Snowbirdxx
Well-Known Member
The forward lower cowl is attached with phillips head -10 screws. These screws are going through oversize holes which are in the cowling. These oversize holes allow small movements of the cowl without creating stress at one point.
The top forward and rear screws though are countersunk. If these screws are tight no movement of the cowl is possible and finally the edges of the cowl will crack and fall off.
The repair is not only time intensive, it is unnecessary if the following precaution is taken:
At next time of cowl removal: outdrill the countersunck holes with a stepdrill to 1/2 inch diameter.
When installing the cowl use a Tinnerman washer between the cowl and contersunk screw.
This small mod will keep the edges of the cowl stress free and they will not vibrate off.
Time needed: 2 Minutes Cost: 10cents ( 4 Tinnerman Washers )
TomD
The top forward and rear screws though are countersunk. If these screws are tight no movement of the cowl is possible and finally the edges of the cowl will crack and fall off.
The repair is not only time intensive, it is unnecessary if the following precaution is taken:
At next time of cowl removal: outdrill the countersunck holes with a stepdrill to 1/2 inch diameter.
When installing the cowl use a Tinnerman washer between the cowl and contersunk screw.
This small mod will keep the edges of the cowl stress free and they will not vibrate off.
Time needed: 2 Minutes Cost: 10cents ( 4 Tinnerman Washers )
TomD