prop pitch and air drag

[Nocke]

Dear experts out there,

 

I am in doubt about the effect off prop pitch on slowing down an aircraft with a dead engine, which is not blocked but still windmilling.

The first idea was that the finer the pitch the greater the surface area of blades into the air stream, and the higher the resistance.

But then came the hint that a not so fine pitch would make the engine windmill faster, sucking more energy out of the plane in order to do that.

 

I would be grateful for any reasoned opinion!

 

 

 

Edited April 25, 2020 by 216th_Nocke
mixed up coarse and fine once again ...

[[DBS]Browning]

Regardless of how it works in real life, for IL2, the only way to find out of it has any effect and what that effect might be, is to test it in game. 

[Megalax]

Thing is, you need engine oil pressure to move the blades at all in most CS Props. Unless there are safety features built in like a DHC Beaver prop that has springs that move the blades to near feather when the oil pressure cuts out, then where ever your blades are when the engine cuts out is where they will be staying.

[ZachariasX]

1 hour ago, 216th_Nocke said:

I would be grateful for any reasoned opinion!

The more coarse pitched you have set your propeller, the slower it will windmill. It takes a lot of energy to windmill your prop at 2000 rpm or so (which it will maybe do at flight speed in a GA, or 1000 or so rpm in a warbird). This energy is what is breaking your plane while you try to glide it. A prop windmilling in fine pitch will make you (for practical purposes) go down the way a piano goes.

 

The drag if a standing propeller, even though pitched fine, is far less. This is why your primary goal is to make the propeller stop turning. Having it feathered gives you both least frontal drag as well as no induced drag through cranking the engine.

 

If your oil system is breaking down such that you cannot control the pitch anymore, you're in deep. On multi engine aircraft, it might well happen that the prop overspeeds such that it blows its bearings and comes off, usually making a little fire as the melting steel will ignite any residual lubrication of the prop gearing etc.

Edited April 25, 2020 by ZachariasX

[Bremspropeller]

2 hours ago, 216th_Nocke said:

But then came the hint that a not so fine pitch would make the engine windmill faster, sucking more energy out of the plane in order to do that.

 

That thought is not correct, though. It's just a matter of torque-budget between prop and engine.

Making the engine turn requires torque extracted from the airstream. The flatter (finer) the pitch, the more torque you can extract. An almost feathered prop can't extract much torque from the airflow.

 

How the engine (prop) fails depends on your prop-governing system. Some systems might fail and have the prop self-coarse, while some might fail and self-fine.

On propeller-turbines you might have direct drive engines and power-turbine engines. On the latter, the prop and gas-generator are mechanically de-coupled, so the prop won't turn the engine, but just the turbine.

[Nocke]

I'll try to reformulate my question.

I do not know what angles the prop blades can go to - but let's assume full fine pitch would be 0 degrees, i.e. blades are frontal into the airstream, and full coarse would be 90 degrees, i.e feathered, blades parallel to airstream. 0 degrees would result in maximal drag at least for a non-moving prop, 90 in no drag. Both positions would give no torque and no windmilling, that would happen at, say, 45 degrees. What I don't understand is this: While said 45 degrees position would offer less resistance to the airflow than the 0 degree position, would it still accelerate down the plane faster because somehow additional energy would go into turning the engine? If so, how does it generate that with the smaller area into the airflow? 

Or maybe shorter, to what ZachariasX said: Why is the drag of a standing propeller less? Please don't answer "because it takes power to move the prop". I know that. My probably wrong assumption is that the energy you can get from the airstream would be proportional to A x delta(v), A being the blade area normal to airspeed, delta(v) the decrease in air velocity you can achieve.

And while typing this I guess I answered it myself: A spinning prop generates a higher delta(v) (in flight direction) because it additionally diverts air into the azimuthal direction.

[Nocke]

Found this, experimental work.

I started thinking about this wondering if to slow down the plane coming on for landing I should go high or low pitch. Low pitch seems to be the answer. Interesting to see how the answer depends on pitch.

[Bremspropeller]

2 hours ago, 216th_Nocke said:

I'll try to reformulate my question.

