Propeller feathering
 

Hello,

I am curious about propellers feathering systems. From what i found out searching the internet, single engine aircrafts don't have this system. Why is that? And if u experience an engine failure in a single engine aircraft...........if not feather the propeller, what do you need to do and why?

This previous thread might help: http://www.pprune.org/flying-instruc...e-failure.html

The engine failure has already determined what you need to do: land the airplane. Your only choice is if it will be gentle or violent.

Low altitude (below 500 feet above ground - during take off, initial climb or landing):

Lower nose pitch to avoid losing airspeed, land straight ahead if possible, or make slight turn left or right if needed to avoid obstructions. Large turns reduce lift and will cost you altitude or speed.

Fuel control to "cut-off." Turn off ignition. (post-landing/impact fire prevention)

Lower flaps once committed to a landing point - it allows a slower touchdown speed.

Unlatch doors before touchdown - in case the landing forces jam the doors and prevent escape

In cruise:

A. Maintain altitude while slowing to the published "best glide speed" for the particular aircraft. (Usually about equal to best climb-rate speed (Vy) but not always. Something you should have memorized before flying any aircraft as pilot in command). "Best glide speed" will give the longest glide distance.

B. Look at the ground and choose a suitable landing area within glide range. Plan how to reach that landing area. Do this BEFORE attempting an engine restart (below) to maximize terrain visibility and landing choices.

C. Run through the engine re-start checklist. Which also should be memorized - varies with aircraft - but generically:

Fuel selector to "both" tanks, or opposite tank - in case it is just one empty tank or a fuel-pipe blockage

primer lever in and locked (if installed) - in case the primer has come unlocked and interrupted fuel flow.

Fuel boost pump on (if installed) - increases fuel pressure to engine, in case the engine's own internal fuel pump has failed

magnetos/ignition - cycle through settings (right - left - right - both) - in case one magneto has failed

fuel mixture to full rich - to ensure maximum fuel flow

carburetor heat "ON" - in case the engine failure is due to carburetor icing blocking the engine air/fuel intake.

(If memorized, all of the above should take about 5-10 seconds)

This is a key place where the unfeathered, windmilling prop is actually a plus - if your checklist has solved a problem such as an empty/blocked fuel tank or failed magneto, the spinning prop may crank the engine back to life.

Otherwise - engage starter.

If engine failure is clearly catastrophic (oil covering the windscreen, or engine sounds signaled a major breakage) - the restart checklist can be skipped. Focus attention on a safe forced landing.

D. If restart fails, follow plan to glide to chosen landing area. Once below 500 feet, proceed as above with the low-altitude engine-out procedure.

Again - all of the above is a generic summation for handling a engine failure in a single-engine fixed-wing aircraft. Before flying any aircraft - READ THE MANUFACTURER'S MANUAL and know the specific procedures for THAT airplane...!

There are some motor gliders with front mounted propellers that feather for soaring flight. But in most single engine airplanes if the engine fails you are going to land very soon, in the next 10-15 minutes or less. On the other hand, depending on weight and conditions many twin engine airplanes will fly on one engine or at least greatly extend the range you have to find a runway.

There are some engine/propeller configurations that, when the engine fails and the oil pressure drops, the propeller will feather.

hi

I use to instruct, including in such planes as the piper arrow (with constant speed prop).

part of the instruction of course was to demonstrate engine out landings, and the POH indicated selecting the minimum drag position (ie, pulling the prop control aft) for the prop. It makes a big difference and can be felt right away.

Many pilots called it feathering , but it really wasn't, as the prop kept rotating.



The POH glide distance was predicated on pulling the prop control aft (coarse pitch , I screwed up before and marker inbound was right) or slowest rpm.



So, you can SORT OF FEATHER but not fully feather the prop in a constant speed prop plane...it is a bit of semantics. But again, selecting low RPM does give you better glide.


BUT BE CAREFUL as you are only simulating loss of the engine and when you add power it should be in the order of: mixture rich, prop high rpm (forward prop control) and then forward throttle.


Does this make sense to you guys?

Oh, and variable pitch props and constant speed props can be different things so be very careful. I flew one very old bonanza one time that had a prop that could be selected to one of two pitches, but it was not done as constant speed props work...but that's another post

It's been years since I've flown a British prop but isn't "fine" full forward (high rpm) and full aft "coarse" (low rpm.)

markerinbound


I screwed up...early when I wrote the first post...low rpm is selected to maximize the glide

I am wrong

will try to correct.

Tork
 

Can you explain why we don't feel torque effect while in the air.