Relentless NXT, Facts!

[Lockheed Bob]

Re: Relentless NXT, Facts!

Great job Kevin. Glad you are OK.True about the important things in life. See you in Reno.
Lockheed Bob

[Wild Bill Kelso]

Re: Relentless NXT, Facts!

EVERYONE needs to buy Kevin a beer at Reno. Nice work!

[Victor Archer]

Re: Relentless NXT, Facts!

EVERYONE needs to buy Kevin a beer at Reno. Nice work!

I think everyone should buy a t-shirt and a hat from him!
just ordered 2 of each for me and my boy.

[Stevo]

Re: Relentless NXT, Facts!

I just order a shirt too

[Randy Haskin]

Re: Relentless NXT, Facts!

close your eyes for 1 minute and visualize the top 3 or 4 things that occupy the bulk of your time. I found in those six minutes gliding over the mountains very unsure if I would make it that those few things that took most of my time where no where in my mind.

Excellent words.

[440_Magnum]

Re: Relentless NXT, Facts!

Was there any aluminum in the oil? It is rare, but sometimes if a crankshaft seal is pushed out and there is aluminum in the oil then there was a failure of the crankshaft thrust face.

Or there is always crankcase pressurization above 5 inches of water, some causes - damaged guide boss, loose oil filler gasket, blocked or frozen engine breather tube (and no whistle-slot in tube), blocked or frozen air passages in air/oil separator.

There are other causes of seal leakage but are not usually seen with it being pushed out like you describe.

Hope you and Lycoming figure it out.

Was just re-reading the story, and I'm curious about something- If the only mechanical problem was the crank seal, why would the oil temperature be shooting up so fast? Assuming that it hadn't puked the whole oil supply out, of course. It seems to me that the oil temperature shouldn't rise until so dramatically until the engine actually started starving for oil, so I have to wonder if there wasn't another internal problem that generated all the heat and possibly enough crankcase pressure (or allowed the crank to move around enough) to push the seal out as well. I'm certainly curious.

Bottom line- GREAT story, GREAT flying, and thank God Kevin's OK!

[Relentless]

Re: Relentless NXT, Facts!

Was just re-reading the story, and I'm curious about something- If the only mechanical problem was the crank seal, why would the oil temperature be shooting up so fast? Assuming that it hadn't puked the whole oil supply out, of course. It seems to me that the oil temperature shouldn't rise until so dramatically until the engine actually started starving for oil, so I have to wonder if there wasn't another internal problem that generated all the heat and possibly enough crankcase pressure (or allowed the crank to move around enough) to push the seal out as well. I'm certainly curious.

Good observation. I am sure something else caused the seal to go but not sure. I suppose the oil temp rose so quick because the probe is right where the return comes from the external oil cooler and if oil was pumping out the seal it was not going to the cooler?

[AAFO_WSagar]

Re: Relentless NXT, Facts!

Certainly is a good engine detective story isn't it! I have never worked on an aircraft engine but have a few ground pounder rebuilds under my belt (plus a year of college auto mechanics) as well as too many years as a fleet manager....

The thing that gets me is the relationship between the bump and then the leak....

Assuming that the seal letting go was the only cause of the rise in temp, is it possible that the bump was some sort of anomaly with an atmospheric pressure change so great and so rapid as to cause a differential in pressure enough to push out the seal???

That's sort of a "sci-fi" type of "theory" but it (thump) does throw in a bit of mystery to the problem... I also wonder, since it all seems to have happened so fast, could the thump that Kevin felt have been the engine doing something funny and just shook the airframe enough to make him feel that it was aerodynamic in nature?

Certainly an interesting diagnosis problem!

Can't wait to hear the final outcome....

[AAFO_WSagar]

Re: Relentless NXT, Facts!

Kevin, is the engine dry sump or wet??

Wayne

[440_Magnum]

Re: Relentless NXT, Facts!

Good observation. I am sure something else caused the seal to go but not sure. I suppose the oil temp rose so quick because the probe is right where the return comes from the external oil cooler and if oil was pumping out the seal it was not going to the cooler?

Without knowing more specifics about the engine, I couldn't guess. When I think "crank seal" I don't normally think of a seal between the high pressure oil plumbing and the outside world, I think of a low pressure/splash seal. Sure, it leaks FAST when its gone, but its not like there's direct engine oil pressure blasting against that seal so that losing the seal wouldn't directly cause the oil pressure to drop the way (for example) blowing out a plug in an oil galley or blowing a line to an oil cooler would. Any leak will eventually cause loss of pressure, circulation, and cooling, but a leak that is just exposed to crankcase pressure (not oil galley pressure) won't usually show on the gauges until enough oil is gone so that pickups start getting uncovered. How much oil do you carry? An auto engine can only lose a couple of quarts before the pressure will start to flutter because the pickup is sucking air, but at the other extreme a big diesel or a radial can lose gallons before anything goes awry with either the pressure system or the oil cooling. Of course it also depends on how the sump is drained (if dry sump) and the exact oil routing.

I'm sure a teardown will reveal if anything in there was generating a ton of heat. Maybe it was all just due to the seal popping out.

[First time Juke]

Re: Relentless NXT, Facts!

Excellent story. Well done Kevin.

Is it possible that someone did not tighten the bolts after installing the engine and turbo into the AC ? Can't be that easy ? Is something causing negative vibration in the engine compartment ?

I had to say profesionally flown emergency situation...and a well flying " glider " !!!