Stratolaunch: General Company and Development Updates and Discussions

[Rocket Science]

Airplanes aren't Legos.

Nope, they are Erector Sets… 

[robertross]

Interesting quote from WSJ artitcle

The cost of developing such a mammoth plane, Mr. Rutan added, "historically had been judged as prohibitive." But the logjam broke after engineers came up with "innovative processes to build very large structures" out of composite materials, according to the veteran designer. "Now, it's quite affordable," Mr. Rutan said, and that's one of the reasons the Stratolaunch team decided to lift the veil on the plans.

I wonder what the process was.
jb

IIRC, the new Dreamliner doesn't require the use of an autoclave to manufacture the composite wing structures - maybe that's the reason.

[sammie]

Just to add about the possibility of this new aircraft carrying (WK3?) to carry outsize cargo. The An-225 is often considered too large to be easily operated at regular airports due to wingspan, WK3 would be even worse. Also if you really want to carry something bigger then the 4.4m currently available it could be carried on top of the An-225. But usually such large cargo's are shipped with truck and barge.

And of course large blimps will dominate the outsize cargo market in a decade or two.

[RanulfC]

Wrong again.  It is going to be the same.  LOX spheres will be required. Same goes for GN2 and He cylinders.   There is a reason launch vehicles don't use tanker trucks.  Also, RP

Most airports don't have "haz-cargo" handling and loading/unloading facility sized for this or for processing spacecraft.

Ok I'll bite; "Why?" Why do you need the "spheres" and what are the "reasons" LVs can't/don't use tankers for propellant loading?

(Also keep in mind the idea that the fuselages may carry the propellant load or part of it to altitude)

Admittidly "MY" experiance may be unusual (I've actually spent far more time on Air Force bases than international airports ) but I have seen the quite large Haz-processing area at LAX, and a smaller one at Little Rock both of which were processing 747s at the time.

Randy

[RanulfC]

Sure, but LH2 will give it a much larger payload to orbit while keeping within the carrier aircraft's capabilities. Many orbital airlaunch concepts assume hydrogen for this reason.

And many don't Liquid-Methane, Cryo-Propane, etc have all been suggested to aviod the majority of the boil off issues, so it's not a black-and-white choice here

Edit: Plus, if SpaceX ever wanted to license one of Rutan's novel swivel-wing recovery methods for a booster (hint, hint)- this would be a good way to end up with such a license...

Would the 'feather' actually work for a booster trajectory? Last I'd heard from Rutan the feather doesn't work at orbital reentry speeds but it SHOULD be good for suborbital...

Randy

[robertross]

Wrong again.  It is going to be the same.  LOX spheres will be required. Same goes for GN2 and He cylinders.   There is a reason launch vehicles don't use tanker trucks.  Also, RP

Most airports don't have "haz-cargo" handling and loading/unloading facility sized for this or for processing spacecraft.

Ok I'll bite; "Why?" Why do you need the "spheres" and what are the "reasons" LVs can't/don't use tankers for propellant loading?

(Also keep in mind the idea that the fuselages may carry the propellant load or part of it to altitude)

Admittidly "MY" experiance may be unusual (I've actually spent far more time on Air Force bases than international airports ) but I have seen the quite large Haz-processing area at LAX, and a smaller one at Little Rock both of which were processing 747s at the time.

Randy

The amount of propellant required would be too large to fill from tankers, and the hazards too great. A single-source 'sphere' (optimum storage device in this case) can allow for pressurized filling of the vehicle from a good distance away, and if a drain-back is required (due to a leak in the piping or the vehicle), it has somewhere to go all at once.

[sprocket]

Yeah, I mean there is a legitimate rejoinder to these anecdotes "They laughed at Columbus, but they also laughed at Bozo the Clown", but personally I think that people who haven't studied the problem in detail making handwavy dismissals based off of a single execution attempt is just plain ridiculous.

~Jon

We suffered though endless pages here of why this is all a boondoggle. The people behind this project aren't stupid. They've disclosed only those facts that can no longer be hidden. Wouldn't our time be better spent speculating on what is really going to be be dropped from this thing?  Let's see. Meant to carry lots of people. 30,000 ft. 500,000 lbs. I, for one, look forward to Jon's next major blog entry.

[iamlucky13]

Space launch is such an interesting field. I wonder where computers or even airplanes would be if people in those fields were as used to drawing hasty generalizations from single data points.

"Sam Langley's Aerodrome didn't work out, so that obviously shows that heavier than air flight can't work"...

~Jon

Oh believe me, it happens in both those other fields, too. I'd say it's actually a lot more prevalent in the aircraft industry than in the space industry.

In all these fields, the armchair engineers sat in their armchairs and watched while the Sam Langley's made excellent attempts and failed and scoffed at dedicated amateurs like the Wright Brothers even as they cracked the secrets of their field.

It will probably cost way more than ten times as much to build this one-off, six engine, twin hulled behemoth than it cost to buy an old, used L-1011.

Still, one data point....

