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Flat pitch Hartzell

Deweyclawson

Well Known Member
I recently purchased a 2012 RV10, 390 hrs, TTSMOH, TT airframe. IO540, Blended Airfoil Hartzell CS, MT prop controller.

I flew it home from TX, 7hrs, and Tue flew about an hour. Wed I took a puppy to just S of Albany, NY (2 hrs) and another guy took her on to her furever home in Maine. I took off on the return leg and was level at 8,000 IFR, just on top of the clag, about 63% power, 22inches, 2100rpm, or so and about to lean and the rpm ran away. 2700rom.

Yanked the throttle back, could not change the rpm with the prop lever. Prop had gone to flat pitch. Next thing I looked at was oil press. All OK. Started immediate turn back toward lower ground (was over the Catskills) and better wx and said the magic word....EMERGENCY. Landed at Kingston-Ulster airport, NY.

Found the only mechanic on the field. He was in the middle of 2 week vacation but came in to help me. We talked to Penn Yan and to NE Propeller Service. They gave us some ideas to look at.

1. Linkage was connected and worked OK ran eng and prop was not controllable.
2. Moved the prop by hand and each blade moved OK. rotate blades. OK
3. Stick a paper clip in the zirk fittings on the prop. Only grease in there.. OK
4. Removed the oil filter and inspected it for metal shavings. Looked OK. Front main bearing hasn't spun and blocked the oil passage.
5. Removed prop governor and drove 3 hours to New England Prop Service. They tested the governor and it checks OK.
Drove home 10 hours.
Out of ideas.

HELP!!!
 
The prop did not ?run away?. 2700 rpm is the normal red line. If the governor failed in cruise you would have seen a lot higher rpm. Somehow the governor setting slipped to the high rpm stop.
 
The prop did not ?run away?. 2700 rpm is the normal red line. If the governor failed in cruise you would have seen a lot higher rpm. Somehow the governor setting slipped to the high rpm stop.

Not necessarily.

The governor is nothing more than a pressure regulator. Oil pressure output from the gov increases blade angle, thus lowering RPM. If there is a large leak between the gov and the piston in the dome, or if there's not enough oil going into the gov, then the big spring in the dome will push the piston into the low pitch stop.

The test in the SI determines either of two things. 1. Excessive leakage after the governor, or 2. not enough oil being supplied to the governor. Since the governor checked out fine, possible failures are the big plug in crankshaft is leaking, one of the o-rings in the prop piston has failed, or there's not enough oil getting to the governor due to a blockage or there's a leak upstream.
 
Not necessarily.

, then the big spring in the dome will push the piston into the low pitch stop.

m.

If the stop has been properly adjusted to barely allow 2700 rpm at zero speed, then at cruise if you?re up against the stop you?ll see well over redline.
It could be a coincidence-system just leaky enough to get 2700 rpm, but no more- but that?s quite a coincidence.
 
"I'll bet it was cold up there. OAT? Oil temp? Oil type?"
Phillips 20w50, 25 hrs on the oil, Reiff pre heat, sump, cyls and oil cooler heated for 2 hours before first start. temp on gnd was about 35F. 120F befoe run up. 2 hrs at 9,000ft with everything in the green. 30 min to refuel then t/o. Cold oil could not possibly be an issue.

"If the governor failed in cruise you would have seen a lot higher rpm. Somehow the governor setting slipped to the high rpm stop."
New England Prop Services tested the governor and could find nothing wrong. I have a hard time believing the gov fixed itself.

"then at cruise if you’re up against the stop you’ll see well over redline."
But I had the throttle pulled back to about 22" MP. I did not spend a lot of time looking at the tiny rpm gauge on the EFIS. I just saw it was way higher than it should be and pulled the throttle back. It may have been past redline, but I wasn't going to stare at it long enough to figure that out.

I think RocketBob is correct, we need to determine if oil pressure is correct to the governor.

Bob, email sent.
 
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I think RocketBob is correct, we need to determine if oil pressure is correct to the governor.
I agree.
And if you aren't sure what the max. RPM was, you should also download the EFIS data and confirm it didn't exceed the limit that requires a propeller inspection.
 
