Eagler's Nest
Airframes => Single Seaters => XL => Topic started by: Jeff XL79 on July 05, 2024, 06:14:28 PM
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When I bought my casler 45 cut case style engine it had a hummelbird engine mount with it. On this style mount the rubber dampening inserts are on a ring surrounding the back of the engine . They are right up against the rear plate of the cut case. What this does is put the mounts at station 1 bolted directly to the metal gussets. Is there any special requirement for bolting this way? Seems like it would be a lot of shear. Seems like there would also be rules for washers and bolts as far as grade and size. It looks like it will take a 5/16" in all four corners. Luckily the pattern is close to station one's size putting the bolts near the edge.
Any tech suggestions?
Jeff
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How about a picture?
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This is the back of the engine.
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Here is how it will fit at station 1.
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I never have seen a mount like that. Is it tapped? (scratching head)
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No, it's not tapped. The mount at the firewall just has these flanged tubes welded to the mount in four positions. I've seen mounts like this before with the rubber isolators right up against the rear of the engine case. I just didn't know if there were specific rules for this type. Washers, bolts, ect..
Jeff
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I believe the fog is beginning to lift. :) There's a smaller piece of tubing welded to the bottom of the long tubes that I can't see for the bolt to go through? The vibration damper is nothing more than a donut with a big washer in front that this mount bolt goes through? If so, I would think there would be a steel bushing inside the donut with an ID the same as the mounting bolt, OD the same as the donut. It would be a little shorter than the thickness of the donut, and there would be a wood washer on the inside of the firewall for the nut to pull it all together.
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Here's a couple more pics. This should clear it up.
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One of the rubber dampener.
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I think I've heard somewhere that a picture is worth a thousand words. :) Just run a bolt trough it and the firewall/fuse, put an AN970 washer on it, nut, and as they say in England, "Bob's yer Uncle."