(TL;DR debrief) Well, Imma have a snickers....

hindsight2020

Final Approach
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hindsight2020
...cuz I'm gonna be airplaneless for a while.

Took ye ol lawnmower for the monthly run and do some intermittency troubleshooting on the gear I've been battling for a year since the last annual. Halfway up the climb I feel a somewhat abnormal vibration, which doesn't say much, as these lycos rattle like a paint mixer on a normal day. First I thought it was a mag dropping offline, and it sorta seemed that way when I isolated the left vs the right. Went back to both and kept climbing but decided to turn back to home plate as the spidey senses kicked in. The vibration then went from a hum to a bop bop bop bop, then whaaaapapa pap pap pap!! and all hell started shaking out front.

Pulled power swung back to home plate and started throttle jockeying, it didn't get better so left it pulled back. Declared the E-word and managed to hit high key on partial power at 6k. The gear came down without intermittency (would have been a hell of a day to have a compound emergency).... and the ipad overheated. I thought that was rather apropos (don't bring toys to do a man's job type of thing).

At any rate, hit tower up and told them the plan. Thankfully the class D had just emptied and was able to time my descent without concern for traffic. There was not gonna be go-around power, not with the vibration I was experiencing at any power above idle. Uneventful landing all in all, I really got lucky my go-nowhere profile is one of climbing WOT to 10.5k within 10 miles of the field. So that gratuitous habit ended up working out. Otherwise, with the glide ratio of this greased brick, I was looking at having a chat with the boys at Texas DPS to call the frau and tell her homeboi was effing off at the airport instead of watching the kid (sue me :biggrin:) and now needs a ride at the county line.

Made the runway, thanked tower for their help as I'm rolling, and managed to cut the engine with enough momentum to tokyo drift into the hangar row.

Now the waiting game. Mechanic won't be around for two weeks. Did get a local one to help me take a lookie loo, since I didn't find any oil, no loss of oil pressure, and no oil all over the windscreen like we usually get with power losses. The initial look inside the cowl wasn't too surprising given the symptoms.
1695610822002.png1695610871832.png1695610924917.png

So yeah. I think it's f%(^d. Love how the nuts ended up neatly and symmetrically aligned on the baffling, ready to greet me with the one finger salute, even after all that slipping and yawing. Looks like the studs failed in shear, and probably forward to aft in sequence, which explains the change in vibration amplitude and freq. So it was really a good call to pull power, I guess I could have pulled sooner given hindsight (badum tsk), but I would have not been able to make a key if I had pulled any earlier. Meat bag over metal loss at this point, honestly.

Now the waiting game. #3 cylinder. The thrustuds are trashed, so that alone means bad news probably. We will see what transpires once the mech pulls the barrel and we take a look. I am curious to learn what we can find out about the root cause of the stud failures. Some theory on simple fatigue based on the shear faces, but it's too soon to tell, since we don't know which one failed first. Once we pull the barrel I think the picture will become more clear.

I am glad it happened solo, also glad it didn't happen 2 years ago when I decided to cross the bermuda triangle lol. What a hobby.

We'll see what kind of damage an IRAN on this nonsense will end up running, but if it gets close to an OH, she's probably done. I had no plan to continue to own this thing for another 12 years. Certainly not the way I wanted to transition airplanes, but that's how life goes.

I'll keep you good folks updated on what we find out, depending on what we're looking at I have a fork on the road incoming, so if anybody has good leads on a well worn RV-6A, this is as good time as any. Everybody stay safe out there.
 
What a day you had! Great work getting it back down with no harm or foul. Hate to hear what happened but at the end of the day the important things are safe (you) and those other things can be repaired or replaced.
 
Wow. Sorry to hear your engine ate itself, more or less, but glad you're on the ground writing about it. Glad you had the climb up plan, too. We analyze or speculate the crap out of the failures, and probably don't spend enough time talking about the good outcomes and good choices. There's lessons to learn in success, too.
 
Glad you're okay. This place would certainly be duller without you. I lol'd at the bit about the nuts laying there to give you the one finger salute.

My experience was that the IRAN was about 1/5 of a rebuilt engine. I didn't have to buy a jug though. The time is the biggest problem. Don't think that's improved much, although I don't hear as much bitching online about it as I did a year ago, so maybe.

