REFLECTOR:Flying without Cowl Fasteners

[reflector@tvbf.org]

I know this is only slightly applicable, but it's a datapoint.

At one time we were flying the Berkut prototype this way.  We were using 
very stiff carbon cowls and thought the wing interface camlocks were all we 
needed.  At speed, the lower cowl (pressure side) balooned up 
significantly, and cracked in many places.  Fortunately the forward edge 
didn't come all the way out from under the fuselage lip, or it would have 
become a scoop, increased pressure and departed.

I know the non-pressure side doesn't have the same amount of force on it - 
but as it tapers toward the spinner, there's significant lift on it, trying 
to pull it outward.

I'd stick with screws and nutplates.


At 08:31 AM 4/21/03 -0600, Scott Derrick wrote:
>Is anybody actually flying without cowl fasteners where the cowl meets the 
>fuselage?
>
>The plans call for a lip extended rearward from the fuselage that the cowl 
>slides inside of.  Screws(through the fuselage lip) and captured nuts(on 
>the cowl) are then installed about every 6 inches along this overlap.
>
>Some ,all non-flying or not-tested I guess, say they are not using any 
>screws?  Merri says he has built a U shaped slot instead of just a lip for 
>he cowls to slid into so he doesn't have to use screws.  This 
>sounds  doable and secure.
>
>I'd really like to reduce the number of screws(uncaptured) used to hold 
>the cowl on since they have a tendency to come un screwed during flight 
>and put large nicks in the prop.
>
>I'd also like to use something that has some flight hours on it.
>
>Scott
>
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