PaulD

My Feedback: (39)

I am about to build my 46" Katana P kit and will be installing my Saito 72 on it. I have had this engine on 2 other planes so far - Morris Sledge 540 and Accel/OMP Katana 40 and found on both planes the vibration was excessive. Yes, I balance all of my props and I've tried everything from a 14x4w, 13x4W to 12.25x3.75. On the Sledge, I had the covering on the wings vibrating like a drum and on the Katana the engine would visibly shake on the mount. For fuel I run Heli 30%.

I am curious if anyone else has experienced this with the Saito 72 and other profiles and did you do anything to improve it. I love the engine itself esp. on profiles and want to stay away from 2 strokes.

Paul

AFSalmon

My Feedback: (3)

I can't say that I've heard of this being a problem at all. No more vibration issues than a 2-stroke. Could it possibly be a bent crank on that engine?

rcplanenut

My Feedback: (12)

You may want to check your low speed needle. If it's set to rich it will make the airplane shake real bad. Be careful setting it too lean will burn your motor up. I have a Saito 82, 100 and a 220. All of them came set real rich from the factory.( good for breakin I guess). just my opinion

PaulD

My Feedback: (39)

The motor did this vibration thing right out of the box. I even took it back to the LHS where I bought it and he ran it on his test stand and said it was fine.

Another issue I forgot to mention is that on the Sledge, the motor would work it's way thru the motor mounts from the vibration. I have heard that the Sledge kits were supplied with Maple that was not hard enough but man, I could never keep the engine mounting bolts tight!!!!

I was lust looking for build suggestions that might reduce the problem.

Paul

rcplanenut

My Feedback: (12)

Try leaning out the low end

hockeyrules99

My Feedback: (7)

I've read about a couple of Saitos with a real bad shake to them....turned out to have something to do with the carb ....the Saitos were 100's though...
If you go to the four stroke thread and post a question to William Robinson.....Very helpful guy..
John

AFSalmon

My Feedback: (3)

Running an engine on a test stand that is securely anchored to a bench is not going to show vibration issues necessarily. Just because your LHS ran the engine and said it was fine does not mean it is. If you have access to a dial micrometer I would check the crank to see if it is slightly out of round.

PaulD

My Feedback: (39)

THanks Mike,

I will get the crank dialed by my machinist. I need to do that anyways since when I pranged my Katana the engine took a good hit on the spinner.

Paul

aviti

My Feedback: (54)

I've run a 72 and 82 on my Sledge and both vibrate a lot. Neither has been crashed and both run without noticeable vibration on the bench. I can really feel the vibration when trying to set the needle. My low end is fine....I just attributed it to the airframe and engine combo. Others have said the same thing on the profile forums....about the Saito 82 and also the YS 63.

I also have a YS 110 on the OMP 65 Yak and the vibration is almost none. You'd think the bigger 4 stroke would be worse. The 65 Yak flies so much better than the Sledge that the vibration on the Sledge has almost gone away....I almost never fly it anymore...haha.

I'm just starting to build my OMP Boxxer....hope the 72 or 82 won't vibrate too much in this airframe...

hkilian

Aviti,
I have the same model/motor combination that you mention - OMP Yak 65 and YS 110. The motor shook so badly, it broke and loosened the mounting rails and the structure they are glued to (this is an ARF). I have been flying the model before discovering this and am very impressed with the Yak.
I'll rebuild the front end regluing and strengthening the motor mount area and try it again. Since I'm still breaking in the YS (a little over 1 gallon so far) I will also pay attention to the low end needle setting as other posters have mentioned. Question for you: did you alter or enforce the structure on your YAK before mounting the YS engine?
Herb

TailTwister

My Feedback: (1)

First, break the engine in for a bit (40 ounces maybe?), and then tune the low end. The factory has them pretty rich. you want a pretty crisp transition from low to high. for a 72, I like the Pro Zinger 14x4.

Next, after about a gallon of fuel, set the valves to the minimum clearance, and retune for a crisp transition.

It taks about a gallon for a good break in.

Pretty much, I only fly Saitos and electrics now. When new, and rich, they shake pretty good.

westy1957

My Feedback: (2)

Try with a prop 13X6.... I Think it will go better..... [)]

AFSalmon

My Feedback: (3)

TailTwister is right on the mark with break in. The 4S engines require a significant more amount of breakin than the typical 2S engine. If tuned improperly they will shake like mad.