PlaneKrazee

My Feedback: (14)

I have run a small .60 Ross twin, Saito .90TS and OS 1.60 twin and all have less power pulse and vibration than engines half their size. These engines are all extremely smooth and truely run smoother than engines of 1/2 their displacement.

Is this true for large gas engines as well?

Would a DA 100 be smoother overall compared to the DA50?

Antique

My Feedback: (4)

Yes

H. Wayne S

My Feedback: (18)

YES is a good answer.

rmh

I have the latest version of the ZDZ80 single - -having run many singles -of different brands - I believe this particular single to be as smooth or smoother than many twins -
This not meant as an advertisment - simply something I observed
It appears ZDZ changed the crank counterbalance -and even tho I have run a number of these 80 singles - this one IS different -
I had other flyers familiar with the 80 singles also check it out - all agreed it is smoother and very noticably so -
Maybe it is a lucky " happening - Frankly I am not certain. One monkey don't make no show -
My other singles all have a certain out of balance phase which tho slight - is detectable.
I just tried running in a particular glo single - a .46 non bearing /non ringed -so called ABC type that is the roughest SOB I ever saw - simply very poorly fit and will take some time to fit in to make it even tolerable .
It is going bye bye
Twins do have a built in design edge (boxer twins.)
However -there are some older gas twins I have run that are frankly rough as a cob---
Some guys can screw up anything --

Antique

My Feedback: (4)

Smoothest single I ever had was a Red Max 42cc made from a brushcutter..Had a heavy crank like a G62...
I have a customer that says his ZDZ 80 single shakes his plane apart...Production tolerances maybe ?

rmh

Never saw a shaky one - but all of the others I have had or run, had some midrange transition that could be felt.
Any shake I have found in these -is typically -- low speed mixture and or the use of a POS propeller.
-the worst shakers in all model engines -is the YS 1.40 four stroke - these will knock the balls off a pool table.
Talk about a basic design characteristic.

rjmdubois

I think it's difficult to say how shaky a particular engine is just based on the observation in a given model.

Last week I was comparing two brisons 3.2, one in an 16 lb. Extra and the other in a 20+ lb. P-51. The Brison mounted on the P-51 was SO smooth, compared to the Extra. To test further, we changed the propellers, and the result was the same. My hypothesis is the heavier the plane, more smother the engine seems.

Of course it could be just a difference in production runs.