10x for the plane sounds like the right ballpark...it might even be low. But the L1011 is probably a very small portion of Pegasus program's cost, and the conversion work probably actually cost more than the aircraft itself. Allen's aircraft will be a huge cost up front, but if his market develops like he wants, it will be only one small part of the whole operation.

I suspect he's looking at development and construction costs similar to what Sea Launch faced for converting their launch platform and tender, and that company has held together so far, albeit after struggling through a bankruptcy. Meanwhile, Allen is facing a fairly competitive environment these days.

[InvalidAttitude]

Its simply wont happen, a non-sense. Very small market for this, and to build this plane will be much greater undertaking than simply stitching two 747 together.

[simonbp]

Would the 'feather' actually work for a booster trajectory? Last I'd heard from Rutan the feather doesn't work at orbital reentry speeds but it SHOULD be good for suborbital...

Well, for the sake of the passengers of SS2, I certainly hope so!

For booster recovery in general, a lofted trajectory (climbing fast to orbital altitude and then burning out) is best, and is generally similar to the tourist suborbital trajectories. This is especially true if you have a wing to allow you to climb almost (but not quite) vertically. The second stage of the "StratoFalcon" (?) doesn't not seem to be much smaller than Falcon 9, also implying a lofted trajectory (which puts more dv load on the second stage).

I think I agree with the suggestions that the "Falcon 9 with a delta wing" shape is a placeholder showing the minimum development option. I'm sure Scaled has some different idea about how it should look. The second stage, though is probably set, thus keeping maximum commonality with F9.

[iamlucky13]

Other questions:

The engine cowls on the "Falcon 5".  Don't think they needed them "the first time".  Only the corner engines, the last 4 of 9, project beyond the tank diameter on the Falcon 9.

With a high altitude start, they probably want bigger nozzles for better Isp. Plus making them more aerodynamic will improve the carrier aitcraft range.

It might also let them use a common thrust structure with the Falcon 9.

As for buying two old 747s to canabalize and stitch together, I find that hard to believe.

This one puzzles me somewhat. The rendered fuselage has only superficial similarity to the 747 around the nose.

Most importantly, the 747 is a low-winged aircraft. The entire fuselage structure around that area is designed to support the wing from that location. A high-winged aircraft would need probably about 40' of fuselage completely rebuilt.

However, the entire fuselage aft of the wing is different, too. It seems most likely to me they plan on using a lot of the systems (hydraulics, electrical, etc) if anything, but a minimal amount of the structure.

Might make an interesting airliner project to compete with the A380…

Even the A380 only fits at a few airports that had to modify their terminals to make it work. This wouldn't even come close. There's also no advantage for a twin fuselage for an airliner, unlike the need to center the cargo for Stratolaunch.

[savuporo]

Just an observation. I've seen about half a dozen statements like "people behind this project aren't stupid" - of course they are not, but such statements can also be seen as argumentum ad verecundiam.

[neilh]

Yeah, I mean there is a legitimate rejoinder to these anecdotes "They laughed at Columbus, but they also laughed at Bozo the Clown", but personally I think that people who haven't studied the problem in detail making handwavy dismissals based off of a single execution attempt is just plain ridiculous.

~Jon

We suffered though endless pages here of why this is all a boondoggle. The people behind this project aren't stupid. They've disclosed only those facts that can no longer be hidden. Wouldn't our time be better spent speculating on what is really going to be be dropped from this thing?  Let's see. Meant to carry lots of people. 30,000 ft. 500,000 lbs. I, for one, look forward to Jon's next major blog entry.

Indeed. A Falcon 9-derived stage serves as a "payload" with relatively low development risk and cost. It can also help with initial working out of systems and starts to bring in an income stream for the company, much like Falcon 1 did for SpaceX. Once the basic system is working and the development risk of the carrier aircraft is retired, they can then move onto other higher-risk launcher efforts.

Just to toss some random ideas out... Besides flyback systems, I'm particularly curious about how having access to a large carrier helps close the case for an SSTO. What about a jet-powered first stage or SSTO, as danderman described on another thread, which could also use the jets to increase the capacity of the carrier? Heck, could the case for a laser-launch system be improved if both the laser and launcher are above most of the distorting atmosphere?

It mighty be fun to create a separate thread brainstorming space-related uses for a giant carrier plane.

[Rocket Science]

Other questions:

The engine cowls on the "Falcon 5".  Don't think they needed them "the first time".  Only the corner engines, the last 4 of 9, project beyond the tank diameter on the Falcon 9.

With a high altitude start, they probably want bigger nozzles for better Isp. Plus making them more aerodynamic will improve the carrier aitcraft range.

It might also let them use a common thrust structure with the Falcon 9.

As for buying two old 747s to canabalize and stitch together, I find that hard to believe.

This one puzzles me somewhat. The rendered fuselage has only superficial similarity to the 747 around the nose.

Most importantly, the 747 is a low-winged aircraft. The entire fuselage structure around that area is designed to support the wing from that location. A high-winged aircraft would need probably about 40' of fuselage completely rebuilt.

