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3D modelers wanted for concept aircraft project

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posted on Jan, 10 2006 @ 11:13 AM
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As some of you might have been following, a few of us have been discussing various aircraft configurations for a super-short take-off and landing unmanned strike fighter designed to operate from “small” aircraft carriers. www.abovetopsecret.com...

The three current designs are:
1. A forward swept wing:


2. A bi-diamond wing:


3. A ‘conventional’ canard design:


The next stage of the project is to find ways of objectively analyzing their relative merits and make informed guesses as to how they’d perform.

As part of this we’re going to need 3d models of the aircraft –reasonably accurate ones. Initially these models will be for illustration. But we also hope to put the designs through airflow analysis software which would require 3d models (we won’t know the formats, scales etc until we’ve got the software lined up).

So if you have AutoCAD or 3D studio Max, please volunteer.
Thanks.




posted on Jan, 10 2006 @ 11:19 AM
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I'll 'ave a go. Do you know if you need polygon or nurbs model's? Also, if you have line drawings in plan views, that'd be good.



posted on Jan, 10 2006 @ 11:57 AM
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I have Autocad and Solidworks. Count me in.



posted on Jan, 10 2006 @ 12:35 PM
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I have AutoCad and solidworks too...
JIMC5499 Solid is probably better suited for this kind of complex solidbody design, and since it has better simulation/math cababilities....

maybe we could divide the job somehow?



posted on Jan, 10 2006 @ 09:33 PM
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Thanks for the offers of help.

Here’s an annotated scale drawing of the first design;

Full sized image: tinypic.com...

If you can’t do it that accurately, don’t worry; we can still use models that look right for illustrative purposes. But the models we use when we come to airflow analysis (touch wood) will have to be quite precise.



posted on Jan, 10 2006 @ 09:38 PM
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Link correction for larger image: tinypic.com...



posted on Jan, 10 2006 @ 11:35 PM
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Originally posted by northwolf

maybe we could divide the job somehow?


that sound's like a good idea. My skill's are mainly in the eye candy/animation area, using Max and Maya etc., so maybe I could be most useful in the illustration area's.



posted on Jan, 11 2006 @ 08:30 AM
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I have five years experience in building military aircraft structures and design sheetmetal structures for a living. I can take a shot at the fuselage. How much composite structure do we want to use?



posted on Jan, 11 2006 @ 09:48 AM
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Jim,
Are you thinking of modeling the external form or a full internal-external arrangement? If the latter, then I can give you more info on the provisional internal layout –which you could tweak/modify in light of your experience and difficulties you come across.

We’d aim for a high % of composites –particularly on the wings.

Remember, you’re the expert in this field so don’t be shy to make decisions on changes if you are seeing something which needs changing. Where the design is particularly fuzzy at the moment is the splitter plate/air intake assembly. My knowledge of these is partial and based on close observation rather than schooling. I know that the JSF has a new type of intake technology which is supposedly cheaper and lighter –and stealthier –and easy to copy (at least the Chinese think so with their modified FC-1). –if we knew more about the hows and whys of that then it’d be cool.



posted on Jan, 11 2006 @ 10:48 AM
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Guys, the airflow analysis (“flow dynamics”) could be done with this open source (free) program: gfs.sourceforge.net...

It has some limitations but is a good starting point and produces good visual effects. I’m finding out what file formats the models will need to be for it.

Also, I’m on a dial-up connection so there’s sadly no hope of me downloading the 40mb program files etc. So any volunteers to actually do the testing?

Thanks for all the help. I love it when a community pulls together.



posted on Jan, 11 2006 @ 11:39 AM
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Originally posted by planeman
Jim,
Are you thinking of modeling the external form or a full internal-external arrangement? If the latter, then I can give you more info on the provisional internal layout –which you could tweak/modify in light of your experience and difficulties you come across.


The way to do it is to make the aircraft as a solid to get the exterior shape and profiles correct to enable airflow testing. Once you have it where you want it, you can then build the internal structure inside the solid model. I have access to airfoil cross-section generation software once we get a bit further along.

As far as composite structures go the leading edge of the wings, the horizontal stabilizers, the rudder, the ailerons, the flaps, landing gear doors and possibly the transition where the wings join are all candidates to be made from composite structures.

One thing I have noticed is that this box wing is going to have a tendency to channel airflow and will reduce maneuverability. This is a primary reason why boxed wings are not more common.

Are you by any chance a Babylon 5 fan? This wing looks like you took it from a Whitestar.

[edit on 11-1-2006 by JIMC5499]



posted on Jan, 11 2006 @ 11:51 AM
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I'm too busy to do any of the modeling, however I do have an SLS machine at my disposal and could probably sneak a scale prototype or 2 in amongst our regular builds, if that would be of any advantage.
Cool project, I wish I wasn't so cad-heavy at work right now so I could get in on the modeling fun.



posted on Jan, 11 2006 @ 02:44 PM
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I have access to SolidEdge, autocad and CATIA (although I'm very, very green on CATIA).


