Any Ideas. I'm repairing a friends RV-12iS cowl now, 110hrs TT. Cowl burned by #1 exhaust pipe, size of a quarter, bottom of induction NACA scoop ramp. He tried to repair it and it burned again. He put header warp on #1 pipe. It failed. I got involved, cowl was already burned, but put metal tape on inside of cowl and put on higher quality header wrap. I removed wrap with way 5-6 hours of service to do condition inspection. It was falling apart. I hate header wrap.
Here are my To-Do's and ideas:
Being a metal guy (RV-4/RV-7) I am a fan of riveting on a SS shield sandwiching in insulation. I have access to dry Kevlar or Carbon and Glass. Thinking make my own insuation used metal tap on the composite material. Use adhesive to bond it all on to inside of cowl and minimizing thickness, as to not take up too much room.
The distance of #1 pipe and cowl is not much. The gap is TBD, since exhaust is off. His #1 pipe was seized in cylinder, due to deposits, preventing it to rotate and allow more room. Now that the whole exhaust system is checked, cleaned, serviced, heat muff modified (extra rods, safety wire of hose clamps) and the SB-00001 anti rotate flat springs I think position can be adjusted. The exhaust definitely drifted to the right. However there is not much room.
I asked Van's support and they said the builder might have trimmed cowl too short? I asked and he said the trim line embossed in cowl. Can also check gap between cowl and spinner. Regardless it is fixable and can be prevented from happening. RV-12iS might want to add a tad more to cowl trim line for Min (but acceptable) spinner to cowl gap.
WHAT ARE YOUR IDEAS?
Here are my To-Do's and ideas:
- Cowl burn repaired, with high temp epoxy, do high temp cure (if I can find the materials).
- Refinish damaged paint, but instead of base-coat/clear-coat, use high temp black. Bottom ramp of NACA scoop ramp, should look good and be more durable.
- Exhaust system is getting flat spring SB-00001, to keep exhaust pipe drift, adjust for max #1 pipe to cowl clearance.
- Make a strap-on (hose clamp) heat shield.
- Bond or rivet on metal heat shield to cowl with some insulation between cowl a metal shield -OR-
- Stick on Commercial metalized insulation shield.
Being a metal guy (RV-4/RV-7) I am a fan of riveting on a SS shield sandwiching in insulation. I have access to dry Kevlar or Carbon and Glass. Thinking make my own insuation used metal tap on the composite material. Use adhesive to bond it all on to inside of cowl and minimizing thickness, as to not take up too much room.
The distance of #1 pipe and cowl is not much. The gap is TBD, since exhaust is off. His #1 pipe was seized in cylinder, due to deposits, preventing it to rotate and allow more room. Now that the whole exhaust system is checked, cleaned, serviced, heat muff modified (extra rods, safety wire of hose clamps) and the SB-00001 anti rotate flat springs I think position can be adjusted. The exhaust definitely drifted to the right. However there is not much room.
I asked Van's support and they said the builder might have trimmed cowl too short? I asked and he said the trim line embossed in cowl. Can also check gap between cowl and spinner. Regardless it is fixable and can be prevented from happening. RV-12iS might want to add a tad more to cowl trim line for Min (but acceptable) spinner to cowl gap.
WHAT ARE YOUR IDEAS?
