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Changing props

bobnall

Registered User
Hillsboro, OR
Hi all,

I'm now running a Borer 8241 prop and am thinking about switching to a 7454 that I already have, just for the trip to New Holstein. What kind of increased air speed could I expect and would it help or hurt fuel economy?

I've not run the 7454 before, so just curious what I might expect to see, other than longer takeoff distances and reduced rate of climb.

Thanks for the help.

Bob
 
Bob-

One of the biggest things I have found after flying a lot behind a cub with an 82/41 is that it is a lot harder to slow it down when landing.

Other than that cruise with 8x6 tires was about 105-110 indicated, burned 9GPH on the trip from tx to oh.

Tim
 
On my trip to JC, flying with 31" BW's, I got 7.54 gph running between 2500-2600 rpm. That's with the 8241. IAS was around 90 mph. But that's flying at around 9000' or higher leaned out. Just wondering if it's worth it to put on the 7454 and what the plus or minus might be by changing props.

Thanks for the response, Tim.

Bob
 
Carey Gray said:
Bob,
I've swapped my long prop for my 74/54 several times. Give me a call, I'll tell you everything I know. Shouldn't take more than a minute or two.:D

Carey...

You can't type it out??? I'm debating the same thing..........
 
Carey Gray said:
My attempts at better cruise speed have been entertaining at best.
I've gone from 5.6 gals. per hour at about 80-85 mph with a 82/41, to 10 gals. per hour at 100 mph with a 74/58. To me, it's not worth it. I still put the 74/54 on every so often, but regardless of the prop, it takes a fair amount of energy to get a cub airframe to go fast.
I hesitated to type all of that because I've heard all the stories about how fast other guys can go and how little fuel they burn. Better numbers than I get.
You always have the option of flying slow with a cruise prop.
If you're debating, I'll send you my 74/54 to try. You might like it. Let me know, I'll crate it up.

Thanks Carey...

I have the cruise prop on it right now and I am debating on whether to put the borer on it or not.... The MT prop would be nice...but the price tag is not!!

Tim
 
Bob,

The biggest factor that came in for me was the time to change
the prop. I'm on floats and the 82 is perfect. To go to
N'Olstein I could gain 10 mph and save an hour over a 10 hour trip.
However it takes me 2 1/2 hours to change the prop ...
then I have to spend another 2 1/2 to change it back.

And, of course. I may drop the damn thing getting it on and
have to repair the float.



(six days one hour 23 minutes)
 
Thanks for the info, guys. As I suspected, I'll just stay with the 8241. that way I get more airsheen time getting from point A to B. And after I started this post I got to thinking (I'm in trouble now!) that in order to LEGALLY change the prop, I would have to have it written in the log and signed off and possibly have a new weight and balance done (think $$$). More complications than I want.

Besides, if the wx is misbehavin', I just might have to stop somewhere in Idaho, and if I do that, then I won't make NH 'cause I won't want to leave, and that makes things even more cheaper, and that means the 8241 would be the better prop to have, and.......geez, why don't we move the NH Fly In to MOOSE CREEK???

And thanks for the offer, Carey, but if your prop is as OLD and UGLY as your airplane is, then I DON"T want it on my new, rebuilt, pristine, no-bugs-on-the-leading-edges Super Duper Cub :lol: . (I'll call you tonite).

Thanks, guys.

Bob
 
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