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Which CAD was used to design Stratolaunch?

Which CAD was used to design Stratolaunch?

(OP)
Very impressive! Does anybody know which CAD did they use? Was it NX, CATIA, or something else?

www.cadroad.com

RE: Which CAD was used to design Stratolaunch?

I wonder why they have (apparently) two flight decks ? There have been several airplanes with twin fuselages, but typically only one flight deck.

another day in paradise, or is paradise one day closer ?

RE: Which CAD was used to design Stratolaunch?

The flight deck on the left is empty and unpressurized. Future options I guess. (There's a link on Drudge today for the whole story.) I'm not in aerospace but it is my understanding that Catia is the preferred tool for aerospace design.

RE: Which CAD was used to design Stratolaunch?

Looks like the pilot and copilot have had a spat.

RE: Which CAD was used to design Stratolaunch?

Adobe Photoshop

RE: Which CAD was used to design Stratolaunch?

Job postings note a preference for Solidworks (or equivalent) in CAD experience. The first handful of employees that've worked on it, which I found on LinkedIn, claim proficiency in many CAD/CAE software packages, though.

Otherwise can't really tell. Solidworks is apparently being used by more larger scale projects like this. A friend of mine who worked at Firefly before a recent downsizing said that's what they used. I was quite surprised, expecting something more like you mention - NX/CATIA or maybe Pro/E or something with similarly advanced analysis functions. Using Solidworks and external CAE analysis and simulation software like Ansys is apparently not uncommon in advanced engineering companies like these, though.

RE: Which CAD was used to design Stratolaunch?

So far what I can see it looks like SolidWorks.

Chris, CSWP
SolidWorks '16
ctophers home
SolidWorks Legion

RE: Which CAD was used to design Stratolaunch?

But we do know that the engines were designed using NX.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Which CAD was used to design Stratolaunch?

The lack of elegance of curvature on the fuselage indicates SolidWorks.

RE: Which CAD was used to design Stratolaunch?

Quote (TheTick)

The lack of elegance of curvature on the fuselage indicates SolidWorks.

Honest question: What is lacking in SolidWorks that is needed to generate more complex curves? Do higher-end CAD systems have dedicated tools for this type of task?

I cannot imagine a shape that I couldn't make in either of the lower-end CAD systems that I have experience in, SolidEdge and SolidWorks. However, I fully admit that my imagination may be the limiting factor here; aerodynamic, flowing shapes have never really been my job.

RE: Which CAD was used to design Stratolaunch?

It's got this weird look of some sort of advanced-beginner training model. Not speaking so much to the capabilities of SW so much as the type of design that often emanates from middle-of-the-road users venturing into more daring territory for the first time.

Fuselage looks like a pair of scaled-up Cessna 172s with B-1 noses scabbed on. "Corners" of rear half of fuselage are not C2 continuous. Flat side walls surrender a lot of structural integrity inherent with a more cylindrical/conical shape.

I can only speak about CATIA from the perspective of a downstream client. However, I had a lot of "under the hood" experience with UG/NX surfacing. If I was designing ANYTHING with math-critical surfaces, it would be in NX or CATIA (not even Creo).

RE: Which CAD was used to design Stratolaunch?

I did some work on the MLG integration at a subcontractor and everything we did was in CATIA V5.

RE: Which CAD was used to design Stratolaunch?

The space between the fuselages is for payload and I had assumed the flat sides were deliberate to maximise that space. . . . Or perhaps they were designed in Solidworks.

je suis charlie

RE: Which CAD was used to design Stratolaunch?

If they truly -did- do the structure in SW it would be the first I'm aware of. The only people I know, personally, who use SW in an aerospace context have used it for engines and mechanical systems.

Solidworks and other "middle of the road" CAD packages have come a long way since I last worked with them several years back. They have been incorporating a lot more freeform surfacing tools, flow and thermal analysis, and some FEA tools. I have not used any such tools. I was just surprised to learn of it. It's possibly just something that makes 'pretty pictures' that will make minor/less-critical design work "look better" or make pretty pictures for advertising materials that make them look like a more advanced/competent engineering team... or maybe it's pretty legit. I dunno. The people I know using Solidworks use more established CAE tools.

RE: Which CAD was used to design Stratolaunch?

I find it hard to believe that the shape is limited by the capabilities of the CAD tool. Sure SW is seen as CATIA-lite. I suspect that the licence fee is lower and the capabilities similar. Someone starting out now has more options that 10 or 20 years ago, and isn't married to the big CAEs (CATIA, PATRAN, NASTRAN).

I think the shape is the shape they want, from CFD. Flat sides improve the wing end plate effect, I doubt the the payload has much impact on this design decision. Those enormous MLG bogies must be murder to retract (into a sensible shape).