Good luck with it.
 
Good job...funny about the those nuts, as when I looked at that second picture, I couldn't at first tell what I was looking at, because they aligned themselves so well that to my untrained eye, they looked like they belonged there.
 
"but decided to turn back to home plate as the spidey senses kicked in"

fwiw - that's the part I applaud. too many crashes have occurred when people get distracted trying to fiddle with things in the air.
 
Condensed condensed cliffs notes, he was flying instead of listening to his wife and watching the kid
I see we glossed over the fact he flies a lawnmower.

As someone who’s plane has been down for almost two years, I feel your pain
 
I opened this thread, looked at the first post before starting to read and thought, "ain't making it through this one". But as I read, I was pleasantly surprised and the prose and tempo. Nice job, hope it's fixed quickly. What type of lawnmower plane is this??
 
...cuz I'm gonna be airplaneless for a while.

Took ye ol lawnmower for the monthly run and do some intermittency troubleshooting on the gear I've been battling for a year since the last annual. Halfway up the climb I feel a somewhat abnormal vibration, which doesn't say much, as these lycos rattle like a paint mixer on a normal day. First I thought it was a mag dropping offline, and it sorta seemed that way when I isolated the left vs the right. Went back to both and kept climbing but decided to turn back to home plate as the spidey senses kicked in. The vibration then went from a hum to a bop bop bop bop, then whaaaapapa pap pap pap!! and all hell started shaking out front.

Pulled power swung back to home plate and started throttle jockeying, it didn't get better so left it pulled back. Declared the E-word and managed to hit high key on partial power at 6k. The gear came down without intermittency (would have been a hell of a day to have a compound emergency).... and the ipad overheated. I thought that was rather apropos (don't bring toys to do a man's job type of thing).

At any rate, hit tower up and told them the plan. Thankfully the class D had just emptied and was able to time my descent without concern for traffic. There was not gonna be go-around power, not with the vibration I was experiencing at any power above idle. Uneventful landing all in all, I really got lucky my go-nowhere profile is one of climbing WOT to 10.5k within 10 miles of the field. So that gratuitous habit ended up working out. Otherwise, with the glide ratio of this greased brick, I was looking at having a chat with the boys at Texas DPS to call the frau and tell her homeboi was effing off at the airport instead of watching the kid (sue me :biggrin:) and now needs a ride at the county line.

Made the runway, thanked tower for their help as I'm rolling, and managed to cut the engine with enough momentum to tokyo drift into the hangar row.

Now the waiting game. Mechanic won't be around for two weeks. Did get a local one to help me take a lookie loo, since I didn't find any oil, no loss of oil pressure, and no oil all over the windscreen like we usually get with power losses. The initial look inside the cowl wasn't too surprising given the symptoms.
View attachment 120853View attachment 120854View attachment 120855

So yeah. I think it's f%(^d. Love how the nuts ended up neatly and symmetrically aligned on the baffling, ready to greet me with the one finger salute, even after all that slipping and yawing. Looks like the studs failed in shear, and probably forward to aft in sequence, which explains the change in vibration amplitude and freq. So it was really a good call to pull power, I guess I could have pulled sooner given hindsight (badum tsk), but I would have not been able to make a key if I had pulled any earlier. Meat bag over metal loss at this point, honestly.

Now the waiting game. #3 cylinder. The thrustuds are trashed, so that alone means bad news probably. We will see what transpires once the mech pulls the barrel and we take a look. I am curious to learn what we can find out about the root cause of the stud failures. Some theory on simple fatigue based on the shear faces, but it's too soon to tell, since we don't know which one failed first. Once we pull the barrel I think the picture will become more clear.

I am glad it happened solo, also glad it didn't happen 2 years ago when I decided to cross the bermuda triangle lol. What a hobby.

We'll see what kind of damage an IRAN on this nonsense will end up running, but if it gets close to an OH, she's probably done. I had no plan to continue to own this thing for another 12 years. Certainly not the way I wanted to transition airplanes, but that's how life goes.

