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Possibly taking on a hangar queen J3C-85, any advice?

Surprised nobody mentioned it, but there is no such thing as a J3C-85! There are J3C-65s that have C85 engines installed.

There was a question about the O-200 STC from Univair. Keep in mind that that STC is only eligible an airplanes with metal spars and a specific fuel tank in the wing. It doesn’t work for wood spar wings! It has also been said that the prop specified in the STC makes for a bad combination of prop, engine, and airframe.


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Out of interest (possibly) A lot of guys both on this forum and off advised (with years of experince and full respect) flying the J3 away if everything seemed fine. Engine compressions were good, turned over sweet (having been torn down now everything was still pretty much in spec) so all in all seemed like I wasted my time tearing down the engine, until the crank went for NDT. It was very badly cracked, engine shop recons if I had run it, it could have said cheers at any time! The joys of buying old aircraft with unknown histories.
 

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Out of interest (possibly) A lot of guys both on this forum and off advised (with years of experince and full respect) flying the J3 away if everything seemed fine. Engine compressions were good, turned over sweet (having been torn down now everything was still pretty much in spec) so all in all seemed like I wasted my time tearing down the engine, until the crank went for NDT. It was very badly cracked, engine shop recons if I had run it, it could have said cheers at any time! The joys of buying old aircraft with unknown histories.

Actually, I’ll offer congratulations! This is an excellent time and place to discover that crank flaw. The alternative could really suck. Good luck on the rest of the project, and good job using an abundance of caution!

MTV
 
You may not think finding the crack is a good thing, but it really is. I know of someone losing their entire prop off a C-85 (yellow tagged crank) due to crank failure. Thankfully, it was a perfect example of a deadstick landing onto the nearest farmer's field with no damage.
 
Sounds like a bad prop strike in the past. In general a lot of the older cranks were tender and had very, very minuscule cracks from various misadventures over the years. The one in my 1959 C-90 had 3.

When the oil would get warm you would get a bit of seepage that would land on the windshield. The tiny cracks were discovered during overhaul of the bottom end and a new crank was acquired. The nice people at Aircraft Specialty Services said that as a practical matter it was highly unlikely that the crank would have come apart suddenly absent attainment of an RPM well beyond the capability of the engine (in which case you likely had a bigger problem at hand). Sounds like yours was on the other side of the spectrum so enjoy the security of the new crank.

Oh, I only have one small piece of constructive criticism of your purchase. The tires are too damn small. Please fix that, too. :lol: Otherwise, geniet die vlieg in u nuwe vliegtuig en baie geluk!
 
Sounds like a bad prop strike in the past. In general a lot of the older cranks were tender and had very, very minuscule cracks from various misadventures over the years. The one in my 1959 C-90 had 3.

When the oil would get warm you would get a bit of seepage that would land on the windshield. The tiny cracks were discovered during overhaul of the bottom end and a new crank was acquired. The nice people at Aircraft Specialty Services said that as a practical matter it was highly unlikely that the crank would have come apart suddenly absent attainment of an RPM well beyond the capability of the engine (in which case you likely had a bigger problem at hand). Sounds like yours was on the other side of the spectrum so enjoy the security of the new crank.

Oh, I only have one small piece of constructive criticism of your purchase. The tires are too damn small. Please fix that, too. :lol: Otherwise, geniet die vlieg in u nuwe vliegtuig en baie geluk!

Baie dankie Oom! ek is besig om die tires reg te maak, moenie worry nie!
 
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Out of interest (possibly) A lot of guys both on this forum and off advised (with years of experince and full respect) flying the J3 away if everything seemed fine. Engine compressions were good, turned over sweet (having been torn down now everything was still pretty much in spec) so all in all seemed like I wasted my time tearing down the engine, until the crank went for NDT. It was very badly cracked, engine shop recons if I had run it, it could have said cheers at any time! The joys of buying old aircraft with unknown histories.

It's great that you found the cracked crank. You might have a desire to tear the whole plane apart. If possible, just focus on making it safe to fly. Get a year or two of flying in before you proceed. You can slowly rebuild a cub by doing one wing one year, then the other wing....and so on.

Tim
 
je spreekt nederlands?

Net 'n bietjie Afrikaans, maar dis amper die selfde. South Africa has 11 official languages, English and Afrikaans (a spin off of Dutch) being the only two languages of European decent, the other 9 are all of African decent and quite different!
 
It's great that you found the cracked crank. You might have a desire to tear the whole plane apart. If possible, just focus on making it safe to fly. Get a year or two of flying in before you proceed. You can slowly rebuild a cub by doing one wing one year, then the other wing....and so on.

Tim

Thanks Tim, the rest of the Cub is actually in really good condition. It would seem, I have to have her x-rayed in the next bit and then will know for sure
 
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