ETLB Squawk Forums — Archive

The Huns got me!!

So there I was, 200 feet AGL and climbing having just lifted off the sod runway. Flak was bursting all around me and I was taking small arms fire along with larger gun shells. The Huns had crawled through the roadside ditches and culverts to within two miles of Blue Sky Ranch Aerodrome (35KS) in Haysville, Kansas. I was the only plane airborne. They were laying in wait to pounce on the first plane off the runway, I was it!

Bill Bailey (a.k.a. Avenger) was in the hangar doing maintenance on his warbird; "Big Red" (Taylorcraft). He saw me take off to the south and listened to my engine becoming quieter. Then it got real quiet.

The Huns had launched coal-gas fired barrage balloons, each dangling several heavy cables hoping to snag an unwary airplane. Flying there was like running through a cornfield and trying not to hit any stalks.

While pleased with my defensive maneuvering, I was getting into fighting position. Then the engine on my trusty AirBike suddenly quit. Like right now! I thought I had a seizure or had taken a bullet in a piston. The prop stopped at the 12:00-6:00 position, not good  for an off-airport landing in a dirt field. Except for the exploding shells and gunfire it was quiet. Or relatively speaking as I now concentrated on gliding my plane to earth.

Almost all of Kansas is an airfield, there was one right below me, all I had to do was dodge the center pivot irrigation unit. This field on alternate years has crops of wheat or corn. The stubble this fall is a mixture of those dead debris. Immediately the stick was pushed forward and my eyes were focused on the ASI until it registered 45 mph. and stayed there.

A quick scan of the temperature gauges showed normal readings, all fuel valves were on, both mags were up. I didn't know what went wrong but would figure that out once on the ground.

The AirBike is not known for its gliding capability. I kept the nose down until about 20 feet above the field then pulled back on the stick. Upon touchdown, I didn't flare very well and was flung several feet back into the air. Next touchdown was OK but then I rolled across a rut formed by one wheel of the center pivot unit. Up in the air again then down to a rolling stop. The Huns must have thought I was going to fight them on the ground because they released their barrage balloons, turned around, and ran away. It was real quiet.

Well, that is the theatrical version, now the rest of the story in a sensible fashion.

Pre-flight and engine warm-up were normal as was the dual mag check. The takeoff and climb at 6500 RPM was normal until the engine quit in less than two minutes from liftoff. I had actually throttled back to cruise (5800 RPM) just seconds before. The field below me was about half a mile square, plenty of room to land in.

While on the ground in that field, I looked for a probable engine failure cause. A cursory check of the engine revealed nothing abnormal, the prop swung through its arc with normal resistance and smoothness.  Then I heard Bill Bailey hailing me as he walked from the road onto the field. He knew that my flight was never quiet. He came to investigate and help.

One pull started the engine, I ran it at 6500 RPM for longer than the previous flight and it seemed normal. I lined up on the dirt field for a takeoff. That is until the engine started running rough. One magneto was intermittent and caused some backfiring. Prior to this I thought I would just take off and fly back to the aerodrome. But now I wasn't sure what the problem was. So, I decided not to.

Bill noticed a farm access road connecting the field to the paved road. I taxied over to it and parked. After we had some discussion, I called the police and asked for an escort so I could taxi on the road the two miles back to my hangar. They complied and sent three squad cars. One stopped traffic at the intersection, one was behind me and one came later to collect some information. The road was now clear of traffic so I taxied on it to the hangar driveway.

The officer asked for my name, phone number, and drivers license. I complied and thanked them heartily for their cooperation. They said their report would identify me as "miscellaneous road blockage." I said that is better than trying to explain an airplane taxiing on the road. Things are rather quiet in the Haysville area so I actually provided some excitement for them ?

That's my story and I am sticking to it. Next step is to figure out why one mag is intermittent. Yes, I could have  shut down the one mag and tried to fly home on the other one.  But I did have a convenient alternate way of getting back and chose it. Also, I still am unsure if that is the only problem. I took the safe road home. One off-airport landing in an evening is enough.

Paul D. Fiebich

PS The first photo below shows the field I landed in, however this photo was taken just prior to harvest last year.

PSS I would have liked to have taken a photo through my windscreen of taxiing down the road but I was busy avoiding mailboxes, trash cans and signs.

Paul glad you made a succesful emergency landing. Sounds like vibration might have detached one of the wires under the flywheel. I had that happened several years ago.

