Hi again,

I got my new BCMA engine in the mail today, Yea for me.

However, I have another question.

Do I need to build a plywood box or s/thing above the muffler so I can mount this engine? I've seen a few photos....but.

Thx

Dan

You have several options. You could build a box. you could get longer standoffs, or you could build a secondary firewall with anti vibration built in.

Hey that sounds great!

Tell me how to build w/ antivibration. Please.

I'm also going to install T-nuts for a camera mount. All the Vib. I get remove is great!

Thanks,

Dan

There are many instructions online for many different types of anti-vibe engine mounts. RC Report had an article mid summer 2007 of a 'false' firewall using fuel tubing and silicone. However, I think the ticket for you is the same as what I did on my Byrons CAP 21. I went to a truck dealership and asked for Freightliner grill guard mounts. They are about 3/4 inch thick rubber, maybe 3/4 inch diameter with independent 1/4 inch standard thread studs protruding from each end. These studs are imbedded into the rubber, secured by washers buried in the rubber. The studs are not attached to eachother, making for totally independent rubber mounted studs.

I would post a pic of these, but my camera was stolen (found, but not returned yet per trial). I can give you these pics of my CAP's building progress. These are very easy to work with, and can be mounted directly to the engine mounts, or with the use of another firewall.

Or any other type of mount your imagination can muster.

These mounts were used for a 45cc homelite gas conversion. They show no signs of failing. If they can hold a 400 pound grill on a truck, they can hold an engine to your plane. Some more pics:

Thanks very much Deadeye,

That looks great! I like your setup also w/ the tray on the back of the firewall w/ the fuel tank tray mounted as one piece. Great idea!

I'll look for a dealer to find them.

Dan

Dead eye,

This doesn't feel that great. I'm getting a little frustrated.

I went to the truck parts supply and they didn't have exactly as you show. You can see the pic below.

Besides that, the threads on my mount are 5mm.

I can feed the bolts right through without using the threads inside the Rubber spacer, but when tighten it down it doesn't feel like much cushion/isolation. I'm also worried that it might come loose during flight, or does lock-tight take care of that? What about a rubber washer on the other side?


Your setup/spacers seem better. What do you think?

I bought 8 spacers so I "could" cut one down thinner and install it on the other side for each stud. But my bolts are too short. (I got the longest 5mm bolts they had at my local Ace H/Ware)
Help

Dan

Or you could do what Randy did and buy A nice little Jtec muffler that is side mounted and the tubes come out the bottom. Then you could mount direct to the fire wall. Jtec may even have A nice vibe mount made just for your engine if you ask. I just used one of there vibe mounts for A YS 1.40 in an Extra and there was zero vibe to the air frame. I'm not sure of all they now carry but I am sold on there mounts.

Dan,
Those are fender mounts you have there. I have a friend that successfully used them on a gas engine a bit bigger than yours, but he used an aluminum 'false firewall' so the brass inserts could not pull through. Can't remember how he did exactly, as that plane died a horrible death.

I wish my camera wasn't stolen from me, or I could show you exactly what I have. I will attach a cheesy paint drawing to explain it further. The the silver is the steel,the black represents the rubber, which totally encapsulates the stud's anchor washers. Notice that both studs are independent of each other with only rubber connecting them. I have noticed that some rubber mounts are harder rubber than others, so dig around in the bag for the gummiest ones for that size engine.

J-Tec does make a decent mount, but I've noticed the bushings don't last very long.

Right, I understood what you had from your explanation before, and the photo Thanks. By the way, I printed it out and took it w/ me to the dealer.

I was disappointed w/what I bought, they just didn't have that at the dealership I went to. I just figured on being creative w/ what I had to work with.

For me that's a part of the fun. But I decided right away I like your set-up and wanted to copy it. S/how it will work out, I'm the persistent type, to a fault s/times. Haha

I'm going back to work on my wing set-up with the fiberglass stabs. Get off the engine mount for a while.

Remember..?

http://www.rcuniverse.com/forum/m_66...tm.htm#6649273


Thanks again,

Dan

P.S. I got my cowl and wheel pants in the mail from fiberglass specialties too. yahoo! (and my 2 missing servos from Tower)