My short lived Cub 0.049A

706jim on Fri Jan 10, 2014 1:28 am

I bought an OK Cub 0.049A to use on a home designed profile U/C airplane.

Built it and took it out to fly (maybe around 1960 or so; would a year one way or the other matter much today???)

Snow on the ground, castor oil based fuel, temps in the low 40's.

Flew the plane several times that afternoon; no dust, no overheat, castor oil based fuel.

At the end of the day, my OK Cub was WORN OUT. ZERO compression.

Anybody else here have a Cub last for one hour?

roddie on Fri Jan 10, 2014 9:24 am

706jim wrote:I bought an OK Cub 0.049A to use on a home designed profile U/C airplane.

Built it and took it out to fly (maybe around 1960 or so; would a year one way or the other matter much today???)

Snow on the ground, castor oil based fuel, temps in the low 40's.

Flew the plane several times that afternoon; no dust, no overheat, castor oil based fuel.

At the end of the day, my OK Cub was WORN OUT. ZERO compression.

Anybody else here have a Cub last for one hour?

I never owned an OK Cub engine... but I have to ask the question... Did you ever try replacing the glow plug and gasket? Sometimes an "insulator" can fail in the plug... it's not uncommon. Where you state that it was cold weather, the extreme temperature difference may have caused this to happen. Glow plugs were a relatively new concept back then... and were much better engineered in later years.

If you still have the engine.. try putting a different glow plug on it.. and a NEW plug gasket. You may just be surprised with renewed compression.

Roddie

Mark Boesen on Fri Jan 10, 2014 9:28 am

Actually 60 minutes of run time, 12 flights (5 minutes each) wasn't that far off the mark, for a Cub. That and improper fuel or break-in would shorten life as well. If you find one new/like new really tight and can break it in carefully, you can get some time out of it, but most never came close to the tolerances the Cox was able to produce.

The worst engine was the Wen-Mac, can't remember the series right now, early sixties(?) but the inside of cylinder had a groove around ports, that would wear the piston out in 3-4 flights.

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My short lived Cub 0.049A

My short lived Cub 0.049A

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Re: My short lived Cub 0.049A