Monte

Paul I can not think of anything witty to say ; but I am glade your safe and sound.

Paul:
Glad you took the bird to a safe landing under hard enemy fire. A bullet might cut off an ignition wire.
Best is to find out what when wrong. Having two ignition sistems in the 503 why the failure of one of them would silence the engine? I hope you find the problem soon and get ready to give back some presents to the enemy.
Great scenery from emergency landings  around your area and good idea not to get airborne until problem is solved.

Ricardo

Excellent observation Ricardo, and one that factored in to my decision not to fly off the field using only the "good" magneto. And why did the engine run on the "good" mag on the ground during the restart but didn't work when flying? Maybe I had not returned one mag switch to its full ON position following the pre-flight mag check? When both mags were on, the engine would intermittently run rough when I was ready for takeoff from the field but didn't run rough during the static test? Several things to check out later in the week. So far some of this is a mystery. Hopefully I have some easy (and inexpensive to fix) loose or disconnected mag. related wires.

Paul

Sorry to hear that the Huns got you.  Must have provided a few anxious moments. You made some good choices to turn this incident into a good ending. Hope you quickly find the culprit and get the Huns on the run again.

I had a stator that would quit working when it got warm. Dam Huns

Well Paul, you must have hit one of those pockets of air that did no have oxygen in it,

Hi Paul
Glad your ok and had a safe landing. I am sure you will find the answer. Keep us informed.
Bob

If it was going to quit, I'm glad it happened where it did.

Looks like you did a fantastic job of gittin' 'er back down. Congratulations.

Sounds like you owe some doughnuts. I can always be paid with doughnuts, even though I have nothing to do with enforcing the law.

Flydog saw the answer.
I suggest you tether a balloon to mark the position where the engine quit, since there obviously is insufficient O2 there.

I notice that you are always attacked at or near the airfield. Perhaps you should move.  

Was the first 1.000 hours so filled with excitement?

Again, very good job of handling the emergency. Many people hurt themselves or wreck their planes as a result of emergencies just like yours because they panic, or they try to do too much.

you'd of really had some fun if you'd pulled the smoke knob as you went down!

it's always good to practice emergency landings as part of your flying program. and believe me there is a difference between a engine at idle and a dead engine....more drag from the prop.

monte

Quoted from PUFF you'd of really had some fun if you'd pulled the smoke knob as you went down!

I'm guessing the smoke might be a little thin with the engine dead.

Quoted from texasbuzzard it's always good to practice emergency landings as part of your flying program. and believe me there is a difference between a engine at idle and a dead engine....more drag from the prop.

monte

I agree.  With my Airbike I used to routinely kill the engine over the airport and glide down to a landing.  I got pretty good at touching down and rolling to a stop directly in front of the hangar.

Quoted from radfordc

I agree.  With my Airbike I used to routinely kill the engine over the airport and glide down to a landing.  I got pretty good at touching down and rolling to a stop directly in front of the hangar.

I used to do that with my B1RD (land with the engine off) , but I'm pretty far from being comfortable enough with my own ability to do that with the Tandem Air-Bike (The Flag). That's a good reason to be flying isn't it. I'll have to go over to the county airport (T-78 ) and practice.

I Spent several hours at the hangar yesterday afternoon attempting to determine the reason for the engine-out and loss of power when running on the "bad" mag. This loss of power clued me in to start at the plugs instead of mag wires. After all, the engine did "run" on the "bad" mag alone but it had no power and eventually would die.

All the plugs looked good except for one, it looked terrible.
The perimeter of the end was horribly pitted as is the overhanging electrode end.

The profile view shows part of the thread melted away and the center electrode actually welded to the overhanging electrode. This spark plug was definitely out of commission.

This is a strong indicator that it wasn't a mag problem at all. Instead the mag that fired this plug (and one in the other cylinder) was working. The engine just could not run on one cylinder. Typically, I use the Iridium plugs, but during the last Condition Inspection, I put these in to "use them up."

The engine would run on the other mag alone if the "bad mag" was shut off. With both on, the engine ran rough.

Additionally, when removing the spark plugs, I discovered this plug was loose in its threaded hole! Two things are likely here:
  1. I didn't tighten this plug sufficiently during installation, it loosened and allowed "leakage" which may have caused the arcing that damaged the spark plug.
  2. I also made an error when installing two adjacent plugs. One retains its compression gasket, the other does not. The one that does not retain its compression gasket goes in the hole with the temperature sending ring.

