Max wood prop length c90-8 '11

hunt/trapak88

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Curious as to the longest prop (wood) I can legally run on my newly bought 11. It has a c90 motor. I've heard conflicting arguments, and I've gathered that wood/metal legal lengths are diff. I would like to run as long and flat as I can. Also heard the cattos are smooth as butter and pull hard. Obviously looking to the best clim performance, of course this is something I should prolly worry bout after I learn to fly :) thanks in advance
 

Troy Hamon

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You are right that you should learn to fly first. Nothing wrong with knowing your airplane and getting as familiar as possible with the maintenance and equipment side of things though. Getting familiar with the type certificate is a good thing. Especially on these old planes, a fluency with the type certificate can be really helpful.
 

Float Pilot

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This is the prop I had on mine with a 90 horse. A 74 inch with a 40 pitch. It worked great on floats and on big tires. It was not so great for cruise.
There are probably all sorts of STCed props out there.... I stayed away from wood because they migt eventually absorb water and become unbalanced.

9. Propeller - Sensenich fixed pitch metal model M76AK-2. +24 lb. (-53)
Eligible with Items 311D(5) and 311C(9) engines only.
Static r.p.m. at maximum permissible throttle setting:
No additional tolerance permitted.
Item 311D(5): Not over 2425, not under 1950.
Item 311C(9): Not over 2550, not under 1950.
Diameter: Not over 74 inches, not under 72.5 inches.
10.
 

gbflyer

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If I recall correctly A-691 allows for a 78" "wood" (no manufacturer given) prop. The fellas at MT propeller felt that this opened the door for their 2 blade fixed pitch prop as the core is indeed wood.

It's been a few years though. Sit down with the TCDS and see what you think. Then have your IA read it too.
 

Float Pilot

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As for a Catto prop .. Call them and find out...

A-691
Page 13 of 21
Engines and Engine Accessories - Fuel and Oil System (cont.)
311. D. (5) C-90-8F (with propeller Item 5, 6, 7, 9, or 101) Use actual weight change
(Bendix-Stromberg carburetor, Continental Part No. 530726 and engine
cooling baffles per Piper Dwg. 11258 Change E are required with this engine.)
Engine Limits: All operations, 2475 r.p.m. (90 hp)
Propeller Limits:
Static r.p.m. at maximum permissible throttle setting:
Not over 2350, not under 1950 for landplane and not under 2050 for seaplane.
No additional tolerance permitted.
Diameter: (with Item 5 propeller) not over 71 inches, not under 69.5 inches.
(with Item 101 propeller) not over 76 inches, not under 70 inches.
 

Mr. Pid

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you probbly ought to do an STC search to see what's approved. The TCDS is for original equipment, not supplemental equipment.
 

ifdale

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Curious what diameter and pitch catto? I'm looking at getting one.

I've got a Sensenich AK76-2-42. Great prop. I was running it as a 40 and it had excellent takeoff and climb, since then I've repitched two inches and now it cruises much better.
 

hunt/trapak88

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Craig catto emailed me back and told me a guy just a 8034 catto on a c90 cub and take off was very nice..
 
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