Stratolaunch Discussion Thread

N14AZ · Wed Oct 18, 2017 12:03 pm

Some new pictures have been published when Stratolaunch hosted Vice President Mike Pence earlier this month:

Source: http://www.stratolaunch.com/news/VP-MikePence.html

And another pic from the day when they stated the engine for the first time (for the first time on the carrier aircraft, of course):

Source: https://www.wired.de/collection/tech/st ... t-flugzeug

JetBuddy · Fri Oct 20, 2017 3:49 pm

Great pictures. Hoping to see it in the air soon.

Dutchy · Fri Oct 20, 2017 3:52 pm

Still a bizarre construction, can't wait to see if it works.

parapente · Mon Oct 23, 2017 12:30 pm

I have such a nasty feeling about this and RB's project.I sadly think both will go the way of the 'Spruce Goose'.
There is of course so much going on in the space field right now.But there will (as ever) be winners and losers.
In terms of business Europe,Japan,India,Russia and China all have their government supported programmes and the business that goes with it.That does not leave much.Already there are small sat launchers out there with too many more (including this one).
If it was so lucrative then you would be seeing Elon using Falcon1's but he isn't.And anyway you can always add them to other bigger missions at a much lower cost.
I think the NZ guys will go bust first,quickly followed by RB's 747 idea and also finally this one (others have already stopped).
Yup I know it's pessimistic ,wish I wasn't.

Noshow · Wed Oct 25, 2017 8:12 am

No need to get too sceptical. These projects seem to progress fast. Quite different from the old bureaucracy of big space organisations with long schedules and enormous costs that avoid risk at any cost.
Stratolaunch's issue is that it looks to be too big for modern micro satellites. Maybe they can carry some "bus" into space, with some dozens of satellites in it or similar?

WIederling · Mon Oct 30, 2017 8:25 am

Noshow wrote:
No need to get too sceptical. These projects seem to progress fast. Quite different from the old bureaucracy of big space organisations with long schedules and enormous costs that avoid risk at any cost.
Stratolaunch's issue is that it looks to be too big for modern micro satellites. Maybe they can carry some "bus" into space, with some dozens of satellites in it or similar?

Stratolaunch capabilities appear to not reach beyond ~6t for LEO and ~2t for GTO ( even less after GEO insertion ).

the carrrier isn't much more than a ".2 stage" :-)

zanl188 · Mon Dec 18, 2017 11:44 am

Stratolaunch conducted a taxi test over the weekend. Video available - I’ll post later if I can locate it.

zanl188 · Mon Dec 18, 2017 11:50 pm

Press release and video regarding taxi test here:

http://stratolaunch.com/news/StratolaunchTaxiTest.html

AirlineCritic · Tue Dec 19, 2017 7:37 am

It does look very, very weird. I wish them luck. Would be great to see this actually take off (in the business sense, too).

parapente · Tue Dec 19, 2017 11:37 am

What it needs is something like a NASA SRB underneath it.NASA has fully re-developed the new one for their new big rocket and indeed flown an even bigger one under the previous manned plan now long since cancelled.Should get a decent payload up with something like that.

zanl188 · Tue Dec 19, 2017 12:20 pm

SRB weighs 1.3 million pounds fueled. Stratolaunch aircraft max payload is 500,000 pounds.

Slcpilot · Mon Feb 26, 2018 10:43 pm

Enjoy!

https://youtu.be/-AY-HC4sUGU

parapente · Tue Feb 27, 2018 2:09 pm

Thx nice vid' making progress.
I note that Orbital ATK has only one flight left in its manifest using the Tristar launcher.But why should the behemoth be better than using the tried and trusted Tristar?Ok it can launch 3 at a time but to me that's missing the point (unless you want to launch everything into the same orbit-which is unlikely).Clearly it was originally designed for a bigger (mini Falcon) rocket which didn't work out.Seems it doesn't have a proper mission but I am sure they know what they are doing.

