Used google and the search bar to check first and didn't find anything so excuse me if this had been posted/discussed before. Being an A&P myself I found this article to be pretty interesting and a huge game changer in piston driven aircraft if its ever allowed. Curious what everybody thinks. Take care.

Lucas

http://blog.aopa.org/opinionleaders/201 ... ee-engine/

Best idea I've heard in a long time. Makes so much sense that there is no way the FAA will go along with it.

Too bad...

Down there in the US do you guys have to follow TBO hrs? Up in Canada we can run on conditions after TBO for as long as we feel comfortable...

A1Skinner wrote:Down there in the US do you guys have to follow TBO hrs? Up in Canada we can run on conditions after TBO for as long as we feel comfortable...

Part 91, not for hire ops are the same way down here.

I do believe that commercial operations can run past TBO as well, they just have to request and receive an extension somehow. I'm not 100% on that though.

Ok. So then whats he doing thats so special, if we're all doing it already? If he was building it using todays engine technology it would be one thing, but being a Lycoming clone, its still 50 year old tech...

A1Skinner wrote:Ok. So then whats he doing thats so special, if we're all doing it already? If he was building it using todays engine technology it would be one thing, but being a Lycoming clone, its still 50 year old tech...

I kinda agree. I'd rather just have a Lycoming and run it as long as I feel comfortable rather than have to report a bunch of stuff back to the engine manufacture. You know ECI isn't going to receive/review/store all the required data mentioned in the article for free, nor would I expect them too.

Thats what I was thinking Whee. The way we are doing it now works pretty good. No need to re invent the wheel I don't think.

For our purposes its a moot point, but think about the application in a certified, for-hire aircraft! Or better yet, a company with a fleet of aircraft!

In Army Aviation we've been installing HUMS in the fleet. Who knows if we'll ever make the leap from time-based maintenance to condition-based maintenance, but it would drastically reduce the operating cost of our aircraft to only replace items when they need replacing, not when a time-limit comes up.

Not sure about this but it seems to me that there could be some benefit in establishing the condition of the engine when it comes time to sell. Instead of just trusting you, the buyer would have the benefit of the records kept by the manufacturer and could continue the impeccable care you have been providing. Or not, in which case his resale value might be a topic of negotiation for the next buyer.

CamTom12, so common sense

BeeMan wrote:Not sure about this but it seems to me that there could be some benefit in establishing the condition of the engine when it comes time to sell. Instead of just trusting you, the buyer would have the benefit of the records kept by the manufacturer and could continue the impeccable care you have been providing. Or not, in which case his resale value might be a topic of negotiation for the next buyer.

Would it increase the value enough to cover all the expense of the program that you have put in? It would have to to be a benefit...

You guys might be missing something. There are certain types of failures that happen all at once, as a result of some number of cycles, or vibration, or heat load, or metallurgy. Many of these types of failures will show no visible evidence of a problem until the moment it breaks. A lot of things will wear out over time, and you can watch the wear happening at a steady rate until the part is no longer safe. But there are plenty of parts that do not fail this way, they fail immediately when they reach some specific set of conditions..

Propeller blades and helicopter rotor blades are known to do this sort of thing. This is why most helicopters have life limits on the rotors. I have ZERO helicopter experience, so you rotorheads feel free to chime in here and correct me if I'm wrong. But I do know that rotor blades on many helicopters have a life limit, because of exactly this kind of failure.

During the early 1980's, the F-1 raceplanes at Reno were using cut down aluminum Cessna 150 propellers. Something like 56 inch diameter and 66-68 inch pitch, turning at 3800-4000 RPM. One of the engineers in the group with a degree in metallurgy and stress analysis warned the group that the props would run just fine, with no visible cracks, until the moment they broke in flight, at about 25-33% of the semi-span of the blade. There is a very famous photo of a guy landing his Shoestring racer with the entire engine hanging a foot below the airplane by the throttle cable and safety cable, because the metal prop broke at that exact spot. So they outlawed metal props, because wood or composite props did not have that kind of "instant" failure mode.

The point is that this same principle would possibly apply to certain engine components. Taking a crankshaft out of an engine and X-raying it every 2,000 or 4,000 hours may not be such a bad thing.

EZFlap wrote:You guys might be missing something. There are certain types of failures that happen all at once, as a result of some number of cycles, or vibration, or heat load, or metallurgy. Many of these types of failures will show no visible evidence of a problem until the moment it breaks. A lot of things will wear out over time, and you can watch the wear happening at a steady rate until the part is no longer safe. But there are plenty of parts that do not fail this way, they fail immediately when they reach some specific set of conditions..

Propeller blades and helicopter rotor blades are known to do this sort of thing. This is why most helicopters have life limits on the rotors. I have ZERO helicopter experience, so you rotorheads feel free to chime in here and correct me if I'm wrong. But I do know that rotor blades on many helicopters have a life limit, because of exactly this kind of failure.

During the early 1980's, the F-1 raceplanes at Reno were using cut down aluminum Cessna 150 propellers. Something like 56 inch diameter and 66-68 inch pitch, turning at 3800-4000 RPM. One of the engineers in the group with a degree in metallurgy and stress analysis warned the group that the props would run just fine, with no visible cracks, until the moment they broke in flight, at about 25-33% of the semi-span of the blade. There is a very famous photo of a guy landing his Shoestring racer with the entire engine hanging a foot below the airplane by the throttle cable and safety cable, because the metal prop broke at that exact spot. So they outlawed metal props, because wood or composite props did not have that kind of "instant" failure mode.

The point is that this same principle would possibly apply to certain engine components. Taking a crankshaft out of an engine and X-raying it every 2,000 or 4,000 hours may not be such a bad thing.

Maybe I am missing something EZ. Up here our props are calendar timed. You can have a 0 time prop sit for 10 years, and then it has to be overhauled again before used, even though it has saw no use.
I agree that pulling a crank every so often may not hurt, but maybe I'm of old school thought. If I'm gonna pull my engine, send it to an engine shop so they can tear it down, pull the crank and x-ray it, would it really be much more to put it back together with new pieces?

Our rotor blades are composites. They get 'rebuilt' at TBO, but I'm not entirely sure what that entails. We can sometimes tell a difference when rotor smoothing between higher-time and lower-time blades (total time, not time since overhaul) so I'm pretty sure the spars don't get replaced and are more flexible on the older blades.

Other than because of projectiles, I've never heard of any of our blades coming apart. And they aren't flown easy.