With the governor off and looking at the governor base pad, you should be able to put air pressure in the bottom left oil hole in the governor base pad of the crank case. If the prop changes pitch, the prop is probably OK. If it does not change pitch, then listen for air leaking into the crank case. If the air is rushing threw the back freeze plug in the crank, you will hear it. If the freeze plug hass come loose, you'll have to pull the prop and replace it with a new one. Special tool needed to do it right.
 
Also make sure the drive gear is engaged while putting some finger pressure in the splines, and verify it rotates with the prop turning.
 
This is your next step:

https://www.lycoming.com/sites/default/files/Propeller Oil Control Leak Test Procedure.pdf

Let me know if you need the test plate. I have one I would be more than happy to loan you.

Bob;
I tried sending a PM and an email and it appears neither of those worked.
If you could send me your test plate, I would certainly appreciate it.Could you send it to:

Peter Heidrich
Richmor Aviation
1155 Flatbush Rd.
Kingston NY 12401

I will ensure it finds it's way home along with what ever this costs you.

THANK YOU..
 
I recently purchased a 2012 RV10, 390 hrs, TTSMOH, TT airframe. IO540, Blended Airfoil Hartzell CS, MT prop controller.

I flew it home from TX, 7hrs, and Tue flew about an hour. Wed I took a puppy to just S of Albany, NY (2 hrs) and another guy took her on to her furever home in Maine. I took off on the return leg and was level at 8,000 IFR, just on top of the clag, about 63% power, 22inches, 2100rpm, or so and about to lean and the rpm ran away. 2700rom.

Yanked the throttle back, could not change the rpm with the prop lever. Prop had gone to flat pitch. Next thing I looked at was oil press. All OK. Started immediate turn back toward lower ground (was over the Catskills) and better wx and said the magic word....EMERGENCY. Landed at Kingston-Ulster airport, NY.

Found the only mechanic on the field. He was in the middle of 2 week vacation but came in to help me. We talked to Penn Yan and to NE Propeller Service. They gave us some ideas to look at.

1. Linkage was connected and worked OK ran eng and prop was not controllable.
2. Moved the prop by hand and each blade moved OK. rotate blades. OK
3. Stick a paper clip in the zirk fittings on the prop. Only grease in there.. OK
4. Removed the oil filter and inspected it for metal shavings. Looked OK. Front main bearing hasn't spun and blocked the oil passage.
5. Removed prop governor and drove 3 hours to New England Prop Service. They tested the governor and it checks OK.
Drove home 10 hours.
Out of ideas.

HELP!!!

Also make sure the drive gear is engaged while putting some finger pressure in the splines, and verify it rotates with the prop turning.

When checking this, make sure that the drive is checked though several prop rotations. I had one that had several teeth sheered off causing it to feel fine for most of the revolution but slip at specific spot.
 
Had a friend who had something similar happen in his RV-7 - except he ran away to 3075 rpm and had to do an overspeed check on the prop/engine.

His problem was one of the plugs in the engine which had come loose so oil was not porting where it should to the governor. Sorry, can't be any more technical but I know there are various plugs/ports which are closed or opened depending on whether you are running fixed pitch or CS prop.
 
Your experience sounds very familiar! My RV-8a had the same symptoms!

The forward portion of your crankshaft is hollow. There is a freeze plug aft of the forward main bearing on your crankshaft. Oil is pumped into this hollow space to actuate your prop. In my case this freeze plug had shifted and allowed the oil to return to the crankcase. Thus adequate pressure could build up to actuate the prop. I applied air pressure to the system and the prop did actuate. This mislead me for a while. But the prop governor is not a high volume pump. I was putting air in fast enough to build pressure but the governor could not put oil in fast enough. The key though was that I could hear air entering the crankcase. When I pulled the prop and looked into the hollow crankshaft, I could see that the freeze plug at the back was cocked a bit. If you find something similar, don't waste your time trying to reseat the old freeze plug. It won't hold for more than an hour or two. Just replace that bad boy and your on your way!

Good luck!

