Aero Design Senior Project Community Ideas

[kach22i]

Originally Posted by ChazInMT

I've gotten comfortable using the "Draw" program in MS Word. It lets me do basic stuff, then I "Snipping Tool" what's on the screen to make it a .jpg. It's nice to be able to illustrate what I'm trying to convey to hopefully make it easier to figure out what I'm trying to say.

Thank you for the information, I have never tried that, might have to look into it.

Is this yet another way to test vehicle aerodynamics?

USS Gerald Ford Test Catapult System With Vehicles 2017

https://www.youtube.com/watch?v=enIr9rrLZl4

No ground plane, but they do hit the water plane - eventually.

EDIT:
Not doing roof spoilers, right?

http://www.ebay.com/cln/dougl-hubba/...f/120579188011


Up in the flow?

http://www.stanceworks.com/forums/sh...ad.php?t=37178

[kach22i]

Going back to the first page where I said:

Originally Posted by kach22i

So there you go, my concept deals with plan view sweeps and curves to cup or deflect the air flow and air pressure. Coupled with top edge and corner treatment of spoiler shapes, undulating/wavy/curved/serrated and so forth.

I wanted to get these ideas down in graphic form before I forget I had the idea.

Scheme-1 can have similar variations to the schemes which follow it; that is to say with the middle part extending or the rear corners extending. Five schemes outta cover most of the intent. Go back to the hovercraft splitter and whale fin for further variations of the edge textures.

These schemes more or less just explore the basic overall shapes I would look at if I have the time, money and facilities. I would also need the help of someone that knows how to measure the differences and conduct the testing.

I did roughly pencil in the possible vortexes coming off the back because the straight across, concave and convex rear spoilers will most likely be engaging these forces. They might roll upward, scoop up and disrupt/split, or deflect off these swirls in that order respectively. I have no idea which way is best at the moment. Our past forum discussion leads me to believe that the best we can do is delay the onset. And none of these five schemes even pretends to do that. We would have to look at a design with long and tall vertical fins for that if I'm not mistaken.

Question is which monster would you choose to tackle first, filling out the template (orange dotted area) or taming the vortexes? That is for future studies to consider I suppose.

Aerodynamics by George Kachadoorian | Photobucket


That last scheme #5 is supposed to look more flat and horizontal like in the section to the right of it. I just ran out of room on the sheet of paper. If you go back to the Porsche 911 examples, it would more like the later Teatray/Whaletail type and not the earlier Ducktail type.

There you have it, besides the various textures and little waves, we have in elevation straight top edges, arcing top edges, dipping top edges.

These are in any combination with plan views of straight across spoilers, concave and convex.

This cascade of alternates is the product of trying to look at this in 3D, and not strictly in a linear or orthometric/orthogonal way.

EDIT:
Looking at my own work on screen now, these shapes as a collection look as if they were taken off some primitive looking dinosaurs.

[ChazInMT]

Originally Posted by kach22i

Is this yet another way to test vehicle aerodynamics?

Actually, I think it might be.




I have considered testing some aero ideas using a built up flat top platform in a pick-up truck bed.


[/URL]

Basic mechanics like this ish.....With yellow dots as pivot points, basically a platform on pivots with a feedback rod pushing on a scale to give relative force ratings. It could be made to have scales under the front and back as well to measure lift/downforce variations. A scale model would be fixed to the test bed, and A-B-A testing done ad nauseam.

[freebeard]

Works for me, except the platform should be over the front bumper as high as possible.

And the truck should be capable of 250mph.

[kach22i]

I found this while doing an image search.

XCOR Lynx: DIY Aerodynamics
Posted on September 26, 2013 by Bryan
XCOR Aerospace blog | Page 5

Engineer Mike Valant drives an XCOR wind test truck back and forth on the taxiways of the Mojave Air and Space Port during a test series.

