Author Topic: Metal pads under engine (Read 3621 times)

Gary Anderson · « **on:** January 29, 2008, 06:28:40 PM »

Hi guys, I was just wondering how many of you guys install metal pads between the engine and the wood motor mounts? I have always done this and was wondering if most builders feel this is a necessary thing to do? I have seen where some haven't installed metal pads and the motor is imprinted in the wood. I guess I will always use this feature on my planes, maybe its just added weight. Just another one of my dumb questions (maybe I have to much time on hand, Ha Ha.)

Marvin Denny · « **Reply #1 on:** January 29, 2008, 08:47:37 PM »

I do. 0.063 Alum alloy. Slightly longer and wider than the engine mount beams

Bigiron

Glen Wearden · « **Reply #2 on:** January 29, 2008, 09:23:19 PM »

I have made pads cut from old credit cards. Very thin, very tough, and they seem to distribute the pressure so the engine lugs don't eat into the wood mounts. Also, almost not weight. Glen

Brett Buck · « **Reply #3 on:** January 30, 2008, 08:10:13 AM »

Quote from: Gary Anderson on January 29, 2008, 06:28:40 PM

Hi guys, I was just wondering how many of you guys install metal pads between the engine and the wood motor mounts? I have always done this and was wondering if most builders feel this is a necessary thing to do? I have seen where some haven't installed metal pads and the motor is imprinted in the wood. I guess I will always use this feature on my planes, maybe its just added weight. Just another one of my dumb questions (maybe I have to much time on hand, Ha Ha.)

Not a dumb question at all. Almost everyone uses the pads in some form for exactly the reason you describe. I use .090 6061 T6 aluminum (cut from an old 'Stop' sign!). Any thinner or softer and it doesn't work as well. Just glue them in place and it's like you have custom motor lugs and there will never be any significant compression of the mounts. I use two separate pads as opposed to the "u"-shaped type, because I need the space right behind the engine for the tank.

Brett

Dennis Moritz · « **Reply #4 on:** January 30, 2008, 08:51:03 AM »

A club member quieted a bad vibe some on a Miss Sarah with 1/8 inch steel pads. Profiles. This one did not like the Fox 35 mounted for foxberg. Full fues planes are more stable, less in need of a steel pad.

Andrew Hathaway · « **Reply #5 on:** January 30, 2008, 10:24:31 AM »

The pads don't need to be metal, the plastic mounting pads for profiles work just fine. I've cut pads for profiles from scraps of ABS plastic in a pinch. Spreading the load over a larger area seems to be a little easier on the mounting surface. It's almost second nature at this point to make a set of pads for every new plane.

Bob Reeves · « **Reply #6 on:** January 30, 2008, 03:36:22 PM »

Gary, Glen and Brett.. Please go into your profile and delete your zip code, your zip code is trying to pull up a weather site that no longer exists and slows down the forum for some of the users.

If you need more details go to the main forum and search for zip code, it will bring up a couple threads this was discussed at length.

Gary Anderson · « **Reply #7 on:** January 30, 2008, 04:57:46 PM »

Quote from: Bob Reeves on January 30, 2008, 03:36:22 PM

Gary, Glen and Brett.. Please go into your profile and delete your zip code, your zip code is trying to pull up a weather site that no longer exists and slows down the forum for some of the users.

If you need more details go to the main forum and search for zip code, it will bring up a couple threads this was discussed at length.

Hi Bob, I deleted my zip code, I had deleted it before, must not have done it correctly. I hope I did it right this time, Thank you,Gary

Brett Buck · « **Reply #8 on:** January 30, 2008, 08:19:20 PM »

Quote from: Bob Reeves on January 30, 2008, 03:36:22 PM

Gary, Glen and Brett.. Please go into your profile and delete your zip code, your zip code is trying to pull up a weather site that no longer exists and slows down the forum for some of the users.

Hmmm, I looked at my profile and I see where it goes, but it's not filled in. My City/State was filled in, so I deleted that.

Brett

Glen Wearden · « **Reply #9 on:** January 30, 2008, 09:18:13 PM »

My zip code's not there; never has been, as far as I know. Glen

Bob Reeves · « **Reply #10 on:** January 31, 2008, 02:57:38 PM »

Ref. Brett's post, looks like if you have city and/or state it also tries to load the weather site.. Look at the little red X at the left of your posts.. This is an image it's trying to load from citywx.com, citywx.com is off line and has been for several weeks.