Greg Chapman
 
UPDATE

Talked to the mechanic today. He finally has the test plate, and gasket, that Lycoming calls for. Thanks Bob. ran the eng iaw the SI and the pressure is 5.5 lbs. kind of low. Checked the oil screen and it is clear. The oil filter also had no metal parts. I don't know if he was going to take the prop off this PM or not.

Is there any possibility that it could be anything other than the freeze plug???

Thanks to all who have chimed in. More updates as I get them.
 
Update 2

Talked to the mechanic today. crank plug is well seated. air pressure using Bob's test plate is about 5 psi. Should be 6-35. happened to move the crank and the air pressure jumped. When lifting on the crank air pressure jumps up to mid range. Mech. called Penn Yan and they thought it is a bad bearing.

The mech is way behind on his work and does not have the time or knowledge to fix this. He does not do eng overhauls and does not want to get into an eng change.

1. Options:Take the wings off and bring it home on a trailer, about 4oo miles.
2.Take the eng off and drive/send it to Penn Yann for rebuild/replace depending on what is wrong with it. Then go back and put it back on.

Plane is at Kingston, NY. there is no hanger space available there but I might be able to use the mech's hanger depending on his work load at the time.

Penn Yann is roughly half way from my home to Kingston.

Since I am not a mech, I am leaning on bringing the plane home on a trailer. Any comments on what it takes to remove the wings would be appreciated.
 
When doing this test, because of the shop air blowing oil off the main bearing halves there is going to be some variation in pressure as you move the crank around. Oil is the seal, and really this test is measuring the main bearing clearance absent of any leak past the plug.

So to reiterate the clearance between the main bearing and the crank is filled with oil and this oil forms a seal for the oil flow being provided by the governor for the prop. That said, if there is not enough main oil pressure the higher pressure and volume of oil from the governor won't be held, if the plug is tight and sealing.

Here's what I would do, given the circumstances. I would put the prop back on, and put a 100W straight grade oil. I would also shim the oil relief valve to get 100 psi on runup and cycle the prop. This may be enough to get you home.

Since there is nothing in the filters or screens, you should be safe to fly.

It may be that the governor you have has a small pilot valve and is not able to keep up with the main bearing leakage, and some large clearances opened up to a point where the oil supply from the governor can't keep up.

I would not be looking at pulling the wings and transporting, the risks of damage are greater its a whole lot more work than pulling the engine.

What are your typical oil pressures? Do you have a log from the efis or engine monitor?
 
The one concern I would have on Bob's suggestion here is that if you do have a bad front bearing, it may do something bad while you are flying. I don't really know -- maybe Bob can comment on that further. Is a clean oil screen and sufficient oil pressure really enough of a blessing to fly?

I do agree that disassembling the whole plane would not be a good choice. If you can't fly it to where it needs to go, pull the engine and haul it there.

It seems surprising to me that moving/lifting the crank makes a big change in the leak rate -- would have to be a really loose bearing.

When doing this test, because of the shop air blowing oil off the main bearing halves there is going to be some variation in pressure as you move the crank around. Oil is the seal, and really this test is measuring the main bearing clearance absent of any leak past the plug.

So to reiterate the clearance between the main bearing and the crank is filled with oil and this oil forms a seal for the oil flow being provided by the governor for the prop. That said, if there is not enough main oil pressure the higher pressure and volume of oil from the governor won't be held, if the plug is tight and sealing.

Here's what I would do, given the circumstances. I would put the prop back on, and put a 100W straight grade oil. I would also shim the oil relief valve to get 100 psi on runup and cycle the prop. This may be enough to get you home.

Since there is nothing in the filters or screens, you should be safe to fly.

It may be that the governor you have has a small pilot valve and is not able to keep up with the main bearing leakage, and some large clearances opened up to a point where the oil supply from the governor can't keep up.

I would not be looking at pulling the wings and transporting, the risks of damage are greater its a whole lot more work than pulling the engine.

What are your typical oil pressures? Do you have a log from the efis or engine monitor?
 