Unfortunately, at the moment I'm a little snowed under with work, but hopefully if I get things sorted it'll clear in a week or two.


I have a massive book on aerofoil sections here (well, upstairs in the other office), hopefully I'll be able to pick out a few suitable aerofoil sections from that.


But you need to sort the wingloadings, wing area and engine thrust first - thats how a design is started. I'd recommend not doing much CAD till that is sorted.



posted on Jan, 11 2006 @ 04:50 PM
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That’s what I like, a get stuck in attitude.

WARNING: Dry techie post

Kilcoo, the engine thrust and wing area have been hashed through on the other thread.

All three proposals for evaluation have a Eurojet EJ-200 main engine with 13,500lbst military power and 20,250lbst with reheat. The EJ-200 is 4m long and 0.85m diameter (the annotated image above is roughly to scale). It weighs 2,286lb giving it a thrust to weight ratio of 5.9:1 at maximum thrust. It also features a 3d TVC nozzle which would increase weight slightly. Overall the thrust to weight ratio is significantly better than the strike fighters it’s designed to replace.

They also have a Rolls Royce AE3007 derived lift jet which kicks out 6,764lbst (non-reheat) forwards of the COG. That has 2d TVC via post-exhaust vanes, at 20 degrees aft through to 5 degrees forward (breaking). The AE3007 weighs 1,617lb and is 2.87m long and 1.392m diameter (max).

Talking specifically for the FSW design which is the first one, the wing area is approximately 25m² which is 17% greater than the X-29’s 21.4m² (areas given as underwing surface).

Re Wing loading –we don’t have figures for that. But given the FSW we’d expect them to be higher than conventional designs with the most stress at the root. Because of this we haven’t decided whether to put wing hardpoints on it (I vote no but want to at least do flow dynamics analysis on them out of curiosity). The wing would have to be largely composite. Of note, since we have no pilot to worry about, hi g loadings are possible –limited by weapons, airframe and systems –for this reason we do not feel confined by loadings in the same way a piloted aircraft design is. The FBW controls (a given) could be used to limit wing loading. Since we are not actually going to build the damn thing, we can just work on the assumption that suitably strong composites exist to form the high load structures (clearly they do).
Wing loading sources used as primary research:
aerodyn.org...
www.nasa.gov...



posted on Jan, 12 2006 @ 09:06 PM
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Planeman

Your drawing is good, but I need more info to build a model. The cross-sections that you have need more dimensions and I need dimensions from the tip of the nose to the planes used for the cross-sections.



posted on Jan, 13 2006 @ 02:47 PM
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Guys, I’m away for a while.

Jim, I’m reticent to give you too many measurements as my own estimations may be slightly out. You have a free rein to model it to ‘look’ right to you, within the general configuration provided. One key thing is that after the initial aerodynamic texting we wil want to make changes anyway.

Re the cross sections. D-D is 8.6 m aft of the nose and E-E is 5.3m aft. The air intakes are approximately 5.9m aft of the nose. If we can get the flow dynamics running adequately, I hope to attempt to model the thrust of the lift jet hitting the ground to assess whether the main intakes are in danger of injesting the lift-jet's exhaust, but that is in the future.

The basic configuration of the lower fuselage is much like the Tornado; it gets wider just aft of the intakes:

Sorry for the crap illustration.



posted on Jan, 13 2006 @ 04:07 PM
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Thanks. Those measurements will help. I have some time this weekend and will see what I can do. The area where the wings join is going to be a bear, but I don't see any problems other than that.



posted on Jan, 14 2006 @ 02:16 AM
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Hey I like this kind of challenge.
Good to see some 3D modelers on board.



posted on Jan, 14 2006 @ 09:11 AM
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Originally posted by nullster
Hey I like this kind of challenge.
Good to see some 3D modelers on board.


nullster

Is that your work in the Art Gallery? There is some beautiful images there. My 3D background is limited to the CAD part of it. If I were to give you the models in a compatable format could you do renderings like those in the Gallery?



posted on Jan, 14 2006 @ 09:23 AM
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Jim,

The one thing that's definitely going to get moved around and changed a lot on you is the wing. I'm assuming you're going with SolidWorks on this. I'd definitely place the wing in as a component(s) of an assembly with the distance from the nose cone to the leading edge as the parameter that sets it in (and then the distance from the centerline of the fuselage to say the centerline of the midline chord as the z axis set in point). That way, when calculations are run for stability and control and it is found the wing needs to be shifted fore or aft, you can just change those two set in parameters.

I have SolidWorks as well, so if you need anything, just let me know.

plane,

Have you selected an airfoil yet? I haven't been keeping up here lately, lots of other stuff going on.

Good luck on your efforts and let me know if there is anything I can do.




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