a70eliminator

Hi, just aquired a 1/4 scale cub with a Zanoah g38.
Tried twice, I start the engine and taxi the plane up and down the field, and something else falls off.
The plane has never been flown, seems to have been built meticulously except for either his srews were all loose
or the vibrating engine is just shaking it apart, my fingers were tingling from trying to manipulate the
T- screw fast adjutment.
I tried a different supposedly balaced 18x10 prop but more of the same, the muffler was loose so I locktite the thred and retighten.
The motor is mounted on some good looking ruibber isolators too.
Could it be normal and I'm just not used to weed wacker motors in comparison to glow powered.
When it idles the wings just sit there shimmy back and forth, it seems like the whole airframe is shaking apart, it's a brand new out of the box engine.

mogman

Probably best to get rid of the rubber mounts. Hard mount to the firewall is the best way, (in my humble opinion.)
Single cyl. gassers do vibrate quite a bit more than glow motors. Make sure the prop is properly balanced

All Day Dan

My Feedback: (5)

The best way to reduce vibration is to inrease the mass that is being vibrated. Rigidly connect the engine to the firewall without the isolators. Dan.

flyinwalenda

My Feedback: (5)

I have a 38 on a 4-Star 120 (kit-built)and it's a paint shaker. It's mounted right to the firewall. Even tried putting the heavy end of a prop opposite of the crankshaft lobe(heavy end of prop at 12 O'Clock at TDC) and it helped a bit but it still shakes. Had to silicone all of the screws for the cowl, canopy, etc...to keep them from turning out ! I've flown it for 5 years and this winter I'm going to have to open-up the wing and make some repairs as it's starting to sound like a maraca when I carry it !
I have gas engines on all of my larger planes and now even a 10 & 15cc size and the G-38 shakes worse than any of them. I run a Quadra 41 and it's smoother than the 38 and the G-62's I have run smoother as well. The 38 is a reliable and easy starting engine that will last forever but the newer 30+ CC engines run so much smoother with less weight.

Lifer

My Feedback: (1)

I had an SPE 43cc that was a shaker. After several years it literally shook itself to pieces when it broke both mounting lugs on the left side. Prop was balanced but that did not help. Glad the engine's gone, to tell the truth. The new designs are soooo much better.

3136

if the idle is set too low and it's too rich it will shake more, get some help from someone that runs gas at your club.
Also check the prop balance again, both blade and hub.

Lifer

My Feedback: (1)

If you're referencing my comments, believe me, all that has been tried! The engine is a converted, chinese industrial engine. Gone, but not missed.

ahicks

My Feedback: (2)

I had one that was making me nuts too. Suggest you check the crank run out and the prop bolt to make sure it's straight? I agree as well, mixture often has something to do with it.

They all shake, but if anything's wrong, they REALLY shake!

Lifer

My Feedback: (1)

The engine is gone. All my new engines seem to have "DLE" cast onto the side of the case!