Firewall Forward

December 19, 2012

Time to Saddle up those Ponies! Hanging the Engine!! - 2.0 Hours

The BIG DAY is here! This is definitely one of the high points of the whole build... similar in magnitude to mounting the wings, sitting in the cabin for the first time, and other great highlights. Recently, as I have given this so much thought (almost to the point of overkill), I contacted my good friend Mike Rhodes. Mike lives in Milwaukie, not far from here, and he has a fabulous finished RV-9A hangered at Troutdale. He took me flying last summer over the Columbia River Gorge area, and has offered me hints and help on several occasions. He's a great guy. Recently he emailed me a written summary of engine hanging that he wrote up. That, along with the "Illustrated Guide to Engine Hanging" I got from VAF, has allowed me to get prepared as well as I think it's possible for one to prepare. So Mike offered to stop by today after work and lend me a hand. He suggested that too many helpers is like too many cooks in the kitchen. Counterproductive. So I refrained from inviting a lot of friends that I might have otherwise.

I asked my Dad to come over, just to hang out and watch. My brother Larry and his son, my nephew Phillip, also came by. They're both very good at mechanical things and Larry owned a Cessna years ago. Oh! And then there's Maya, my 7-yr old granddaughter. There's nobody more eager to help than her! So I pretty much had things ready when Mike showed up. I had the hoist set up, the engine picked up off the bench, hanging there, my Lord mounts, hardware and tools ready to go, and the shop heater going full-tilt to warm it up in here. I had turned the airplane around so she was facing the garage door. I figured we could open the door if, for some reason, we had to have more room.

We pretty much followed the protocol and our hands were busy, so I didn't get any pictures of the process itself. It went so quickly and smoothly, that it was done in less than an hour! Mike had to scoot out of here to take his bride to dinner, so I didn't even get a picture of him. But I can't thank him enough for his expertise and his help. Thank you, Mike!

I'll describe how we did this, hoping to help someone else about to attempt the same thing. I think one of the most important things to realize is that because of the design of the Dynafocal mount and the geometry involved, the bolts point forward and inward at compound angles. In fact, it's sort of shaped like a cone when you think about it. Which really makes me wonder why this mount isn't referred to as the "conical mount". The conical mount is, in fact, more cylindrical in shape when you consider that the bolts are all pointing the same direction and are parallel to each other. There's nothing conical about it! Makes no sense to me. Anyway, my point is that the mount only fits the engine really well when all the bolts are tightened. I think this is why so many have been so frustrated trying to hang their engines. If you think about this during the installation process, I think it will help you.

Okay, so we started just like the instructions say, starting at the top right corner and putting that bolt in first. It was easy. Then move over and install the other top bolt on the left side. A bit of pushing and aligning was necessary, but it didn't take long to get it in place. The third bolt, on the bottom right corner, was actually the most difficult one, as it turned out. We had tightened up the top bolts but things weren't lined up down below. We found that loosening them up allowed us to move things around. We pushed and pulled and raised and lowered the engine a bit and finally managed to get that third bolt pushed in far enough to catch the threads from the bolt on the hole in the engine case. Then, using a wrench, tightening on the bolt actually threaded it through the hole in the engine case. I managed to get a washer and nut on it, and pulled it into place. At this point, I thought we should tighten up all 3 bolts to pull the engine in close on the mount. I was hoping this would just pull the 4th hole into alignment, but alas, it didn't quite work that way. Here's where the genius of Mike's experience came to the rescue. He suggested we loosen all 3 bolts first. So we did that. Then we put a drift pin through the 4th hole, struggling a bit to get it through the rubbers and finally into the engine case. This is the same drift pin, incidentally, that I made and used to mount the wings. It's about 4" long. Once the drift pin was in place, we tightened up the 3 bolts enough to pull the engine into place, but not all the way tight. Having the drift pin in place kind of forces the engine into the right position as you tighten the three bolts. Now, the 4th hole was in pretty good alignment and we were able to pull the drift pin out with some pliers and put the bolt in place. It still didn't go quite as smoothly as planned. It wouldn't go all the way in. It was in place, but it was being difficult and wouldn't just slide in. So I grabbed a wrench and turned on it, over and over, hoping it would pull things into place like the third one did. But the bolt just spun in the hole, going nowhere. I didn't realize it was already in the hole and just turning in place. So we pulled the bolt and looked in there, and did it over again with the drift pin. Once I knew the bolt was in the hole, just not sliding in smoothly, I finally grabbed my rubber mallet and very lightly tapped on the bolt. It slid right into place! I quickly put a washer and a nut on and that was it! I tightened them all down and it was time to celebrate!

Here we are at that point. You can see my Dad, my brother Larry, little Maya, and me. All smiles. Mike scooted out of here and I didn't get a picture of him. We'll make up for that some other time.

Here's another shot of my Dad, Larry, my nephew Philip, and Maya.

Later, after everyone left, I spent some time examining each bolt, and the nut on the end. The holes for the cotter pins were out just a bit too far from the slot in the nut, indicating that I needed at least one more washer on each bolt. So I carefully removed one nut at a time, and slipped on another washer, then tightened up the bolt and nut again. They're all tight now and the cotter pin holes are perfectly positioned for the pins. I'll put them in very soon. What a great day!!

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