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Author Topic: Fox crank break  (Read 1126 times)

Offline Larry Renger

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Fox crank break
« on: October 01, 2018, 01:08:24 PM »
OOPS! I thought they broke at the intake port.
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Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Online Dave Hull

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Re: Fox crank break
« Reply #1 on: October 01, 2018, 01:30:38 PM »
Hmmm. I suppose that a crank like that one, with the scallops to try to increase counterweighting, is going to be more vulnerable to disk failure. Just like a blown Cox, no?

I just worked on a Fox this morning. I stoned the mismatched machine marks on the intake window. It was too much work to get them all, especially in the corners---where one of these days it's going to break!  That one has a full disk, though, so maybe I will be spared your particular sorrow...

Sorry to see your busted piece. Was that what you had in the Kania yesterday?

McSlow
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Offline Larry Renger

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Re: Fox crank break
« Reply #2 on: October 01, 2018, 03:28:39 PM »
Quote from: Dave Hull on October 01, 2018, 01:30:38 PM
Hmmm. I suppose that a crank like that one, with the scallops to try to increase counterweighting, is going to be more vulnerable to disk failure. Just like a blown Cox, no?

I just worked on a Fox this morning. I stoned the mismatched machine marks on the intake window. It was too much work to get them all, especially in the corners---where one of these days it's going to break!  That one has a full disk, though, so maybe I will be spared your particular sorrow...

Sorry to see your busted piece. Was that what you had in the Kania yesterday?

McSlow

Yup, it sure put a crimp in flying the Ringmaster.
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Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline Tim Wescott

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Re: Fox crank break
« Reply #3 on: October 01, 2018, 03:36:34 PM »
JB Weld?  Plumber's solder?  Surely there's a fix!
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AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline RandySmith

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Re: Fox crank break
« Reply #4 on: October 01, 2018, 05:48:37 PM »
Nope that is a typical place that they break, and also at the crank window,  the undercut at the  round counterweight is a big reason they break there, it is  NOT typical that they break because the  crank was  ground on both side to make a better balance,  There is just a huge design flaw in the  FOX cranks

Randy
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Offline Jim Kraft

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Re: Fox crank break
« Reply #5 on: October 01, 2018, 06:55:09 PM »
I had one that broke two cranks right at the counter balance. Fox replaced them both no charge. After that no problem. It is still going strong after many hours of running. Like Randy said, I think the undercut may have been to much. I have broken two cranks in Madewell 49's, but they broke right in the intake port. Last but not least, a McCoy 40 Red head. Broke in the intake port.

The Fox was stock except for the bypass plug. Fox Super fuel. Both times it was in level flight 4 stroking.
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Jim Kraft

Offline Larry Renger

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Re: Fox crank break
« Reply #6 on: October 01, 2018, 11:05:27 PM »
MECOA bought all the old parts, but no crankshafts for the 35. Time for a new run of Zoot cranks, Randy! Find a good source of Adamantium and they will last forever! Impervium would work fine too. Sadly the current run is made from Unavailabilium.  ;D
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Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline GERALD WIMMER

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Re: Fox crank break
« Reply #7 on: October 02, 2018, 03:49:30 AM »
It would be nice if MECOA made a 70th Anniversary edition and some new parts. The reality now is they have never been cheaper second hand on Ebay and a ton of them are out there waiting for new owners. If you fly enough you break cranks and wear out engines , must have busted at least 1/2 a dozen cranks now but mainly small diesels of DC and PAW manufacture. Regards Gerald
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