During a high altitude cruise.
I have an idea that if engine has that has stopped firing because of fuel starvage, or ignition failure, a windmilling propeller on a piston Twin/Multi caused by air passing through the blades, creates more drag than an engine which has been purposely seized/brought to a stand still (by starving it of oil, etc).

A single engine failure on a Twin during take off leaves very little time (none) to gain control* before aiming for the ground...Brown flight suit time... ...!


Paul...

* the magic, instant prop feather button... ...?

Does the .air file model feathering ?  As in, can you see a yaw difference between feathered and not, engine off ?

(gonna go try it myself         )

I mean, aerodynamic modeling. Felt yaw, reduced airspeed.

Fozzer wrote on Mar 20^th, 2007 at 10:08am:

At one time I used to overhaul the unfeathering accumulators used on the majority of GA aircraft with CS props.http://www.americanpropeller.com/MTSPECS.htm
Quote:


Quote:

There's a good reason for that. Propeller is the correct spelling.

PS. http://www.mccauley.textron.com/prop/prop-tech/pg04feather.html

OK.. for the record, it's modeled quite realistically (to a guy with less than a dozen R/L multi-engine hours..  lol )

Level cruise 25/25 and leaned is about 180kias.

I used the auto-pilot for consistency. After pulling the mixture on the non-critical (right) engine (and going to full power on the good engine), the airspeed falls off as expected... the auto-pilot starts compensating for the yaw/pitch and if you do not pull the dead engine prop to full coarse... it just keeps getting worse. I let the airspeed get down to 105 and the bank to almost 10* ..  Once you pull the prop full coarse; everything improves and stabilizes. The bank minimizes and airspeed settles to about 125knots.

I never did use key-strokes to feather completely, so the prop was still wind-milling.

I think the real-world solution is to hold 5-7* of bank and just enough rudder to keep the ball about 1/2-ball off center. I'm sure it's more stable that way, because the auto-pilot uses only bank to hold a heading. In the Seneca I've flown, there's a spring linkage (like that between the nose-wheel and rudder) between the ailerons and rudder, so you have to kinda fight it a little. That makes for a VERY tired foot by the time you're STANDING on the rudder to land in a cross-wind..

Hagar wrote on Mar 20^th, 2007 at 1:33pm:



Done it a few times, with various models... my payware DC-3 has working autofeather buttons, and behaves about as you'd expect with one engine secured... although the dead prop  takes some time to stop turning altogether. Not all models out there have the ability to go all the way into feather, though.

BTW, this reminds me: when I took that B-17 ride, I noticed  during the takeoff roll that the copilot had his hand on the glareshield right next to the autofeather buttons until after rotation (about when we cleared the fence), at which time he took over the quadrant while the pilot steered with both hands. I guess in a brute like that, if there's any hope of a go-around with a sick engine, that prop must be feathered immediately.

Fozzer wrote on Mar 20^th, 2007 at 10:08am:


In which case you hope that the prop is designed to coarsen under oil pressure and feather using spring pressure - hence it will always failed to the (almost perpendicular) feathered position, which still encourages a small rotation of the prop (if the engine is not seized) which comes in useful of you were wanting to start the thing again.