[Poelzer]

I am curious as to what most people do when attaching your glow engine to a glass filled motor mount. Do you:

1) Tap in threads
2) Drill a hole and use sheet metal screws to hold the engine
3) Drill a hole and use bolts with "acorn" lock nuts?
4) Something else

[Ken Currell]

I used to use self tapping screws but I will be changing to threaded holes and machine screws.

The self tapping screws seem to put too much stress around the hole. Maybe I'm not drilling them large enough. They arms on the mount just seem to break off too easily.

Ken C

[Noin]

I assume that you are asking because you see pros and cons from all of the options you listed. Self tapping stresses the arms holes. Threaded holes could possibly strip or cross thread. Bolts and nuts require a small flat spot to be ground on the bottom of the arm for the nut to rest flat.

I have always used the nut and bolt method as I figured the small amount of material that I had to remove for the nut to sit flat was not enough to compromise the strength of the arm and I can't see the nut pulling through the hole.

[mustang man-rcu]

Machine screws and nylon insert (acorn) nuts. Never had that combination come apart.

Steve

[nony]

I use #6 socket head sheet metal screws (Dubro).

I've found the NBW (nut, bolt, and washer) set up to be too fiddly....

[Guest]

Originally Posted by Poelzer

I am curious as to what most people do when attaching your glow engine to a glass filled motor mount. Do you:

1) Tap in threads
2) Drill a hole and use sheet metal screws to hold the engine
3) Drill a hole and use bolts with "acorn" lock nuts?
4) Something else

Drill hole big enough for bolts to cleanly pass through and in appropriate locations, countersink a hole in the bottom of the mount large enough for a blind nut to snugly fit in place.....cut off the prongs from the blind nut and press in place with some 5 minute epoxy to hold it.....

Voila, glass mount with threads that will never strip and an awkward nut you never have to hold Have done this for years never had a problem.

[Dave Holmes]

Now that last suggestion just makes too much sense. I guess that's why most of us haven't thought of it!

[Guest]

Originally Posted by Dave Holmes

Now that last suggestion just makes too much sense. I guess that's why most of us haven't thought of it!

I would like to take credit but I stole the idea from someone else

Necessity is the mother of invention, in our pattern models we do frequent engine removals so tapped threads in the glass just get destroyed and we cannot get a tool in to hold a nut, so this is the only decent option that works well

I have also seen people leave the prongs on the blind nut and heat it while inserting it so that they go into the nylon.

[Gary Maker]

Chad wrote:"Drill hole big enough for bolts to cleanly pass through and in appropriate locations, countersink a hole in the bottom of the mount large enough for a blind nut to snugly fit in place.....cut off the prongs from the blind nut and press in place with some 5 minute epoxy to hold it..... "

Chad.

Great idea! This is one of the best ways that I have heard of doing this type of mount.

Up to what size of an engine would this be good for? I have a DP Edge 540 that came with a glass mount and a Saito 1.80 is the recommended engine for this plane. I have ordered one of the new Saito 2.20's and was wondering if this mount would be ok for this larger four stroke using the above idea?

I have not used a glass mount on any of my larger Saitos as I always thought the aluminum mounts, drilled and tapped and then lock nutted in place was a stronger more sure method of mounting a large four stroke, although it is a much more expensive way of doing it!

[Guest]

Originally Posted by Gary Maker

Chad wrote:"Drill hole big enough for bolts to cleanly pass through and in appropriate locations, countersink a hole in the bottom of the mount large enough for a blind nut to snugly fit in place.....cut off the prongs from the blind nut and press in place with some 5 minute epoxy to hold it..... "

Chad.

Great idea! This is one of the best ways that I have heard of doing this type of mount.

Up to what size of an engine would this be good for? I have a DP Edge 540 that came with a glass mount and a Saito 1.80 is the recommended engine for this plane. I have ordered one of the new Saito 2.20's and was wondering if this mount would be ok for this larger four stroke using the above idea?

I have not used a glass mount on any of my larger Saitos as I always thought the aluminum mounts, drilled and tapped and then lock nutted in place was a stronger more sure method of mounting a large four stroke, although it is a much more expensive way of doing it!

I have done this with up to a YS 160 DZ (probably not much less power than the Saito 2.2, and far more powerful than the 180).

I also use 4-40 size bolts to hold down this size of motor And 1/8" lightply with carbon laminate for the firewall

This is the engine mount I use (soft mount of my own design)

http://nbengineering.net/mount2.jpg