I'm new to petrol (oh ok, "gas") engines - just ordered my first, a Zenoah G26, for my Eindekker.

I've had mixed advice re soft-mounting it: some insist it will shake my plane to bits hard-mounted, others say hard-mounted is better if prop's balanced ok. Also, the G26 in particular seems to crop up as a vibration-prone engine in other forums.

Any advice/comments would be appreciated. I don't want to move it far forward, so am currently leaning towards rubber washers.

Thanks,

Cam

Hard mount it.

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The problem with soft mounting is that the engine will shake all the screws, nuts and bolts off, in some instances.

The G26 isn't a "shaker". It just shakes a little more than the G23. When you produce more power with essentially the same size engine, the power pulses are stronger, but not a huge amount stronger.

I like my carb needles to stay where I put them. It is easier to compensate for vibration in the airframe construction than to continually be chasing carb settings around the planet.

The competition folks in pattern must soft mount because of noise regulations. You probably do not have that to contend with. That is the only reason that I would ever soft mount an engine. Soft mounts increase weight and contribute new failure modes.

Excellent - we have a consensus

Thanks for the replies - anyone else care to comment or are we agreed that hard-mounting is the winner?

Cam

That's the same advice I got a couple years ago when I bought my first gas engine....a G23.

Tried a few soft mounts, and never liked 'em.

Just flew my G-26 again this Sunday morning in my Chippy.

" vibration-prone " ? Rediculous !

Thanks guys - the "hards" have it! That will make my planned installation easier too, so glad to hear it!

Cheers,

Cam

hard with rubber under-mounts to reduce vibrations

Used hard mount on mine. Haven't had any vibration problems.
Did get more power with a 17/6 instead of a 16/8 APC prop. At least it pulls the plane with more authority.

Mike---Try an 18x6 mejz. I have found that to be the best for the G26

I am not exactly sure what is considered to be a "soft mount," but with my Roto 25, which is similar in size to the G26, I use the Dubro vibration reducing engine mount and it works fine. I think it was this one:

http://www2.towerhobbies.com/cgi-bin...?&I=LXD633&P=7

with the rubber inserts. The stiffness of the elastomerics can be adjusted via the mount.

-Ed

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That is a good mount. I'd just rather shake the model. Besides, there isn't any way to use that mount on the G26. But you probably knew that.

On a lighter engine, such as the MVVS 1.6 or the Evolution 1.6, I would be tempted to use the Dubro mount and, in fact, have upon several occasions. I'm not familiar with the Roto engines as yet.

Order some spare "rubbers" for it. You'll wear them out.

Ed,

I realized that the Dubro mount probably couldn't be used with the G26, but figured there might be one available for it. When I ordered my Roto25 from RC Showcase I also needed an engine mount and that's the one they sold for the engine, so I bought it. It was my first experience with any type of engine mount with rubber isolation. I have to say I am not disappointed with it. The plane doesn't shake and the engine doesn't appear to either. The Roto25 seems pretty smooth, so maybe it has to do with that. I did tighten the mount down pretty well.

Thanks for the tip on buying replacement elastomerics.

-Ed

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As with everything else in life, soft mounts vary quite a bit from brand to brand and model to model. Making a firm recommendation for or against them is not what I am about. Certainly, there are some well designed soft mounts that do a tremendous job and actually do provide benefit from their use.

I won't mention the manufacturer, but it is an old, trusted name in mounts and mufflers. I had one of their soft mounts installed in a Goldberg Ultimate Bipe. I hated it. The engine, an Enya R1.20, shook badly at idle, regardless of how tight the doughtnuts were compressed. I ended up replacing the firewall and going with a traditional solid mount. Since then, I am very selective about the type of soft mount that I use, which is seldom, if ever.