Thanks

Randy Powell · « **Reply #11 on:** January 31, 2008, 08:36:39 PM »

I use a threaded aluminum mounting setup that bolts to the motor mount. The engine bolts to the aluminum. Works pretty well.

Gary Anderson · « **Reply #12 on:** January 31, 2008, 09:18:43 PM »

Quote from: Randy Powell on January 31, 2008, 08:36:39 PM

I use a threaded aluminum mounting setup that bolts to the motor mount. The engine bolts to the aluminum. Works pretty well.

Hi Randy, how thick is the aluminum you use? Do you tap the aluminum or do you drill holes through the aluminum and install a bolt? I guess you would have to allow for tank height? This system would make it easier to try different engines. Have you had any problems with engine coming loose? I thought about this method but was going to weld studs to mount engine too. One eight inch material seem to be thick enough! Would appreciate a little more in put from you, thank you Gary (I was thinking of stainless, reason, I can get it free)

Andrew Hathaway · « **Reply #13 on:** January 31, 2008, 10:35:03 PM »

I use universal mounting plates for profiles quite a bit. Personally I don't trust my tapping skills combined with the soft aluminum I can run through my scroll saw. What I do is drill all 8 holes, then counter sink the bottom of the holes that match the engine pattern and bolt the engine to the plates with tapered seat 4-40 bolts, washers, and nylon locknuts.

phil c · « **Reply #14 on:** February 01, 2008, 08:52:54 AM »

I use threaded brass inserts. Find they work much better than blind mounting nuts, and there is no need for pads. The engine actually sits on the brass inserts and barely touches the mount.

Bill Little · « **Reply #15 on:** February 01, 2008, 10:08:54 AM »

Then there those that use 1/8th" id brass tubing set into the holes on Classic planes so that they don't have to move where the maple mounts go..........

Randy Powell · « **Reply #16 on:** February 02, 2008, 01:16:07 AM »

Gary,

I use some 3/8" square aluminum stock and 1/2" square engine mounts. I put a chunk of CF tube though the mount and use a threaded steel pad (suitably machined out like swiss cheese) threaded to take the bolts though the mount and drill and tap the aluminum pad for the engine. You're right; different engine, different set of aluminum mounting pieces. Pretty easy. No, I've had no problems. I stripped out one of the engine mounting holes once. Again, pretty easy to fix; just replace the aluminum piece.

I've got a picture somewhere, but can't seem to find it at the moment.

Chris Wellington · « **Reply #17 on:** February 02, 2008, 03:26:16 AM »

Quote from: Andrew Hathaway on January 30, 2008, 10:24:31 AM

The pads don't need to be metal, the plastic mounting pads for profiles work just fine. I've cut pads for profiles from scraps of ABS plastic in a pinch.

Circuit (glass fibre) board also works : F2D models use this under metal bearers.

Gary Anderson · « **Reply #18 on:** February 02, 2008, 11:33:58 AM »

Quote from: Randy Powell on February 02, 2008, 01:16:07 AM

Gary,

I use some 3/8" square aluminum stock and 1/2" square engine mounts. I put a chunk of CF tube though the mount and use a threaded steel pad (suitably machined out like swiss cheese) threaded to take the bolts though the mount and drill and tap the aluminum pad for the engine. You're right; different engine, different set of aluminum mounting pieces. Pretty easy. No, I've had no problems. I stripped out one of the engine mounting holes once. Again, pretty easy to fix; just replace the aluminum piece.

I've got a picture somewhere, but can't seem to find it at the moment.

Thanks Randy, if you find your pictures, would love to see them. I understand your instruction but old saying picture worth thousand words. I appreciate everyone's input and it seems there is many, many ways to do anything we do. This forum and forum of this nature is a great help to many of us and I thank all that takes their time and helps make this possible. Have a great day and keep them in the air, Gary

FLOYD CARTER · « **Reply #19 on:** February 13, 2008, 01:13:28 PM »

Just how much compression of the wood mounts is deemed unacceptable? I don't use metal pads, but I always use rock-hard maple mounts. Even on my oldest models, when I remove the engine, I can't detect any compression on the motor mounts.

