Constant speed prop ****** ******'s... [Archive]

Turd_Ferguson

6/20/2011, 03:52 PM

Watching Ice Pilots over the weekend. They were ferrying the plane pictured below to Turkey...While at cruise, they had the #1 prop overspeed. HTF does this happen? Is it not having feather control of the prop or what? I've googled it, but still can't wrap my head around it...TIA.

http://channel.nationalgeographic.com/staticfiles/NGC/StaticFiles/Images/Show/59xx/590x/5900_Ice-Pilots-ep7-01_05320299.jpg

OutlandTrophy

6/20/2011, 04:00 PM

Usually when the prop governor loses oil/pressure the blades flatten out and speed way up but the thrust goes down.

You're correct in that you lose the ability to feather the prop.

Mjcpr

6/20/2011, 04:01 PM

I'll feather your prop in a minute.

Mississippi Sooner

6/20/2011, 04:05 PM

I have no idea what's going on here.

Turd_Ferguson

6/20/2011, 04:06 PM

Usually when the prop governor loses oil/pressure the blades flatten out and speed way up but the thrust goes down.

You're correct in that you lose the ability to feather the prop.Oh ok...they acted like the engine was gonna fly apart and there was nothing that could be done...I'm sure it was for affect.

pphilfran

6/20/2011, 04:07 PM

Usually when the prop governor loses oil/pressure the blades flatten out and speed way up but the thrust goes down.

You're correct in that you lose the ability to feather the prop.

Yep...sounds about right...

pphilfran

6/20/2011, 04:08 PM

Oh ok...they acted like the engine was gonna fly apart and there was nothing that could be done...I'm sure it was for affect.

With the blades flattened out I would imagine the engine would turn into a high rpm paper shredder...

Turd_Ferguson

6/20/2011, 04:15 PM

With the blades flattened out I would imagine the engine would turn into a high rpm paper shredder...Understand, but I would think protocol is to cut the fuel to it if no feather response.

pphilfran

6/20/2011, 04:18 PM

Understand, but I would think protocol is to cut the fuel to it if no feather response.

You would think there would be a over rev cutoff...once those blades flatten it will only take a moment to rev up...but I ain't no plane expert...

Turd_Ferguson

6/20/2011, 04:20 PM

...but I ain't no plane expert...Nor I...just a wannabe...

StoopTroup

6/20/2011, 04:37 PM

I've seen them do this on a test stand and it only takes one little mistake to have this happen. I'm surprised it would happen to someone with a lot of experience flying that particular plane but in Aviation you can't immediately rule it out. Hopefully further investigation will maybe clear it up.

KABOOKIE

6/20/2011, 04:41 PM

Usually when the prop governor loses oil/pressure the blades flatten out and speed way up but the thrust goes down.

You're correct in that you lose the ability to feather the prop.

I am truly amazed at OLT’s impressive knowledge of constant speed propellers. Most pilot’s don’t have this knowledge even well into their flying career.

Now that being said, losing the oil pressure to the prop govenor doesn’t always mean the loss of feathering capability as most aircraft of this type use oil pressure to set the blade pitch. Losing oil pressure alone would cause the prop to go to feather. Losing the governor would cause a runaway scenario that could be controlled by reducing the power lever or cutting off the fuel supply to the affected engine. However, if the airplane has enough forward airspeed simply doing either of these actions would not solve the problem as the air loads alone would be enough to drive the RPM fast enough to turn the blades to a minimum or fine pitch setting.

StoopTroup

6/20/2011, 04:41 PM

You would think there would be a over rev cutoff...once those blades flatten it will only take a moment to rev up...but I ain't no plane expert...

We had one do this that had a Turbo on it and the guy did that and the turbo was so hot it caught fire. He had to start it back up to put the fire out. That was also a test stand. Imagine if you were flying and all of a sudden a bunch of things start happening all at the same time and you do one thing wrong.....then you can set a whole different scenario going. Confusion can ensue...and then you have a real problem especially if you forget to quit flying the plane.

StoopTroup

6/20/2011, 04:43 PM

I am truly amazed at OLT’s impressive knowledge of constant speed propellers. Most pilot’s don’t have this knowledge even well into their flying career.

Now that being said, losing the oil pressure to the prop govenor doesn’t always mean the loss of feathering capability as most aircraft of this type use oil pressure to set the blade pitch. Losing oil pressure alone would cause the prop to go to feather. Losing the governor would cause a runaway scenario that could be controlled by reducing the power lever or cutting off the fuel supply to the affected engine. However, if the airplane has enough forward airspeed simply doing either of these actions would not solve the problem as the air loads alone would be enough to drive the RPM fast enough to turn the blades to a minimum or fine pitch setting.

Good stuff.

pphilfran

6/20/2011, 04:44 PM

Good stuff.

yes it is...

texaspokieokie

6/20/2011, 05:08 PM

if you can't feather the prop, cutting off fuel isn't gonna keep engine from over revving.

StoopTroup

6/20/2011, 05:15 PM

if you can't feather the prop, cutting off fuel isn't gonna keep engine from over revving.