I do not know what angles the prop blades can go to - but let's assume full fine pitch would be 0 degrees, i.e. blades are frontal into the airstream, and full coarse would be 90 degrees, i.e feathered, blades parallel to airstream. 0 degrees would result in maximal drag at least for a non-moving prop, 90 in no drag. Both positions would give no torque and no windmilling, that would happen at, say, 45 degrees. What I don't understand is this: While said 45 degrees position would offer less resistance to the airflow than the 0 degree position, would it still accelerate down the plane faster because somehow additional energy would go into turning the engine? If so, how does it generate that with the smaller area into the airflow? 

Or maybe shorter, to what ZachariasX said: Why is the drag of a standing propeller less? Please don't answer "because it takes power to move the prop". I know that. My probably wrong assumption is that the energy you can get from the airstream would be proportional to A x delta(v), A being the blade area normal to airspeed, delta(v) the decrease in air velocity you can achieve.

And while typing this I guess I answered it myself: A spinning prop generates a higher delta(v) (in flight direction) because it additionally diverts air into the azimuthal direction.

 

Don't make things more complicated than they need to be:

 

- a flat pitch prop (low pitch) will give you maximal frontal area, hence maximal aircraft-velocity component drag

- a coarse pitch prop will give you minimal frontal areae in aircraft velocity direction

- if the prop turns, there's also angular velocity involved, which changes the net-angle to the relative airflow and the net airflow-velocity

- propeller drag is dependant on blade-angle to relative wind

- hence, if prop doesn't turn* and if it's feathered, it has the least amount of drag achievable

 

*The prop might also not turn because of a seized engine or a turbine engine with core-lock (ouch) => that certainly will NOT produce the least amount of drag with the paddles in other than a feathered position.

[ZachariasX]

3 hours ago, 216th_Nocke said:

And while typing this I guess I answered it myself: A spinning prop generates a higher delta(v) (in flight direction) because it additionally diverts air into the azimuthal direction.

That has not much to do with any of this, especially regarding the graph you posted.

 

It seems to me that you cannot relate "it takes power to" with "more drag".

 

The power that is required to crank the propeller (just try to do it for once, then imagine how mch it takes to crank a propeller 2000 rpm) is directly taken away from the power budget you have that makes your aircraft go forward.

 

If (simplified example) you have an aircraft with four engines, 1000 hp each (4000 hp total) and it would go 400 km/h and you lose one engine, then you have 3000 hp left to pull you forward. if you could feather the rotten engine's prop we assuming zero drag of feathered blades for the sake of this example. Power budget for double speed requides is to cube, hence on only three engines you will go about 360 km/h.

 

If you however have a windmilling prop consuming 300 hp for cranking the shaft, then you end up with a net forward power of only 2700 hp. This makes you go 350 km/h.

 

in this simplified example you lose 10 km/h just due to the fact that you draw power to crank that dead prop. The drag provided by a fully flat (fine) stopped prop is much less, as you can see that the frontal section of the prop on a B-17 (to stress my simplified example) is very small compared to the frontal section of the whole aircraft.

 

Now as the worst case, if you are gliding and you have a windmilling prop, you can see the difference to the prop stationary very well in motor gliders. For instance this one:

Spoiler

It has a fixed pitch prop. If you are cutting the engine in flight to fly it as a glider, it will have a very bad sinkrate as long as the prop turns, cranked by the slipstream. You have to slow down until the prop stops, and as soon as it stops you can accellerate to the previous speed again and Lo and Behold, it's still a bad glider but not that bad. The difference in flight performance is marked. If you are gliding, your power budget to go forward is VERY small to give you acceptable flight performance. The drag of a flat surface in the wind is only large at higher speeds. At slower gliding speeds, it is not that large. However, a windmilling prop will eat all the power even at slow speeds. It is not an airbrake. It eats your power budget to go forward.

 

A windmilling prop is a @Bremspropeller. Literally.

 

Edit: Some use the prop pitch governor as an "airbrake of the last resort" in aircraft that cannot feather the prop, such as the AT-6 for example. This way, if the engine goes the way of the Dodo, you go fully coarse on the prop to glide as far as you can, maybe (if you're lucky) you can enter the pattern and (if you're more lucky) you even come in slightly high. You can the set the prop to fine and this "set the brakes" to make the prop windmill faster and increase the sinkrate of the aircraft and not overshoot the field.

