ORIGINAL: swk550
Matt,
Sorry to hear about your loss. I am in the final stages of building the same airplane (red version) using the Mintor 38cc, ES Composites ES40G pipe and a home made isolator mount. Thanks for the advice on making the mounts. It's been some five plus years since I made the last monut for a OS140 rear exhaust engine. I'd like to keep the build thread going, so I am posting some pictures of my set up. The mount ended up being 4.124'' diameter, 1.06'' thick. I cut the firewall back 0.25 too much, so I had to add 0.25 spacers for the standard 3'' long Mintor standoffs.
SWK550
Thanks Steve, no biggie really. That's the good thing about ARFies....somebody else did the work so no emotional ties to it.
As it turned out the Mintor burried a foot deep in farmer dirt. Reasonably soft in other words. Great thing about a rear mounted carb, no crap inside the engine. Just a few bent fins easily straightened and a quick run under the faucet had the engine looking like new. The hit pushed the shaft back a bit so I removed the carb/reed block and rapped the shaft back into position. It looks like the whole thing was saved. Tough little engine
Your mount looks great. It will work fine. I build mine with studs through the face that stand offs could be screwed onto from the front. This way I can mount the donut on the firewall first. BTW, I had put in a choke servo in my set-up. I have photos in the OS33GT for Pattern thread
Speaking stand offs, mine were standard McMaster Carr issue, 2 1/2" long. I turned them down from 3/8" to 5/16" to shave some weight. These were about half the weight of the stock stand offs. After the hard hit I expected them to look like pretzels. Well, there wasn't a scratch on them which tells me that the usual stand offfs one gets with the engines are way overbuilt. The soft mount is another story...completely destroyed; soft enough to have probably saved the engine