Stratolaunch: General Company and Development Updates and Discussions

[Robotbeat]

Reminds me of the Spruce Goose. Carbon Cockatoo?

Not a bad choice of moniker.. but since Cockatoos tend to be (a) big, (b) proud, (c) noisy and (d) incredibly destructive, we'll need to wait for flight test to tell if it fits.

I think it may be a better fit for ITS. But I hope not.

[KSC Sage]

The picture with Allen standing on the wing is surprising to me. I can't tell for sure what is a mat laid down to protect the wing surface, and what is actual wing, but it looks like there are many many fasteners sticking out of the wing surface. Would seem that this eats into the advantages of composite construction in two ways. It makes for an aerodynamically dirty surface and requires hard points and washering all over the place to spread the loads out and create flanges.

I guess we will never know, but I am curious about the magnitude of the weight saved with composite construction in this project.

Matthew

When I visited their manufacturing facility they explained the composite construction doesn't save much weight.  What it does do is it allows them to reshape and slightly change the plane's OML while in construction and later during testing.

[CameronD]

The picture with Allen standing on the wing is surprising to me. I can't tell for sure what is a mat laid down to protect the wing surface, and what is actual wing, but it looks like there are many many fasteners sticking out of the wing surface. Would seem that this eats into the advantages of composite construction in two ways. It makes for an aerodynamically dirty surface and requires hard points and washering all over the place to spread the loads out and create flanges.

I guess we will never know, but I am curious about the magnitude of the weight saved with composite construction in this project.

Matthew

When I visited their manufacturing facility they explained the composite construction doesn't save much weight.  What it does do is it allows them to reshape and slightly change the plane's OML while in construction and later during testing.

When the weight saved by going to composite construction on a B777 equates to several extra passengers and slightly longer range, that sounds strange to me.  Precisely how much does depend upon exactly which structures you're using the composites for, but that it doesn't save "much" does sound strange to me.  Maybe they're not using a lot of composites in the end?

For one-off construction and complex structures, composites make a lot of sense but for simpler structures like spars, beams, landing gear and seat rails, aircraft-grade alloy is cheaper to buy and easy to machine, so not so much.  Cost can go either way.  As with most things aerospace, I guess the final answer is "it depends"..

[Lars-J]

For one-off construction and complex structures, composites make a lot of sense but for simpler structures like spars, beams, landing gear and seat rails, aircraft-grade alloy is cheaper to buy and easy to machine, so not so much.  Cost can go either way.  As with most things aerospace, I guess the final answer is "it depends"..

I think much of this in aerospace can be explained by the old adage "when all you have is a hammer, every problem looks like a nail". If you have experience with composites, you tend to use them even when you should not. And vice versa.

[CameronD]

For one-off construction and complex structures, composites make a lot of sense but for simpler structures like spars, beams, landing gear and seat rails, aircraft-grade alloy is cheaper to buy and easy to machine, so not so much.  Cost can go either way.  As with most things aerospace, I guess the final answer is "it depends"..

I think much of this in aerospace can be explained by the old adage "when all you have is a hammer, every problem looks like a nail". If you have experience with composites, you tend to use them even when you should not. And vice versa.

Hmm.. that hasn't been my experience working with Boeing/Airbus: in airliner fabrication historically they've been reluctant to use composites for anything serious and it's only been relatively recently (last 15 years or so) that they've both embraced the "plastic plane" concept with both arms.  I guess you could argue that now they've gone too far the other way?

How I do miss the old chemi-mill line.  Some of the parts you could fabricate were works of art!
   

[Robotbeat]

Part of the reason they don't save much weight is that we're still refining our models of damage tolerance (etc!) for composites. They're a much more complex material. So we end up putting a lot of margin in various steps. What you end up with is matrginal weight savings, some manufacturing advantages for certain types of shapes, and actually a very sandbagged design with lots of hidden margin that we're not certified to take advantage of but which exists nonetheless. So you could argue there's a big safety factor there as well.

[FutureSpaceTourist]

New article by Alan Boyle but not much new info:

Billionaire Paul Allen hopes his ‘ginormous’ Stratolaunch plane will fly this year

http://www.geekwire.com/2017/paul-allen-ginormous-stratolaunch-super-plane/

[FutureSpaceTourist]

Looks like the Stratolaunch website has some new (or at least new-ish) photos of its aircraft under construction: stratolaunch.com

https://twitter.com/jeff_foust/status/852978324813090816

I've attached the images I found.

[Chris Bergin]

Ooooh!

https://twitter.com/PaulGAllen/status/869959551553904640

.@Stratolaunch came out of the hangar for fuel testing. More pictures soon!

[russianhalo117]

Ooooh!

https://twitter.com/PaulGAllen/status/869959551553904640

.@Stratolaunch came out of the hangar for fuel testing. More pictures soon!

An anchored engine run up test is to occur on final fueling test.

[FutureSpaceTourist]

Some more photos; haven't yet found higher-res public ones.

[TomH]

WaPo Article:

https://www.washingtonpost.com/news/the-switch/wp/2017/05/31/paul-allen-just-rolled-out-the-worlds-largest-airplane-and-he-ready-to-take-on-the-rocket-makers/?utm_term=.ba5c497877bd

[CameronD]

Ooooh!

https://twitter.com/PaulGAllen/status/869959551553904640

.@Stratolaunch came out of the hangar for fuel testing. More pictures soon!

At risk of stating the obvious:  That is one big aeroplane!!!! 

[Rocket Science]

I really would like to fly this aircraft!

[MATTBLAK]

Anyone know if some of the propellants for the air-launched rocket are carried within the plane's fuselages before launch?

[JBF]

With no nose cones it's obvious that the radar systems are not installed. Without a cockpit picture it is hard to judge how close it is to flying.

[TomH]

Anyone know if some of the propellants for the air-launched rocket are carried within the plane's fuselages before launch?

That is a good question; as well as can they de-prop back to the mother ship in case of a scrub. I would not like to be the person landing that thing with the rocket fully propped after a scrub. I wonder if they would even jettison the prop.

[TomH]

I really would like to fly this aircraft!

Something in my the back of my mind screams, Those horizontal stabilizers should be tied together! Even if the elevators remain separate.

[Bubbinski]

Great to see the big bird rollout.

If they use a solid booster like the Pegasus they wouldn't need to concern themselves with de-tanking the propellant after a scrub. The articles I've seen indicate the first launches from this bird in 2019, and also talked of launching up to three Pegasus rockets. How solid is this info? And is there anything about a bigger solid fueled rocket being proposed, like a "Liberty-light"?

[FutureSpaceTourist]

Scaled Completes Tow Test of World’s Largest Composite Aircraft, @Stratolaunch. @PaulGAllen

https://twitter.com/scaledc/status/870034720825856000