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FEATHER


fushi

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Gentlmen,

The overhead Propeller RPM levers cannot set FEATHER, but the Auto Feather switch ON and CTL + F2 keys functionally work to set FEATHER.

Sincerely,

Kan-ichiro Fushihara

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The prop levers do work.

Shut down one engine inflight (fuel lever all the way back). Move the prop lever for that engine all the way back into feathered position and within a few seconds the propeller will come to a standstill.

Finn "wothan" Jacobsen

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That works, yes. But why can I take of with prop levers set to full feather? I'm just a bit confused because on my C-130X the prop levers have a direct effect on engine performance and gauge readings too. In the Twotter working those levers don't seem to change anything for me.

Don't get that wrong (maybe I'm not operating things correctly) but on the C-130X (which is also turboprop) I can lower engine performance by either pulling the throttle back OR pulling the prop levers back a little.

In the Twotter latter does not work.

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I asked something similiar but got no answer yet. The prop levers don't seem to do anything. I can even start with them set to full feather. Are the levers actually functional here or am I doing something wrong?

Observating the Torque Pressure gauge and Propeller RPM gauge, I have confirmed that the prop levers works qualitatively.

The prop levers do work.

Shut down one engine inflight (fuel lever all the way back). Move the prop lever for that engine all the way back into feathered position and within a few seconds the propeller will come to a standstill.

Finn "wothan" Jacobsen

I have done just as you did; however, the propeller doesn't come to standstill within several seconds.

Sincerely,

Kan-ichiro Fushihara

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  • Aerosoft

Observating the Torque Pressure gauge and Propeller RPM gauge, I have confirmed that the prop levers works qualitatively.

I have done just as you did; however, the propeller doesn't come to standstill within several seconds.

Sincerely,

Kan-ichiro Fushihara

I just tried it again:

1) on AP at 500 feet

2) auto feather on (green indicator on)

3) hit the fuel switch on the fire panel (easiest way to shut down an engine)

4) the engine will stop and feather in a few seconds.

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You might also need to fly slower.

Thats at least what I have to do in both my Digital aviation Piper Cheyenne and Eagle soft Commanche !

So I guess that this once more is a FSX "feature".

Finn "wothan" Jacobsen

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Ok, I see someting now. The prop lever does indeed seem to effect someting. However a prop rpm at 75% when the lever is fully feathered?

387221Issue_02.jpg

The right engine is fully feathered here. Is that correct that the prop rpm stay that high???

Thanks for the help.

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Ok, I see someting now. The prop lever does indeed seem to effect someting. However a prop rpm at 75% when the lever is fully feathered?

The right engine is fully feathered here. Is that correct that the prop rpm stay that high???

Thanks for the help.

Yes, depending on a lot of factors that would not be uncommon. You will be putting a good strain on the reduction box though and feathering a running engine in flight is not the most common situation. Not sure if FSX does it, but you will make some serious noise with the blades flapping air sideways. Mechanics hate it when it's done long on floaters, whips up a lot of spray the engine sucks up from the back.

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Feathering the props with the engines running will offcourse not stop the props.

With the props feathered, they act as huge centrifugal blowers, sucking alot of air in both from the front and the back of the prop. This air is expelled outwards from the prop. This requires a great deal of torque, but doesn't produce any thrust.

Feathering is used when an engine fails during flight to reduce drag from the dead engines propeller.

Autofeather is used duri ng takeoff where an engine failure is most dangerous and time is limited for the pilots to feather the engines manually.

Finn "wothanp" Jacobsen

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  • Aerosoft
Feathering the props with the engines running will offcourse not stop the props.

With the props feathered, they act as huge centrifugal blowers, sucking alot of air in both from the front and the back of the prop. This air is expelled outwards from the prop. This requires a great deal of torque, but doesn't produce any thrust.

Feathering is used when an engine fails during flight to reduce drag from the dead engines propeller.

Autofeather is used duri ng takeoff where an engine failure is most dangerous and time is limited for the pilots to feather the engines manually.

Finn "wothanp" Jacobsen

Hey Finn, go back to apres ski and stop simming or I call your wife and tell her you are online!