I'll keep you good folks updated on what we find out, depending on what we're looking at I have a fork on the road incoming, so if anybody has good leads on a well worn RV-6A, this is as good time as any. Everybody stay safe out there.
Great job on handling the emergency! I've got to ask where I'm Texas you are that you feel the need to be at 10,000 in case of an engine out (and how you get there in a NA spam can).
 
...cuz I'm gonna be airplaneless for a while.

Took ye ol lawnmower for the monthly run and do some intermittency troubleshooting on the gear I've been battling for a year since the last annual. Halfway up the climb I feel a somewhat abnormal vibration, which doesn't say much, as these lycos rattle like a paint mixer on a normal day. First I thought it was a mag dropping offline, and it sorta seemed that way when I isolated the left vs the right. Went back to both and kept climbing but decided to turn back to home plate as the spidey senses kicked in. The vibration then went from a hum to a bop bop bop bop, then whaaaapapa pap pap pap!! and all hell started shaking out front.

Pulled power swung back to home plate and started throttle jockeying, it didn't get better so left it pulled back. Declared the E-word and managed to hit high key on partial power at 6k. The gear came down without intermittency (would have been a hell of a day to have a compound emergency).... and the ipad overheated. I thought that was rather apropos (don't bring toys to do a man's job type of thing).

At any rate, hit tower up and told them the plan. Thankfully the class D had just emptied and was able to time my descent without concern for traffic. There was not gonna be go-around power, not with the vibration I was experiencing at any power above idle. Uneventful landing all in all, I really got lucky my go-nowhere profile is one of climbing WOT to 10.5k within 10 miles of the field. So that gratuitous habit ended up working out. Otherwise, with the glide ratio of this greased brick, I was looking at having a chat with the boys at Texas DPS to call the frau and tell her homeboi was effing off at the airport instead of watching the kid (sue me :biggrin:) and now needs a ride at the county line.

Made the runway, thanked tower for their help as I'm rolling, and managed to cut the engine with enough momentum to tokyo drift into the hangar row.

Now the waiting game. Mechanic won't be around for two weeks. Did get a local one to help me take a lookie loo, since I didn't find any oil, no loss of oil pressure, and no oil all over the windscreen like we usually get with power losses. The initial look inside the cowl wasn't too surprising given the symptoms.
View attachment 120853View attachment 120854View attachment 120855

So yeah. I think it's f%(^d. Love how the nuts ended up neatly and symmetrically aligned on the baffling, ready to greet me with the one finger salute, even after all that slipping and yawing. Looks like the studs failed in shear, and probably forward to aft in sequence, which explains the change in vibration amplitude and freq. So it was really a good call to pull power, I guess I could have pulled sooner given hindsight (badum tsk), but I would have not been able to make a key if I had pulled any earlier. Meat bag over metal loss at this point, honestly.

Now the waiting game. #3 cylinder. The thrustuds are trashed, so that alone means bad news probably. We will see what transpires once the mech pulls the barrel and we take a look. I am curious to learn what we can find out about the root cause of the stud failures. Some theory on simple fatigue based on the shear faces, but it's too soon to tell, since we don't know which one failed first. Once we pull the barrel I think the picture will become more clear.

I am glad it happened solo, also glad it didn't happen 2 years ago when I decided to cross the bermuda triangle lol. What a hobby.

We'll see what kind of damage an IRAN on this nonsense will end up running, but if it gets close to an OH, she's probably done. I had no plan to continue to own this thing for another 12 years. Certainly not the way I wanted to transition airplanes, but that's how life goes.

I'll keep you good folks updated on what we find out, depending on what we're looking at I have a fork on the road incoming, so if anybody has good leads on a well worn RV-6A, this is as good time as any. Everybody stay safe out there.
Can I buy your hydraulic power pack just kidding, kinda
 
Wow! Now only imagine how bad it would've been if you had a continental! :p ;)

Only kidding. Sounds like you did a great job - hopefully the engine repairs aren't too bad.
 
Great job on handling the emergency! I've got to ask where I'm Texas you are that you feel the need to be at 10,000 in case of an engine out (and how you get there in a NA spam can).

