MIBO A-10
- ARF
Seller:jet time Details:
$6,500.00
| 10/8/2008
| Classified Ad
We will rotate YOUR AD in this spot if you select "Forum Featured" when placing or editing your ad!
Posts: 2438
Joined: 1/19/2002 From: Anchorage,
AK, USA Status: offline
Hi everybody,
(This is a 3D modeling project, not an RC "build", but some of you jet guys might enjoy it.)
I live in Anchorage, Alaska, where we've had an operational squadron of F-22's since 2007. After seeing the flight demo of the Raptor at this summer's air show, I was inspired to finally do this one in 3D/CAD. It will probably be a 6-month project, but will be more accurate than other 3D models of the F-22 that I've seen.
It's an impressive aircraft in real life, (!) and a hugely-challenging 3D project. Since this is a 3D modeling project, rather than an RC project, it's on my imaging-related site at http://www.mikejamesmedia.com.
Posts: 2438
Joined: 1/19/2002 From: Anchorage,
AK, USA Status: offline
The shape of the F-22 wing...
Usually, I can figure these things out in a few minutes, with some drawings and a little CAD work. In this case, I haven't solved the issue yet, which is...
Looking at the Lockheed-Martin front view of the F-22, there appears to be some odd combination of anhedral, twist (washout) and curvature. Having tried many combinations in my 3D software, none of which produced an image like the drawing, I'm wondering if some of you (perhaps a Lockheed-Martin employee) might know why this is. (And, assuming that it's not proprietary, I hope you'll clue me in!)
Posts: 2438
Joined: 1/19/2002 From: Anchorage,
AK, USA Status: offline
I've just solved the problem, using a very simple tool. A few years ago, I did an article on slicing up a plastic display model, for the purpose of obtaining cross sections for plans. At the time, I had no intention of building an F-22, but used it as the example. ( http://www.nextcraft.com/plastic_to_rc01.html ) I kept some (low-res) copies of the scans I produced from that model, and have used them several times in my F-22 project. They obviously used Lockheed-Martin drawings, as well as photos, etc., and it's remarkable how well those scans fit.
Anyway, in 3D, I created some "spars" from those scans, and also created a test wing. (My test wing had 1 degree positive AOA at the root, twisting to -4 degrees at the tip. (for a net total of 3 degrees twist) and 3 degrees of anhedral. It wasn't quite right. But, when I did a boolean operation, where those spars and my test wing were combined, the differences stick right out. (images attached) I can definitely make an accurate wing out of that result.
_____________________________
Mike James RC Design and Building - www.nextcraft.com
Posts: 2438
Joined: 1/19/2002 From: Anchorage,
AK, USA Status: offline
Hi everybody,
The overall shape of the aircraft is getting close now, aside from the wing/fuselage joint, which is ongoing. So, I'm starting to add "boolean cutters", which will be used to create many of the doors and vents that are visible on the exterior.
Posts: 2438
Joined: 1/19/2002 From: Anchorage,
AK, USA Status: offline
Here are some links to published 3D models.
One word of caution... Some of these models are great, and some are lousy, disguised by texture maps ( "paint" ) to look a lot better than the actual polygonal structure. That alone is the major dividing line between quality and "not". So be careful when you see something that looks like a "bargain".
Posts: 6635
Joined: 12/7/2001 From: Oak Park, CA, Status: offline
Thanks for the links.
I am P.O.d that Wilcox lost the model of the F-18 he bought. it was pretty good and cost 3K IIRC. They used it to make a full scale F-18 for "Independance Day" I think.
Posts: 2438
Joined: 1/19/2002 From: Anchorage,
AK, USA Status: offline
Hi everybody,
With the exterior shape very close to final. I've made a large number of boolean cuts, which create many of the doors and vents that are visible on the exterior. (Images here were made just after the cuts... Later, the doors will be appropriately colored, textured, and animated.)
Printable Version
All Forums >> RC Airplanes >> RC Jets >> Building an F-22 Raptor in 3D/CAD 
Building an F-22 Raptor in 3D/CAD - 
