My Lanier Stinger 60 ARF came with motor mounts that are not rigid , they flex slightly especially at low rpm. Once the throttle is advanced they smooth out quite well.
I have never had a problem with them but the guys at the field think they are dangerous and could fail. Also they say that there vibration effects the motors operation - it is a Saito 80.
I have about 3 hours flight time on them and they look and perform fine. Plane flies extremely well , except requiring over three oz added to the tail to get it to balance. I think a 2 stroke engine 60 to 90 would be heavier and thus require less tail weight.
Is there an issue with these flexing motor mounts? Any suggestion , thoughts , ideas etc.
Thank you in advance.