Hi, looking to the community for help as we are stumped.

First details on the Propeller:
SP7WE Propeller 2D30-405 AG100-2 Blades
March 2019 Overhaul, 200 hours since overhaul.
Overhauled with the RSW bearing STC

The Issue
Propeller performs normally except it reaches a failure condition.
Failure condition is reached upon performing a power off stall, or basically lowering the manifold pressure below 20 with a very high nose up attitude [Power off Stall practice].
Once the issue happens, propeller fails to govern, requiring flight at 20 on mainfold, prop lever has no function, fly back home slow and try to keep altitude
After landing, and cycling propeller, returns to normal operations [governs, responds to prop handle input]. One note is it is a bit slower to respond

What we've tried so far

Oil change [switched to W100]
Lubricate propeller and bearings with Aeroshell 5
Inspected hoses from governor - new as of 2019 and no issues observed


Has anyone run into this failure condition on a 2D30 before? The issue is 3/3 reproducible after attempting a power off or power on stall.

Thanks in advance!!

Nick,

Better then 20 years of 135 float beaver as DOM out in western AK and never heard of this.

First question is did anyone get eyes on the oil pressure during this event?

Second, I would pull the CW stop covers and see if you don't have somthing ammis inside, I've had one of the blots break but we knew it right away.

Also, I can't recall exactly which prop needs it or not but there is a little cone/nozzle that goes into the the end of the crankshaft. Need to variefy the correct condition exists.

Sure seems like a low oil pressure or governor event, the props themselves are mostly bullet proof.


Rocket

rocket wrote:
Also, I can't recall exactly which prop needs it or not but there is a little cone/nozzle that goes into the the end of the crankshaft. Need to variefy the correct condition exists.

Sure seems like a low oil pressure or governor event, the props themselves are mostly bullet proof.


Rocket

I bet it's an AN14-B. That's what's going on. Take a nose oil pressure and you'll see it. I had one do this fresh off the test cell.
That valve needs to be seated and sealed properly. My bet is that it's a bit loose in there.
John

Thanks greatly for the leads on what to look for, on the last flight we laser monitored the oil pressure before the stall practice and we did not see the pressure drop.

Will share this with the A&P and we will look into cone/nozzle valve at end of crankshaft.

Hi thanks again for the help!
I can confirm it is an AN-14-B

John / Rocket would either of you mind listing the rough steps after removing the propeller to inspect and repair the valve? I want to make sure I have a good understanding of what we will be getting into. We might be able to get started at the shop Monday morning.

Also with the 2D30 propeller are there any differences in overall operation compared to the Hartzell - anything to look out for? I have spent a great deal of time google searching but have not found any additional should-know's or gotchas on it. I am very open to learning and appreciate all the wisdom and experience!

Nick,
this is just one of those things best not figured out from some guy or two on a forum, even if it is the BCP

My first call would be to Ron Hollis at Covington, there is another gent, don't recall his name, who was taking over for Ron. Next call would be to Jerry at Dominion prop in Anchorage. Seeing as your in Seattle there has got to be a good engine and prop guy down there willing to square you up.

Ok, when you get an engine the prop shaft can come in three conditions, one is nothing in the bore, the other is a flat plug with an internal hex, and the third looks like a little cone or funnel sticking out.

The plug just threads in and the cone is held in place by a flat plate full of holes and this is held in place by two drilled head filister screws saftied together accordingly. John upthread has a grasp of the engine model variant that comes in each condition and I don't, perhaps he can chime in.

You can pull the prop cylinder cap and look with a flashlight and see which you have through the prop nut. Gotta look hard as its about ten inches in there. You should have the cone with the 2D30. Hmm, wonder if you need it for the Hydromatic?

BTW, went down memory lane this evening, 17,783 photos, looking for one for you, seems prop changing time is no time to be screwing with a camera or phone. Must be all the oil sheening up the pond.

To be honest I'm not sure what exactly the cone does and to be double honest I'm nut sure this is your problem.

I would spend some time getting governor P/N and get a hold of whoever did it, wings west?, and make sure you got the correct model for your prop.

Had a couple shops at lake hood switch to a Hartzell without changing the governor, makes pilots mad. You didn't switch from a Hartzell recently did you?

Ok, one thing, for dogs sake don't over torque the prop nut. Read the installation instructions in your DHC-II MM then read them again. Hang on bar as instructed, strike bar near the hub with specified hammer weight, JUST ONCE FOR F sake, that's it. I've bent large and long pieces of steel with a fat assistant hanging six feet out banging with a sledge trying to get one loose more times then I can count. Do it just as it says, don't use a torque wrench as the MM doesn't say to right, right. Look at me, I sound like one of those old fat bald guys, ha ha ha. Oh wait...

Be smart, be safe.