However, the entire fuselage aft of the wing is different, too. It seems most likely to me they plan on using a lot of the systems (hydraulics, electrical, etc) if anything, but a minimal amount of the structure.

Might make an interesting airliner project to compete with the A380…

Even the A380 only fits at a few airports that had to modify their terminals to make it work. This wouldn't even come close. There's also no advantage for a twin fuselage for an airliner, unlike the need to center the cargo for Stratolaunch.

Try to figrure this...

[iamlucky13]

Interesting quote from WSJ artitcle

The cost of developing such a mammoth plane, Mr. Rutan added, "historically had been judged as prohibitive." But the logjam broke after engineers came up with "innovative processes to build very large structures" out of composite materials, according to the veteran designer. "Now, it's quite affordable," Mr. Rutan said, and that's one of the reasons the Stratolaunch team decided to lift the veil on the plans.

I wonder what the process was.
jb

I've got some ideas.

One of the biggest costs for composite manufacturing is the tooling. Tooling costs grow rapidly with size and accuracy requirements. Single use tooling is less expensive individually, but more difficult to justify the cost for high accuracy. The accuracy requirements for wind turbines, as far as I've been able to tell, are not nearly as high as for aircraft wings, which helps simplify things for the wind turbine industry.

One possibility would be smaller tooling sections that are aligned using metrology tools that were available a few years ago, like laser trackers.

IIRC, the new Dreamliner doesn't require the use of an autoclave to manufacture the composite wing structures - maybe that's the reason.

They do. Each of the major structure suppliers has their own set of autoclaves, and they are very big:

787 wing autoclave

But there's another big cost. Bigger structures mean bigger autoclaves,  which means more money.

There are room temperature curing resins, but they're more difficult to work with.

I have seen thermosetting resins be partially cured locally with heat lamps to make parts easier to handle. I presume they don't do this normally because of time, uniformity, and desire for high pressure compression during final cure. I wonder if Scaled has proven out full, uniform curing of large structures with small heat sources.

That doesn't address fiber compaction, but maybe for one-off production, Scaled is satisfied with being extremely meticulous about their layup process and fiddling with huge vacuum bags.

Lots of smaller composite parts are made by using clamp molds to apply pressure instead of air pressure, and electric heaters built into the molds, but those are even more expensive unless you're building really high volumes.

[Thorny]

Try to figrure this...

Despite the caption, that is actually an F-82 Twin Mustang, not two P-51s bolted together. The F-82 was an all new aircraft that started from the P-51H design, but diverted from it radically. It was not two P-51s.

[iamlucky13]

The "Stratolaunch" name goes back to at least May of this year.

The trademark was applied for May 4, 2011. From the USPTO record:

Goods and Services    IC 039. US 100 105. G & S: Freight transportation by aircraft and spacecraft; Transportation of passengers and/or goods by aircraft and spacecraft; Travel and tour information service; Travel courier and travel guide services

[Rocket Science]

Try to figrure this...

Despite the caption, that is actually an F-82 Twin Mustang, not two P-51s bolted together. The F-82 was an all new aircraft that started from the P-51H design, but diverted from it radically. It was not two P-51s.

No, I guess I did not make my point clear as to the big "why"?
(P.S. I was being rhetorical)

[iamlucky13]

Try to figrure this...

Despite the caption, that is actually an F-82 Twin Mustang, not two P-51s bolted together. The F-82 was an all new aircraft that started from the P-51H design, but diverted from it radically. It was not two P-51s.

No, I guess I did not make my point clear as to the big "why"?

I'm afraid you still haven't. You quoted my whole post, but it discussed several different topics.

Were you asking why the twin fuselage on the F-82 but not on a passenger jet?

They needed a second engine and bigger wings to lift the extra fuel for longer range, and they wanted a second pilot to reduce fatigue on long overwater flights. Basing it on the P-51 saved development cost, and the separate cockpits avoided disadvantaging one crewman with a backseat view, as he was not a systems operator, but a full co-pilot.

In some ways it was similar to the twin-boom P-38, but that plane had a central fuselage and was single-seated.

If you're carrying passengers, you need a large pressurized volume, something neither the F-82 nor the Stratolauncher aircraft require. Two fuselages is not a structurally efficient way to provide that volume.

If you were asking why I think modifying two 747's to this configuration is more difficult than building the F-82, you'll have to point out which part of what I said in my previous post you disagree with.

[Lurker Steve]

If all else fails, maybe you could use it to carry submarines 

Suppose you don't want to send your sub thru the Panama Canal, or thru the Suez Canal, or around the Cape of Good Hope, or around Tiera Del Fuego. Just hook it up to Stratolaunch, and fly it wherever you want.

Gee, come to think of it, wouldn't Stratolaunch be better as a giant seaplane, like Spruce Goose? Could eliminate landing-gear weight.

Even if you off-loaded all of the Trident missles at one coast, and re-loaded them at the other coast, do you really think you can get permission to fly that nuclear reactor (or perhaps Subs have multiple reactors ??) over land ? How does that reactor get cooled during flight ?