Are the holes on the Great Planes adjustable motor mount pre drilled(the ones you use to attach the engine to the mount)? I plan on using it to mount a saito .72. Anyone have any suggestions for other adjustable motor mounts for the saito?

No the beams are not predrilled on the GP adjustable motor mount.

Thunder Tiger makes an adjustable mount. Like GP, it is 'universal' so the beams are not drilled for the engine.

The only mounts that will be pre-drilled for the engine will be non-adjustable and likely the same brand as the engine. I know OS markets mounts for some of their engines.

go to the hardware store(or home depot) and buy a 6-32 or 8-32 tap set(will have drill bit and tap) then you do your own(on a 72 it will be a 6-32) then all you wil need is 4 6-32 hex head screws

I think it is the Great Planes mount that has lettering raised on the side of the mount that is flush with the firewall. You have to grind or sand these off so that the mount is flush. It is a pain....

editted for spelling

I just installed a Super Tiger G75 on a Great Planes motor mount. I have an extremely well equipped shop with drill press, cross drill vice, etc. But I bought a "Dead Center Engine Mount Hole Locator" marketed by Great Planes for the installation. The hole locations were marked extremely well. After making the marks I then used a hand drill with appropriate sized drill bit and followed up with the correct sized tap. One of the best and cleanest installions I've made with no binding.

Yea i have a saito 56 and i plan on trading it for a 72 tomorrow. On the current GP motor mount the holes are drilled for .46 sized engines. I had to grind the holes for the front landing gear off of the mount since the carb on the 56 is blocked by it. Are there any other adjustable mounts without the ladning gear holes? Id prefer adjustable because drilling more holes is not really and option.

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Don't let the number of holes in the firewall throw you for a loop. Just obtain some 3/16" wooden dowel stock, put a stick in your drill motor (as you would a bit), grab some sandpaper and run the drill with the wooden dowel inside of the folded sandpaper. Stop frequently and check to see if the size is right to plug the old firewall holes. When the dowels are the right size, use some epoxy to glue them into the firewall. Sand to smooth things out and reapply some epoxy to the firewall. There, you now have a clean slate of a firewall and can drill wherever you want for new holes.

Learning how to drill engine mounts is easy, if you have the proper instructions. RCM (now defunct magazine) used to have books that consisted of collections of tips. One of these books had articles on how to do exactly what you are dreading doing. I used to dread it too, until I learned how to do it properly. Now I drill and tap just about any kind of material with confidence. It would be nice if you could find some of those books and absorb their knowledge. Lots and lots of time savers and how-to's.


Ed Cregger

The chances of finding any other mount with the same spacing on the firewall holes is virtually zero. Most likely you will have to buy another GP, or drill new holes in the firewall.

A Saito 72 and a Saito 56 have the same bolt hole spacing. The only difference is the 72 is just a little wider down in between the beams.

Close enough for Dremel work......

I like Dave Brown mounts as they are lighter that Great Planes mounts and the base is round. It is the lightness that I like and that is important on the nose of a plane. You will just have to learn to drill and tap a mount so you might someone to help on the first one. If you check with Horizion the Saito company does make mounts, if you want to check, but not sure if they are predrilled and tapped.

Hello,

Why not just buy the Saito motor mount already drilled and tapped for the .72? It's a 1 piece metal mount. About $29.00. You can order it from Horizon Hobby. Saito makes good all-metal motor mounts for all of their engines. Besides, I think it is better to mount a 4stroke in a metal mount, not plastic.

Good luck on your project,

Smackdown