Thorp Air Command - T18.net

Not sure about the "doubler" in the exit of the cheek. Mine don't have it ? Bought them from CSA and they seen to be working OK W/O one.

RB

I'm sure it depends on how rigid the cheeks are. The fiberglass cheeks coming from CSA right now are pretty thick and a bit heavy and as you point out probably don't need it. If youre lucky enough to ave one of the Richardson, Shabler (sp?) or lay it up yourself cowls you'll most likely need a doubler though.

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Lee Walton
Houston, TX
N51863,N118LW
KEFD

I put a doubler right on the trailing edge of the gill on the cowl cheek. I used a piece of 6061t6 .125x1.000 alum Extruded, not sheet. The extruded material is stiffer than sheet material. It is flush riveted to the inside of the cheek flushed up with the edge. It runs part way into the curve at the top and at the bottom. Its not real visible unless you are looking for it as it is inside the cheek. It does stiffen the edge of the GILL considerably. I don't get any movement whilst the thing Is running or during flight. It was a pain shaping the alum to fit it, probably could have done without it..Dan

Ya Boy ! That fiberglass stuff is nasty ! I still had to cut a paste my parts to get the fit I wanted...and that was a big pain in the rear radiator ! I would rather wrestle with a good case of Monty's Revenge than a batch of the sticky slime !

RB

Here is what one metal cowl looks like with a rear cheek doubler:

The "original" fiberglass molds copied this.

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Bob Highley
N711SH
SN 835
KLAL

That doubler has a nice contour.
I wonder if this contour could be designed to act as a nozzle?
That would recover some of the exit velocity as the heated engine air re-enters the free stream.
I wouldn't say it could provide thrust, maybe just some drag reduction?
It might be easier to do on the fiberglass cowl cheek, in the form af a lay-up, followed by adding fairing filler or grinding away until some data is obtained ...to find out if it works or you just wasted a week of effort?