Dead Stick Landings and Prop Pitch

[Red Hayek]

Your engine has died but the prop is still turning. Assuming you can still change it, how should the prop pitch be set?

[razo+r]

set it to the gliding setting, so that they won't have a big ressistance surface.

[bart]

Your engine has died but the prop is still turning. Assuming you can still change it, how should the prop pitch be set?

 

I had an engine failure in flight, so started messing about with the prop pitch on the way down. I found the aircraft speed bled off much slower with the prop pitch set to its coarsest setting (lever all the way back). I guess this is the prop almost feathered and in this position produces the least amount of drag. The prop still turned but speed management in the glide was much easier.

 

 

I thought at the time ED modelled this really well, I was impressed :)

 

 

Got the old girl down in one piece too!

[Art-J]

I had an engine failure in flight...

 

So did I. It was called "runnig out of fuel" :D.

 

Used to not giving a flyin sh..t about fuel load in the Mustang, because any amount above 25% is plenty on our small maps in DCS anyway, I was quite surprised that now I have to carefully monitor tiny fuel supply in this other, British airplane :).

 

Back to the topic though, yes, lowest RPM setting by definition gives the least drag (because of more coarse prop pitch), so that's the way to go.

Edited August 29, 2017 by Art-J

[Weegie]

I had an engine failure in flight, so started messing about with the prop pitch on the way down. I found the aircraft speed bled off much slower with the prop pitch set to its coarsest setting (lever all the way back). I guess this is the prop almost feathered and in this position produces the least amount of drag. The prop still turned but speed management in the glide was much easier.

 

Now you went and said that I've been tying myself in knots thinking about it

 

So here is how I see it & I have no idea if it's valid or I'm losing the plot.

 

Prop in fine the engine is presented with the minimum load, so the prop angle to the airstream will be less making it easier for the engine to turn the prop.

 

Using the car/motorcycle gear analogy (Yes Yes I am well aware of the deficiencies in using this analogy). First gear load to engine is minimum, this is why you can easily over rev the engine in first but not in top and why you cannot pull away in top gear (you overload the engine and stall).

 

When setting valves in a motorcycle if you want to turn the engine using the back wheel you put the gear box into top gear, as it presents the engine with maximum load, but the converse also holds true, that is why it's easier to turn the engine.

 

So the way I see it here is when the prop is placed into coarse it's presenting maximum drag to the airstream, which allows the engine to be turned easily, therefore reducing the drag of turning the engine, so allowing you to glide further due to reduced overall drag.

 

I'm guessing that if you could continue the blade angle further to a feather position then the blade would be perpendicular to the airflow and then stop turning altogether

 

Have I completely lost it? :clown_2:

[philstyle]

So the way I see it here is when the prop is placed into coarse it's presenting maximum drag to the airstream, which allows the engine to be turned easily, therefore reducing the drag of turning the engine, so allowing you to glide further due to reduced overall drag.

 

Yes, coarse pitch for engine-failure flight. Fine pitch just adds drag without thrust.