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-   -   a couple printed ideas (https://vansairforce.net/community/showthread.php?t=147771)

Steve Melton 07-10-2018 10:58 AM

Quote:

Originally Posted by BHunt (Post 1272440)
For testing purposes or indefinitely?

flap bracket fairings, it will always be a mystery because I don't plan to take them off and do the required testing to accurately determine the exact speed increase. all I can tell you is my airspeed indicator says I'm faster with them.

A blurry video:

https://youtu.be/qAnGe40-o9Q

Chkaharyer99 07-10-2018 10:47 PM

Quote:

Originally Posted by Steve Melton (Post 1272473)
thx for the compliment. these are simple models and really having a project makes you learn the software. that's why I try to have projects.

ABS is cannot withstand the temperatures under the cowl. I've been wanting to do some ducts. send me a sketch with some dimensions and I'll make a mold.

Thank you!

Understood regarding ABS temperature limitations. I have a sketch. I can email it to you.

I would like to use the 3D ABS model as a plug for a fiberglass oil cooler plenum.

Check your PM.

Thanks,

Charlie

Steve Melton 07-11-2018 03:41 AM

preheat duct. this one operates at about 180F if I remember correctly. fiberglass reinforced at the connection point. internal wire spring. it has been thru a couple winters use and is in original condition. no delamination of the fiberglass. scuffed with 80 grit before bonding. I'm happy with it.













pull on the lower wire to release it. does not scratch paint.










Steve Melton 07-11-2018 06:47 PM

AS-2004X
 
give me some feedback for orientation. need to modify the base for flanges and improve the sweep.


rv7charlie 07-11-2018 07:04 PM

Looks like many commercially available products, and what most people do when they make one. But, while I'm no authority, all the reading I've done while preparing for my alt engine project indicates that the shape depicted will result in all the air flowing through the left side of the core. The sharp curve to the right can be expected to go turbulent at the 'corner', resulting in little flow through that side of the core.

There may be more current research, but in Aerodynamics of Propulsion (Kucheman and Webber) the most efficient shape for a short diffuser approximates the mouth of a trumpet, with the edge touching the side of the core being an acute angle.

If you think about it, we're trying to achieve the same kind of things that musical instruments are trying to achieve: efficient 'coupling', or impedance matching of source to load. There's a very good reason that musical horns (and horn shaped loudspeakers) are shaped the way they are.

Charlie

Steve Melton 07-11-2018 08:37 PM

this could be better. need a different shape.


Chkaharyer99 07-11-2018 08:39 PM

Quote:

Originally Posted by Steve Melton (Post 1272814)
give me some feedback for orientation. need to modify the base for flanges and improve the sweep.


You do great work! Fast too! I saw your PM. Agreed.

I sent you an email with modifications.

Thanks again.

Steve Melton 07-11-2018 09:02 PM

if I printed a guide vane inside, could a layup be made. how would you do that?

no use installing a fancy external oil cooler if you can't achieve it's full capability

Chkaharyer99 07-11-2018 09:12 PM

Quote:

Originally Posted by Steve Melton (Post 1272847)
if I printed a guide vane inside, could a layup be made. how would you do that?

Probably not if the fiberglass layup was done on the inside of the 3D plug. On a one piece unit, the vane would trap the fiberglass layup making release of the layup very difficult.

Maybe the layup should be done on the outside and the vane be installed as a secondary process?

Thoughts?

Steve Melton 07-11-2018 09:16 PM

ABS may be able to survive on the firewall if it was trapped by fiberglass.


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