Rocket

ps. Lost my phone under a cabin unfreezing pipes the other day, you know, living the dream. Try: rocket at glassywater dot com

What we had happen on the one I dealt with was that the transfer tube, supplying the oil from the crank up through the "nozzle" to the prop, had come loose in the back. This was in the mid 90's so I'm doing this by memory. During overhaul, the tube assembly was removed and not plated back to the interference fit properly. That allowed the tube to work forward just a little, so the pressure leaked. It wasn't really apparent to look at, but the whole setup was just a little forward of where it should have been, if I remember right. We usually didn't remove that assembly when we overhauled, if the tube was tight, but for some reason, someone had tried in this case. In ours, you could see a pressure drop in the nose case port.
From what I'm hearing, you've got to be losing oil flow through the governor and it either doesn't want to pick it back up, or it's flowing and not going where it's supposed to.
Talk to Dick at Northwest Prop. The only other guy I'd put alot of faith in for something like this would be Gordon at Kenmore, but I'm sure he's long retired by now.
I'll try to get to the shop tomorrow and see if I have anything in my manuals or notes about it....I should have. I used to have all the oil flow charts memorized....now I can hardly remember what I had for breakfast....
John

Check the counterweights on the prop, the kidney bearings lock up from lack of grease or the wrong stuff. I lube them with a small o mount of molybednum before each flight on my old T-6.

When is the last time the prop hub has been greased too? Pilots/mechanics like to skip greasing the prop because they don’t like to clean windshields. Make sure it’s the proper grease.

Or could be your prop Governor going out. The prop goes to full course pitch when it acts up.
I’m betting 90% it’s the governor that needs to be looked at.


Totally off topic, I had a hydromatic prop on a geared 1340 do weird stuff, ended up being a cracked transfer oil tube inside the geared portion of the engine, used compressed air on the oil lines with the sump off to find the issue. Less than 100 hrs on the rebuild.

Thanks everyone for the notes and feeback, I'll be on the phone with the prop shops tomorrow as soon as they open. The rebuild was by Hope in 2019.

We extensively lubricated the prop and still had the issue - cleaned a lot of grease off the windshield!

Did some extensive testing on it over the weekend and we found the issue does not only occur in a stall condition, we managed to encounter it during slow flight and steep spirals - basically the conditions to cause the failure were lowering manifold pressure to 15 or less & being airborne. After all failures, simply landing on the water and doing a runup/cycling the prop was all that was required to "reset" the issue and return to normal ops.

Will probably take the propeller off this coming week and start going through all the suggestions in the thread and notes we get from the prop shops. We also keep coming back to the governor

Nick.

No reason to pull the prop unless you find that cone/nozzle part is not there, should be able to variefy by removing the cylinder cover and looking carefully down the middle of the prop nut.

I'm thinking governor as well. Was it OH at the engine change? How many hours and years on it?

Rocket

So let me get this straight...are you going to low pitch or high pitch when it fails?
John

Governor was overhauled, p/n 1A2-G5
161.5 operating hours ago, 5/21/2019

Usually the fail condition goes like this.

1. Start at Cruise, 110MPH, Manifold 28, Prop 18.5
2. Pull Back power to 10 of Manifold for commercial maneuver [Slow Flight, Steep Spiral, Stall, Go around practice, etc]
3. Push propeller lever forward to prepare for adding power [this step does not really make a difference]
4. Add power back in after completing flight maneuver *****
---> At this point the propeller fails to govern, it will hit 2300RPM at only 24 inches of manifold.
---> Once failure hits, moving the propeller lever has no effect [as shown in the video]
----> The failure is brought on by adding power back in, not by moving the propeller lever.
5. Landing on the water, and cycling the prop makes the issue go away.




Here's a video of it after it hits the failure condition:
https://photos.app.goo.gl/LunE5W4AW7CtgSJZA

Photo of propeller




Spent another day puzzling over it as the hangar does not have space yet to bring it in, we are wondering if perhaps the wrong counterweights are installed. Prop Overhaul was by Hope Aero in 2019, Engine prop and governor were all done at once 161.5 flight hours ago.

Will absolutely check for the cone/nozzle part once we get it in the hangar. Excited to inspect this.

Thanks for all the support this one is really a puzzling issue.

Rocket,

Here is a parts catalog. Might be easier pointing at the part your talking about. I’m not familiar with the nozzle you are referring to. I know a hydromatic prop is completely different.

http://www.dustersandsprayers.com/PDF%2 ... ellers.pdf

It's actually an engine part and found in the 985 parts book. If I recall in my parts book it's one of those hand drawn additions in a later printing even the p/n is hand drawn.

Rocket

Ha, i miss remembered the drawing, means I was wrong, darn free internet advice

Not sure why the overhaul doesn't come with this part? Old timer who trained me said to take it off the old one cause, then reinstall on the O/H


Rocket

OK I'll bite why are you referring to this as a "commercial" maneuver ??

Quote:
2. Pull Back power to 10 of Manifold for commercial maneuver [Slow Flight, Steep Spiral, Stall, Go around practice, etc]

Ahhh haaa!!

