Magna

Hi all

As my excelleron 90 stock antivibe mount isolator broke(no replacement available at local hobby shop), I'm thinking of doing a hard mount. Problem is my YS110 is too narrow for the Excelleron hardwood beam mount. So I need to fabricate an "extender" from the hardwood beam mount to the YS110 mounting flange. I planned to use some SIG/Midwest Birch ply that is 6mm thick.

The extender will be 2 pcs, one on each side. They will be mounted onto the engine mounting flange and then drilled and mounted onto the plane hardwood beam mount.

Attached is the picture of the hardwood mount. Cutting it off and replace with conventional nylon mount is not an option.

Any issues?

Vertical3-D

My Feedback: (20)

seems like it should work, I don't have experience with the YS engines or larger 4 strokes in general, but my .61 shakes a little so I think long term I'd want some kind of anti vibration aluminum mount, my plane has it's stock mount(nylon/plastic w/e they are made from) and Im thinking about getting an isolated aluminum one, I don't want this one to crack itself or the firewall in the long run...someone who knows more of that engine and plane can help more though I'm sure...

maukaonyx

I have the Excelleron 50 and got rid of the stock antivibe mounts when they let the plane vibrate really bad with my OS 70 on it. I too added wood mounts as you describe, with plywood at first because I had some on hand. It turned out too weak for my taste, so I ripped it out after a few weeks, with lots of work with a Dremel. I added hardwood mounts from the local hobby store, and they are the right solution to me. They are harder, stronger, and more durable than plywood. I epoxied and screwed the mounts to the stock mounts. Just my experience and opinion! Jon

PS I have been flying it several months with the hardwood add ons and it works great.

freakingfast

My Feedback: (3)

How about a Kevlar mat under the plywood sandwich? You could keep the ply thinner yet stronger. Some tri stock around the new extender at the firewall could help too. Optionally you could cut away the top ply only in the area where the engine mounts if the engine’s centerline is important to you. If you choose to mount on top of the ply, soak some thin CA in the edge of the ply and mounting holes in area where the engine mounts to help keep the ply from crushing. Re- tighten mounting screws after a few flights. As maukaonyx said the new beam is best if it is hardwood. Think about grain direction too.

freakingfast

My Feedback: (3)

Another option, but I'm still not a fan of soft mounts. I think they suck up too much engine power.

http://www.dbproducts.com/ look under "VibraDamp Sport Rail" the rubber ends can be turned to the sides.

togatoga

My Feedback: (42)

Hi, Jesse , did tell you about those lousy isolator blocks! You will have to build up the supports to the same height as your anti vib system so that the thrust line is unchanged. I used multilayer ply for strength, a ***** to cut but works. Use fg on top to minimise compression of the wood.
The Kevlar idea from freakingfast looks good too.
If i had a lot of time to spare, i would fabricate 2 strips of thick aluminium sheet, mount the engine on it with screw and nut and bolt the aluminium piece on the beams with wood screws. That would be ideal.

Magna

Hi all

Thanks for the tips especially the kevlar sandwich.

Togatoga

I think partly of the silicone isolator fail was my fault of overtightening too much that its compressed on the hardness of the silicone it failed.

Before hardmounting, I managed to get the MK soft mount with rubber damper but its 91FS size which fit the YS110 but the YS110 is a lot more powerful than OS91FS.

So after I fabricate new mount on the beam for the MK. I fabricated some 2 sheet of aluminium plate for a thickness of 3MM to keep up with the original mounting line/position. But on test running it, the MK rubber was way too soft as expected above, it really rock and roll. So no good!

That when I decided doing a hard mounting. I ended cutting 2 piece of extender with is 2.5in by 1in that is 8mm thick to match the thrust line. The material used is SIG/MIDWEST Birch Plywood(that has 5 lamination) 6mm thick from LHS and another hardwood ply that is 2mm thick (also another 5 thin lamination). I epoxied them and coat it as well and left it cure for couple of hours. I then mount the extender to my engine and then the extender is mounted onto the hardwood beam mount on the plane with 4xM4 bolt and T Nut. I also use M3 bolt to mount the engine onto the extender to allow a thicker edge from the hole vs using M4.

Its very secure now but the hardwood did get couple of extra holes due to the above 2 setup.

I may put in an aluminium sheet between the extender and the hardwood mount for strength/sheering proofing...

I have not test it yet and hope to do it this week. I have to keep an eye on to ensure no shearing. Will likely run it for a tank on the ground and see how it goes!