Noshow · Tue Feb 27, 2018 2:29 pm

Could there be any big military payload waiting to be launched? It's big size capability does not seem to be needed for most commercial satellites today.

DIJKKIJK · Tue Feb 27, 2018 3:40 pm

I have a question about this. How did Scaled Composites, a company with zero experience in building large airplanes, manage to come up with such a sophisticated design?
They say that it is mainly based on the Boeing 747-400. But even so, I would imagine it is rather difficult to re-engineer a large aircraft like the 747-400 to create this.

Were they helped by Boeing?

zanl188 · Tue Feb 27, 2018 4:04 pm

Trouble with air launched is if anything happens to that specialized airframe - you’re done.

Rejected takeoff and aircraft goes off the end and burns. Program over without a second airframe.

euroflyer · Tue Feb 27, 2018 4:09 pm

Scale is not so much a problem when you already have experience in aircraft manufacturing, which they already got with the White Knight (I and II) projects, in collab with Virgin. Also, it's very easy for such a company to hire specialized personel through consulting firms and strong subcontractors
Also, it doesn't hurt that they're Northrop owned

DfwRevolution · Tue Feb 27, 2018 7:04 pm

Noshow wrote:
Could there be any big military payload waiting to be launched? It's big size capability does not seem to be needed for most commercial satellites today.

Stratolaunch is a "midsized" vehicle. As mentioned by WIederling, payload is approximately 6,000 kg to LEO and 2,000 kg to GTO. That's equivalent to a Delta II. By contrast, vehicles like the Atlas V, Ariane V, and Falcon 9 are generally 4,000 - 8,000 kg to GEO orbit (or more) depending on vehicle configuration.

Does the military have need for a carrier aircraft like the NB-52? Not to my knowledge and not likely to merit a custom-built aircraft.

AirlineCritic wrote:
It does look very, very weird. I wish them luck. Would be great to see this actually take off (in the business sense, too).

As an engineer and enthusiast, I love seeing experimental projects like this. It will be remarkable to see this beast fly. Just watching it taxi at 40 knots its pretty cool.

I share the widespread skepticism of the business case. It's a lot of overhead. The past experience of SeaLaunch and Orbital ATK have not made a compelling case that the range flexibility, simplified facilities, or performance boost from mobile launchers results in a competitive advantage.

Maybe it can find a role in a space tourism capacity? I don't know. Virgin Galactic already has a carrier aircraft of their own.

KarelXWB · Wed Feb 28, 2018 9:09 am

Dutchy wrote:
Still a bizarre construction, can't wait to see if it works.

It looks like a similar construction as the Virgin Galactic mother ship.

WIederling · Wed Feb 28, 2018 9:35 am

it is a typical Scaled Composites design. only "Scaled"..UP :-)

no suprises there.

initially the mock ups shew complete 747 noses. not much left of those.

engine control, gear control and the basic concept of control surface actuation were
transplanted from the 747 ?

cougar15 · Wed Feb 28, 2018 9:37 am

There was a good question in the comments section to the photo in the database. ´Who has the pants´ on, the right or the left driver?? Very interesting machine, can´t wait to see it airborne!!

Max Q · Wed Feb 28, 2018 10:54 am

The most bewildering part of this design to
me is not joining the two booms at the tail
with one continuous horizontal stabilizer

They would seem to have eliminated the possibility to add great strength and rigidity by not doing this

Instead they’ll have two separate horizontal stabilizers widely separated
that will not be ‘flexing In harmony’

I would think that could create problems

LightningZ71 · Wed Feb 28, 2018 2:44 pm

The only potential saving grace for this project is the sometimes mentioned possibility of it being fitted with a removable cargo pod that will allow it to take oddly shaped or just overly large cargo via air. It does have quite a bit of actual payload capacity, and the potential possibility of a cargo pod that can swallow items that are just too large (but not heavier than...) for the AN-225 to fit could MAYBE give this thing more use. The second issue is that it is quite restricted in the number of runways that it can reliably use. It's wingspan is extreme, as is it's landing gear track.

estorilm · Wed Feb 28, 2018 3:05 pm

Max Q wrote:
The most bewildering part of this design to
me is not joining the two booms at the tail
with one continuous horizontal stabilizer

They would seem to have eliminated the possibility to add great strength and rigidity by not doing this

Instead they’ll have two separate horizontal stabilizers widely separated
that will not be ‘flexing In harmony’

I would think that could create problems

I noticed the exact same thing, overall the design would appear to be very strong (I'm sure it probably still is..) but wow, just visually looking at it overhead without the joined tails makes the entire thing look almost... delicate.

