RPM setting ?

Speedy

Speedy

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Speedy
I recently bought a Beech B-23 Custom with the 0-360 Lycoming 180 HP. The POH says not to operate for extended period between 2150 - 2350 RPM due to the prop. The guy I bought it from had it 10 years and said he never noticed any vibrations and did not operate at those settings.

I've flown it noq for 10 hrs and runs smothe as silk. I don't run it between those settings either.

Anyone else have that subject on their POH ? Is it only on Beech ? Heard from a friend with a Cherokee with the same issue.

Thanks
 
A number of engine/propeller combinations were found to have torsional vibrations at particular RPM that were undesirable. The theory is that operating at those combinations for extended periods would result in issues like snapped crankshafts. You won't feel these vibrations, they're internal to the crankshaft.

The best advice is to adhere to the limitations set forth. You'll probably never notice anything if you don't, but you won't like what you'd observe if you do.
 
Ted DuPuis said:
A number of engine/propeller combinations were found to have torsional vibrations at particular RPM that were undesirable. The theory is that operating at those combinations for extended periods would result in issues like snapped crankshafts. You won't feel these vibrations, they're internal to the crankshaft.

The best advice is to adhere to the limitations set forth. You'll probably never notice anything if you don't, but you won't like what you'd observe if you do.
Click to expand...
:yeahthat:
 
What???? We can't debate this and stretch it out to a 4 page thread? Is the board dead this morning?
 
Too tired for a debate. Plus Ted's right.
 
Yours isn't the only type with such an issue. The Grumman AA-5B with the original McCauley prop has a yellow arc from 1850-2250 saying "avoid operation in this range while descending" and it is a vibration mode issue. So, what Matt and Ted said is good advice -- follow the limitation/ recommendation in the POH for best reliability and maintainability of your propulsion system.

BTW, the Tiger restriction goes away if you do the STC replacement of the OEM prop with the Sensenich prop which came as stock from the factory on the later AG-5B Tigers. You might see if there is a similar option for your Mouse.
 
Thanks I had heard about that before I bought it. Why not change the prop ? Is that even possible ? Friend of mine bought a Warrior that had an engine swap (150 to 180) with the 337. Also put on a longer prop and a better pitch.

Love this little plane but wished it climbed a little better,
 
Yes it is possible to change to a combination that does not have the limitations.
 
Lots of airplanes have these restrictions, the geared Continentals on the 421's have a fairly wide RPM range that is not to be used for long time periods. I am not sure how they word it, but basically you transition through that RPM range going from take off power to climb/cruise power. I think the max RPM for take off is 2350? and the max continuous is 1950. :D
 
Jaybird180 said:
What???? We can't debate this and stretch it out to a 4 page thread? Is the board dead this morning?
Click to expand...

Not much to debate. It's a simple restriction.

Yes, one can change the prop to get rid of the restriction if you really want. But the only reason to change it would be if you wanted a different prop for other reasons.
 
If you have not already done so, join www.beechaeroclub.org

There is a wealth of information on that site. I was looking at a mouse before buying a Tiger. I joined ($50 a year) and learned more in 15 minutes on that site that I would have learned in 15 years on my own. The member are all super cool and helpful.

I think this same advice goes for anyone thinking about buying. I have been an AYA member for some 15 years. When I was thinking about a DA40 or SR20, I joined their owners associatoins/clubs to learn more about the planes and support. It was money well spent, and even though I bought the Tiger I still get some good magazines and emails from those groups.
 
Beech Aero Club member here as well; the information I've received in return for signing up has payed for itself many times over.
 
Speedy said:
Thanks I had heard about that before I bought it. Why not change the prop ? Is that even possible ? Friend of mine bought a Warrior that had an engine swap (150 to 180) with the 337. Also put on a longer prop and a better pitch.

Love this little plane but wished it climbed a little better,
Click to expand...

Your prop can be "re pitched" by a prop shop to make it a climb prop. However your cruise speed will decline.

Ask a prop shop on what they can do.
 
Speedy said:
Thanks I had heard about that before I bought it. Why not change the prop ? Is that even possible ? Friend of mine bought a Warrior that had an engine swap (150 to 180) with the 337. Also put on a longer prop and a better pitch.

Love this little plane but wished it climbed a little better,
Click to expand...

I have heard of the 150hp E3D to a 160hp D2G conversion for the Warrior... Never heard of the 0320 /150hp -0-360/ 180 hp swap though.... The 150 hp PA-28-151 had a 74-DM6-058 prop.. I repitched mine to 61 and didn't loose much in the climb dept... I assume the 0-360 needed a 76" diameter prop..:dunno:
 
My Stinson has a restriction with the metal prop.

Unless the harmonic area is in a range that you will actually use, just stay out of it and move on.
 
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