He’s in the Cam Antonio area. Our field elevations are around 1500msl and airports are long ways apart. We (wife and I) flew to GLS for lunch yesterday at 7500. Would’ve gone higher if the 172 had more oomph. As it was, there was plenty of time spent outside glide range of an airport even massaging the route to minimize it.

Our motor is closing in on TBO (hours, not years) and while not making metal it’s also not continuing to inspire confidence at the same level it did 4 years and 1100hrs ago.
 
Good job making it back safely. Well done!

Some theory on simple fatigue based on the shear faces,....

Hope you find a better explanation, because if the rest of the engine has seen the same hours and stresses as that cylinder, the entire thing is suspect.
 
Looks like a job well done. And yeah, being stuck in a field for 3+ hours with the "authoritayes" isn't the best of times, even if you didn't do anything wrong. In our case, they managed to "forget" to bring us water every single time even though it was August in Texas on a clear blue skies 100+ day.
 
Condensed condensed cliffs notes, he was flying instead of listening to his wife and watching the kid
Cigar for the man with the exemplary reading comprehension! Well done sir, beautiful subtext pickup. No seriously, if I keep this one up I'm gonna need ya to sport me a couch for a night or two. *checks siiiiiiiiix* :biggrin:

Great job on handling the emergency! I've got to ask where I'm Texas you are that you feel the need to be at 10,000 in case of an engine out (and how you get there in a NA spam can).
Not a need at all, just an ancillary happenstance of how I happen to run the engine when I'm not going anywhere. The purpose of these flights anymore was to run it WOT in a climb to get those temps up nice and hot, then zig zag at my typical cruise fuel flow for another half hour or so in the local area to burn off whatever moisture is in the oil. So I just end up there on the regular (9-10.5k). As to getting there, it's never been an issue on the Arrow, especially solo, even with full fuel as I did in this particular instance.

But yes to your macro point, it's a pitifully underpowered lawnmower, and climbs as such above 10, so handicapped by Piper. They should have mated it properly with 250-260hp (my preference these days would be 300hp for 4 seats) like they did on the PA24, but we all know that story and it's water well under the bridge at this point.
Can I buy your hydraulic power pack just kidding, kinda
You joke, but if I have to resort to parting this thing out, that is the first thing that's coming off. Then the wings with a yellow tag for the bolt holes, since we know that wing time limiting final AD will eventually come and there'll be a residual market for them, me thinks. The 430w and RC allen EADI I'll keep for the EAB.

Wow! Now only imagine how bad it would've been if you had a continental! :p ;)
Absolutely. Of course, I wanted to remain inclusive on this anecdote and bypass my long-ago disclosed and obvious bias towards Lycoming engines. I do consider the relative integrity of both that barrel and the mating surface to have been outstanding in this incident, given how long I ran the engine post (presumed) first stud failure. I make no mystery of my bias towards Lyco barrels. And yes, this anecdote will further reinforce my confirmation bias towards that preference going forward.

The bigger point I do want to underscore is that, whatever flavor of placebo we need to get us to partake in this death trap hobby (in the eyes of the pedestrian majority), is in fact the right type of placebo! I stand in solidarity with my Conti-powered brethren on that front. :)
 
Our IO-360A3B6D shed two nuts just like than when my partner and his new bride were over the ocean flying back from the Bahamas. Luckily no bad vibes. Our mechanic found no damage in that cylinder, so he replaced the snapped studs and all of the case through bolts.

That engine happily flew for many years after that, and made 400 over TBO. You never know ‍♂️
 
Our old O-320 snapped off a stud. No vibrations or leaks, we just found it. We replaced the stud and continued flying.
 
Our IO-360A3B6D shed two nuts just like than when my partner and his new bride were over the ocean flying back from the Bahamas. Luckily no bad vibes. Our mechanic found no damage in that cylinder, so he replaced the snapped studs and all of the case through bolts.

That engine happily flew for many years after that, and made 400 over TBO. You never know ‍♂️

that's both reassuring and terrifying. :yesnod:
 
Our IO-360A3B6D shed two nuts just like than when my partner and his new bride were over the ocean flying back from the Bahamas. Luckily no bad vibes. Our mechanic found no damage in that cylinder, so he replaced the snapped studs and all of the case through bolts.