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Mathjis dont talk to me like my wife :-D

She is screaming at me like 2 PT6A's, urging me to focus on our vacation instead of chatting with sim-fools in this forum.

But it is too hard for me not to be kept informed of whats going on here :-)

Finn

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I have done just as you did; however, the propeller doesn't come to standstill within several seconds.

Sincerely,

Kan-ichiro Fushihara

Is this problem peculiar to me, because there isn't this problem on the default King Air of mine?

Sincerely,

Kan-ichiro Fushihara

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Dear Mathjiskok,

Yes I'm sure, because just after the Prop lever had couldn't set FEATHER then CTL + F2 keys has set FEATHER.

So, it's not the actual harm, I'm thinking.

Sincerely,

Kan-ichiro Fushihara

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Mathis & Wothan,

The props on the Twin Otter are not feathering for me either. I have mentioned this a few time in a few threads but did not get any response.

I have pulled the RPM lever into full reverse to put it into the feather detent position, but it appears the Twin Otter has the same problem that the Cheyenne experienced until that issue was patched.

I suspect you would know I confirmed this, but yes, I did confirm the engine was shut down -- fuel isolation switch toggled, fire handle pulled, and confirmed torque, RPM, and TIT all confirmed the engine was off.

I waited several minutes and the prop just kept windmilling with no sign of letting up. When I landed and rolled to a stop, the prop of the shut down engine then wound down to a stop. So, that's the ultimate proof that the engine was shut down.

Cheers,

Ken

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I can confirm that. I just set everything up for feathering left prop. On the ground the prop feathers and stops. "Beam" the Twotter up (slew and F4) and the prop starts windmilling again. Land with one functional prop and the lest stops again. And so on...

In the air, the props will no feather no matter how slow you fly.

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Private_Cowboy,

This might help ...

The prop lever (aka RPM lever) simply manually rotates the prob blade angle. If you move the prop lever full aft then it rotates the prop blades to the feather position, which means rotated enough so that without engine power turning the crankshaft the prop will not rotate in the aircraft's slipstream.

However, with engine power coupled to the propeller as you pull the prop lever aft then the RPM level will go down for a given power setting. Above a certain minimum RPM setting, the prop on most piston twins have a governor that engages and regulates the prop blade angles automatically to maintain a constant RPM speed with changes in manifold pressure. This is why these systems are called "constant speed props."

But with engine power engaged, as you pull the prop lever aft with manifold pressure set above an idle setting then you can increase the pressure on the engine to failure point. This is because as the blades rotate they expose more surface area to the air as the blades spin around. This increased resistance lowers the RPM value for a given manifold pressure setting (piston engines) or inlet turbine temperature (ITT) for turboprop jet engines. So, with the engine still running and the prop in the feathered position, you will still get an RPM value because the engine is still turning the crankshaft.

It's similar to taking your hand and putting it outside a car at 55 miles per hour. If you hold your hand out slicing the wind you feel little air resistance. But if you rotate your hand so that it's like a paddle against the air you feel a rapid increase in air resistance against your palm. Same principle for the prop blades.

When the engine provides power to the prop, then the rotation is providing thrust. But when the engine is shut down then you want the prop to stop turning because a turning prop blade causes more drag than one that is standing still. If the engine is shutdown, then the prop is not supplying any thrust. So, rotation just from airstream produces no thrust, but causes increased drag.

Hope this helps.

Cheers,

Ken

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I have not used the CNTL + F2 keyboard command to feather the prop. Can we please modify the aircraft so that you can feather the prop simply by moving a prop control lever full aft on a controller?

Cheers,

Ken

Of course, I also hope so, though I have assigned CTL+F2 to a button on the HOTAS COUGAR throttle lever.

Sincerely,

Kan-ichiro Fushihara

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On the float version th e propeller is animated unfeathered in order to make it look right when floating with the engines shutdown.

The real floater has "zero thrust latches" build in to keep the unfeathered during startup.

Wothan

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  • 1 month later...

Two months and no updates on this issue?! I can confirm this issue. I cutoff the fuel for the #2 engine, pulled prop lever all the way back, turned on auto feather, hit the emergency fuel cutoff switch, no feather. I slowed down to stalling speed, still no feather. Cycled every single switch and lever that had anything to do with it, nothing.

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