I had placed the gasketless plug in the wrong hole! That plug had no gasket, the other plug in that cylinder head had two (it's regular gasket, and the temperature ring).  With no gasket, the plug leaked, vibration likely further loosened the plug. Under this condition, combustion was incomplete, hence the oily look of the plug. The other plug in this head was also oily, but not pitted. Looks like this problem was my own maintenance error! Punishment is 20 lashes with a piece of rubber fuel tubing in addition to this grief !!

A portion of the physician's creed says "do no harm." Well, while working on the plugs I broke one of the two wires that connect the temperature gauge to the temperature sending ring. Why are these things so damn fragile?

I cut the remaining wire and brought the ring home where I opened up the "clamp." Next, I will take this back to the hangar, attach the two wires (and solder it) then put it back under a spark plug.

The weather is currently unsuitable to work outdoors and do a static engine test run for verification that this was the only problem. It may be several days before conditions are comfortable. I will know more then.

The mystery of why the engine quit still remains. Even with one spark plug inoperative, the engine should have continued to run. Just maybe, the "leaky" spark plug factored into it? But, the engine ran fine on one mag when I tested it after landing and during the taxi back to the hangar.  However, there is a difference in "loading" during a static engine run and when flying. The problem isn't resolved yet.

Paul Fiebich

That piston and cylinder look OK?

If this plug was loose it could not transfer its heat to the cylinder head. Maybe that is the only reason the plug cooked?

Hmm thanks for the update...bloody gremlins

Hope you find the cause.....soon

Thanks for the fine report Paul!
As far as I understand, the engine quit because it was working on both magnetos and one of them was fouling because of the bad plug, that could create some sort of electrical problem in the entire  system affecting the other. While running with the OK system only, the engine had no problem. Just a guess.
LMAO about the punishment. Sort of chinese discipline.

Engine out analysis

The weather finally warmed enough last week to make working in the hangar at least close to comfortable.  Following the removing the spark plug and noting its deteriorated condition, I was concerned about the piston and cylinder wall.

It didn't take very long to remove the head.The combustion chamber looked pretty grubby as did the spark plug. However I saw no physical damage. It looks as though some of the leakage around the spark plug seeped between the head and the cylinder top. There is no gasket there. There is however a metal gasket that surrounds the cylinder top and gets compressed when the head is bolted in place. The rings around the piston area is where the gasket is.

The piston top had no damage either, just carbon build up.

The marks on the cylinder wall gave me some concern. However I believed they were only discoloration because I could not feel anything with either my fingertip or my fingernail. I called L.E.A.F. and asked them about this. They said, "don't worry about it, if you can't feel anything, it is only discoloration and to go ahead and run the engine."

The sidewall of the piston as viewed through the intake port showed similar discoloration, Again, I could not feel anything. The marks can be rubbed off with a cloth. These marks are closest to the spark plug without the gasket.

Assured that there was no physical damage to the engine, I reassembled everything and torqued the bolts/nuts to specs. I then ran the engine for 20 minutes at various RPMs and with both mags on and then shutting one then the other off. The engine ran fine.

When the weather is comfortable with mild temperatures and a southerly wind, will make a test flight around the airport and over landable terrain.

In analysis, this is how I conclude the engine quit.

Before takeoff, part of my pre-flight activity is to run the engine at full power (6500 rpm) and shut off one mag, then the other to make sure that both mags work. They did, I then make sure both mags are on and take off. The spark plug that shorted out must have been close to doing that just before it did short out. Had it been shorted out during the pre-flight mag check, the engine would have died when the mag powering the two good plugs was shut off. It didn't. The engine cannot run on one cylinder.

The spark plug without the gasket may have leaked intake air causing a lean combustion over time which damaged and shorted that plug. The heat may have risen too quickly to register on the CHT gauge in the cockpit and the engine seized during the completion of my climb out. This may have been aggravated by my pulling the power back from full throttle (rich) to cruise position (somewhat lean). The engine stoppage was only about 5 seconds or less from the throttle change position. This was my original thought when the prop stopped suddenly in flight.

By the time I glided to a landing, checked out what I could, then restarted the engine it had cooled enough to release the seizure. The engine started on the first pull. I taxied back to the hangar using only the "good mag."

