ORIGINAL: NJRCFLYER2
It is more difficult to attach a nose ring with a removable cowl model, but it can be done. Bob Moulder did it in his Focus II with a SAP180 and it worked great. Basically, he made a CF tube mount that held the nose ring. You can do without it if the mount is made a little stiffer. You lose some of the vibration damping, but it is still better than a hard mount. I've run soft mounts with and without nose rings with 2C glow, and it's workable. It's just a question of tradeoffs between that bit of wobble you get without the nose ring when hitting high G's, and the longevity of your servo pots & gears. I think it's still worth it in most cases for engines of this size.</p>
Single cylinder engines definitely benefit. But I've soft mounted the 2 cylinder engine I've used before (BME106). There is a difference there too. I am an advocate for soft mounts....several key benefits.
The nose rings I've made recently were simple 1/32" aircraft ply glassed on both sides. I have also used rings completely made of rubber.....worked fine. In fact, for some engines with large prop drives, a rubber nose ring is a simple solution since you can stretch it over the drive washer. That's what I've had to do on the Mintor for example