Gents,
I want to share with you my pain and disappointment as I embark on my cowl modification/repair.
A year ago when I took my plane to the paint shop I noticed small crack in the primer paint in my lower cowl. I had 50 hours on the RV and never saw this before. The crack was on the outside of the cowl adjacent to the mixture pivot shaft. I have a Silverhawk FI system with Vans standard vertical induction cowl. Additionally I have the standard rotation mixture setup on the Silverhawk FI (CCW for ICO).
Since my plane was in pieces at the paint shop when I noticed the damage I asked them if they could ?blister? the cowl in the area where the damage was. They agree and I told them I would email them instructions and dimensions for the blister the following Monday (I dismantled the RV on Friday at the shop). On Monday morning I called and told them I was emailing the instructions. They told me the blister was completed and that it looked great.
Fast forward 5 weeks later when I re-assembled the RV. The blister looked great but it wasn?t the dimensions I wanted (or believed I needed).
Another 30 hours passes flying my newly painted RV. During my conditional inspection I noticed the paint was cracking where the ?blister? was added. I knew there wasn?t enough clearance that I had hoped for. Add another 30 hours of flying the RV with my wife and now it is time to take the RV back to paint shop so that they can fix/detail several areas they missed the first time. Additionally they agreed to repaint the ?blister? fix.
After loosing sleep worrying about cutting the cowl up I started on the fix yesterday. I decided to make a mold of the finished outer shape. Using modeling clay I sculpted the final shape (with some setback for additional external fiberglas. Then with some PVA and wax I covered the clay and adjacent areas on the cowl and glassed up the mold. 12 hours later I removed the mold and cut out the section of the cowl. Today I will glass up the (from the inside) of the cowl. I will keep you posted on the progress.
I believe the excessive vibration of the engine is caused by poor hot starts. I don?t recall any really bad hot starts however it only takes on to cause this damage. It is my hope that once completed and painted the blister will be unnoticeable and never crack again.
The photos below show the cracks in the cowl (paint) and the inside of the cowl where the aluminum tape shows the impact marks from the bolt on the mixture arm.
I want to share with you my pain and disappointment as I embark on my cowl modification/repair.
A year ago when I took my plane to the paint shop I noticed small crack in the primer paint in my lower cowl. I had 50 hours on the RV and never saw this before. The crack was on the outside of the cowl adjacent to the mixture pivot shaft. I have a Silverhawk FI system with Vans standard vertical induction cowl. Additionally I have the standard rotation mixture setup on the Silverhawk FI (CCW for ICO).
Since my plane was in pieces at the paint shop when I noticed the damage I asked them if they could ?blister? the cowl in the area where the damage was. They agree and I told them I would email them instructions and dimensions for the blister the following Monday (I dismantled the RV on Friday at the shop). On Monday morning I called and told them I was emailing the instructions. They told me the blister was completed and that it looked great.
Fast forward 5 weeks later when I re-assembled the RV. The blister looked great but it wasn?t the dimensions I wanted (or believed I needed).
Another 30 hours passes flying my newly painted RV. During my conditional inspection I noticed the paint was cracking where the ?blister? was added. I knew there wasn?t enough clearance that I had hoped for. Add another 30 hours of flying the RV with my wife and now it is time to take the RV back to paint shop so that they can fix/detail several areas they missed the first time. Additionally they agreed to repaint the ?blister? fix.
After loosing sleep worrying about cutting the cowl up I started on the fix yesterday. I decided to make a mold of the finished outer shape. Using modeling clay I sculpted the final shape (with some setback for additional external fiberglas. Then with some PVA and wax I covered the clay and adjacent areas on the cowl and glassed up the mold. 12 hours later I removed the mold and cut out the section of the cowl. Today I will glass up the (from the inside) of the cowl. I will keep you posted on the progress.
I believe the excessive vibration of the engine is caused by poor hot starts. I don?t recall any really bad hot starts however it only takes on to cause this damage. It is my hope that once completed and painted the blister will be unnoticeable and never crack again.
The photos below show the cracks in the cowl (paint) and the inside of the cowl where the aluminum tape shows the impact marks from the bolt on the mixture arm.
![Cowl Cracks1.jpg](/community/proxy.php?image=http%3A%2F%2Fexperimentalaero.com%2Fphotos%2FCowl+Cracks1.jpg&hash=08a7a63223d9f97b1f0c8b15359f38a9)