Upgrading from c-85 to c-90

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Carl Webster » Wed Feb 18, 2004 5:46 pm

Don Goode wrote:

We have been trying to work the thrust HP equation for a C-90. We agree that a C-90 is best for a 140. Is the 82 HP you mention a C-90 with a 71/52 prop? Is that static thrust HP?

Could we use a 71/54 to get the reasonable 80 static thrust HP at an even lower RPM? Please let us know. tia, Don

I believe the way Continental figures it is no matter what the prop pitch is, if you turn 2475 RPM you get 90 HP. I know a guy who has the c9012f with the 7154 prop. He says his static is about 2150 and he climbs at about 5-700 fpm in cool weather. He gets a good 110 mph. His airplane will run off and leave mine. I have a c8512f with a 7148 prop, and at 2400 rpm I get about 105 mph. I think I would like to have a c9012f with a 7150 prop. I think that would get a good climb and pretty good speed.

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Tom Weeks » Wed Feb 18, 2004 7:47 pm

Victor,

I wonder if I could get a copy of that pattern also? It would be greatly appreciated! Thanks.

Tom Weeks

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Dave Brickner » Wed Feb 18, 2004 11:58 pm

Victor, I have the C-90 12F upgrade in my 1946, but I don't think I have the part you were referring to. Please send me a drawing of that "doubler" also.
I'll reply to such kindness.

Dave Brickner

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Victor Grahn » Thu Feb 19, 2004 7:44 am

Ok, I didn't realize I was sitting on such an important piece. Bob I'll box this thing up and mail it out. Essentially, this is two pieces. A "lip" that extends out into the airstream to help with pulling the air out of the cowling. And a "doubler" that rivets over the top of it, creating a "sandwich effect".. The doubler, then the lip, then the cowling, all riveted together. You may or may not, be able to use the "doubler" that is already riveted on the back lower, air exit, of your cowling. After all was said and done I was not able to use my "old" doubler. Had to make a new one. For anybody that's interested, you can make a "pattern" of this lip/doubler, but it's like trying to get a good, flat, sheet, pattern of an orange peel, very difficult to make a compound curve flat. Best thing to do is use this as a pattern then mail it onto the next person. This thing is very much a "compound curve" it's bending in several directions at once.

Victor

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Bob Campbell N76944 » Thu Feb 19, 2004 9:57 am

Victor, when we started this quest had no idea that we were trying to find a piece of "national treasure"

Our AP/IA was quite taken back that we came up with a pattern so quickly. That's what belonging to the 120/140 organization is all about. :clapping We have a very talented friend that can fabricate this for us and has agreed to do so.

Dave, I will forward to you just as soon as we get the pattern transferred to metal.

Again thanks everyone for the input and discussion about HP and advantage of the c-90

We started this overhaul last November
hoping we could be back flying by now on skis, well as you all know "it ain't over till it's over" I think a rather famous baseball catcher made that astute statement.

Bob Campbell

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Bob Campbell N76944 » Tue Feb 24, 2004 3:50 pm

Victor, received your package this morning with the patterns, THANKYOU We will get tansferred to sheet metal asap. Then will forward to Tom Weeks as soon as we can. Again many thanks.

Bob Campbell

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zoome » Wed Feb 25, 2004 12:09 pm

Why would you want to change from a 85 to a 90--you get so much more by going to 0-200--speed power ???

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Dave Brickner » Wed Feb 25, 2004 8:36 pm

THANK YOU very much Victor. I got the package with the pattern.........I owe you. I'll git ya for this one way or another...... Thanks again!! That's what make this club neat..neat people!!!!