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Building Integrity
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Date: 8-13-2016
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Number of Hours: 10.00
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Manual Reference: Section 2
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Brief Description: Big Day, lots of pics, new ideas
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So in consulting with Wayne Blackler on these oil issues a while ago, he gave me several things to think about and mods, he himself was wanting to try in order to drop his temps a bit. One of them was to close off the cowling exit area to more closely match the inlet area. The other was to add channels inside the cowling to help direct air out of the cowling instead of just being a big turbulent mess inside. I've decided to make both a reality today.
First of all, the exit area on my cowling is HUGE. I made it that way on purpose to avoid air separation from the cowling on the trailing edges. And THAT was a success as oil flow tests show laminar flow all the way to the trailing edge. BUT, that meant a huge opening aft of the engine. Ideally, you want your exit area to be about 10% larger than the inlet area to accelerate the air into the prop, but using a 4" prop extension I had very little room to close down the cowling before hitting the prop. I went ahead and laid up 3 plies BID on a flat board, then baked it for an hour. I then pulled it off, trimmed it to fit that inside of the upper cowling and bonded it in using 2 plies BID tape. Later I will finesse the shape to clear the prop flange and make it a little sexier. :)
The second task was to help direct air out of the cowling using channels. However, I had a second motive for this one. I would use these channels as a way to block off the exhaust pipes from heating the roll servo and wing roots which has been causing problems. Using aluminum sheet, floxed and glassed to the lower cowling should produce some interesting results. I'm excited to test fly em. I would LOVE to be able to remove the reverse naca on the upper cowling if these do the job :)
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3 plies BID
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Wetted out and baked
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trimed to fit with 2 plies BID Tape
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