Siddley Hawker wrote:That's not a totally unusual occurrence. The center portion of the intake on both the G1 and the F-27 are not cycled like the rest of the intake and are continuously heated. If the heater switches are on the heat is on and every so often one will let go. It'll get your attention.
It sure got our attention!! LOL! Being that it was very dark, and the fireworks lit up the night sky. We damned near crapped! We is talking VERY bright.
Another thing that'll get your attention is late selection of prop/intake heat if you enter icing conditions with it off. It didn't happen to me but a local carrier back in the day. They were motoring along with the F-27 at 10,000 and entered icing conditions. The Captain reached up without thinking and flipped the prop and intake heat on. When the ice came off, the left engine auto feathered and the right one coughed. That'll soil yer breeks.
godsrcrazy wrote:This picture was posted earlier on the site. The right engine did not feather as it was running. The way the propeller was bent the engine had to be running. http://www.flickr.com/photos/tsbcanada/9563435527/
It kept coming out of feather - it would not stay feathered.
Another thing that'll get your attention is late selection of prop/intake heat if you enter icing conditions with it off. It didn't happen to me but a local carrier back in the day. They were motoring along with the F-27 at 10,000 and entered icing conditions. The Captain reached up without thinking and flipped the prop and intake heat on. When the ice came off, the left engine auto feathered and the right one coughed. That'll soil yer breeks.
One of the first things my instructor told me about at US Air......if you encounter icing conditions with the anti-ice off, it's way better to leave it off. I think it was Mohawk who lost an airplane in the early days, learning that lesson the hard way. It's pretty much a guaranteed engine out it this happens.
godsrcrazy wrote:This picture was posted earlier on the site. The right engine did not feather as it was running. The way the propeller was bent the engine had to be running. http://www.flickr.com/photos/tsbcanada/9563435527/
It kept coming out of feather - it would not stay feathered.
This will happen if you don't turn the mags off when you feather. The engine has not been "shut down", it's just been feathered. Fuel and oil etc are still being fed to the engine....and it'll keep running, feathered, or not. You gots to pull the mixture off, and kill the mags. Don't kill the mag "master" though....laugh not...it's been done!
Siddley Hawker wrote:
One of the first things my instructor told me about at US Air......if you encounter icing conditions with the anti-ice off, it's way better to leave it off. I think it was Mohawk who lost an airplane in the early days, learning that lesson the hard way. It's pretty much a guaranteed engine out it this happens.
That is why they call it engine(or nacelle) anti-ice. Supposed to be already heated prior to(or at least soon after) entering icing conditions so there is no buildup. Although some people do like to rely on the auto function. I have seen an auto function repeatedly coming on in cloud with no ice accumulation(and associated loss of performance) but then not come on when it should.
I did hear once about one of these electrical anti-ice lighting up the intake malfunctions on a Dart. He shut it down and landed at destination in the unforecast 30 knot crosswind in blowing snow that had popped up with his alternate down as well.
Siddley Hawker wrote:
One of the first things my instructor told me about at US Air......if you encounter icing conditions with the anti-ice off, it's way better to leave it off. I think it was Mohawk who lost an airplane in the early days, learning that lesson the hard way. It's pretty much a guaranteed engine out it this happens.
That is why they call it engine(or nacelle) anti-ice. Supposed to be already heated prior to(or at least soon after) entering icing conditions so there is no buildup. Although some people do like to rely on the auto function. I have seen an auto function repeatedly coming on in cloud with no ice accumulation(and associated loss of performance) but then not come on when it should.
I did hear once about one of these electrical malfunctions on a Dart. He shut it down and landed at destination in the unforecast 40 knot crosswind in blowing snow that had popped up with his alternate down as well.
But....even forgetting to turn on "anti" icing equipment "after" encountering icing conditions, should NOT result in an engine flame out. Not the best design here, methinks? All in all though, the F27 remains one of my favourite types. Really enjoyed it.
My understanding is that the engine had failed (i.e. "stopped"). So while what you say is correct, I assume it was past that stage.
Also, they tend to stall in feather because of the load of the feathered props, so to keep it running you have to add a bit of throttle.
It's a while since I flew them, but if I remember correctly you have to push the button back in to stop the feather pump; if you don't, it just continues to pump the prop back to fine, because the locks are not engaged with the oil pressure being continually supplied (by the feather pump). Is that correct?
It's been so bloody long!
If you have any throttle at all, they will "diesel" like a '69 Buick! You have to pull he feathering button out to stop the pump? Pushing it back in, un-feathers it.. Seem to remember it popping out on it's own....but it's been a while...and I'm really old. LOL
godsrcrazy wrote:This picture was posted earlier on the site. The right engine did not feather as it was running. The way the propeller was bent the engine had to be running. http://www.flickr.com/photos/tsbcanada/9563435527/
It kept coming out of feather - it would not stay feathered.
This will happen if you don't turn the mags off when you feather. The engine has not been "shut down", it's just been feathered. Fuel and oil etc are still being fed to the engine....and it'll keep running, feathered, or not. You gots to pull the mixture off, and kill the mags. Don't kill the mag "master" though....laugh not...it's been done!
Doc I am no crash expert and I have never sat in the front of a DC-3 but this totally makes sense that the right engine was trying to make power. I have never seen a picture of blades bent like that unless the engine was making power. Simply wind milling in or out of feather the blades would have stopped and bent back as soon as they contacted the ground.
If the blades kept coming out of feather I would imagine the drag would have been huge if the engine was at idle.
Either way glad to see they got it on the ground with no serious injuries.
