just a demo. That's normally launched by dropping it from an old Lockheed L-1011; it doesn't need this monster. They need something bigger to launch. There was a contract with Pegasus for a "Pegasus II", but that didn't work out. The "Dream Chaser" mini-shuttle is a possibility, if that ever gets built.

The 747 engines are probably used. There are lots of retired 747s around, many at the Mojave boneyard. Great aircraft, but a fuel hog by current standards.

Re: Paul Allen's new rocket-launching plane

#83

Post by kevin_thibedeau »

innergame wrote: post #66

I feel overcome by the Dianne Kruger effect, to an extent I don't remember feeling any time recently. I'm becoming more and more interested in news about rocketry (due to SpaceX of course) but I'm still a full on space-pleb. I see something like this and my intuition screams "Woah! Of course! Why don't other rocket companies do this? What's wrong with them?!" But the rational part of my brain kicks in and slaps me do…

The traditional rocket companies have no interest in reducing launch costs. Now they're looking like fools for letting SpaceX patent critical tech they could have developed 20 years ago.

Re: Paul Allen's new rocket-launching plane

#85

Post by averagewall »

ufmace wrote: post #43

The really interesting question - does the modest increase in initial velocity and altitude with a boost out of the lower atmosphere make it practical to build a Single Stage To Orbit rocket? If they can, then it's an impressive achievement. If not, then it doesn't really seem worth the trouble.

While having fewer stages sounds simpler and easier, that's not necessarily a major cost. Having a big and powerful 1st stage is a major cost so this should allow either a cheaper 1st stage or a heavier payload.

Re: Paul Allen's new rocket-launching plane

#86

Post by PhasmaFelis »

jeffbarr wrote: post #78
bogomipz wrote: post #60

Does anyone have any insight into how the dual flight decks are utilized?

There's only one flight deck and it in the right-hand fuselage. I was at a recent friends and family day at Scaled Composites and was able to see and touch this amazing plane.

Both fuselages seem to have identical windows. Is that just so they can use the same tooling for both, or is there something else in the left fuselage? Passenger/observer seating, maybe?

Re: Paul Allen's new rocket-launching plane

#87

Post by PhasmaFelis »

ufmace wrote: post #43

The really interesting question - does the modest increase in initial velocity and altitude with a boost out of the lower atmosphere make it practical to build a Single Stage To Orbit rocket? If they can, then it's an impressive achievement. If not, then it doesn't really seem worth the trouble.

Technically I think the carrier plane counts as a stage, so two-stage-to-orbit is the minimum.

Yes, I know what you meant. :) Interesting question.

Re: Paul Allen's new rocket-launching plane

#88

Post by robotresearcher »

tacticus wrote: post #62
jameshart wrote: post #48

Earlier quoted context omitted.

Is 4. really doable? Would have thought landing while carrying a fully fueled rocket might be pretty high risk.

Could always dump fuel on the way back.

Not from the Pegasus solid rockets.

Re: Paul Allen's new rocket-launching plane

#89

Post by schiffern »

Animats wrote: post #82

Scaled Composites built it. It should work. Although Rutan has retired, the company goes on. It's interesting that they didn't connect the tails, like the old Lockheed P-38, but there's probably some good reason for that. Launching a Pegasus XL has to be just a demo. That's normally launched by dropping it from an old Lockheed L-1011; it doesn't need this monster. They need something bigger to launch. There was a con…

>The 747 engines are probably used. There are lots of retired 747s around, many at the Mojave boneyard. Great aircraft, but a fuel hog by current standards.

Correct. They just flew in two used 747s and cannibalized them for parts. http://www.seattletimes.com/business/boeing-aerospace/paul-a...

>The crew’s flight deck is literally that of a 747.

>Allen bought two used jumbo jets formerly flown by United Airlines and cannibalized them for parts that account for about half the empty weight of the Roc.

>So although the shell of the cockpit and all the rest of the plane’s body is new — hand-built by Scaled Composites from carbon fiber composites — various key pieces and systems, including avionics, hydraulics and fuel subsystems, are salvaged 747 parts. BAE Systems was subcontracted to disassemble the 747 and install its systems on the Roc.

>The cockpit seats look old and used because they are. The seats as well as the controls the crew will manipulate and the windows they’ll look out of all came from the 747s.

>So did the plane’s six Pratt & Whitney engines, which are already refurbished, cleaned, wrapped and set aside in a corner, ready to hang on the airframe when it’s finished.

Re: Paul Allen's new rocket-launching plane

#90

Post by nbanks »

jacquesm wrote: post #29

I'd really hate to see that thing land in a crosswind, I don't think I could watch it.

They could always use a chase car like they do with the U-2 Dragon Lady because of its ridiculous wing span. This wouldn't help you avoid watching it, though. youtu.be/W2tnCDBkIoI
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