As for the second cockpit ... maybe that's reserved for payload operating crew ?

another day in paradise, or is paradise one day closer ?

RE: Which CAD was used to design Stratolaunch?

The round shape of most higher altitude transport aircraft come from the fact that they are basically flying pressure vessels built for human "cargo". The payload for this aircraft is all external (between the fuselages). I would bet that the sections with flat walls are not pressurized (thus not intended for humans), so their construction could be simple rectangles. I would guess that the only areas intended for possible human occupancy are the cylindrical shaped front sections of the fuselages. The article I read said that the crew is in the right flight deck. The left one is vacant and unpressurized. The left one was probably designed that way for aerodynamic symmetry and for potential later occupancy.

Interestingly, just this morning I saw a picture in the book "How to Make a Spaceship" of Burt Rutan (designer of the above aircraft) when he was 10 years old with one of his first homebuilt balsa wood and paper model airplanes. I can highly recommend that book for anyone interested in the development of commercial spacecraft.

RE: Which CAD was used to design Stratolaunch?

It looks like since it's a one off or small fleet plane, that the design and tooling figure large in the project cost. I think this is a case of making one thing twice is easier than making two similar things once.

SCI can certainly make beautiful and crazy things without a straight line in them, however they get to lines on paper and coding in machines. The 'liquid shape' aspects of the thing may not have been critical, that the approach of sistering a couple giant Short 360's solved their problem. I think the FBW aspects of the thing must be very interesting. With the weak but significant fuselage coupling, it must be like operating a couple large planes in formation, except if you break formation, everyone dies.

RE: Which CAD was used to design Stratolaunch?

From: https://en.wikipedia.org/wiki/Scaled_Composites_St...

"To cut development costs, many of the aircraft systems have been adopted from the Boeing 747-400, including the engines, avionics, flight deck, landing gear and other systems. Two former United Airlines Boeing 747-400 aircraft (Serial numbers 28715 & 28716) were acquired and taken to the Mojave Air & Space Port for cannibalization."

RE: Which CAD was used to design Stratolaunch?

The White Knights 1 & 2 do something similar, two identical looking fuselages instead of a right and left hand.

RE: Which CAD was used to design Stratolaunch?

Quote (JNieman)

Solidworks and other "middle of the road" CAD packages have come a long way since I last worked with them several years back. They have been incorporating a lot more freeform surfacing tools, flow and thermal analysis, and some FEA tools. I have not used any such tools. I was just surprised to learn of it. It's possibly just something that makes 'pretty pictures' that will make minor/less-critical design work "look better" or make pretty pictures for advertising materials that make them look like a more advanced/competent engineering team... or maybe it's pretty legit. I dunno. The people I know using Solidworks use more established CAE tools.

I use both Solidworks and Catia extensively- the difference between the two is much, much narrower than it was 10 years ago.

When you go to Catia, you get that last 5% of capability with surfacing. I would say that any surface that you could create in Catia, you could also create in Solidworks, but the process, level of accuracy attainable, and number of iterations/amount of time required to get to your final shape with good underlying math is bigger in Solidworks.

As far as CAE, I use Solidworks' native analysis package a fair bit for stress and strain analysis, as well as for mold flow checks- and it's perfectly functional as a first pass solver. On simple stress/strain problems, in my experience, Solidworks results and ANSYS results always agree. What Solidworks doesn't handle well is more complicated problems- collisions, flexible parts, parts with nonlinear characteristics, very large dynamic assemblies, etc. So for 95% or so of CAD users, Solidworks provides all they will ever need.

In the aerospace world (which I'm not a part of) it almost certainly isn't enough on its own.

RE: Which CAD was used to design Stratolaunch?

You guys must be joking. Any CAD package I know of, in sufficiently incompetent hands, could have generated that fuselage profile.

It looks like one continuous nasty loft, from bow to stern done by some junior-designer hired 1 week after the into course.
The fwd fuse corner fillet and the wing "fairing" blend look terrible. Maybe there was some need to compromise, for unseen internal issues.
The tail will have interference drag at the root. More than if it looked more like the marketing promo models.
Reality probably bit somebody on the a**, and this is just what they settled for.

STF

RE: Which CAD was used to design Stratolaunch?

I think they should've tied the two horizontal stabilizers together P38-like to make a stronger box structure.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Which CAD was used to design Stratolaunch?

(OP)
Regarding the flat sides. They need a big ground clearance for the payload, therefore the height of the fuselage is given. But it is not worthy to make its width similar, thus getting closer to the cylindrical cross-sections. That would mean extra material and weight for nothing in return. Having said that, I am not an aerospace engineer.

There were some interesting comments suggesting inexperience of the designers. A honest question (I do not live in US) - is it possible in US that someone inexperienced is hired to do such kind of job? If yes, what is the reason? Is it because all experienced aerospace designers would not want to leave their good jobs for some dodgy startup or what?

www.cadroad.com

RE: Which CAD was used to design Stratolaunch?

