Vibrations on observer EB

[Helirono]

Hello,

I've a big problem of vibrations on my Observer EB. The engine works well but I've big vibrations problem on the which are recorded on the camera. There is no tracking or other vibrations due to the mecanic. I'm certain that my vibrations problems come from the Zenoah G26. I've bought that heli for have a good definition of aerial video, but we couldn't use that video due to that vibrations.

Is there something to do to decrease that vibrations on the camera mount ?

I've a second problem of interferences which I tell you on a second topic :-(
Thank you for your answer,
Renaud SILVESTRI

[Brady Longmore]

how much oil are you adding to your fuel mix?

[Helirono]

Hello,

My oil ratio is 4%, so 25:1
And my cam a Sony HDR-HC3 with the Super SteadyShot activated.

Have you any idea ?

Thank you,
Renaud SILVESTRI

[Brady Longmore]

Well, the best help I can offer is to tell you how I have been instructed to mix the oil by Gary Travis, sponsored Bergen pilot.

He says the best is 5 ounces of oil ( Blue Marble brand if possible ) to every 1 Gallon of fuel.

I did some converting for you since you are in Europe and operate on the metric system. We silly Americans and our silly measurements. :D

5 American Ounces = 147.8 ML
1 American Gallons = 3.7 Litres

Which I think comes to about 3.9 % if I did my calculations correctly. So, it sounds like you are about right for your oil mixture.

Are you sure it is the engine causing the vibrations? If so, then you must need to do some tuning to your needles. But, vibrations can be caused by other things not being in balance, or set up correctly. You might have a slightly bent main rotor shaft for example.

[cbergen]

25:1 on the oil mix is OK.

Where are your needles at right now, how many turns out?

Did you dial indicate the fan in to less than .002"?

What headspeed are you running in a hover?

What pitch do you have setup in the hover?

[Helirono]

Yes, at my firts mixing fuel, I had some troubles with that "odd" measurement to convert it to "universal" :glasses2: measurements.

High and low needles are 1 3/8 turns.

The headspeed is 1600.

In the hover, the pich is 6°

When I was assembling the Observer, yes, the dial indicate the fan less than 0.002".

[cbergen]

Your headspeed is a little on the high side, bring it down to 1450-1550. This will also bring the engine RPM's down a little and reduce some of the engine vibes as well. Don't change your pitch, just your throttle.

Your needles are in the ballpark, so stick with that.

[Gary Travis]

I agree with Chris on the headspeed, around 1450 should be good. Also with the HC3 set the camera at 16/9 and the use of a wide angle converter should do it for you.
Gary

[Helirono]

Ok,

Thank you very much for your info. We'll test all that points when we will have received our crach kit. I hope it'll doesn't come by boat :lol:

Thank you very much for your help. If the problems persist, I'll call you again :roll:

Thank you,
Renaud SILVESTRI and Stéphane ROUTIN

[rbort]

Have you considered balancing the G26 engine? Maybe you have a "bad" one out of the batch as Chris would call it. Also, 25:1 oil mixture seems like alot. I use Blue Marbel myself and 32:1 is plenty enough even with lifting heavy loads.

Just another opinion...

-=>Raja.

[Helirono]

You think the motor could be bad balancing form its conception ?

Renaud

[heliplt]

Try all of the simple things first as Chris Bergen suggested: Fuel mix, pitch, head speed and the needle settings , this very Important. I did have the G26 in my Bergen EB balanced…. just because I wanted it ultra smooth. All of the simple things should be taken care of first.

Good luck 

Check in to getting Gary Travis’s Gasser set up video ,It’s well worth the money.

[Crjbenny]

I have had vibe problems and Gary Travis generously offered to give me a hand. He showed me that my heli would go from paint mixer to ultra smooth by richening the mixture and loading the engine before lift off.

Gary can tell you more but with a good and rich mixture and the head loaded before you leave the ground the exhaust note goes from a buzz to a smooth purr and its smooth as glass.

A freind of mine put a dial indicator on the crank of his brand new G26 and found it about 2 thousandths out of round so that coud be a problem like you guys mentioned earlier.

Yeah... Pretty much what everyone allready said. I just wanted to sound smart.