Climb prop C-90

[RaisedByWolves]

Hey guys, we have a 7EC with a C-90-12 and a sensenich 76AK-2-48. I was wondering what is approved for a climb prop, or could we re pitch the obese have. We are only seeing 2200-2300 on takeoff


Tom

[Beach Bum]

Hey guys, we have a 7EC with a C-90-12 and a sensenich 76AK-2-48. I was wondering what is approved for a climb prop, or could we re pitch the obese have. We are only seeing 2200-2300 on takeoff


Tom

I believe approved propellers will be listed on the airplanes type certificate or STC. We installed a C-90-8 and a metal propeller on our J3... All listed on the TC.

[aktango58]

I took mine in and had the pitch re done. I think I ended up at a 43 or so.

A good prop shop will give you a good idea where it should go if you have the existing rpm and tell them where you want it.

Note: use a reliable tac, not the one in the dash to verify the existing rpm!

[RaisedByWolves]

Note: use a reliable tac, not the one in the dash to verify the existing rpm!

I found out today, that the tach records the RPM but doesn't record the time, and it looks like a newer tach with only 280HR

[RaisedByWolves]

I have been doing some reading, sounds like 42 pitch is about right, Can a prop shop re pitch a 48 to 42? Where can i find a "localish" prop shop in new england?

[Super11XP]

Not sure if this will help or not, but in a conversation with Craig Catto, he told me that his 76x36 on a c-90 @2200-2300 was outpulling the whirlwind ground adjustable even when it was set to give a static rpm of 2600. Then there are the guys that run thier o-200s up to and over 3000 rpm and swear that thats the way to go. All experimental of course...

[aktango58]

Doesn't Tim have a champ?

Maybe you could do a long term borrow to test it out....

[RobS]

I used to have a C-90-12 in a J3/PA11 configuration and ran the sensenich 76AK-2 in a 37 pitch and it was under on TO by about 25 rpm and was a real performer when light.

[Roger Peterson]

I am using a 76AK2-40 on a 0-200 on floats and it is a great performer. Think 42 would be too much pitch. Great Prop.

[skywagon8a]

Where can i find a "localish" prop shop in new england?

Try http://www.sensenichpropellers.com/Main.html?Home.html They are in Windham CT at the airport. You might be able to fly in, have it done and fly home.

[Chuck Avon]

On new C85-12 on tcraft i have a McCauley 1B90 cm 74/43 static rpm 2400 t/o 2500 climb 1200 ft per min cruse at 2500 rpm 107 kt the engine has 9 hr on it now so it's still braking it in

[cruiser]

According to the chart in the Univair catalog 76AK-2-46 is standard and 48 is a cruise prop. Sensenich Propeller Service in in PA has given me good service in the past, they are also in North Windham, CT. Google them. Note that this is NOT Sensenich propeller manufacturing although they would probably give good service also. Similar names, different business as I understand it. Jim

[cruiser]

Tom, Sounds like it's time for an Aircraft Spruce and Univair catalog for your reading room. The Spruce catalog is a little heavy on the knees though. Good luck, Jim

[Jon B.]

Tom,

I bought a new 76AK-2-44 from Univair for my 90hp Champ (same engine as you have). I didn't care for the performance, so took it to a prop shop and had it pitched to 42.

The take-off and cruise both improved considerably! In fact, it went faster with that pitch than at 44.

I don't think a shop can change it that much, though. It seems to me theycould go 4-5 inches in either direction from original.

Jon

[aktango58]

'NEW' does not mean correctly pitched

[sburg58]

I run a Sensenich 76AK-2-46 on my C90-12 experimental cub. I see about 2300 to 2350 on takeoff, cannot get to redline at cruise unless in a descent, thinking 42 or 43 would be better.

Roger, flying and fishing where it is cool, what a great deal! Too hot down here! We are heading North on Tuesday.

Stan

[JP]

42 on my C-90. Works really well.

[tempdoug]

925# cub, 7440 mccauly, 2650 climb not quite 80 cruise, sets you back in the seat on takeoff. for just a little more cruise a 41 or 42 would be right in there. These cattos for exp like clint says still look cool.

[willyb]

Tom I would use the prop Roger uses.Yours may be able to be pitched down that far.Check with Douten I am pretty sure that's what he runs.You should be able to go to redline in level flight.
I run the Mac 75-35 0n my 0-200.I cruise at 2550@93mph.I don't believe it is approved on the 90.
I met a guy at Lockhaven with a J-3/85 who was running a new M/T composite prop.He said it was an approved prop and worked really well.

Bill

[tempdoug]

Not sure if this will help or not, but in a conversation with Craig Catto, he told me that his 76x36 on a c-90 @2200-2300 was outpulling the whirlwind ground adjustable even when it was set to give a static rpm of 2600. Then there are the guys that run thier o-200s up to and over 3000 rpm and swear that thats the way to go. All experimental of course...

Clint what are you running on your 90, I like the way you try all this stuff. doug

[JP]

I have been doing some reading, sounds like 42 pitch is about right, Can a prop shop re pitch a 48 to 42? Where can i find a "localish" prop shop in new england?

http://www.airplanepropeller.com/

A very good shop over in CT.

[Super11XP]

I am currently running a 69x41 on my c-90. I see about 2550 static and a little over 2600 on climbout. I don't think that it is really that great of a prop-not enough diameter. Craig is currently building a 76x38 for me that I am really excited about. we'll see how it works when I get it. He is really busy.