Consequently, it wasn't a mag problem at all.

Based on this information, do you have any thoughts?

Paul Fiebich

That is a classic seizure.

Quoted from fiebichpv The heat may have risen too quickly to register on the CHT gauge in the cockpit and the engine seized during the completion of my climb out. This may have been aggravated by my pulling the power back from full throttle (rich) to cruise position (somewhat lean). The engine stoppage was only about 5 seconds or less from the throttle change position. This was my original thought when the prop stopped suddenly in flight.

By the time I glided to a landing, checked out what I could, then restarted the engine it had cooled enough to release the seizure. The engine started on the first pull. I taxied back to the hangar using only the "good mag."

A CHT gauge is unlikely to register high cylinder/piston temps in time to warn you of a coming seizure.  Only an EGT can do that, and you would have to be looking at the EGT gauge, because it can happen in less than 20 seconds.
I have a 503DCDI with dual CHT gauges and dual EGT gauges.  I will fly if one of my CHT gauges dies(until I can install a replacement),  but I WILL NOT fly without dual EGTs on a dual carburetor engine.
Future plans are to replace the  dual CHT and dual EGT gauges with one MGL TC-1 four channel gauge.  It not only monitors CHT and EGT temps,  you can set alarms for each channel, and it has a warning light at the top of the dial face.

Paul,
You do have EGT gauges, yes?

Paul the piston skirt in that last pict shows the result of a seizure as does the other pict of the cylinder. I would at least pull the cylinder and check the piston very closely. The skirt should have knurling which retains oil between the cylinder and piston. If any area does not have this replace the piston and hone the cylinder. If you fly stay in the pattern just in case. IMHO I would not fly, the cylinder and piston does have damage....it looks like my engine after I landed in a cotton field.

Monte

Here's an EAA video about piston failure and how to identify the reason. Very good information.

http://www.eaavideo.org/video.aspx?v=3594806859001

Note that with the engine having been run back to the hangar there has been some post-seizure burnishing done to the cylinder wall.

I concur with disassemble and inspect closely.  One area I would check is the ring(s) and grooves in the area of that scoring.  They have gotten scored and be prone to leaking at that point.

Thanks for your responses Ace, Steve and Monte. Yes, I have a CHT and a EGT on each cylinder and exhaust. Neither gauge showed a high temperature during my engine out. I believe you are correct when stating that the seizure can occur faster than the gauge can respond. Thanks for the webinair link Dick, I will check it out in the next day or so.

Regarding the cross-hatching, don't you mean on the cylinder wall instead of the piston? The cylinder wall shown does retain its cross-hatching. Three pistons I have that were removed from previous overhauls have no cross-hatching.

George, what do you mean by a "classic seizure?" Please define or explain.


Paul Fiebich.

Quoted from fiebichpv

George, what do you mean by a "classic seizure?" Please define or explain.


Paul Fiebich.

You say your engine shows no damage yet it is totally obvious in the pictures it has seized up, that's the very odd part . perhaps you just don't know what you are looking at but pics of seized pistons like this are all over internet.
Your piston is "scored" and ruined. The mark on the cylinder is smudged melted aluminum stuck on it.
As to the likely cause, From reading your posts i guess you have a lot of hours on it and from seeing how you go about checking it I make an assumption you never pulled the cylinders off and  never decarboned the piston ring groves.
When the piston rings get stuck by carbon build up you get a blow-by and seizure occurs without indicating any temperature spike, this happens typically around 300+hours,
That said I cant rule out carburetor problem either, but if your rings were not stuck to begin with they are almost certainly stuck now from the seizure.
To fix it you need a new piston and rings , possibly for both cylinders , you need to remove the aluminum from the cylinder with muriatic acid , then renew the crosshatch on the cylinder with the honing tool.

Paul the piston skirts have very fine grooves running horizontal to the top of the piston. They are required to keep oil between the piston and cylinder. Cross-hatching of the cylinder is required for seating the rings when new. Your cylinder can be saved, toss the piston and rings. I would also pull the other cylinder and inspect it too. As George stated you do have excessive carbon buildup on the piston, head and probably the ring grooves.

Monte

Thanks for the detailed information George. The engine has 137 hours since its rebuild 9/2012. I will view the webinair today then decide on my course of action. Considering the amount of flying I do and the distances from home base I travel, it looks like an upper rebuild is in order.

Paul Fiebich