Rocket, you stuck a memory chord!.

There’s an odd Seal that is in the Prop spline area in the hub, when installing the prop it’s essential that it does NOT get scrapped or torn when sliding the propeller onto the Crank shaft! Happens a lot with newbies. We usually slabbed a ton of grease on the crank shaft spline area and In the prop hub, and carefully slide the prop with the crane positioned correctly to the slant of the aircraft sitting onto the crankshaft without damaging that seal.

My bet now holds 99% on that propeller hub seal. I’ve have that issue before. A torn seal will not drive the propeller no matter how much oil pressure, it leaks past the seal,

The seal is located inside the prop hub, halfway, you can barley feel it with your fingers, you CAN replace it, but the prop needs to be pulled completely off the crankshaft.

Item 38, 39, or 40. I can’t remember but call the prop shop. With the prop off you can feel for tears.

Nick, just now was able to watch your video.

Have you guys exercised the prop? It's vary possible the prop blades are sticking under flight loads.

Have your mechanic read the following a few times so it all makes sense:

You'll need two 4' long sections of 2x4 and two pieces of 1/4 or 3/8 line about 6' long. Out toward the tip you are going to tie the boards on flat to the face, the flat side of the blade so you can use them to swing the blades in unison with two guys back and forth from high to low pitch stop to stop.

First pull the prop governor oil hose off the fitting just under the prop on the case. It will get messy. Keep all these works scrupulously clean right. Not asking I'm telling.

Now, before you start you need to pump about 4 shots of grease into each blade hub bearing.

Then move the blade to high pitch. Stop. Grease another 4-5 shots.

Now be carful, you can blow out the seals around the prop ends on these so only grease what I've said to.

Now work the blades together from stop to stop 20-30 times nice and easy, be smooth and work together. Keep an eye on the CW and feeling or hearing anything jerky etc.

You've got the STC to get rid of the kidney bearings and uses the nylon slider assembly. Wonder if they got the bolt too tight? Your stc paperwork comes with installation instructions and should have a service memo or ICA. Should be a line about a feeler gage between the bronze washer like bushing and the CW assembly. I always finger some aeroshell where the two slide against each other at the 100 hour. Regardless grease this up accordingly per the instructions before exercising the prop.

Ok where was I, did it get a little easier along the way? It's subtle. Mostly you will be blowing out oil through the governor oil line and sucking air so it will feel different as you get the oil out of the way. It's one of those touchy-feely zen things so pay attention.

Ok, now one more shot of grease both sides then ten strokes stop to stop but stop on the opposite pitch, one more shot of grease, exercise, repeat about six times at high pitch and six times at low.

You may need to do this once a year, say at annual. We had one that needed this every spring, had the big 4S blades. Only had a few through the years that needed this in the spring.

One more thing, don't get this girl airborne until you've figured her out, trouble shoot on high speed taxi only. You on wheels or floats?

You do something stooped and I promise to piss on your grave!

Make good choices, be smart, and fly safe.



Rocket

AKJurnee wrote:Ahhh haaa!!

Rocket, you stuck a memory chord!.

There’s an odd Seal that is in the Prop spline area in the hub, when installing the prop it’s essential that it does NOT get scrapped or torn when sliding the propeller onto the Crank shaft! Happens a lot with newbies. We usually slabbed a ton of grease on the crank shaft spline area and In the prop hub, and carefully slide the prop with the crane positioned correctly to the slant of the aircraft sitting onto the crankshaft without damaging that seal.

My bet now holds 99% on that propeller hub seal. I’ve have that issue before. A torn seal will not drive the propeller no matter how much oil pressure, it leaks past the seal,

The seal is located inside the prop hub, halfway, you can barley feel it with your fingers, you CAN replace it, but the prop needs to be pulled completely off the crankshaft.

Item 38, 39, or 40. I can’t remember but call the prop shop. With the prop off you can feel for tears.

AKJ,

Are you talking about the Little Giant seal inside the cylinder?

If the seal at item 39 is damaged, and I've seen more then a few, you have oil all over your windshield, lot of these got missinstalled at lake hood, then they flew out west and straight to the Naknek River at PAKN or the 5NK pond where I had to deal with it: billable hours! Hard to believe but I've shouldered a few of these off and on by myself back in the day and I'm not a big guy, more guts then brains I supose, got smarter and made sure the pilot didn't sneek off to get lunch or the bar til I was done. If some meathead didn't over torque the prop nut I usually had the whole thing off and on in an hour, a touch more if she had the spinner and the required safty wire. Later came to love the big Hartzell...


Rocket

Rocket,

Yes that seal, but I forgot about the tell tale oil leak over the windshield thing! Long day.

Great story! I bet you backed a pickup truck up to the prop, used the bed rails and a 5 gallon bucket for the oil that spills out? brings back memories of crop dusting for me.

Back to square one I suppose. I hope he finds the issue and I'm curious of what it is.