[paul borga]

Hey Guys,
I recently bought a Seagull Seafury arf and am planning on installing a webra 120 speed on her (right after I make a few cosmetic changes)...would the setup benefit from the use of a Dubro Vibration Reducing Motor Mount 1.20 2/4-Stroke or would the regular one provided in the kit suffice? ....cheers!

[hitechflyer]

Mounting the motor as rigid as possible is the best.

So called rubber isolators of any sort increase vibrations.

Iv'e been down that road

[Flypaper]

Try removing the rubber mounts from your vehicle and see how it vibrates.
I used to make my own rubber mounts for the gassers from the snowmobile gas tank fuel pipe rubbers that go into the tank.

[Midair]

Originally Posted by hitechflyer

Mounting the motor as rigid as possible is the best.

So called rubber isolators of any sort increase vibrations.

Iv'e been down that road

Originally Posted by Flypaper

Try removing the rubber mounts from your vehicle and see how it vibrates.
I used to make my own rubber mounts for the gassers from the snowmobile gas tank fuel pipe rubbers that go into the tank.

Interesting. Two different schools of thought. I've never used motor vibration dampening devices. Commercial examples have been around for a long time. Back in the 70's and 80's many pattern flyers flew with them, but I haven't seen too many actually being used in today's models.

Peter

[Flypaper]

Glow engines up to 60 size don't need them but the bigger 4 strokers and gas do need them because of the intensity of the vibrations.This old Cap 10B used to have a Quadra 42 on it but since changed to electric. You can see the black rubber on the firewall. Don't pay attention to the finish as she is a real old girl.

[Midair]

I don't use vibration dampeners on any of my models. Even my DA 50cc powered Extra 260. Although I still have glow, I now fly primarily gas and electric. The only stipulation is that on the bigger gassers, never do an engine run-up without the wings attached otherwise the airframe will shake and shiver like a dog crapping razorblades. Lol.

[cosmith]

Do any of the commercially available ones fully isolate the engine from the firewall, or do they all still use a through bolt with a rubber "washer" so to speak?

For it to be fully effective the mount needs to have separate hardware to secure itself to the firewall and to secure the engine to it. This is how any automotive engine mount that I've ever dealt with has been.

I suppose a bolt through a rubber washer could have some damping effect but the hardware is still in contact with the engine and the airframe to transfer vibration. I think I read somewhere that a set up like this can actually increase the amplitude of the vibration by allowing the engine some movement independent of the airframe...meaning normally the airframe itself damps some of the vibration. Hence the reason our planes vibrate less with the wings on.

If there were something available that worked as it should I would be very interested...it hurts to watch an expensive large scale airframe shake the way they do with gas engines.

[Midair]

I've only seen the "bolt through rubber" dampeners for model use, but there could be a variation of the type you describe, available. Not to derail this thread, but it would be interesting to know what other people are or are not using.

[Skidoo55]

I recently bought a super nice 2 meter pattern plane, that has a Hyde vibration mount on it. It also has the nose ring to capture the front of the motor. Without the front ring, I would supect that this motor (YS160) would dance all over the place in there. I googled the hyde mounts, and they definitely require the front ring, which is basically a metal hoop with a rubber O-Ring in it.

As long as your prop is balanced, the motor is going to stop shaking as soon as it comes off of idle. I don't think that the webra 120 is going to shake much, so I think you could go either way, I would try a rigid mount first... I think it will work fine. I have another plane that basically had my 120AX mounted to hardwood rails, and it didn't shake at all. I think yours will be the same.

[paul borga]

Yup, thanks guys......I'll use the provided motor mount....now I'm off to research the do's and don'ts of painting over ultracote.....cheers! (plane in photo not mine, just what it looks like out of box)