I'm interested in the discussion as well. I believe I'm going to be converting my Stinger with Brisson 3.2 to a soft mount.

The vibes are shaking everything apart. The sheet metal screws holding my fiberglass on are either falling out in flight or wearing big holes in the glass parts. I even converted the main screw holding my cowling on to a 1/4-20 nylon wing bolt to try to dampen the vibration. It's threaded into a 1/2" think piece of hard ply that was tapped for it. It backed out less than 10 minutes into the flight and the wing cover/canopy flew off. I've also had glue joints holding my hinges in break loose, but that could just be me.

I think alot of the problem is that the Stinger fuselage is a C-channel design - that is, it has only 3 sides. The firewall is only supported on 3 sides. Structurally, the top is not restrained, although covered by a fiberglass piece. That really allows the fuse to twist all the way back to the wing mount bulkhead.

After having done a search here on soft mounts, it seems to me that using a soft mount subjects the airplane to less vibes but increases the vibration load on the engine. I think I'll need to go with that.

The Stinger fuselage is quite narrow, only a little wider than the mounting flanges for the Brisson. I'm considerinig ways to soft mount it in the available space and would appreciate feedback on the different systems and would like to see pics, web site links, etc, if anyone has them.

Right now I'm thinking I will drill the firewall out and install the J-tec rubber grommets thru the firewall. The engine would be mounted directly to the grommets with the same bolt that holds the grommets into the firewall, using large washers on the face of the grommets. Suggestions?

PS - roadhor, didn't mean to hijack the thread. Hopefully we'll both get usefull info.