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Old 04-08-2014, 10:09 AM   #15 (permalink)
kach22i
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Quote:
Originally Posted by k-vette View Post
Wow, I've never seen that vortex tip recovery system before - nice find.

One thing I've picked up by posting over a hundred images in the "Wind Tunnel Pictures" thread is that any smoke wand point just a few inches off centerline draws the air off to the side of the vehicle canopy, not over it's roof.

There are a few shots where the air rolls over the tops of the doors (where they used to put raised rain gutter lips) at the plane intersection of roof and side window glass. This is one of the potential major vortex starting areas, yet I have yet to see a vortex here which is non-CFD generated. There are images of smoke tunnel vortexes, but only in fairly extreme case studies.

My suggestion is to go ahead and plan on building this bulbous nosed canoe shape, keeping in mind that the larger you can radius the corners (top to side planes), the better off you will be.

Also, I would not put anything unguarded and rotating within arms rear of curious hands.

NOTE: One way to avoid the complexities of building a radius corner on a compound curve is to build this shape like I did on the acoustic absorber, but use 4-inch (in lieu of 1/2") foam on the top piece. You will now be able to sand down the corner with an almost 4-inch radius. Internal fillets for strengthening can also be used to reinforce this right angle connection.

If loss of internal volume or foam weight are a concern I suppose you could always hot wire the excess material out.

Another option is stacking material layers at the corners or getting involved with a bunch of bevels or smaller pieces.

Just using the KISS Method here, thicker foam is silly stupid simple - my style.

If you build this before I build my small boat please post the construction details and shoot me a PM in case I miss it.
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Last edited by kach22i; 04-08-2014 at 10:23 AM..
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