Floyd

Randy Powell · « **Reply #20 on:** February 13, 2008, 02:18:04 PM »

Gary,

I used a modified version in the new classic plane (due to limited nose area to work with). The pics are posted in the building thread. In this case, I used 3/8" x 1/2" maple and just made sure there was a good tie to the doubler since the mount was shaved down to about 1/4" under the aluminum motor "pad". But you get the idea. I also had to use some blind nuts (I hate using those) to connect the aluminum to the maple again due to the limited space available. But it should work fine. It does have CF tube running though the maple to prevent crushing. The whole setup works quite well and if you manage to strip out a motor mounting hole, just cut another chunk of aluminum and put another one in. Makes things pretty easy.

Bill Little · « **Reply #21 on:** February 13, 2008, 07:27:14 PM »

Quote from: FLOYD CARTER on February 13, 2008, 01:13:28 PM

Just how much compression of the wood mounts is deemed unacceptable? I don't use metal pads, but I always use rock-hard maple mounts. Even on my oldest models, when I remove the engine, I can't detect any compression on the motor mounts.

Floyd

I don't know the answer Floyd, but on all the planes I built before I started using the pads, there was always a foot print of the engine mounting ears sunk into the maple.

Gary Anderson · « **Reply #22 on:** February 13, 2008, 10:29:14 PM »

Quote from: Bill Little on February 13, 2008, 07:27:14 PM

I don't know the answer Floyd, but on all the planes I built before I started using the pads, there was always a foot print of the engine mounting ears sunk into the maple.

Hi Bill, thank you for your answer. Years ago! after a flying session I noticed the engine would get loose, thats when I figured out the wood would compress and started using metal pads. I'm cheap, I use sheet metal I get from the shop. The amount I use is just scrap. I also notice it helps to remove any vibration from the engine. Many, many different way to do things and they all seem to work. Thanks for your input, Gary

Leo Mehl · « **Reply #23 on:** March 12, 2008, 06:31:53 PM »

I use circuit board material from Radio Shack that has a jillion holes drilled in it. It is about 1/16" thick and puts engine same hight as tank if you use 1/16" tank platform on the engine crutch. Also takes some of the movement out of the engine. I just epoxie it to the motor mount and redrill them from the bottom after the glue has cured.

Gary Anderson · « **Reply #24 on:** March 13, 2008, 09:51:48 AM »

Hi guys,

This is a picture of one of my ugly metal pads I made for a Merco 40. Its made out of sheet metal material 1/16 thick. I will clean it up before I install it in my new Ares, Nobler ship. Have a great day, Gary

Leo Mehl · « **Reply #25 on:** March 14, 2008, 01:39:50 PM »

This the material i use for my pads. Platform and pads are same thickness and the pads are glued to motor mount with epoxy and then redrilled from the bottom. Works for me.

Bryan Higgins · « **Reply #26 on:** March 19, 2008, 09:10:01 PM »

Can you use a metal pad plus thin rubber applied as well to dampen vibration.
Like for use with four strokes or big .60 2 strokes.?

Leo Mehl · « **Reply #27 on:** March 20, 2008, 05:07:48 PM »

I also used these same pads under my Big Jim Super Tigre 60. Still running good after 7 years and mounted with 4-40 bolts.

Ray · « **Reply #28 on:** March 20, 2008, 05:35:35 PM »

Quote from: Leo Mehl on March 20, 2008, 05:07:48 PM

I also used these same pads under my Big Jim Super Tigre 60 (...)mounted with 4-49 bolts.

Ah-hmm.. 4-49. Well, I know about 2-56, 3-48, 4-40, 5-40, and 6-32. I used oversize bolts on the only plus- 50 engine I ever used (an original 1948 sparky Anderson Spitfire that my uncle loaned me to mess with -- he said he never got it running right, even after learning what the spark advance was all about). The 6-32s fit it just right.

"Where'd you get your 4-49s?" he askd, tongue held deeply in his cheek . .

Leo Mehl · « **Reply #29 on:** March 20, 2008, 09:21:28 PM »

Quote from: Ray on March 20, 2008, 05:35:35 PM

Ah-hmm.. 4-49. Well, I know about 2-56, 3-48, 4-40, 5-40, and 6-32. I used oversize bolts on the only plus- 50 engine I ever used (an original 1948 sparky Anderson Spitfire that my uncle loaned me to mess with -- he said he never got it running right, even after learning what the spark advance was all about). The 6-32s fit it just right.

"Where'd you get your 4-49s?" he askd, tongue held deeply in his cheek . .

OOps I ment 4-40. Just a slip of the finger. Story of my life.

Author Topic: Metal pads under engine (Read 3621 times)

Chris Wellington