topwinguk

Anybody had bad experience with the Dubro vibration isolating engine mounts? The reason for the question is that during a flying session yersterday, a friend was flying a new 80" scale Mustang which had just 6 flights on it. During the last flight the engine, an SC 120 4cycle, cut suddenly and on landing the engine was almost out of the model and one of the metal engine mounts was found to have cracked totally off. As I am about to install a similar mount in the Lazy Ace that I'm building I thought I'd see if there is a common known fault! I've been flying $ cycle engines for some while and have had paxolin mounting plates fail through fatigue but would have expected the elastomeric inserts in the Dubro version to eliminate fatigue problems.

Any ideas guys.


Tony

fancman

My Feedback: (16)

I've got the 76" Lazy Ace that I've had a Dubro mount in for more than 10 yrs. Originally I had a Saito 150 on it and switched to a RCS 1.4 gas engine about 6 yrs ago. All this time with the same mount. No problems at all.

Don M.

My Feedback: (5)

I have used these mounts on all my engines for 10 years - never a failure. I used the 688 for a MVVS 26cc gasser with a tuned pipe and I now have an OS 120 FS mounted on a 686 ( rated for a .91 ) because I wanted a smaller footprint on the firewall - no problems.

flipstart

Great mount-heavy duty, well made, I have an OS 1.60 FX mounted on one in a N-28 and it works great. The mounting screws to firewall fit tight in mount, so be careful in marking for T nuts, they have to be dead on.

tigreguy

I am at the stage of putting an Enya .80 4 stroke in a Goldberg Tiger 60. Using the Dubro anti vibration mount puts the prop thrust washer/prop about 2+ inches further out past the front of the fuselage compared to a .60 2 cycle.
The rear carb pushes the engine out about 3/4" aprox. using the supplied fibre mount and the bulky dubro mount really sticks the prop way out front. Other than the balance differential, will this extra "protrusion in front of the engine compartment create unusual handling problems other than balance and increase in elevator throws?
I was told to use the supplied motor mount and others said the vibration could damage the body structure and or the mount itself.
What do you recommend I do.
Thanks.

JohnBuckner

My Feedback: (1)

Tigreguy do yourself a favor that airframe will handle your Enya 80 just fine with a conventional composite mount you do not need the isolation type. Don,t end up being talked into that and ending up with a ridiculous snooze sticking out.

I have done many 90 to 1.20 four strokes with conventional hard mount and no particular problem.

John

tigreguy

Thanks, John. The hobby shop sold me the $50 cdn Dubro mount and then was told by a friend exactly what you just told me. It is just that being an ARF, it is built pretty light in the front end and thought best not "shake it up" too much. I'll reinforce (epoxy in) some triangle stock behind the firewall, just to be on the safe side. As the package the mount came in is pretty well destroyed now I will use it in another "cowled" stick built project later this summer.
It sure is a real 'puurdy' mount though!

BTW- I used to buy all my RC stuff from Ken Buckner in Calgary, Alberta. Ken owned Calgary Hobby Supply Ltd., could be a distant relative perhaps? quite a coincidence..................
Have a great flying season and thanks again for your reply!
Dave

JohnBuckner

My Feedback: (1)

Hmm no relation that I am aware of, Not that many Buckners around. I believe my family links go back to the Illinois, Mo. part of the country.

Ya purdy stuff on the nose can be neat but you will be happy with the choice to abandon the soft mount on that airplane though. Heck I even have a Enya 80 it really does not thump all that hard at least compared to some. Have done a number of pylon war birds with 110, 115 YS and even those did fine on hard mount. Heck another factor is soft mounts do rob power and for those installations a soft mount is out of the question.

John

scale only 4 me

My Feedback: (158)

I've had the same soft Dubro mount in my Kingfisher for 20 years with a ys120, I replaced the rubber isolators 4 years ago,, I'm a fan

tigreguy

Thanks!
Dave

tigreguy

If anyone is interested, check out our club website- www.amasrc.ca