WIederling · Wed Feb 28, 2018 3:22 pm

Max Q wrote:
They would seem to have eliminated the possibility to add great strength and rigidity by not doing this

That is what you don't want.
Imagine the forces you would have to cope with to keep the fuselages hard aligned via a connecting tailplane.
As it is now you can flex the parts without damage and without weight penalty.

Route66 · Wed Feb 28, 2018 3:25 pm

Noshow wrote:
Could there be any big military payload waiting to be launched? It's big size capability does not seem to be needed for most commercial satellites today.

I read somewhere yesterday that the rocket's payload is going to be relatively small compared to SpaceX, for example.

Max Q · Thu Mar 01, 2018 4:59 am

WIederling wrote:
Max Q wrote:
They would seem to have eliminated the possibility to add great strength and rigidity by not doing this

That is what you don't want.
Imagine the forces you would have to cope with to keep the fuselages hard aligned via a connecting tailplane.
As it is now you can flex the parts without damage and without weight penalty.

I don’t see it, those forces would
be absorbed by a connecting horizontal stabilizer, that’s my point

Francoflier · Thu Mar 01, 2018 6:38 am

Scaled Composites has quite a lot of experience with that design.

I am also perplexed by the potential torsional effort created by even a slight difference in aerodynamic load from each tailplane, but I'm guessing they have enough redundancy built into that system to prevent asymmetric loads.

That thing is nothing but a White Knight Two on steroids after all, and that seemed to work.

parapente · Thu Mar 01, 2018 8:54 am

Thing is it was originally designed to go with a rocket built by Spacex.As I recall it was a baby Falcon (Falcon 1? I am not sure).But the project collapsed.Now its carrying a far smaller rocket.Yes it can carry 3 of these but that misses the point of optimal launch points that an aircraft gives you.
I guess we will see.Anyrate will be great to see it fly!

Max Q · Thu Mar 01, 2018 8:58 am

Worked pretty well on the P38 !

WIederling · Thu Mar 01, 2018 9:34 am

Max Q wrote:
Worked pretty well on the P38 !

Only this here is not a P38. completely different proportions.

einstein: make your model as simple as possible. but not simpler.

Francoflier · Thu Mar 01, 2018 1:02 pm

WIederling wrote:
Max Q wrote:
Worked pretty well on the P38 !

Only this here is not a P38. completely different proportions.

einstein: make your model as simple as possible. but not simpler.

Not only was it much smaller, but it also had a single tailplane, giving the twin fuselage structure a lot more rigidity, which is the issue being discussed above.

WIederling · Thu Mar 01, 2018 2:16 pm

Francoflier wrote:
WIederling wrote:
Max Q wrote:
Worked pretty well on the P38 !

Only this here is not a P38. completely different proportions.

einstein: make your model as simple as possible. but not simpler.

Not only was it much smaller, but it also had a single tailplane, giving the twin fuselage structure a lot more rigidity, which is the issue being discussed above.

engine in the fuselage, much closer together, a deeper stiffer wingbox to take the moment arm of the cockpit...., ....
..as I wrote:
"Only this here is not a P38. completely different proportions."

Designwise connected tail planes make no sense for the structure
and they make no sense for the use case.
( see why the AN225 has no center horizontal stab.)

JetBuddy · Thu Mar 01, 2018 3:30 pm

I agree with Max Q here. The weakest point of this design is the centre wing. With enough force being applied on each fuselage independently of each other, that's where this thing would break apart. Flexibility is absolutely necessary for this design, but not enough structural integrity is also a problem.

