Original Posted By: mboynton(at)excite.com
Sounds like you may have a sick engine! If you have an A80 with aMcCauley1A90 with a 69" dia and 38" pitch you should be able to turn between2440 and 2340 static. That is basically the installation on a Stinson10. If, in fact the prop is a 69/38 and you run the engine up to fullthrottle with the brakes locked/tied down and the RPM doesn't reach 2340there is a problem. Start by checking the accuracy of the tach. You canuse a strobe light for that. If the tach is right, then check that fullthrotle is in fact opening the throtle plate all the way and that youdon't have carb heat leaks into the intake. Check compression andanything else that would cause low power. With that engine and thatprop, there should be no problem turning at least 2350 static. Once yourelease the brakes and accelerate the rpm will increase. The Piet isn'tas fast as a 10 so you may not get the full 2700 rated power. Once youdetermine that the engine is running properly via static rpm, then youcan start playing with props. I wouldn't suggest reducing diamiter. Ifyou want more rpm reduce your pitch. If you talk to a prop shop, theycan retwist the prop to a lower pitch and save you the expense of buyinga new prop.By all means check the engine before playing with the propDavidMichael King wrote:> Hey Guys,>> Maybe you propeller expert types can steer> me in the right direction.>> My GN-1 Aircamper was built in 1985 with an A-80> married up to an Univair wood prop. I am not sure> of the original diameter and pitch. I do remember> the builder's logs indicating 80hp at 2700 rpms.>> The plane went through four owners before I bought> it. It did not have the original propeller, but a metal> McCauley cruise prop.....I think 69 inches in diameter> with a 38 degree pitch.>> I remember when I bought it and first flew the plane> the tach indicated no higher than 2200 rpm on take off.> When I flew it from Corpus Christi to Dallas the rear> tach quite working the first 30 miles of the 400 mile trip.> The front cockpit was covered and I could not see> what the engine was turning.>> To make a long story short, the trip was successfully> made and the broken tach cables, housings and> end fittings replaced. Now I want to take some dual> and carry passengers, but I feel the A-80 is not turning> out 80hp due to a prop miss match.>> I called Ed Sterba Aircraft Propellers, Felix Propellers,> and Hegy Propeller companies. They say it appears> to be an engine/prop miss match. They also said metal> and wooden props of the same diameter and pitch> do not perform the same.. Also manufacturers measure> pitch differently......so a prop from Hegy may perform> differently from one from Sterba, etc...>> A friend of mine has a Hegy wooden 70/40 he will let> me try until I find the perfect match for my plane and> engine.>> Any thoughts are greatly appreciated before I make a> decision which way to go.>> Thanks in advance.....>> Mike King> GN-1 Aircamper> Dallas--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education CenterRt. 3 Box 13Bridgeport, WV 26330-9503(304) 842-8300________________________________________________________________________________
Pietenpol-List: Proper Propeller
Pietenpol-List: Proper Propeller
Original Posted By: "David B. Schober"
Hey Guys,Maybe you propeller expert types can steer me in the right direction. My GN-1 Aircamper was built in 1985 with an A-80 married up to an Univair wood prop. I am not sure of the original diameter and pitch. I do rememberthe builder's logs indicating 80hp at 2700 rpms.The plane went through four owners before I bought it. It did not have the original propeller, but a metalMcCauley cruise prop.....I think 69 inches in diameterwith a 38 degree pitch.I remember when I bought it and first flew the planethe tach indicated no higher than 2200 rpm on take off. When I flew it from Corpus Christi to Dallas the rear tach quite working the first 30 miles of the 400 mile trip.The front cockpit was covered and I could not seewhat the engine was turning. To make a long story short, the trip was successfullymade and the broken tach cables, housings andend fittings replaced. Now I want to take some dualand carry passengers, but I feel the A-80 is not turningout 80hp due to a prop miss match.I called Ed Sterba Aircraft Propellers, Felix Propellers,and Hegy Propeller companies. They say it appearsto be an engine/prop miss match. They also said metaland wooden props of the same diameter and pitchdo not perform the same.. Also manufacturers measure pitch differently......so a prop from Hegy may perform differently from one from Sterba, etc...A friend of mine has a Hegy wooden 70/40 he will letme try until I find the perfect match for my plane andengine.Any thoughts are greatly appreciated before I make a decision which way to go.Thanks in advance.....Mike KingGN-1 AircamperDallas________________________________________________________________________________
Hey Guys,Maybe you propeller expert types can steer me in the right direction. My GN-1 Aircamper was built in 1985 with an A-80 married up to an Univair wood prop. I am not sure of the original diameter and pitch. I do rememberthe builder's logs indicating 80hp at 2700 rpms.The plane went through four owners before I bought it. It did not have the original propeller, but a metalMcCauley cruise prop.....I think 69 inches in diameterwith a 38 degree pitch.I remember when I bought it and first flew the planethe tach indicated no higher than 2200 rpm on take off. When I flew it from Corpus Christi to Dallas the rear tach quite working the first 30 miles of the 400 mile trip.The front cockpit was covered and I could not seewhat the engine was turning. To make a long story short, the trip was successfullymade and the broken tach cables, housings andend fittings replaced. Now I want to take some dualand carry passengers, but I feel the A-80 is not turningout 80hp due to a prop miss match.I called Ed Sterba Aircraft Propellers, Felix Propellers,and Hegy Propeller companies. They say it appearsto be an engine/prop miss match. They also said metaland wooden props of the same diameter and pitchdo not perform the same.. Also manufacturers measure pitch differently......so a prop from Hegy may perform differently from one from Sterba, etc...A friend of mine has a Hegy wooden 70/40 he will letme try until I find the perfect match for my plane andengine.Any thoughts are greatly appreciated before I make a decision which way to go.Thanks in advance.....Mike KingGN-1 AircamperDallas________________________________________________________________________________