On 7/1/2021 9:02 PM, Dean Choitz via KRnet wrote:
i am using the 5.75 or 6 oz fiberglass how many layers do you or should you lay
up to make the engine cowling and do most finish the outer with deck cloth
thanks dean choitz
Sorry I missed this when it was posted....I've got a lot going on these
days. I made my cowling out of two layers of carbon fiber, but given
the top was fairly broad and flat, I added something like a 6" wide X of
scrap carbon fiber inside the top to stiffen it, like the hood of your
car probably has in it. The whole cowling, complete with fasteners,
weighs 3.8 pounds. A slightly smaller Revmaster cowling weighs 11
pounds. It's a tad floppy, but when it's assembled onto the plane it's
good to at least 240 mph (tested). And it's plenty strong. Once I took
off with one whole hinge pin missing...I installed it but "missed" the
opposing hinge half and didn't notice until takeoff. While climbing out
I noticed the right half of the cowling raised up about 6" at the front,
which was a high pucker moment considering the proximity of the prop! I
throttled back and limped back in, but no damage and ready to go again
once the pin was properly inserted.
See more on my cowling construction at http://www.n56ml.com/cowling.html
. There were a bunch of photos that I neglected to label in the throes
of construction, but you'll get the idea.
There's nothing wrong with fiberglass, but I think you'll need more than
just two layers of 6 ounce glass, personally. Having said that, I've
never built a cowling with 2 layers and flown behind it, so maybe
that'll work just fine. You can always add another one to the inside
later, as long as it's not oily when you do it. And yes, deck cloth is
always a good idea on top to minimize the finish work of hiding the weave.
Mark Langford
m...@n56ml.com
http://www.n56ml.com
Huntsville, AL
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