84/43 prop stc for 7gcbc

U

ulookedup

New member
Hey all. im new to the club. any info on an stc for putting a 84/43 borer prop on 0-320 7gcbc. I have spring steel gear so clearance shouldn't be a problem
 
Hi, the following is copied from the type certificate A-759 but really applies only to the S7GCBC (meaning when on edo 2000 floats).

I ran one for years but always put the 76 incher back on when on wheels. Ground clearance will be an issue.

Also, with no competition at this size, McCauley wants an arm and a leg for one. I sold mine a few years ago when I went to the STC for an 0-360 C2E.

Good luck, John

18. McCauley 1A175GMA80 33 lb. (-58)
(a)
Model S7GCBC with Item 204(d) installed and O-320 Lycoming engine
Static r.p.m. at maximum permissible throttle setting:
(No additional tolerance permitted).
Not over 2560, not under 2460
Diameter: not over 80 in., not under 78.5 in.
 
Thats for the S7GCBC 'S' being a seaplane.

Standard gear and tires won't even come close to clearance for an 84" prop. I assume you have more than that.
In fact, a 74" really is marginal on meeting the clearance regulation of 9 inches.
 
Clearance, I have 73 7GCBC with a 8040 sea plane prop on 29" Gar Aero's and have a clearance of 3/8 above minimums. My new prop has about 100 hours and has taken a beating. Currently as we speak I'm getting Scout gear approved and installed on it(not cheap, but will give me another 3 plus inches and better AOA). No way I would run a 84 inch prop, unless you have scout gear and 31" tires. Best of luck, and keep the rubber side down.
 
I currently got a field approval to put the GMA80 on my 7GCBC. BUT the 337 is written so that 29" tires or bigger have to be used. If anyone wanted a copy of my 337 I would gladly give copies for supporting data for someone who is wanting to get an approval. They are getting harder and harder to get field apporovals. In fact I had a copy of a 337 from a guy who got approved for the GMA82/40 (or Borer if you will). But they wouldnt even look at that without doing flight data for airframe/engine. So I decided on going for the one that was at least TC'd for the engine/airframe. IF ANYONE HAS A SPINNER AND BACK PLATE FOR THIS PROP I WOULD BE INTERESTED.
 
Jeff, I too am interested in putting a mccauley 80" prop on my citabria. I would like a copy of your 337 if possible. My email is taffy_76@hotmail.com. Where did you find your prop? does it really take a different spinner and backplate?

Nathan
 
I got the prop from our local shop here and bought the 175GMA80 that is tc'd for the S7GCBC. I did not order it until the knew the 337 was going to fly and it took a long time for the approval, the feds are getting tougher and tougher (or more scared). You can get this prop in 40,41,42 pitch. BTW the 337 will be about 10 pages...........go figure. I will send to you as soon as I get the final paper work, oh and I didnt even order the prop until I knew it was going through. As far as the spinner and backplate, I've been told its different but I also know you can modify the existing one to fit. American Champion used to carry the plate and spinner but since the went to Hartzel they dont carry them anymore. But like I said if someone had the McCaulley spinner and plate laying around and wanted to sell I would be interested.
 
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