I would almost be tempted to fly it out as is, basically a 540 Lycoming with a fixed pitch climb prop. One thing to consider is that you say you declared an EMERGENCY. That gets the FAA`s attention, should you have another problem, the Fed's could hang you for flying your aircraft with a known deficiency. Best of luck whichever you choose.
 
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Don't know your mech aptitude, but removing and transporting an engine is *far* simpler than disassembling an entire aircraft. And the risks of hard to repair damage are much lower, too. And not just from transport, but from the disassembly/reassembly.

We can't make the decission for you, but if it were my a/c and nothing shows up as failing, I'd at least take it around the pattern to see if symptoms recur. Next down the preferred list would be engine removal. Airframe disassembly would be my last resort.

Charlie
 
Update 3

After talking to the experts at NE Prop, Lycoming and Penn Yann, the plan now is to take the wings, tail, and eng off (at Kingston-Ulster) and put it all in my son's 24' enclosed trailer and drive home (400 miles). Stop at Penn Yann on the way home and drop off the eng. The consensus is that the problem is excessive clearance in the front crank bearing. Moving date is tentatively set for Mid March sometime.

I think I can get the eng off with only unskilled help but putting it back on is another matter. Having the plane home will allow me to not be rushed getting it put back together. Have much longer runway with clear approaches to both ends of the rwy for the first flt, Hanger space with lots of room and tools.

Slightly off topic--Monday evening at 6:30 I ordered Hotel Whiskey Extended Range fuel tanks and at 7:30 I received an email confirmation, and the invoice for the deposit. A welcome change from the anticipated 2-4 weeks response time many others here have experienced. HW is now under new ownership. Not only is their customer support a quantum leap ahead of what others have experienced, but it appears they are very capable of maintaining or exceeding the quality of the product previously made. They have even made a slight change for me so I will have an indicator light in the cockpit when the transfer pump is pumping fuel to indicate when transfer is complete.
Tanks should be delivered mid-late March.

Jake, Thanks for the offer. I will let you know when I get closer to setting a date/time. We can all learn how not to take a plane apart.

More updates as I learn more.
 
Update 4

We have a plan.
This Fri, Apr 5, 4 of us are driving over to Kingston with my son's 24' enclosed trailer and F350 truck. Sat we will take the eng, wings, and tail off. Stuff the plane into the trailer and the eng on a pallet in the truck. Mon drive home and drop the eng at Penn Yan on the way.

Jake, If you want to come down on Sat and help us learn how not to take an RV10 apart, please come on down. My cell# is 724-622-0939. We have a 5 BR house rented for the weekend so you can spend the night Sat if we are not done. Andy, the same applies to you. If you want to fly down on Sat, Come On Down.

The prop and the Gov have both been to NE Prop Svcs and found to be just fine. No issues at all with either of those so the problem has to be in the eng.

Many thanks to all those who have added their 2 cents here. Especially Thanks to Bob for sending me his test plate, and to Jake and Andy for offering to go well out of their way to help.
 
final update

In Apr, 4 of us drove to Kingston, NY, took the 10 apart and squished the fuselage, sans eng, into a 24 ft enclosed trailer. Nose gear also had to come off. I got the eng back from Penn Yan Aero (Zero time overhaul done) in Jul and just finished reinstalling it. Still need a new Manifold press hose before running it. Oil is in. wings are on. extended range fuel tanks are going in this week (fuel transfer pump wiring and plumbing done). Tail feathers are going on this PM. It will be flyin on Thur. don't know which Thur.

Penn Yan said the original problem, loss of oil press to the prop, was probably caused by corrosion found on the thrust face of the crank.

It was going to cost $30K (and I already had $8K in it for the tear down) to fix. Only another $6K for complete overhaul to zero time. All 6 cyls were cracked at the exhaust ports. Apparently that is not unexpected for a 3300 hr engine.

The bottom line. It is fairly easy to get the wings off with 3 or 4 folks and a little planning. The wheels have to come off to fit in an 8 ft trailer. Pulling the gear together will only get you an inch of so. It was worth taking the wings off to be able to work at home hanger and remove "get-home-itis" from the equation.

Again, Thanks to all for your help and advice.
 
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