That's why it set the Turbo on fire on that test stand. He had a club prop on it too so once he feathered the prop the wrong way the damn thing took off so quick it scared the crap out of everyone around it. Also....it was on a trailer hooked to a WWII Tug and when it left the ground with the trailer....it flew into the tug and the prop hit the tug. There were around 20 of us watching this idiot as he had a history of doing some spectacular things with flying machines....lol

texaspokieokie

6/20/2011, 05:21 PM

That's why it set the Turbo on fire on that test stand. He had a club prop on it too so once he feathered the prop the wrong way the damn thing took off so quick it scared the crap out of everyone around it.

contrary to what i said above, cutting fuel in that situation should suffice.

i meant (above) when the plane is in the air.

and start the engine to blow out fire (on the ground) is a common procedure.
as opposed to using fire bottles, which makes a big mess.

i was in OANG in tulsa in early 60s & we had C-97s. 4 each, 4360s.

StoopTroup

6/20/2011, 05:27 PM

contrary to what i said above, cutting fuel in that situation should suffice.

i meant (above) when the plane is in the air.

and start the engine to blow out fire (on the ground) is a common procedure.
as opposed to using fire bottles, which makes a big mess.

i was in OANG in tulsa in early 60s & we had C-97s. 4 each, 4360s.

I've got other good stories about the same guy....one includes starting a helicopter that didn't have the main rotors on but had the tail rotor on in the hangar and the other is about an old Convair that he had a guy standing in front of with a fire extinguisher and the dude was wearing a hat and the idiot tried to blow his hat off by feathering the prop and it almost jumped the chocks. Getting hit by Convair Props wouldn't be the way I'd want to go....

I think they made him in charge of safety later....lol

Turd_Ferguson

6/20/2011, 05:32 PM

Getting hit by Convair Props wouldn't be the way I'd want to go....
That'd **** ya off...

King Air meets a deer...

http://www.jesseshunting.com/images/wtail-king-air200-collision-bc-2003.jpg

StoopTroup

6/20/2011, 05:47 PM

texaspokieokie

6/21/2011, 10:45 AM

I've got other good stories about the same guy....one includes starting a helicopter that didn't have the main rotors on but had the tail rotor on in the hangar and the other is about an old Convair that he had a guy standing in front of with a fire extinguisher and the dude was wearing a hat and the idiot tried to blow his hat off by feathering the prop and it almost jumped the chocks. Getting hit by Convair Props wouldn't be the way I'd want to go....

I think they made him in charge of safety later....lol

did his hat fly away ??

i think (not sure) i've seen a C-97 back up a little by feathering prop.
maybe more than one. very vague. i stood fire guard, but we'd be @ each side, not front or back. loved to hear one of those 4360s idle, sounded like really radical cam (very lopey), but when 2nd started it was just a roar.

StoopTroup

6/21/2011, 10:55 AM

did his hat fly away ??

i think (not sure) i've seen a C-97 back up a little by feathering prop.
maybe more than one. very vague. i stood fire guard, but we'd be @ each side, not front or back. loved to hear one of those 4360s idle, sounded like really radical cam (very lopey), but when 2nd started it was just a roar.

I think it did come off as he turned to save his life....lol

StoopTroup

6/21/2011, 11:00 AM

I think it did come off as he turned to save his life....lol

You know....you make a good point and since I had heard some of the stories about this guy, I knew that I didn't want to die because of his lack of good sense that is apparent the moment you meet him but the ones that didn't and thought he was an OK guy....it didn't take long once your life flashed in front of your eyes that maybe standing a football field away might be better than even to the side.

StoopTroup

6/21/2011, 11:05 AM

I'll repeat this again with a few more little details...:D

When you start up a helicopter in a hangar because "hey it doesn't have the main rotors on it"....

Once it starts and you thought you could just start it up and you find out that the tail rotor is run off of the main rotor power and before you could **** it down it had spun around in the hangar and climbed up the wall and the rotor had exploded when it contacted the steel structure of the hangar....the amount of tail rotor debris that is thrown into the air at amazing speed and in the blink of an eye....

I'll let you figure out the rest....

I wasn't around for that but I had heard about it prior to taking a powerplant course...for some reason the School continued to keep him around. I've seen many a person fired for much less.

texaspokieokie

6/21/2011, 11:07 AM

StoopTroup

6/21/2011, 11:19 AM

i didn't comment, but that's what i would have expected.

I had signed up for some classes there and had heard about the guy but thought that it was just One of those rumors that grow to become a tall tail. After the two incidents I later saw...I had a friend that was there for the helicopter deal come out and he showed me the marks on the hangar it happen in and really explained in detail how it occurred. It's was so close to killing some people. That's the one thing I learned about aviation real quick...close calls aren't always treated as serious as they need to be. I'll not say it happens like that in the real world...I was amazed it happened in a School environment. Not exactly the person I wanted to learn anything from.

StoopTroup

6/21/2011, 11:22 AM

I heard through the grapevine that they finally made him sign an agreement that he wouldn't operate any aircraft and that he was just there to teach theory.

texaspokieokie

6/21/2011, 11:25 AM

I had signed up for some classes there and had heard about the guy but thought that it was just One of those rumors that grow to become a tall tail. After the two incidents I later saw...I had a friend that was there for the helicopter deal come out and he showed me the marks on the hangar it happen in and really explained in detail how it occurred. It's was so close to killing some people. That's the one thing I learned about aviation real quick...close calls aren't always treated as serious as they need to be. I'll not say it happens like that in the real world...I was amazed it happened in a School environment. Not exactly the person I wanted to learn anything from.

well, do as i say, not as i do.

old saying (very old), there are old & bold pilots, but no old bold pilots.