Constant speed prop

[breister]

Originally Posted by BobCollins(AA)

I have a question for which someone might have a answer. Why isn't it possible to feather the prop on a RV during a engine failure which would increase the glide range since the drag created by a windmilling prop would be non existent .

Safety.

If your prop governor fails in flight, you can still fly the airplane.

If a full-feathering prop fails in flight, you cannot fly with it feathered.

If your engine fails, you are going down anyway. Fine pitch reduces your glide, but not so much that under ordinary circumstances you cannot pick a place to land. It could even be a benefit, helping you slow.

I've never heard that full-feathering, or even Beta-capable, props are heavier. They might be, but I don't believe it has anything to do with why single engine planes are generally equipped with props that fail to fine pitch.

Twin engine airplanes often have props that fail to feather for the same reason - safety. If one engine or one prop fails, you can still fly the airplane.

[Sig600]

Originally Posted by breister

Safety.

If your prop governor fails in flight, you can still fly the airplane.

If a full-feathering prop fails in flight, you cannot fly with it feathered.

If your engine fails, you are going down anyway. Fine pitch reduces your glide, but not so much that under ordinary circumstances you cannot pick a place to land. It could even be a benefit, helping you slow.

I've never heard that full-feathering, or even Beta-capable, props are heavier. They might be, but I don't believe it has anything to do with why single engine planes are generally equipped with props that fail to fine pitch.

Twin engine airplanes often have props that fail to feather for the same reason - safety. If one engine or one prop fails, you can still fly the airplane.

Feathering props usually have counter weights and an unfeathering accumulator.

[Lindamon]

I have a three blade MT with counter weights and acro governor on my -7. When I idle the engine and pull the prop to low pitch, you can feel the acceleration. Practicing engine outs over my home field, I found myself pushing the prop back in on final most of the time as it was obvious I would overshoot by a lot when flying my normal close pattern. It's a significant difference. Maybe one of these days I will try to figure out what the glide ratio increase is, but for now I have pulling the prop to low pitch as part of my engine out checklist.