• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

Climb prop C-90

Tx
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
 
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.
 
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!
 
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?
 
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...
 
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.
 
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.
 
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
 
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
 
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. :smile: Good luck, Jim
 
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
 
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
 
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.
 
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
 
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
 
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.
 
Did you ever get that prop? I'm interested in the results. I am looking into options for an experimental 11 with C90
 
Tom, when my buddy owned that plane I put a brand new 76AK-2-42 on it. Don't know why someone would have taken it off unless something happened to it.
 
Yeah I ended up with a new 76ak-2-42 and it turns up 2500 on takeoff.

If I was exp I would be looking at a catto. Glenn had one on his o-200 powered cub, and now has a sensenich ground adjustable that he is very happy with
 
I'm experimental so I think I'll research the Catto 78-38.... Sounds like SUPER11XP likes his. This experimental realm is fun.....so many options. I always got frustrated when doing restoration that I could not change some things that I wanted to because my other planes are certified.....like I said....this is fun
 
My C85 stroker has a C90 cam, 85 pistons 8.6-1 and would not turn a catto 7636 above 2250 static. I never flew it on my J4 because it couldn't get me off the pond that my Mac 7440 does.

Glenn
 
I have two 76AK-2-42 props and both Limit the engine to around 2350rpm on C90-8. I'd like to repitch one to 38.

Dave
 
My C85 stroker has a C90 cam, 85 pistons 8.6-1 and would not turn a catto 7636 above 2250 static. I never flew it on my J4 because it couldn't get me off the pond that my Mac 7440 does.

Glenn

great info Glenn. It's not like you can rep itch one either....so I better do my research. I have a 76AK-2-40 on my 90 TCraft on floats and that works good.i am interested in the weight savings of the Catto
 
Back
Top