Simviation Forums

OK, go ahead and laugh!  ;D

I've conducted searches on this forum, Wikipedia and Google... I think I'm entering the wrong keywords.

What does it mean to "feather" the props? What actually happens? I know the Prop Pitch controls thrust and rpm by rotating the blades, but I don't get "Feathering".

Thanks for entertaining a so-called "veteran".

Joe

I always believed that feathering meant pitching the blades so that they were not facing the oncoming airflow, so there is less drag... e.g. if an engine fails it gets feathered so it doesn't create lots of drag on the blades...

I may be wrong?

[quote]I always believed that feathering meant pitching the blades so that they were not facing the oncoming airflow, so there is less drag... e.g. if an engine fails it gets feathered so it doesn't create lots of drag on the blades...

I made be wrong?

Yep, "feathering" simply means the leading and trailing edges are in line and perpendicular(a better word is welcomed) to the wing. Turboprops feather to stop the prop's rotation. While in flight a dead engine's prop would be feathered to reduce aerodynamic drag.

Yep, "feathering" simply means the leading and trailing edges are in line and perpendicular(a better word is welcomed) to the wing. Turboprops feather to stop the prop's rotation. While in flight a dead engine's prop would be feathered to reduce aerodynamic drag.

Perpendicular... hmm, If the air if moving -> and the prop is _  Is this feathered? To me the air is going -> over the wing  _ so perpendicular is |. That, to me, would create more drag.

Yep, "feathering" simply means the leading and trailing edges are in line and perpendicular(a better word is welcomed) to the wing. Turboprops feather to stop the prop's rotation. While in flight a dead engine's prop would be feathered to reduce aerodynamic drag.

Perpendicular... hmm, If the air if moving -> and the prop is _

Perpendicular doesn't seem quite the right description. Picture the prop blades rotated at 90 degrees to normal so the leading edges of the blades are facing forwards to cause minimum drag. Here's a photo. Both props are feathered.

OK! I guess that's the end of this question.

Thanks for the picture, that's what I thought.

To explain the difference, operations-wise, between "feathered" and merely at a normal low A of A:

Most variable-pitch-equipped prop units have an "autofeather" function- a pushbutton action on the part of the pilot, as opposed to dragging the prop lever back.  Instantly sets the prop blades to feather (a term, BTW, which comes from the feathers on an arrow).
This saves precious time, which can be critical in a twin, where asymmetric thrust after loss of power in one engine makes the pilot very busy right away, and also reduces the period of time the prop is producing drag, which can make things really nasty very quickly, especially if you lose an engine climbing out. Also buys the pilot a second to secure that engine (power, mixture, ignition) without having to fuss with the prop lever.

 This feathered position is usually  beyond the angle produced by bringing the lever all the way back.

I thought "feathered" was a generic term meaning to minimize the angle of attack.  For example, if the prop is still spinning the "feathered" position wouldn't be perpendicular like that in the photo, it would be at some other angle depending on the speed of rotation and airspeed.  It's the angle at which the prop produces the least effect on the wind (drag, thrust, etc).  A stopped prop would indeed feather perpendicular like the photo.

The term is also used in canoeing/kayaking.  When you remove your paddle from the water and bring it forward for the next stroke you feather it so it slices through the wind.  Same concept.

[quote]I thought "feathered" was a generic term meaning to minimize the angle of attack.

A bit more interesting info on variable pitch/ constant speed Prop's....>>>>

http://www.thaitechnics.com/propeller/p ... rol_3.html

...and a few tips on the use of VP/CS Propeller controls....(the little blue lever)... ;)...>>>

Quote from Pilot Magazine, October 2005

Constant Speed Propellers:

"Everyone knows if you are in fifth gear in your car and the engine's doing 1,500 revs, putting your foot down is going to strain the engine. You must have the revs to absorb the power. The same principle applies to CS Props.
"Rev up, throttle down is the rule. So if you want to increase power, advance the pitch lever first, then the throttle; to reduce power, throttle back before before the pitch lever. That's why you prepare for a go-around on final approach by advancing the pitch lever-then it's ready to absorb full throttle.
"The 'over square rule' is that manifold pressure can be equal to, but never more than rpm, and generally the two should be in step.
Twenty inches with 2,000 rpm. 22 with 2,200, but never 24 with 2,000"

End Quote.

(Try it on the Default Beech Baron)... ...!

Paul....with a variable-speed Motor Bike... 8-)...!

(Try it on the Default Beech Baron)... ...!

You can feather the props on the FS9 default Baron. I forget exactly how it's done now.

(Try it on the Default Beech Baron)... ...!

You can feather the props on the FS9 default Baron. I forget exactly how it's done now.

I don't know it's possible to fully feather the props on the Beech Baron Twin (as appears in you photo, Doug), but I do know that if I pull the prop lever back to fully coarse pitch with a only small throttle opening, it will stall my engine(s)... ... ... ...!

I think I read somewhere, that on an aircraft not fitted with means of fully feathering the prop(s) to reduce drag, upon engine failure the pilot would seize-up his engine by any means, to prevent the prop from free-wheeling and creating excessive drag... ...!

During my daily flight in my trusty Beech Baron, I take great care to observe my Throttle, Prop, and Mixture settings, and watch their effects via my engine instruments; Exhaust gas temperature, Cylinder head temperature, Manifold pressure, Oil pressure and Oil temperature, RPM, Fuel flow, etc, etc.... 8-)...!
Excellent practice....and lots of fun, and satisfaction in getting it right...

Paul...playing with the levers... 8-)...!

(Try it on the Default Beech Baron)... ...!

You can feather the props on the FS9 default Baron. I forget exactly how it's done now.

I don't know it's possible to fully feather the props on the Beech Baron Twin (as appears in you photo, Doug), but I do know that if I pull the prop lever back to fully coarse pitch with a only small throttle opening, it will stall my engine(s)... ... ... ...!

I know it's possible as I tried it soon after FS9 was released. The prop blades are fully animated. It's mentioned in the FS9 Learning Center complete with screenshot but they seem to have forgotten to tell you how to do it.*

Flying on one engine: The Beechcraft Baron 58 with a feathered propeller.

I think I read somewhere, that on an aircraft not fitted with means of fully feathering the prop(s) to reduce drag, upon engine failure the pilot would seize-up his engine by any means, to prevent the prop from free-wheeling and creating excessive drag... ...!

I'm not sure how you would go about doing that or quite what it would achieve.

*PS. Found it.

Twin-Engine Flying Tips

To feather the propeller

Select the engine to control by pressing E+1 or E+2.
Click the propeller control knob and drag all knobs back.
-or-
Use keyboard shortcuts to control the propeller:
- Feather propeller: CTRL+F1
- Increase propeller rpm to high (unfeather): CTRL+F4
- Decrease propeller rpm (in increments): CTRL+F2
- Increase propeller rpm (in increments): CTRL+F3