In 2009 XCOR built a highly precise sub-sonic wind tunnel test model of the Lynx. For some preliminary data before actual wind tunnel visits, we ran tests using our ‘DIY truck tunnel’ as shown above. The truck and its fixtures include precisely instrumented appendages, structures and bit of computing and data recording capability. We also used the truck tunnel after the sub-sonic wind tunnel tests to experiment with some additional design features before returning to the real tunnel a second time.

By the way, this is not the first time that this particular technique has been applied in Mojave and “other places” in the Antelope Valley for aerodynamic development. We wish we could say we invented this technique but we did not. It has been used for many years by both neighbors in Mojave and neighbors to the west and south of us.

Stay tuned tomorrow as we answer your questions and update you on where you can find us on the road!

I've seen scale models of many things done this way, one of them may have been the blended wing designs, will try and find that image.

EDIT: Did not expect to find this picture.

http://projecthabu.com/post/11948925...arch-center-is

The HEIST vehicle was inspired by a previous test performed by Scaled Composites in which SpaceShipOne was evaluated in a similar way, placed on the back of a Ford F-250 pickup truck. This method of testing is perfect for building an aerodynamic database on a low budget, but it does pose some interesting challenges. One problem with this method of testing is vibration and ground noise. The HEIST vehicle solves this problem by isolating the test rig from vibration using four airbags, one of which is shown in photo seven.

I've never seen this one before either.

http://amablog.modelaircraft.org/ama...huttle-models/

Art Arro and Owen Morris release the Gazariator and Space Shuttle for another test flight. The photograph originally appeared in “Mini Orbiter,” Model Airplane News, April 1976, pg. 48, by Terry White.

[kach22i]

One of the topics I mentioned early on in this tread was keeping the rear spoiler at or below the line of the Aerotemplate.

I happened to run across an example today where this was not done.

The Mustang in question did not remain in this configuration for long, the next generation of modifications appear to have been a wing placed high up in the clean air flow which certainly would have resulted in lower drag than this version I'm showing.

Unfortunately I was not able to get a good side view, but did my best.

Aerodynamics by George Kachadoorian | Photobucket


Links to the Mustang project by Vorshlag where the base images came from:
http://www.vorshlag.com/forums/showthread.php?p=57309

http://www.vorshlag.com/forums/showthread.php?p=57230


Here is a good side view of a stock Mustang from a old thread for context.

http://ecomodder.com/forum/showthrea...aps-25379.html


Based on my own pickup truck rear spoiler experiments, the larger you go the more down-force, but it can be to the point of ridiculous. For me it was like towing a large boat or having a giant child crushing down on my truck like some toy car. See the link in my signature for that experiment.

In theory, one could make a rear spoiler like the 1973-74 Porsche 911 RS which lowers lift and lowers Cd, but it might take the engineering skills of someone like Porsche to pull it off.

I'm sure they knew what they were doing even back in the early 1970's and mostly likely would exceed what the novice thinks they know by surfing the Internet. However, that's not going to stop me from having a little fun with it now.

Yep I have sketches drawn up for a rear spoiler on my old air-cooled 911, and have a buddy with a plastics shop that does fabrication. It's going to be awesome, but will have to wait in line on my "to do" list. Brakes, body work and further weight reduction comes first.

EDIT: Some interesting conversation in this old thread.
http://ecomodder.com/forum/showthrea...-25223-14.html

[freebeard]

Those look familiar.

I like the retractable gear, but if those are over-center springs the geometry don't look right.

Maybe we should have the mods carve this off into another thread and let the OP (should he return) have his thread back. His last activity was today at 10:21, but last post was at Permalink 24, on the 3rd.

[Aeroguy]

It's all good. I've been watching the action from the sidelines.

[freebeard]

Alrighty then.

If I had a wind tunnel, these are the variations I'd like to test.



As it is, I hope to run Blender for CFD on the Beagleboard X-15. Open source software running on open source hardware.

[Xist]

Should roof boxes follow an extended template?