At 06:54 AM 4/13/05 -0500, you wrote: >Somebody mentioned that changing to a Corvair on a KR2 would involve >firewall reinforcements. I'm wondering how many folks have an 0-200 or >other heavy engine on their stock KR2 firewall that has NOT been reinforced. >I'll bet there are several, if not many heavy engines (0-200 and Vair weigh >about the same) flying on standard KR2 firewalls that are doing just fine. >Can anybody corroborate my assumption? Jeff, Larry, anybody? ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
I recall talking to Jeanette Rand at one of the Gatherings and she stated that she had an engineer do a study on the firewall. He stated it should be good for 21 G's. I don't know if Marty Roberts did anything over the stock firewall on his as his KR started life with a VW. I did reinforce my firewall a bit as I knew I was going with an 0-200. When I got my "boat" I didn't like the firewall construction (it didn't have the 1/4" ply on it yet) so I removed everything back to the 3/32" ply and started over. I had a piece of 3/4"X 3 1/2" spruce so that's what I used on the top and bottom cross pieces. I added a few extra spruce gussetts to give more glue area at the sidewalls. I also did a two bid wrap of the firewall and overlapped to the side after the 1/4" ply was glued on. Most of this was probably unnecessary and helped to contribute to my 765 pound empty weight. According to my calculator, at 21G's with a 200 pound VW, the firewall should still be good for nearly 17 G's with my 250 pound 0-200. I'm using a HAPI VW mount so the engine placement is the same. I think the Rand 0-200 mount moves the engine forward 2 to 4 inches. Jeff Scott would have better info on that as that's the route he went. Marty's KR used the HAPI VW mount also. The only instance of firewall sepratation I've ever read about was on a KR1 that caught wake turblance on takeoff and was slamed back to the runway. The firewall seprated and ruptered the fuel tank and the pilot ended up with "gallons" of fuel in his lap. There was no fire so he's lucky to be alive. That's one of the reasons that all my fuel is in my outboard wing panels. Larry Flesner
