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Vibration

S

stneki

Well Known Member
Patron
I have 125 hours on my RV7A with an Aero Sport 0-360 ECI engine. The prop is a Sensenich metal prop purchased through Vans. During take off and level flight I have a vibration. When decending it is not near as noticeable. I had the prop dynamicaly balanced. It seams to be better when lean of peak. Leak down and regular compression testing show good. Ignition is a Light Speed II and one mag. Timing is set correct. Carb was just overhauled. Any ideas or suggestions?
 
prop

try repositioning the prop on the crank. Bring #1 cyl to TDC, the prop should be at about 1 o-clock. If the vibration goes away at zero thrust (in a decent) you may have different pitch on the blades. Try checking with a protractor. Also check the track of the blade at the tips.
 
Check for baffle aluminum too close to the cowling, making the interface stiff. I see this often.
 
Bob,

What's a good spacing to shoot for between the aluminum baffle and the inside of the cowl?

Thanks
 
Check your exhaust hangars as well.

They can come loose and that will create the vibration you are describing.

(It happened to me... your description matched my aircraft's symptoms)
 
chepburn said:
Check your exhaust hangars as well.

They can come loose and that will create the vibration you are describing.

(It happened to me... your description matched my aircraft's symptoms)
Click to expand...

Its best to hang the exhaust off the engine and not have hangers attached to engine mounts.
 
Speed-dependent vibration may be something other than engine/prop - look for a loose wheel fairing that will resonant at certain airspeeds or angles of attack and play nicely at others. I've had it once on my left main as a screw worked its way through the fiberglass and lost grip.
 
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