Cub Engine Repair

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Bill Greenwood

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Bill Greenwood
I have a J3 Cub which was blown over when the old and worn tiedown ropes supplied by the FBO broke in a high wind.
Much of the repairs have been done, and we are thinking about the engine, a Cont C90. It was parked, not running at the time of accident, but hit the wooden prop hard enough to crack it before landing upside down. There's no apparent damage visible to the engine, I think the first step is to check the prop flange for runout with a dial micrometer. The shop, wants me to send it out to an engine shop for a complete overhaul. Anyone have direct expericnce with this?
 
I have no experience or expertise, but it seems like overkill to even do a runout if the engine wasn't running.
 
Are you paying for it? Fly it... The engine was not turning when the prop hit.
Is insurance paying for it? If so send it to the engine shop.
 
For what it's worth, some of the worst looking damage to cranks I've seen pictures of during tear down inspections came out of engines that either weren't running or had a very low load on them. In other words, engines that most people would argue in favor of not inspecting.

I'd read the guidance in the service bulletin Bell206 provided and decide how to proceed from there.
 
Unfortunately I've had more than one first-hands look at what can happen at very low RPM situations and what the tear-downs have discovered were all situations that could lead to much worse outcomes than the expenditure of money.
 
How many hours are on the engine? I think the service bulletin that @Salty posted would be the way to go.
 
I just want to add a little comment to this thread.

I keep reading stories on POA about people who have had engine failures, and I was astounded by them. I have never had any big problems at all, but then I read threads like this, and suddenly all those engines going boom I read about, makes a lot more sense.
 
Bell 206 , thanks for your reference from Continental. I note its a Service Bulletin not an AD so I guess it is suggested but legally optional.
I am surprised that they don't differentiate a prop strike when the engine is running, especially under power vs not running. It's hard to see how an impact that is only static, not turning or under load at all can damage connecting rods or especially counterweights. The problem is that what they recommend is so involved, even more than an overhaul, that it is very expensive, I think its up $15,000 to $20,000 even for a simple 4 cylinder engine. As for hours, I don't have the log book here, but think it was about 800. You don't fly a Cub that much or that far, and it was running just fine.
I feel in the end, we will check for runout and go from there.
This is one of those simple lessons that I learned the hard way, Several times I said to myself to go to the hardware store and get tie down chains, about $20 would have done it. I wasn't expecting 50 mph winds in the middle of the winter.
Ryan, this was a no rpm situation, not a low rpm one.
By the way, I don't know if the fbo might have had some legal liability for the ropes which were very defective, but they went out of business shortly after and I m sure have little or no assets.
 
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No insurance Bill? (sometimes ppl don’t think they are covered unless the airplane is damaged while flying; if considered already, pls ignore)
 
The big threat of a prop strike is damage to gears in the accessory case. For a plane not running? I'd have the flange checked and fly it away.
 
Bill Greenwood said:
....and I m sure [the FBO]has little or no assets.
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If the FBO had a valid insurance policy before going TU, and the damage occurred before they went out, it is highly likely that your claim will also be valid. File a claim NOW to get in line for whatever payment may be forthcoming.

You stated the tie down ropes were pretty sketchy. Document that! I’d go to the airport and take photos of every bad rope you can find, with a camera that will time/date stamp the photos.

-Skip
 
An old girlfriend lost her T-Craft due to crappy ropes years ago. Me, I've always provided my own ropes, whether long term tiedown at home or traveling.

If it was a metal prop it might be different, but with a wood prop I'm in the "just check the flange for runout" camp. Unless insurance is paying for it...
 
Bill Greenwood said:
I guess it is suggested but legally optional.
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Correct. But there have been ADs out on prop strikes to. However, as mentioned above, it's not all about what may bend, but what could crack or displace as well.
 
Bill Greenwood said:
Ryan, this was a no rpm situation, not a low rpm one.
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Yeah, I caught that, and I'd be as tempted as the rest to check that it tracks true and get it back in the air, but my point was that it doesn't take as much as people think to do damage.
 
I'd faint and fall over if the FBO did not have insurance - right up to the day it closed - and if they did, the coverage should pay for the damage to the aircraft. That's what it's there for.
 
SCCutler said:
I'd faint and fall over if the FBO did not have insurance - right up to the day it closed - and if they did, the coverage should pay for the damage to the aircraft. That's what it's there for.
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The last FBO with a Cub that I flew with didn't carry a dime of insurance on said Cub which was discovered the hard way...
 
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