12.1.2 Engine Mounts

This entry is part 4 of 50 in the series 12 - Engine / Propeller

Before the engine can be mounted to the airframe, it must first be mounted to the engine mount. The engine mount is what’s known as a “dynafocal” mount. The four bolts all point to the same place which is the center of gravity of the engine.

Here’s the engine mount with the four motor mounts in place.

The trick here is that the bolts can only be screwed in easily when the motor mounts are compressed be tightening the bolts. Which you can’t get in until the motor mounts are compressed by tightening the bolts…  How’s that for a catch-22?

At first, we got the two rear bolts in place but the front bolts were a mile from being in the right position. I called my buddy Albert Khasky. He said that starting the bolts in opposite corners works best. So we started with the left rear. But couldn’t get the front right in position. We tried to move the frame but had no luck. We tried a couple of ways to get the holes to line up. Then I had the idea to use a clamp from one corner of the frame to the opposite corner of the engine. But I couldn’t get the clamp to hold on the engine. So I took a piece of wood and shaped it as a pad.

While I was trying to get the clamp on it, Malcolm said “Hey Don. I think that I can get a small prybar or something between the engine and the mount and pry it into position”.

After that, we had all four bolts in place within about 20 minutes.

Tools of the trade.

Then we moved the plane into the approximate position.

Then we leveled the plane, raised the engine out of the way and attached the cowling.

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