The prop feathering is controlled by pushing in a red feathering button which activates a feathering pump that produces high oil pressure ( 1400 psi as I recall. ) to feather the prop, when the prop is feathered the red button pops back out to the off position.
If the feathering button re-engages and starts the unfeathering process you can stop it by either holding the button in the out position or turning off the master switch.
A engine shut down just after take off can be busy and it can be difficult to deal with a stuck feathering / unfeathering button.
EDITED
Saw the same thing on an A26 when I was apprenticing with Airspray. Pilot tried to feather an engine due loss of oil pressure but it kept coming out of feather because the button didn't pop out and he didn't know to pull it out once the prop was feathered. He couldn't maintain altitude with the windmilling prop and was expecting to end up in the bush or fields but the engine finally seized due to no oil and he made it back to base.
I have zero DC-3 experience but is their single engine performance marginal enough that neglecting to stay coordinated would cause you to descend into the ground? Sounds dumb but in my experience it feels like there's a whole generation of pilots who don't seem to understand the relationship between an inclinometer (or the feeling if their butt on the seat) and those movable foot rests on the floor.
lownslow wrote:I have zero DC-3 experience but is their single engine performance marginal enough that neglecting to stay coordinated would cause you to descend into the ground? Sounds dumb but in my experience it feels like there's a whole generation of pilots who don't seem to understand the relationship between an inclinometer (or the feeling if their butt on the seat) and those movable foot rests on the floor.
LnS.
You are correct. The single engine climb rate is pretty piss poor. Somebody listed the actual numbers earlier in this thread. Having your ass whistling Dixie will not help here.
There is a sump in the oil tank that contains a gallon or so that is only available to the feathering pump so even if the engine runs out of oil you can feather it. You do not leave the pump running as you can deplete the oil and it will likely overheat the pump and then the prop will unfeather. I recall a large spike in amperage that announced the completion of the feathering cycle and the switch was supposed to pop out and shut off the pump. If it didn't you were to watch for it and pull the switch out manually.
To unfeather you (pull the switch out - got this wrong, push it in again ed.) allowing the prop to come out of feather carefully letting the cold engine spin, re-start and warm up and ensuring the prop governor can control the prop.
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Last edited by xsbank on Mon Sep 02, 2013 11:04 am, edited 1 time in total.
Cat Driver wrote:The prop feathering is controlled by pushing in a red feathering button which activates a feathering pump that produces high oil pressure ( 1400 psi as I recall. ) to feather the prop, when the prop is feathered the red button pops back out to the off position.
If the feathering button re-engages and starts the unfeathering process you can stop it by either holding the button in the out position or turning off the master switch.
A engine shut down just after take off can be busy and it can be difficult to deal with a stuck feathering / unfeathering button. EDITED
Interestingly, some turbine aircraft have a feathering button as well. Oil pump stops operating at a certain pressure buildup and blade angle.
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Last edited by pelmet on Wed Sep 04, 2013 10:50 pm, edited 2 times in total.
Not sure if I'm reading that right about the feather/unfeather switch, but you pull the button out if it doesn't pop automatically after feathering so it doesn't unfeather, but you ALSO pull the button to unfeather the engine if conditions allow a restart? If that's the case how does a system like that work?
Feel free to PM in the interest of keeping this thread on the incident in YK.
The feathering button activates the feathering motor to produce oil pressure to move the blades to the feathered position, when the blades are feathered the feathering button pops back to its origonal position.
To unfeather the propellor you push the botton back in to power the feathering motor, the propellor will now start to unfeather and when the RPM reaches 800 RPM You pull the button out to the off position and the air stream will now finish the unfeathering assisted by the engine now running at low power setting.
When temps allow you then apply cruise power.
It is a bit more complicated than that as you first have to make sure the mixture is rich, the prop RPM lever is set in the cruise setting and the mags are on.
I also carried a good luck item with me, a lucky condom.
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Last edited by Cat Driver on Sun Sep 01, 2013 7:40 pm, edited 1 time in total.
I was scratching my head a little trying to follow the posts here on what happens when you push, pull, push again, etc. the feathering button, so I went googling, hoping for clarification. Found the following site. Well written and interesting reads and appears to have been authored by people who know their stuff.
Several good write ups on the ins and outs of DC-3 feathering systems - how they should work and often don't work.
If it becomes necessary to unfeather the propeller after an engine shutdown in flight, perform the following:
1...Airspeed.............................................to 117 IAS kt or below.
2...Skis (if installed)..................................DOWN
3...Firewall Shutoff Valve...........................PUSH TO OPEN
4...Turn propeller 8 blades with starter before unfeathering (to check for hydraulic lock.)
5...Fuel tank selector................................AS REQUIRED
6...Carburetor air......................................RAM
7...Throttle...............................................CLOSE
8...Propeller control...................................DECREASE RPM
9...Ignition switch......................................BOTH
10..Fuel booster pump switch......................ON
11..Propeller feathering button.....................PUSH IN (until 800 to 1000 RPM)
NOTE: If the feathering button is held in, overspeeding could occur. When engine speed reaches 800 to 1000 RPM,
release the feathering button and allow the propeller governor to take over.
12..Mixture control......................................AUTO RICH
13..Warm engine thoroughly (to insure complete oil circulation), then increase power to the desired setting.
14..Generator switch....................................ON
15..Fuel booster pump switch........................OFF
16..Skis(if installed)......................................UP
17..Trim.......................................................AS REQUIRED
The preceding is from the Flight Manual for the USAF series C-47 A, B, C, D, HC-47, C-117A, B, C.
