stunthanger.com
Engine basics => Engine set up tips => Topic started by: Larry Renger on October 01, 2018, 01:08:24 PM
-
OOPS! I thought they broke at the intake port.
-
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
-
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.
-
JB Weld? Plumber's solder? Surely there's a fix!
-
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
-
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.
-
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
-
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