Edited April 25, 2020 by ZachariasX

[Retnek]

First question was - as I understood it: how to slow down an aircraft in flight most efficiently just using the prop(-pitch) while the engine is on idle? Not being that much familiar with aerodynamics, engineering and especially the maths behind it -  my guess for the first moment would be: pitch settings for most effective flight with engine producing full power should be the best settings to reduce speed when engine is set to idle. When props rpm and/or the speed of the aircraft change then the props pitch has to be adapted correspondingly to preserve a maximum possible drag.

I hope that's somewhat similar to @Bremspropeller explanations has written above. I can't see a contradiction to @ZachariasX, too.

Is it acceptable to assume: at the moment an engine is set to idle a propeller setting just producing best propulsion will now produce the best drag?

During high speed flight: is an engine quickly set to idle able to "convert" the now massively "incoming" energy mainly by compressing the full lean air in the cylinders? Or will the rpm rise quickly and the pitch has to be changed to avoid over-rev?

(I somewhat suspect my imagination of "inverted forces" - when an engine is set to idle - is too much simplified.)

[ZachariasX]

7 hours ago, Retnek said:

First question was - as I understood it: how to slow down an aircraft in flight most efficiently just using the prop(-pitch) while the engine is on idle?

A turning propeller never receives wind from the same side as the aircraft does. Even on fine pitch, the wind will not be directly on the boad side.

 

The wind wind will always along the chord of the rotating blade, giving the smallest snd most aerodynamic front. 

 

If you fly a variable pitch prop aircraft and you set the throttle to idle in normal flight, what happens is that the aircraft will slow as soon as the torque cranking the prop is reduced and the prop governor will select follow pitch that makes the propeller turn set rpm, meaning that it will go to progressively to fine. During all of this, the AoA of the prop blade does not change as far as its angle to the slipstream is concerned. This means, during all of this the prop has always the same drag.

 

7 hours ago, Retnek said:

Is it acceptable to assume: at the moment an engine is set to idle a propeller setting just producing best propulsion will now produce the best drag?

Always least drag. Theat is what you meant? Sure. See above.

 

A rotating propeller sees the wind go along its chord. Always. The prop pitch you give it will determine the rpm depending on your flight speed. The faster you let it getting cranked by the slipstream, the higher the parastic load and the higher effective (not aerodynamic) drag.

 

7 hours ago, Retnek said:

During high speed flight: is an engine quickly set to idle able to "convert" the now massively "incoming" energy mainly by compressing the full lean air in the cylinders?

Yes. You just switch over from the prop being cranked by the engine to the prop being cranked by the slipsteam. The power required to crank the prop will act as a brake as much as the airframe drag. In all of this, prop drag nover changes much as it maintains somewhat its angle respective to the wind the propeller blade sees. The engine is nothing but an air pump, regardless whether is is on or off. It requires power to crank it. That is where some of the power budget to go forward goes.

 

7 hours ago, Retnek said:

Or will the rpm rise quickly and the pitch has to be changed to avoid over-rev?

As long as the governor is intact, you will always have the rpm you set.

 

7 hours ago, Retnek said:

pitch settings for most effective flight with engine producing full power should be the best settings to reduce speed when engine is set to idle.

Prop pitch is just a function of the airspeed. The power output of the engine produces a given torque. The governor adjusts rpm such that given torque cranks the prop at desired rpm, giving your net power output.

 

7 hours ago, Retnek said:

Or will the rpm rise quickly and the pitch has to be changed to avoid over-rev?

Rpm will not change, as the (functional) governor will adjust the pitch that the engine will turn at set rpm, regardless of whether it is cranked by the engine or by the slipstream. Rpm is a direct function of airspeed and pitch.

 

Think of the prop pitch as the gearing of your car. Changing prop pitch is changing gears. Going to a fine pitch in flight is the same as shifting up. 

 

When you drive your car and just shift up, maintaining rpm, the car will brake down somewhat as soon as you release the clutch, as it is going faster than the new gearing ratio set it, hence the cars momentum will now rev up the engine and you will notice the braking effect of that until the engine is down to the rpm you set it with your gas pedal.

