1984 Mooney M20K 231 for sale

Vince,
How did you find the 3 bladed prop to perform. Many in the Mooney
community seem to believe the 3 blade prop reduces cruise speed by
about 5 knots.

How did you find the 3 bladed prop to perform. Many in the Mooney
community seem to believe the 3 blade prop reduces cruise speed by
about 5 knots.

I believe that's only for the four cylinder models. The six cylinder
ones (as is Vince's 231) do not suffer any loss of cruise speed.
---
Ken Reed
N9124X

"Ken Reed" wrote in message
news
How did you find the 3 bladed prop to perform. Many in the Mooney
community seem to believe the 3 blade prop reduces cruise speed by
about 5 knots.

I believe that's only for the four cylinder models. The six cylinder ones
(as is Vince's 231) do not suffer any loss of cruise speed.

AIUI, the earlier three blade props were not optimal for higher
HP/displacement engines...not like he current stable.

Also, you could run higher RPMs with a three blade that, with a two blade
prop, would could unsuitable noise and vibration.

One main advantage of more blades is that you can use more power for
the same prop diameter and construction. Each blade handles a portion
of the total thrust-power. In a two blade there is about 0.5/0.333 - 1
== 50% more stress per blade due to thrust - for same engine power.

-----Original Message-----
From: abripl ]
Posted At: Friday, February 24, 2006 6:09 PM
Posted To: rec.aviation.owning
Conversation: 1984 Mooney M20K 231 for sale
Subject: 1984 Mooney M20K 231 for sale

One main advantage of more blades is that you can use more power for
the same prop diameter and construction. Each blade handles a portion
of the total thrust-power. In a two blade there is about 0.5/0.333 - 1
== 50% more stress per blade due to thrust - for same engine power.
[Jim Carter]
Isn't one feature of the 3 blade prop a smaller diameter that provides
better ground clearance?

And are you really using more power? Isn't number of blades related to
torque applied to the crankshaft? The engine doesn't change power output
based on the number of blades its swinging does it?

I know that smaller diameters tend to mean lower tip velocity and less
noise for the same amount of torque, but I've never heard more blades
means more power used before. But then, I could be wrong...it wouldn't
be the first time and it probably won't be the last.

I haven't had any issues with cruise speed being lower than I expect.
Then again, I never owned the plane with a 2 bladed prop, but I cruise
as fast as my friend's 231 with a 2 bladed prop at the same MP.

I haven't had any issues with cruise speed being lower than I expect.
Then again, I never owned the plane with a 2 bladed prop, but I cruise
as fast as my friend's 231 with a 2 bladed prop at the same MP.