Now hang a rocket in the center wing, add some unexpected heavy turbulence or wind shear working independently on each fuselage and visualize for yourself how each side starts oscillating back and forth while the yaw dampers are working overtime. It could be a complete disaster.

That being said, these Scaled Composites engineers know better than me. And I really do hope it works.

RetiredWeasel · Thu Mar 01, 2018 4:01 pm

JetBuddy wrote:
I agree with Max Q here. The weakest point of this design is the centre wing. With enough force being applied on each fuselage independently of each other, that's where this thing would break apart. Flexibility is absolutely necessary for this design, but not enough structural integrity is also a problem.

Now hang a rocket in the center wing, add some unexpected heavy turbulence or wind shear working independently on each fuselage and visualize for yourself how each side starts oscillating back and forth while the yaw dampers are working overtime. It could be a complete disaster.

That being said, these Scaled Composites engineers know better than me. And I really do hope it works.

It's not like Scaled Composites doesn't have experience in this type of design. Take a look at this video of the White Knight 2. That airframe flew 95 sorties without any structural damage or severe problems. Albeit, it is a much smaller scale but they have also built similar non-attached twin-boom tail structures aircraft even prior to White Knight 2.

https://www.youtube.com/watch?v=YFdL8b03qdU

Max Q · Fri Mar 02, 2018 2:00 am

The design does put significant stress on the center wing

With two long,separate ‘fuselage bodies’ flexing at different rates
and different amounts this stress
could be significantly reduced by
joining the two stabilizer units and it would be far stronger

There’s also a lot to be said for’if it looks right it will fly right’ it just doesn’t look right

Nomadd · Fri Mar 02, 2018 2:51 am

parapente wrote:
Thing is it was originally designed to go with a rocket built by Spacex.As I recall it was a baby Falcon (Falcon 1? I am not sure).But the project collapsed.Now its carrying a far smaller rocket.Yes it can carry 3 of these but that misses the point of optimal launch points that an aircraft gives you.
I guess we will see.Anyrate will be great to see it fly!

It would have been a Falcon 4 or 5. SpaceX backed out when they realized how difficult it would be. They had better uses for their resources.

zanl188 · Fri Mar 02, 2018 5:16 am

Max Q wrote:
The design does put significant stress on the center wing

With two long,separate ‘fuselage bodies’ flexing at different rates
and different amounts this stress
could be significantly reduced by
joining the two stabilizer units and it would be far stronger

There’s also a lot to be said for’if it looks right it will fly right’ it just doesn’t look right

I would think the opposite is true. With the load spread out on the wing, bending moment & stress is reduced.

WIederling · Fri Mar 02, 2018 12:22 pm

Max Q wrote:
There’s also a lot to be said for’if it looks right it will fly right’ it just doesn’t look right

Only to the right people.
( Too many movies and sleek looking CGI stuff have killed any competence there afaics. :-)

You ask for making a flexible structure that accommodates stress via flexing
into a rigid structure. That won't fly.
Think about the moment that has to be passed
through the tailplane =| tail/fuselage interface.

Same design conundrum for the closed loop wings we've been presented with on occasion.
( another case in point the 787 wing join that failed via a discontinuous excess of structure.)

flyingturtle · Fri Mar 02, 2018 12:31 pm

Dang, how it reminds me of the aircraft Airbus was too afraid to build:

http://www.plig.net/things/pictures/tn/ ... s.jpg.html

David

WIederling · Fri Mar 02, 2018 12:38 pm

flyingturtle wrote:
Dang, how it reminds me of the aircraft Airbus was too afraid to build:

http://www.plig.net/things/pictures/tn/ ... s.jpg.html

Prrfft

Stratolaunch has much more in common with the Z derivatives of German bomber ( and fighter ) aircraft.
see Glider Tug He-111Z:
https://www.militaryfactory.com/aircraf ... aft_id=528

N14AZ · Thu Aug 02, 2018 10:47 am

So? Didn't they plan to make FF during summer 2018? I just made a brief internet Research but didn't find anything new, no new pictures, no new articles, nothing...

