Propeller vibration

[Guest]

I noticed that my T&B needle was vibrating a week ago, engine was running about 2150-2200 rpm.

I reduced rpms to 2000 and the needle stopped vibrating and I also realized that I felt a vibration stop.

I played with the throttle making rpm go up and down and noticed that 2100 and above there was a slight vibration.

Last Sunday I changed the prop and hub combination from the metal McCauley to a wood Sensenich (I keep a hub on the prop so they are easy to swap).

I flew the plane and the vibration is gone.

The metal prop was pitched (can't recall if it was balanced) in the 90's and put on a hub and tracked on this plane. I have owned this prop since 1982. I forgot to track it before I took off, previously it was within 1/16".

The wood prop was new in 1998, I have owned since it was new, and was tracked on a hub too. The track checked to within 1/16" or less on Sunday.

I will have to reinstall the metal prop an check the track I suppose its possible that it was hit by something while tied down that knocked it out of track by a lot and causing the vibration.

Having said all that, does anyone have experience with prop vibration?

Causes?

Best way to fix?

How far out of track does it have to be to cause a vibration?

any advice ...

Thanks, Dave

[AKbrew]

Re: Propeller vibration

I'm interested in seeing the replies as well. I think I have a little more vibration than normal, and notice a distinctive 'shutter' when shutting down the engine. Everything else is normal with engine ops.

[Ragwing nut]

Re: Propeller vibration

Wood prop will absorb vibrations where metal props will magnify. You really can't track a metal prop like a wood one, only verify it is true. Have you touched up the paint on the prop at all? Have you checked to make sure your plugs are good and wires are good? Have you tried changing the phase angle to see if it affected the vibration? Could be anything, could be nothing.

[Howard Wilson]

Re: Propeller vibration

Spinners, same ,none?

[Guest]

Re: Propeller vibration

Spinners, same ,none?

No spinner

Thanks

[Guest]

Re: Propeller vibration

Wood prop will absorb vibrations where metal props will magnify. You really can't track a metal prop like a wood one, only verify it is true. Have you touched up the paint on the prop at all? Have you checked to make sure your plugs are good and wires are good? Have you tried changing the phase angle to see if it affected the vibration? Could be anything, could be nothing.

No paint. Plugs and wires appear to be ok.

Didn't think about installing prop on a different angle.

May try that thanks

[Hank Jarrett]

Re: Propeller vibration

When your prop is running smooth you should put an indexing mark on the prop and hub to make sure it goes back the same way. A slightly out of balance prop with a slightly out of balance crank can counteract each other. Problem is if you put everything back indexed backwards next time the two off balance parts will ADD instead of subtract and you get a vibration.
If you hand prop your plane there are really only two positions the prob can be mounted, but you have to take the hub all apart to switch it. If you pulled the prop and hub and didn't take them apart, this is NOT your problem (unless of course you left the key out, in which case you have a really big problem).
Hank

[Guest]

Re: Propeller vibration

When your prop is running smooth you should put an indexing mark on the prop and hub to make sure it goes back the same way. A slightly out of balance prop with a slightly out of balance crank can counteract each other. Problem is if you put everything back indexed backwards next time the two off balance parts will ADD instead of subtract and you get a vibration.
If you hand prop your plane there are really only two positions the prob can be mounted, but you have to take the hub all apart to switch it. If you pulled the prop and hub and didn't take them apart, this is NOT your problem (unless of course you left the key out, in which case you have a really big problem).
Hank

Key is definitely in.

Thanks

[mike lutz]

Re: Propeller vibration

I have found on neunerous occasions over the last 30-40 years I,ve been tingkering with airplanes,that if you would unbolt it and turn 180 degrees that the vibration will either be gone,or it is worse.Usually it is for the better.An old IA taught me this years ago.Doesn,t cost nothing to give it a try.Although if it has been fine preveiously and just started this,I think I would ckeck the tracking as you metioned.Just my 2 cents worth of what has worked for me in the past.

[Guest]

Re: Propeller vibration

thanks Mike

[waltermrich]

Re: Propeller vibration

When I first got the metal prop I have it had a noticable vibration so I suspected it was out of balance . Sent it in to a prop shop to balance it and it came back smooth as glass, I thought the inspection and blance were well worth it even though it cost a little. Lots of peace of mind

[Gary Snell]

Re: Propeller vibration

I think about everything has been covered, could be track or balance and the imbalance could be caused by the prop alone or in combination with the engine itself. High vibration might sometimes be noticable only at certain RPM when the engine rotational frequency coincides with some part of the aircraft structure (resonance) which is why some aircraft are placarded against prolong operation at certain RPM. Could even be a resonance with a gage needle.

Last thing I would check is the rubber mount bushings. On a champ that I had they were so worn there was almost metal to metal contact between mount bolts and engine case. Much better after replacement. Just sent my McCauley clip tip to Sensenich in CT for complete OH. Cost me $450 and the return shipping was on them. Great service and big difference.

[astjp2]

Re: Propeller vibration

Metal bladed props will fatigue and the blades will cone foreward. Mine went in for repitch and both blades were 1/4" foreward from thier original location. It only had 500 hours since new. I am now using a Ercoupe spinner and will do a dynamic balance with my new ACES balancer when I get back to Alaska. It sure is cute with a spinner. Tim

[Fred]

Re: Propeller vibration

Gary Snell, where is Sensenich in CT ?
Thanks< Fred Stewart

[Gary Snell]

Re: Propeller vibration

Fred

Here they are. Also in PA and GA

Connecticut

FAA Repair Station #X0PR011N
Sensenich Propeller Service, Inc.
Coordinates: (IJD) N41-44.64; W072-10.81

Windham County Airport
21 Airport Road
North Windham, CT 06256

Phone: (877) 456-7944 or (860) 456-7944
Fax: (860) 456-0410
Contact: Will Burbage