I'd have got rid of the inboard part of the tailplane completely, given the intended use (pitch on release etc). Idly thinking, is there any possibility they'd fire the rocket engines before release?

Cheers

Greg Locock


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RE: Which CAD was used to design Stratolaunch?

Greg ,
Getting rid of the inboard Part of the tail plane would put a massive bending load on the end of the tail cone when full up or down elevator was applied.
B.E.

You are judged not by what you know, but by what you can do.

RE: Which CAD was used to design Stratolaunch?

The fuse shape isn't that dissimilar to the B52 (except where they sweep it up to lift the wing) which makes sense as it is also is largely unpressurized.

The critical horizontal tailplane loads would likely be quite asymmetrical already, given those three engines appear to be very closely spaced by airliner standards. Will be interesting to see how much tail shake it has during a full power ground run.

RE: Which CAD was used to design Stratolaunch?

I see the similarity

RE: Which CAD was used to design Stratolaunch?

You guys crack me up. This plane was designed by one of the most experienced and recognized aircraft designers on the planet, Burt Rutan. Google him. If you have followed aircraft design for any length of time you have heard his name, and his company Scaled Composites, mentioned in connection with all the most innovative and record-breaking designs of the last 20 years. If there is anyone more capable of designing an aircraft for a single purpose mission, I don't know who it would be. This plane was not designed for high production volume or peak efficiency. It is intended to safely transport rocket vehicles to a specified launch altitude.

RE: Which CAD was used to design Stratolaunch?

No, Jboggs, that doesn't matter.

They spent untold hours of thorough design time, but these guys looked over the skin shape for DOZENS of minutes. DOZENS. Obviously they know enough to dictate the appropriate modifications. bigsmile

(tongue firmly in cheek, folks, don't take it seriously)

RE: Which CAD was used to design Stratolaunch?

Quote (PrintScaffold)

There were some interesting comments suggesting inexperience of the designers. A honest question (I do not live in US) - is it possible in US that someone inexperienced is hired to do such kind of job? If yes, what is the reason? Is it because all experienced aerospace designers would not want to leave their good jobs for some dodgy startup or what?

For a project of this scale, budget and visibility it is HIGHLY doubtful than anyone even remotely green would be hired to design something like this. The comments of the posters above who know more about who is and isn't an experienced designer make it clear that the designer of this plane is not a new kid on the block.

The other factor is that regardless of Burt Rutan's experience designing aircraft, it's highly doubtful he was the one spending a couple thousand hours in Solidworks creating surfaces- but I would imagine someone like that doesn't just hire CAD operators off the street. I'm sure that the people creating the math for these shapes were highly experienced.

RE: Which CAD was used to design Stratolaunch?

Not to mention that the people willing to risk years and years of investment, and millions of dollars of product (satellites and business ventures) have to feel comfortable using their aircraft. It doesn't matter how 'cheap' you make a craft if no one wants to risk their payload riding along. Let's be practical here.

RE: Which CAD was used to design Stratolaunch?

My humorous comments were taken too seriously. I will clarify.
I have admired Burt Rutan for a long time, having watched his career for decades after seeing my first Long-EZ, walking around a Beech Starship, following the Virgin Atlantic's course as it flew, and cheering on the SS1 project.

This aircraft bears NONE of the characteristics of a Burt Rutan design.

STF

RE: Which CAD was used to design Stratolaunch?

Quote:

This aircraft bears NONE of the characteristics of a Burt Rutan design.

None.

--Scott
www.aerornd.com

RE: Which CAD was used to design Stratolaunch?

Quote (SparWeb)

This aircraft bears NONE of the characteristics of a Burt Rutan design.

It has three lift surfaces and looks really weird... doesn't that sound like Burt to you?

:)

RE: Which CAD was used to design Stratolaunch?

Maybe not Burt himself, but someone who is in Burt's immediate group. It lacks the sleekness that most of Burt's designs had, but it does have the functional approach that he so often used. Or the guy Brains, from the Thunderbirds.

RE: Which CAD was used to design Stratolaunch?

In my opinion it has more Rutan features than you might imagine. First the 100% composite construction. The very high aspect ratio wings. The split fuselage. The long skinny features. True, Rutan is known for canard wings, but there's a lot more than that here. And don't forget, you're looking at only half of a complete design. This carrier aircraft exists for one purpose - to carry the rocket vehicle that isn't even shown. Not many folks have designed two separate aircraft that are intended to function as one.

RE: Which CAD was used to design Stratolaunch?

But Brains didn't design the Thunderbirds. Although I do see some striking resemblance to Thunderbird 2 if this plane were painted green.

--Scott
www.aerornd.com

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