Ty,

It was great to meet you at the GA meet last week, nice to put a face to the names on this board.

The short answer is - yes they have a lot of torque, with less vibration. If it is turning the same size prop as a 40, at the same rpm and pulls the ship as the same speed it has the same torque as its IC counterpart. With electric looks are deceiving, they look small and innocent, but they are like a sawed off shot gun still pack a hell of a punch. You are not alone, others have had this same thing happen several times on the same ship.

The key is to install a stronger firewall to mount to just as you would for a firewall mounted IC engine maybe a bit stronger. Remember we have prop and Rotor spinning and creating gyroscopic forces that the mount has to hold. I don't know if you had a change to see the electric mount the Tom Morris had but it is very strong and similar to what I have used for the past three years with no failures. The main feature is the 3/16" plywood mount ring that is attached with screws to the hardwood beam mounts. When I retrofit the Stuka with electric I used a 3/16" nose firewall to mount to that has four 1/4" small screws through the existing plywood fuse sides in addition to epoxy glue and gussets. The way Tom does it on the profile is to install the mount ring to the front of the beam mounts and screw into them, then adds the side pod for additional support. One other point is once the mount ring is complete saturate it with a couple coats of CA to harden the surface, this will reduce any side to side movement that can work on the mount structure.

Best,      DennisT

Ty
Torque on an electric is just not at all like what we have come to expect with glow. Take any size glo motor you want. Take a PA .75. Put a big apc prop on it. Start it so its running only 50 rpm... no I'm not joking. Now stick it into the side of a GM car's hard plastic interior material that is on the inside side panels. What happens? Right, it stops immediately. I had an accident where a multi battery powered plane got only one pack, not both disconnected. It was put back in the car and this exact senario occurred. Literally 50 rpm. Result? in 15 seconds it ground a 6 inch gash thru the side of the vehicle! And it was no where gonna stop due to the car being there. And that was with only half the battery power in the airplane. THAT is what torque is all about in electric airplanes. I never use less than a 1/4 inch birch ply (not lite ply) motor mount bulkhead in a full size stunter. You can look at my T-Rex or SV-11 build theads for how I mount them. Its a system Rick Sawicki developed. We have never had a motor mount or nose failure. I have been flying electrics in cl about 6 years now and Rick... well, no one but maybe Big Art's demo flight way back when predates him in cl electric stunt that I have heard of.

bob branch

Peter

That is an interesting way to do it! The 1/8 inch aluminum sounds perfectly adequate for a nose mount. I used aluminum rear ie bulkhead mount in an electric strega. 1/8 inch aluminum was not adequate for rear mount with a 4250 nor an axi 2826/12. Had to make an aluminum doubler to stop the flexing. That might give a hint to some as to the amount of torque these things will generate.

bob branch