For time being I post this picture due to its nice background ... (no, not the bl#&§dy hills)

Source (which contains some speculation about what's going on but unfortunately just in German): https://scilogs.spektrum.de/astras-spac ... -glatteis/

FW200 · Thu Aug 02, 2018 12:48 pm

Dutchy wrote:
Still a bizarre construction, can't wait to see if it works.

KarelXWB wrote:
Dutchy wrote:
Still a bizarre construction, can't wait to see if it works.

It looks like a similar construction as the Virgin Galactic mother ship.

Reminds me of the Heinkel He 111 Z

http://www.kheichhorn.de/html/body_heinkel_he_111z.html

https://www.youtube.com/watch?v=LGG0n-PIlp8

http://www.airpages.ru/eng/lw/he111z1.shtml

estorilm · Thu Aug 02, 2018 4:27 pm

Max Q wrote:
The design does put significant stress on the center wing

With two long,separate ‘fuselage bodies’ flexing at different rates
and different amounts this stress
could be significantly reduced by
joining the two stabilizer units and it would be far stronger

There’s also a lot to be said for’if it looks right it will fly right’ it just doesn’t look right

I agree 100%.

I really don't know why they didn't join the tails - I can't imagine clearance being that much of an issue. Just make some small-diameter super strong carbon composite pole that spans the distance (granted I'm sure it would be shaped). It wouldn't do much for vertical AOA differences of the two fuselages, but it would at least ensure they remain laterally stable / parallel.

Maybe it's just going to have minimums that require absolutely perfect weather with zero winds/turbulence.

estorilm · Thu Aug 02, 2018 4:34 pm

Wow actually I just thought of one SPECIFIC (and large) issue with only joining the fuselages by the wing.

While elevator deflections will indeed be neutral (between the two sides) - wouldn't all rudder movement (even being exactly the same between sides) tend to "pull" the tail booms side-to-side laterally as they deflect? Normally that wouldn't be an issue, but that force will be met at the wing joint on this design.

It's hard to visualize or explain while writing, but I can see it in my head. Just seems odd. Though presumably they won't be doing a whole lot of turning lol.

QuarkFly · Thu Aug 02, 2018 4:49 pm

...And it must have one sophisticated system for yaw damping.

And with a large heavy rocket hanging form the center wing, the aircraft will have to handle two kinds of weight-load and aerodynamic effects...for flying with/without a payload.

Maybe pitch trim will be awkward too, without a rigid connection between the two tail sections.

estorilm · Thu Aug 02, 2018 5:55 pm

QuarkFly wrote:
...And it must have one sophisticated system for yaw damping.

And with a large heavy rocket hanging form the center wing, the aircraft will have to handle two kinds of weight-load and aerodynamic effects...for flying with/without a payload.

Maybe pitch trim will be awkward too, without a rigid connection between the two tail sections.

Yup - just seems like any kind of rigid beam (even a very narrow one) would solve MANY problems. Clearance must be a major concern, nothing else really explains it.

LightningZ71 · Thu Aug 02, 2018 9:01 pm

I wonder if they have to account for rocket ignition while still on the launch pylon? That exhaust plume would be rather violent I would guess.

Slcpilot · Thu Aug 02, 2018 11:13 pm

If and when it does fly, I can’t help but wonder if there’s a yoke/stick (?) disconnect feature. Some traditional airliners have some form of disconnect where each control input can control respective elevator halves.

I wonder if there is any provision for each input independently controlling each fuselage in the event of a torsional inequality between each fuselage. This would probably be an emergency situation.

Bonus points for the first cockpit picture too!

Cheers!

SLCPilot

AirlineCritic · Fri Aug 03, 2018 7:14 am

Ok, so we are now arm-chair-designing. And board commentators think they know better than Scaled. Hmm.... I'd put my money on Scaled having done their homework.

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