That engine happily flew for many years after that, and made 400 over TBO. You never know ‍♂️

Well, mech finally got to it today and looked it over. I'm somewhat underwhelmed with the lack of a smoking gun. He didn't pull the jug, but the consensus appears to be a random failure of one stud which maybe/probably/who knows, led to the progressive failure of the others. He was somewhat puzzled with the presence of quite a bit of oil/lower plug oil-fouled inside the offending cylinder. He said he was able to turn the engine, no cylinder components appeared damaged once the rocker cover was removed, and according to him the cylinder even made compression.

So, now the question of "well, how bad?" becomes more germane. He's gonna run me some estimates from the shop in question for the teardown, inspection, and re-assembly. It's a sunk cost at this point given the needed replacement of the studs. I suppose it will end up becoming prudent if not evident, to overhaul that cylinder anyways, which is probably parity cost with an IRAN on it.

The big ? mark is gonna be the obvious game changers: the internals, specifically the crankcase and crank.

On my birthday month too. Yippee. Will keep everyone posted.
 
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Sheet jack, run over to the aircraft section at stuper wally world and get a hole fistful of them bolts. That and some uncle JB to the rescue then you can get back in the air.
 
I don’t know if a teardown is necessary, but I’d certainly want to pull the jug on that cylinder for a look as our mechanic did.
 
I’m remembering from one of Mike bush’s long drawn out talks/seminars at OSH that many mechanics don’t torque stud bolts correctly. That leads to an obvious failure of one, then the rest

Glad you got it back to a runway
 
I don’t know if a teardown is necessary, but I’d certainly want to pull the jug on that cylinder for a look as our mechanic did.
Legally, that's correct. The thrustud(s?) sheared, and I think he said it went inside the case? I need to ask him how he figured that, since he didn't pull the jug. I can't remember all the details tbh, I just zoned out for a few minutes after the words teardown were uttered lol.

At any rate, he gave me the impression splitting the case for said studs replacement was a sunk action. Maybe I misunderstood, perhaps he meant it would be prudent to do so. I'll have to re-engage with him on that front, he was pretty categoric about the need for the split.

The part where he conceded wouldn't be necessary was replacing all studs in the set, though we agreed in the context of a case being split already, that action would be of little added cost. I just need to get the updated pricing on what these variables will run in 2023. I'm awaiting that information from him. I'll make sure and update prices for the benefit of folks on here going forward, since much of the info on this topic is very dated on here.
 
Glad you got it back to a runway
Indeed. It's clear to me now that the jug was going to eventually fail all studs and let go. It was a relatively short lived sequence given no vibration existed during takeoff, and could have ended badly had I needed to keep running it at WOT for too much longer.

We make this stuff look easy, but it was not a given I was gonna be able to make it back to a runway. I joke about the relative expediency of nosing it over on a field and collecting my insurance check, but the wife doesn't find it funny. I realized that's just my cynical sense of humor defense mechanism for life-threatening situations, but she deserves better. So I knocked it off with the insinuations of taking the moral hazard route, once I let my frustrations about the whole thing take a back seat and appreciate what really matters, as your post pointed out.

To be clear, I'd never for one second allow that consideration enter my mental game during an emergency. It is just naturally frustrating to undergo this mess as an uninsured cost is all. It is what it is.
 
Might as well IRAN the mount and do a FF refresh while you’re in there….
Yeah, if I decide to go ahead and proceed with the engine shipoff/teardown, the engine mounts will get refreshed. Prudent, given the vibration-related nature to these failures in the angled 4-banger Lycos. Misc hoses and such will probably be a quick and easy kill to refresh there too. No biggie.
 
Sorry, guy. You remember that retirement discussion in the other thread? Your plane might have just delayed that for you a little bit....

;)
 
The studs that snapped on our engine were not the thru studs (bolts?). He did replace all of thru bolts as the thought was losing the other studs put more stress on rhe thru bolts. But in your case, it sounds like there could be bolt fragments in rhe case. If that’s true, them yes you new to look inside. Bummer
 
Is it really shear that caused the stud failure? Shear would “slice” that stud. Could a sharp tensile force be the cause?

What would happen if you hydrolocked a cylinder in one of these dinosaur engines?

