Fasten Engine Mount to Engine or Airframe first?

[Noah]

Just wondering if it might be easier to fasten the engine mount to the engine first, and then bolt that assembly to the airframe. Then you're not dealing with all that weight and trying to get the engine mount bolts to line up at funky angles. Any reason not to do it this way? The engine mount has already been mounted to the airframe and removed.

[rjcthree]

Mount to engine, assy to firewall. You can use a little leverage - which you will need - with the engine stable. I STRONGLY suggest a second person to help with washers and alignment.

I used the Lord brand mounts. I love the smell of freshly vulcanized rubber.

Rick 90432

[Noah]

Thanks Rick, I've got the Lord Mounts too. Heber Aircraft had the best prices on those. It seems so much simpler to put the engine mount onto the engine while it's on the vertical stand, and then mount the whole thing to the firewall, no tricky angles and alignment with the bolts. But I can't remember anybody ever doing that. Makes me think I must be missing something!

[cyrilmclavin]

Look at the old videos of wartime production the engine & mount assembly was attached to the firewall as a unit. It would be easier just be careful moving the assembly around with the engine crane.

cyril

[deene]

I've done it both ways.

It seems a little easier to put the mount on the engine and then hang on the fuse. Just be aware that the mount is flexible and may require some persuasion to line up with the mount holes in the firewall (even if it has been fitted to the fuse prior to adding the engine). I use cargo straps to move the mount legs around as required to fit.

Another advantage to premounting the engine to the mount is that you can check the position of some firewall mounted items by swinging the engine/mount to the firewall to check clearances with an engine hoist and then swing away for any required repositioning.

[Noah]

I've got a trolley hoist in my garage so moving the engine around and on/off should be a breeze. One thing that did occur to me after posting this is that because I'm building an "A" model, I will have to put the nosegear on prior to getting all that engine weight on there. I'm thinking that I could install the nosegear after the engine mount is fastened to the firewall but prior to releasing the load from the hoist.

[penguin]

I would suggest that you fix the mount to the fuselage first and then install the engine. Tony Bingelis did it the way you are suggesting, but he was clearly more skillful than I am as I just could not get the engine mount to line up with the fuselage when the engine was already installed. Also it was difficult to keep the airplane sufficiently secured without the nosewheel in place. Installing the engine on the mount is not that difficult, especially if you have the engine installation pins sold by Avery.

I think the basic problem is that the engine mount needs a little flexing to fit the fuselage which puts the engine mount pads out of alignment - nothing much that can be done except for some pushing and pulling.

Pete

[rjcthree]

I mounted the mount to the fuse, got it drilled, took a bunch of measurements, then removed the mount and mounted it to the engine. Rick 90432

[Jeff R]

I attached the mount to the engine first and I can't imagine doing it the other way. You have better access to the engine bolts as you can get behind it all. Aligning the mount/engine to the firewall is a piece of cake. It would be helpful to have someone who has done this before help you. I had little idea of what I was doing and it took me hours doing it alone, whereas now I could do in under an hour.

[Chappyd]

Hey Noah,

I hung mine by myself with the mount on the airplane, set the engine up. I didn't find it to be anywhere near a big deal as it's made out to be. A little patience goes a long way in lining up the holes. Went very smoothly and didn't take much time. I used a engine hoist.

Chappy