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Sensenich 2600 rpm Limitation

RV7ator

Well Known Member
A 9A with an O-320 (160hp) has caught a friend's eye, but I can't explain to him why there's a placard "Avoid all operation above 2600 RPM". I'm well aware of the need to avoid continuous operation of any prop in the 26-2700 and 2200-2300 ranges because of the natural harmonics of our four-bangers. What's the deal with this Sensenich hard limit? It's a 2008 vintage 70CM and the placard further warns against repitching under 68".

I like my Hartzells and Whirl Winds!

John Siebold
 
Lots of Hartzell's have restrictions on non-counterweighted engines: take off only at 2700RPM restricting RPM above 2600 RPM for continuous operation.
 
This is a certified prop.....

A 9A with an O-320 (160hp) has caught a friend's eye, but I can't explain to him why there's a placard "Avoid all operation above 2600 RPM". I'm well aware of the need to avoid continuous operation of any prop in the 26-2700 and 2200-2300 ranges because of the natural harmonics of our four-bangers. What's the deal with this Sensenich hard limit? It's a 2008 vintage 70CM and the placard further warns against repitching under 68".
I like my Hartzells and Whirl Winds!
John Siebold

During the certification process Sensenich discovered a harmonic vibration just under 2700 RPM causing them to restrict operation to 2600 RPM max.
 
Also this limit only applies to the Sensenich prop on the 320. If it’s installed on a 360. Then it doesn’t apply. Where is there a Lycoming limitation to avoid continuous operation between 2600 and 2700? Or between 2200 and 2300?
 
Now that's a scary thought!! I hope nobody tries this!

I meant the Sensenich prop meant for the 360.. if you read the install manual, it’s the same document for all engines, and it has on there this 2600 rpm limitation. But then elsewhere it mentions that it doesn’t apply to the 360.. it’s a little confusing to read it, and some people didn’t realize the limitation may not apply to them (with the 360)
 
I meant the Sensenich prop meant for the 360.. if you read the install manual, it’s the same document for all engines, and it has on there this 2600 rpm limitation. But then elsewhere it mentions that it doesn’t apply to the 360.. it’s a little confusing to read it, and some people didn’t realize the limitation may not apply to them (with the 360)

The Sensenich metal prop for the 360 is NOT certified. 2 totally different props.
 
Call Lycoming

Best bet is to call the Lycoming tech support guys and ask about specific restrictions for the specific prop model and specific engine model combination. It'll vary. Some have no restrictions.
 
RPM Limitations

Best bet is to call the Lycoming tech support guys and ask about specific restrictions for the specific prop model and specific engine model combination. It'll vary. Some have no restrictions.

I'm pretty sure Lycoming won't provide this information because the limitations come from the prop manufacturers, not Lycoming.

Skylor
 
No, I called Lycoming directly and they answered the question for all 3 of my prop/engine combinations.
They also had me call the prop manufacturer as well to see if they had corroborating, differing, or additional restrictions. In each case, the two offices agreed.
 
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