Bubblehead
Well Known Member
In July I removed my trusty Vetterman 4-into-2 and replaced it with an AWI 4-into-1 so that I could get a heat cuff working. For some reason my Vetterman's crossover pipes were so close the cuff would burn through.
Here are some pictures of the finished product, although I need to do some more work on the support for the collector. AWI furnishes a plate to rivet to the belly of the fuselage or the firewall. Cable is then used to flexibly connect the exhaust to the plate. I did not want to rivet a stiff plate to the flexible fuselage skin and the geometry did not line up too good for using the plate on the firewall. When I get the support tweaked I'll post more pictures. I also trimmed about 3/16" off the ends of the upper pipes where they went into the collector so the collector would move up closer to the fuselage. This allowed me to avoid modifying the cowling.
I also used some "Aluminized Heat Barrier" from ThermoTec http://www.thermotec.com/aluminized-heat-barrier.html on the cowling directly below the collector. It is adhesive backed on one side, reflective on the other, and has a woven silica cloth in the middle. After the test flight I felt the outside of the cowling and the area where I placed this is significantly cooler that surrounding areas.
The complete gallery of pictures can be found here: http://tangodelta.smugmug.com/gallery/5634125_B9MHz/1/346316274_Ab32N
Original System
Heat Cuff Problem
Old and New
New
Overall the quality of the AWI system is very good, and the new heat cuff provides a bunch of hot air into the cabin. AWI welds studs on the exhaust where the muff goes and that should provide more heat transfer to the air moving into the cabin. They also use a thin stainless steel muff, while the Vetterman system uses aluminum.
Unofficially I think I gained a knot or two but have not taken many numbers, but I am sure it at least looks faster on the ground!
Here are some pictures of the finished product, although I need to do some more work on the support for the collector. AWI furnishes a plate to rivet to the belly of the fuselage or the firewall. Cable is then used to flexibly connect the exhaust to the plate. I did not want to rivet a stiff plate to the flexible fuselage skin and the geometry did not line up too good for using the plate on the firewall. When I get the support tweaked I'll post more pictures. I also trimmed about 3/16" off the ends of the upper pipes where they went into the collector so the collector would move up closer to the fuselage. This allowed me to avoid modifying the cowling.
I also used some "Aluminized Heat Barrier" from ThermoTec http://www.thermotec.com/aluminized-heat-barrier.html on the cowling directly below the collector. It is adhesive backed on one side, reflective on the other, and has a woven silica cloth in the middle. After the test flight I felt the outside of the cowling and the area where I placed this is significantly cooler that surrounding areas.
The complete gallery of pictures can be found here: http://tangodelta.smugmug.com/gallery/5634125_B9MHz/1/346316274_Ab32N
Original System
Heat Cuff Problem
Old and New
New
Overall the quality of the AWI system is very good, and the new heat cuff provides a bunch of hot air into the cabin. AWI welds studs on the exhaust where the muff goes and that should provide more heat transfer to the air moving into the cabin. They also use a thin stainless steel muff, while the Vetterman system uses aluminum.
Unofficially I think I gained a knot or two but have not taken many numbers, but I am sure it at least looks faster on the ground!
