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RV-12 SB Sensenich prop hub

John Acardo

I'm New Here
Completed installation of new replacement hub for Sensenich prop SB. The half I removed was just replaced under previous SB in 2016.

It looks identical to what I removed only black. Have very slight vibration now and checked prop track. Anyone else have this experience?

Thanks
 
Is there no more than .1 degree measured difference between the pitch angle of the two blades?

Pitch difference will cause vibration.

I have never seen the indexing barrel of adjustment pins (newer style hubs) get the blade pitch difference closer than .3 degrees or so, and it is often times even worse.
 
Just installed new D1 clamping hub and set pith to 71 both blades. No vibration of any consequence and climb out good and cruise improved. (Current fuel pressure issue notwithstanding).
Dick Seiders
 
Just installed new D1 clamping hub and set pith to 71 both blades. No vibration of any consequence and climb out good and cruise improved. (Current fuel pressure issue notwithstanding).
Dick Seiders

Dick, do you mean 71 even? The KAI specifies 71.4.
 
John, yes Setting is currrently at 71+/-.1. Testing no t yet extensive as flying has been curtailed by fuel pressure and flow rate problems.
Dick Seiders
 
Air rough yesterday so testing prop perf was difficult but I had 4900 wot static, 4950 climb out, level at 3000 wot showed 5500 but air so rough I had to reduce speed. Will do further testing later.
Dick Seiders
 
4950 rpm in climb may be lugging the engine a little too much. 5150-5200 initial climb is a better pitch setting. Be careful not to set pitch aggressively course thinking it will help top end speed - not good for engine. Shoot for 133mph/115kts at 5400 RPM and you and engine will be happy. Above figures are from my experience with temp around 70F and field evaluation - 1000MSL.
 
Ok Jim and thanks for the interest but haven?t I read in an earlier post that wot llevel flight
at 5650 is the best target?
Dick Seiders
 
Prop and pitch settings

Thanks for all the advice.
Set pitch at 71 + / - .1 and climb out and cruise improved. 5200 rpm on climb out, 5400 in cruise with 115 kts. No vibration!
 
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