First of all, thanks to everyone who has answered questions I've had about construction details in the past. My first self-built plane is coming along great, all the control surfaces are hooked up and ready to go, the covering job looks acceptable for a first time user of monokote, etc.

So now, I'm getting ready to mount the engine, an OS 56fs. I'm mounting it to a Dubro vibration dampening mount, for what its worth.

My question, is - should I drill and tap the mount to accept bolts, or drill through and use nuts, lockwashers, etc. Locktite is a good idea either way, I would assume, as well. What are the pro's/cons of tapping vs. using nuts?

Thanks in advance, I know you guys will have some good insight for me!

-Scott

Scott I like to drill and tap and use a nut to act as a lock nut to keep the engine tight. As for soft mounts on an engine of that size I have not found the need for the added cost but of course that is my personal feeling and I tend to be on the frugal side. Sounds like your doing great and will soon be giving us an update on your planes maiden flight. Keep us informed

Scott, I have those mounts on almost all of my planes. They are well worth the extra cost. I drill and tap mine and use #8 socket head cap screws with a lock washer on top. I've never had one come loose and I don't use thread lock on them Just tighten them up really well.

One word of caution when seting them up. Put the socket head screws in the spools with the lock washer under it before positioning the engine. This is espically important for the screw behind the carb. That carb has the idle and high speed needles on the same side and the highspeed extends back further than any other part on the engine that lines up with the mount screws. My first use of them was on a Magnum 52 fs on my trainer. I came across an OS 52 and switched engines. Everything was exactly the same other than that one screw and I ended up countersinking that spool and using a Stainless flat head screw in place of the socket head. It worked out well. Also remmeber that there is some movement between the mounts and the screw heads, so leave a bit of additional clearance to prevent the carb from banging the mounting screw.

I have a 3D plane that I first put the Mag 52 on. Then I decided to change to a 70. I was able to mill a bit off each mount lug on the inside and was able to use the same firewall holes. Even milling the lugs, I still have plenty of meat for the #8 engine mount screws.

These mount have without a doubt saved me a lot of engine repair time. I bounced my trainer off the runway countless times. I was buying props by the dozen and going through them at the rate of a couple a day. The engine never gave me a problem even with all the whacks it took. I think the motor mounts went a long way in protecting it.

I've got a set of them now that were on a plane I piled in so hard that the engine was in five pieces including the crankcase broke in hald and the cylinder broke off. The mounts are waithing for a plane and are in fine shape.

Don

Scott, those mounts really help out your air frame and radio gear in the long run. I still use the hard mounts on engines up to 1.20 but I shouldn't and I haven't seen any problems yet with any of my planes present or past but if you can afford them then use them.
I drill and tap my mounts then use the fiber locking nuts on the mounting bolts/screws. No reason for lock tight except on the bolts holding the mount to the fire wall.
I just this year got to use one of the vibe mounts from JTEC on A YS 1.40 mounted in A CG Extra I built for A customer. This was the best vibe mount I have ever used, I was very impressed and plan on using them again on some of my own planes. A bit different to mount but well worth the extra work and the price was right. As cheap as I am these will be my four stroke mount of choice from now on.

Hi!
I most of the time drill and tap my mounts...the exception being plastic mounts where just drilling and using machine screws work great. Use this in many of my Q-500 airplanes in combination with Bob Brown plastic engine mounts.
Rubber mounts is not needed!

I'm glad to hear positive reviews of the soft mounts. I'm enjoying building as much as flying, so in a lot of ways, this plane is a test bed for me for a number of different things (engine mounts, flaps vs. flaperons, on board glow driver, etc).

Is tapping a hole difficult? Or to put it another way, is it easy to screw up? I've never done it before, which is why I was initially leaning towards straight holes and bolts. I guess worse case, if you mess up the tap, you can always drill it out...

Thanks again! I only found these forums a little while ago, and they are great.

Scott