Stay with me for a sec. The plug appeared oil fouled and the cylinder had a lot of oil, right? What if that was an oil + fuel mixture? Is it possible that the initial rough running was caused by a cam-lobe issue and the spark couldn’t ignite the wet mess and thus unburned fuel with no where to go started filling the cylinder more and more? And then the rough running turned into a loud bang when the cylinder was full enough of liquid that by TDC it might as well have been a solid (incompressible liquid)? Or it “dieseled” finally? The studs couldn’t take it.

Longshot perhaps. But it’s the stud failure mode that is just wierd (tensile failure, not shear).

Any rod, crank, or bearing damage? Cam lobes look ok on that cylinder?

Paging @Gary Ward for some war stories on hydraulicing an engine…
 
... I joke about the relative expediency of nosing it over on a field and collecting my insurance check... It is just naturally frustrating to undergo this mess as an uninsured cost is all. It is what it is.
Easy to think this way sitting at a computer screen. It's a different story when you're up in the air.
 
Is it really shear that caused the stud failure? Shear would “slice” that stud. Could a sharp tensile force be the cause?

What would happen if you hydrolocked a cylinder in one of these dinosaur engines?

Stay with me for a sec. The plug appeared oil fouled and the cylinder had a lot of oil, right? What if that was an oil + fuel mixture? Is it possible that the initial rough running was caused by a cam-lobe issue and the spark couldn’t ignite the wet mess and thus unburned fuel with no where to go started filling the cylinder more and more? And then the rough running turned into a loud bang when the cylinder was full enough of liquid that by TDC it might as well have been a solid (incompressible liquid)? Or it “dieseled” finally? The studs couldn’t take it.

Longshot perhaps. But it’s the stud failure mode that is just wierd (tensile failure, not shear).

Any rod, crank, or bearing damage? Cam lobes look ok on that cylinder?

Paging @Gary Ward for some war stories on hydraulicing an engine…

Interesting theory. That's what I was hoping pulling the cylinder would have discovered. I've texted the mech to re-attack the issue. I'm awaiting a response.

The consensus on his end of the "conference call" with fellow engine shop folks who work on Lycos is these angled 50hp per jug 4 bangos just fatigue out the bolts, and it's "not uncommon among the type". So yes, certainly overload fail on the ones that failed after, but the first one would be presumed to have been fatigue.

he said he was "able to turn the engine, and the cylinder made compression." Not sure what the symptoms of a hydrolocked cylinder inflight would have been.

I believe it his contention the case is contaminated with the thrubolt/stud/whatever. hence the insistence in going straight to crate/ship and teardown. I'm still puzzled as to why he seemed disinterested in pulling the jug. I'm gonna re-approach the subject when he replies.
 
Seems like a theory of case contamination without any evidence thereof.
I'd replace the studs, scope the cylinder, check the oil screen and absent negative findings fly on.
 
Indeed. It's clear to me now that the jug was going to eventually fail all studs and let go. It was a relatively short lived sequence given no vibration existed during takeoff, and could have ended badly had I needed to keep running it at WOT for too much longer.

We make this stuff look easy, but it was not a given I was gonna be able to make it back to a runway. I joke about the relative expediency of nosing it over on a field and collecting my insurance check, but the wife doesn't find it funny. I realized that's just my cynical sense of humor defense mechanism for life-threatening situations, but she deserves better. So I knocked it off with the insinuations of taking the moral hazard route, once I let my frustrations about the whole thing take a back seat and appreciate what really matters, as your post pointed out.

To be clear, I'd never for one second allow that consideration enter my mental game during an emergency. It is just naturally frustrating to undergo this mess as an uninsured cost is all. It is what it is.
But I like dark humor with sarcastic overtones. I feel it shows higher mental functions. If you were really going to go that route, you wouldn’t joke about it, you just go and do it.
 
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...cuz I'm gonna be airplaneless for a while.

Took ye ol lawnmower for the monthly run and do some intermittency troubleshooting on the gear I've been battling for a year since the last annual. Halfway up the climb I feel a somewhat abnormal vibration,

Didn’t you have a bird strike on the gear recently?

Man! Go play the lottery one time.
 
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