A75 props again
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jack duncan
A75 props again
Anyone know what props are listed (wood/metal) on the STC allowing a A75 to go on a 7AC champ airframe? nothing stated on the TCM A75 tcds E-213. am looking for dia and pitch numbers etc. thanks, Jack
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Paul Agaliotis
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Re: A75 props again
Jack,
I don't know of the STC props used, but it should be a little short prop. Sensenich uses a 70 inch prop with a D or DK blade designator.
I have a customer that has a A75 on his Champ. By the time we got the RPM needed for the 75 horsepower the plane would slug around because it needed a bigger prop. The fuel burn increased to almost 6GPH.
I would recommend not trying to install the A75, if you need more power go to the C75/C85.
Paul
I don't know of the STC props used, but it should be a little short prop. Sensenich uses a 70 inch prop with a D or DK blade designator.
I have a customer that has a A75 on his Champ. By the time we got the RPM needed for the 75 horsepower the plane would slug around because it needed a bigger prop. The fuel burn increased to almost 6GPH.
I would recommend not trying to install the A75, if you need more power go to the C75/C85.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046
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jack duncan
Re: A75 props again
Paul, yeah I agree with that, I was overhauling my tired A65 and said what the heck why not a 75 and see what it would do, other than costing more money, not much occured, I think I'll put my W72CK44 prop back on, and sell the W70DK42, all the DK does is sit out in front and do a lot of spinning and burn gas I might have a couple of C85s lined up, one for a o/h, if I sell the A75 I'll hang a C85 on my champ, airframes setup for it, wg tanks, braces etc. thanks, Jack
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james gevay
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Re: A75 props again
According to STC SA3-435, which I have in my hands.
You can run a Sensenich 70D 40 or 42, or any other wood prop, dia not to exceed 72" nor under 70".
You can also run a McCauley 1A90CM7038.
A 1A90 or 1B90 must not be over 71" in dia nor under 69.5".
Any McCauley prop with the designation of CM or CF are identical except for the tips, the CM tips are squared and the CF are rounded, this is from my McCauley catalog.
I'm running a McCauley 1A90CF7038 on my A75-8F right now, and I always cruised at 2300 RPM's and burned 4.2-4.5 GPH.
You can run a Sensenich 70D 40 or 42, or any other wood prop, dia not to exceed 72" nor under 70".
You can also run a McCauley 1A90CM7038.
A 1A90 or 1B90 must not be over 71" in dia nor under 69.5".
Any McCauley prop with the designation of CM or CF are identical except for the tips, the CM tips are squared and the CF are rounded, this is from my McCauley catalog.
I'm running a McCauley 1A90CF7038 on my A75-8F right now, and I always cruised at 2300 RPM's and burned 4.2-4.5 GPH.
Re: A75 props again
Jim,
What does your 'average' speed come out at 2300 rpm? I suspect not a great deal more than 2150 but should be a bit better. My A65 seems to be about 83-85 at 2150 and slightly over 4 gph, give or take a little. Of course take off is pretty sick at gross and hot weather. My prop is a 74/43 if I remember correctly.
MikeB
What does your 'average' speed come out at 2300 rpm? I suspect not a great deal more than 2150 but should be a bit better. My A65 seems to be about 83-85 at 2150 and slightly over 4 gph, give or take a little. Of course take off is pretty sick at gross and hot weather. My prop is a 74/43 if I remember correctly.
MikeB
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james gevay
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Re: A75 props again
Mike I used to indicate 74 mph in calm conditions, which is about what I did before the conversion. I never really ran accurate numbers before converting so I can't make any accurate comparisons.
I did fly with another Champ and a Chief once or twice, and when we flew together I told them to run the same RPM's that you always do and we flew in formation at the same speeds. I think the speeds were 74 for me, and about 80-83 for the others. This is all indicated, none of us had GPS's at the time, so I don't know how accurate the airspeeds indicators were.
I know the Chief had a Sensenich and I don't remember what the Champ had. On both, when we took off, I would give them about a 5 to 10 second head start and I would have to pull it back some or I would out climb and nearly overtake them. They both had A65's.
Obviously with that climb prop, I used to climb out pretty well for a Champ, but I used to fly alone most of the time.
Before I tore down my Champ, I weighed it, and it came out to 805 lbs, thats with out a headliner.
The reason I say that "I used to" is that my Champ is under restoration.
I did fly with another Champ and a Chief once or twice, and when we flew together I told them to run the same RPM's that you always do and we flew in formation at the same speeds. I think the speeds were 74 for me, and about 80-83 for the others. This is all indicated, none of us had GPS's at the time, so I don't know how accurate the airspeeds indicators were.
I know the Chief had a Sensenich and I don't remember what the Champ had. On both, when we took off, I would give them about a 5 to 10 second head start and I would have to pull it back some or I would out climb and nearly overtake them. They both had A65's.
Obviously with that climb prop, I used to climb out pretty well for a Champ, but I used to fly alone most of the time.
Before I tore down my Champ, I weighed it, and it came out to 805 lbs, thats with out a headliner.
The reason I say that "I used to" is that my Champ is under restoration.
Re: A75 props again
Really glad to see you guys finally post the facts here! 
Of course a Chief will do these speeds with the engine running just above idle, sipping just over 1 gallon per hour. Once a Chief is at cruse (about 120 mph) yes we are burning 4.5 gallons per hour but hey, its worth it!
Had to get this sly jab in!
Joe A
Of course a Chief will do these speeds with the engine running just above idle, sipping just over 1 gallon per hour. Once a Chief is at cruse (about 120 mph) yes we are burning 4.5 gallons per hour but hey, its worth it!
Had to get this sly jab in!
Joe A
Re: A75 props again
Obviously someone has been 'nipping at the rot gut whisky' 
.
Having never flown in a Chief I can't speak for the actual speed but I do know that a Taylorcraft will move right along....even with a A65. On the other hand I can see out of both sides
and don't feel like I'm in a cave. Regarding speed, I never put too much faith in the airspeed indicator other than landing as it seems pretty inconsisitent at higher speeds but my GPS generally will indicate something like 83 or so average overall. I guess if I wanted to go faster I would have kept my Cherokee.
Mike
.Having never flown in a Chief I can't speak for the actual speed but I do know that a Taylorcraft will move right along....even with a A65. On the other hand I can see out of both sides
and don't feel like I'm in a cave. Regarding speed, I never put too much faith in the airspeed indicator other than landing as it seems pretty inconsisitent at higher speeds but my GPS generally will indicate something like 83 or so average overall. I guess if I wanted to go faster I would have kept my Cherokee.Mike