Originally Posted by
cmdiduca
I am just beginning my giant and wanted to find out if it is needed to isolate the engine with rubber mounts. I am going to use a dle 55. I can't seem to get a good answer on this.
Anyone tell you that isolation mounts on these engines are bad don't know the first thing about what they do and why. Harmonics are one thing these engines produce and as the RPM increases the high frequency vibrations can be deadly for electronics that are not properly protected, all of them need to be isolated from the main frame of the plane with the dampening effects of foam to protect them. While you can't stop vibration you can dampen the effects if it with soft mounted engines for the same reason the engine in you car has them. It's true the whole plane has a way of shedding these vibrations but the soft mounts softenes them up and reduces the job the plane has dealing with them. You show me a real plane that doesn't have them and I will eat it, it's not going to happen.
Hard mounts are used alot in the large planes that have opposed engines in them, they run alot smother than a single cylinder engine, a radial runs even smoother, these engines have a balanced throw crank shaft in them that counter the effects of the forces that create the inbalance of a single piston engine, hence they have a harsher vibration in them.
My 1/5 scale hase a soft mount and it is recommended by TF to do so, other mfg. recommend them also and there is good reason for it. It's really your choice.
I used the Great Planes mount in my mustand and it was built up to allow for good air movement to the carb. don't do anything to restrict that no mater how you do it
Leroy