This has been said before but, two blade props are more efficient than 3 blade props (all other things being equal.) More blades lose efficiency, but give greater ground clearance and usually improve takeoff roll/climb slightly. They do not usually make less noise.
Dick, perhaps your oil cooler had a verniertherm problem?
Were YOU happy with the 76-60 prop? Or did you wish you had a different pitch?
Three Blade Prop
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blueldr
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George,
Failure of the verna therm is certainly a possibility. I assumed it was OK because it appeared to be working during the climb, but perhaps my temperature was simply maxed out at that point.
I have two fixed pitch propellers that were supposedly from a fixed pitch model of the T-41 airplane.One is pitched at 50 inches and the other at 60 inches. I tried the 50in. first but I felt it was too thin, particularly in cruise.
The 60in. did a good job on TO and climb and gave me about the same speed and fuel burn in cruise that I had with the stock engine. I bought the propellers and never had them checked for pitch. In retrospect, I can't really feel that the pitch on the 60in. was as marked. The numbers don't seem to add up .
My home field elevation is about 1700'MSL. With a stock engine at gross wt., it used to take me 35 minutes to climb to 9500' to cross the hump en route to Idaho. After installing the Cont. IO-360, with the 60in. fixed pitch prop it took 15 minutes. When I installed the 82in. CS prop it took 11 minutes.
I really believe that I'd just as soon have the FP prop from the standpoint of cost, simplicity and weight. It provides excellent take off and climb and
is almost maintenance free. The C-170 airplane is not really built as a speed demon and the fuel burn with the bigger engine is the same at the same speeds and weights. Obviously the CS prop would be an advantage if one flys a lot of long XC flights, but for my kind of use it doesn't add up.
Failure of the verna therm is certainly a possibility. I assumed it was OK because it appeared to be working during the climb, but perhaps my temperature was simply maxed out at that point.
I have two fixed pitch propellers that were supposedly from a fixed pitch model of the T-41 airplane.One is pitched at 50 inches and the other at 60 inches. I tried the 50in. first but I felt it was too thin, particularly in cruise.
The 60in. did a good job on TO and climb and gave me about the same speed and fuel burn in cruise that I had with the stock engine. I bought the propellers and never had them checked for pitch. In retrospect, I can't really feel that the pitch on the 60in. was as marked. The numbers don't seem to add up .
My home field elevation is about 1700'MSL. With a stock engine at gross wt., it used to take me 35 minutes to climb to 9500' to cross the hump en route to Idaho. After installing the Cont. IO-360, with the 60in. fixed pitch prop it took 15 minutes. When I installed the 82in. CS prop it took 11 minutes.
I really believe that I'd just as soon have the FP prop from the standpoint of cost, simplicity and weight. It provides excellent take off and climb and
is almost maintenance free. The C-170 airplane is not really built as a speed demon and the fuel burn with the bigger engine is the same at the same speeds and weights. Obviously the CS prop would be an advantage if one flys a lot of long XC flights, but for my kind of use it doesn't add up.
BL
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