 

The example I gave with the AT-6 is like you driving down a mountain pass in a car that has engine out and no brakes. You can do that. You have to drive vintage cars like that, even „engine on“. If you drive on a straight stretch downhill, you can do so maybe in third gear, but as soon as there is a bend, you might shift up in second gear, making the engine rev faster to brake down a bit.

 

 

21 hours ago, 216th_Nocke said:

The first idea was that the finer the pitch the greater the surface area of blades into the air stream, and the higher the resistance.

But then came the hint that a not so fine pitch would make the engine windmill faster, sucking more energy out of the plane in order to do that.

If you are gliding with a stopped propeller, a very flat propeller blade is hard to crank, as it is a „high gear“, meaning this windmill will do lots of revs and little torque. It will be hard to push the prop over the compression point of the cylinder, hence you can glide slow like that, without the prop starting to turn. If you dive and go fast, you might just create enough torque to make the engine turn and THEN, you have the good airbrake.

 

Conversely, a coarse pitched windmill will do less rpm but at a much higher torque, hence the propeller has it much easier to crank the engine over the compression point and start windmilling. As it will turn slower, it will brake less then the fine pitched prop though.

 

The frontal surface is only relevant in case of a stopped propeller. As soon as it turns, all props look the same for the slipstream. Also drag increases linear to increased section, whereas it increases to cube in relation to flight speed. Just go slow and it‘s not so bad. If the prop windmills, then you don‘t have that option, as it will crank always to the rpm you set the governor for and always eats that power budget.

 

Is that what you were looking for as answer?

Edited April 26, 2020 by ZachariasX

[Bremspropeller]

Careful, Retnetk and Nocke are talking about a "Variable Pitch Prop" (as in "no governor") - not about a CSP.

 

* Well, one should better call that a variable fixed-pitch prop, as the pitch-angle isn't controlled by the governor, but by the pilot.

 

 

 

 

 

 

[Lusekofte]

Well I have found that a windmilling prop do not act like it is described in literature. 
I will not pretend I am a soecialist in aerodynamic, but not being able to feather the props on one engine on a two engine plane was a bail out now signal. 
I am however a specialist in trying to bring home a stricken bomber in this game. We do not have windmill effect in this game, at least not fatal variations  of it. 
However I noticed if you keep your rpm on 27 

on a p 38 while descending with no throttle applied. I feel it keep the speed down. I might be

wrong. 

[ZachariasX]

1 hour ago, Bremspropeller said:

Careful, Retnetk and Nocke are talking about a "Variable Pitch Prop" (as in "no governor") - not about a CSP.

 

* Well, one should better call that a variable fixed-pitch prop, as the pitch-angle isn't controlled by the governor, but by the pilot.

 

 

Then the example of the stick shift car applies directly. Anyway, I can't make it clearer than that.

 

17 minutes ago, 216th_LuseKofte said:

but not being able to feather the props on one engine on a two engine plane was a bail out now signal. 

You bring along chutes in such an aircraft? I do hear you though...

[Retnek]

3 hours ago, ZachariasX said:

 

Then the example of the stick shift car applies directly. Anyway, I can't make it clearer than that.

 

For me this was all I needed: "During all of this, the AoA of the prop blade does not change as far as its angle to the slipstream is concerned. This means, during all of this the prop has always the same drag." Thx, that's the confirmation I was looking for. As long as we position the props blade (via CSP or manually) in the "most aerodynamic front" it will produce the best propulsion with engine power. Or the best retardation when engine is set to idle.

If you want to slow down an aircraft most efficiently while engine on idle, choose (or manually tolerate) the highest acceptable rpm and adapt the pitch. For a given speed this pitch setting will be the same you would use when accelerating.

Edited April 26, 2020 by Retnek
added "while engine on idle" - just to be explicit

[Lusekofte]

1 hour ago, Retnek said:

For a given speed this pitch setting will be the same you would use when accelerating

This is what I expirience in the P 38 that got constant speed propeller.

Iam not sure if you are able to maintain high rpm with no manifoil pressure on a older manual pitch system. I do not think so

[[DBS]Browning]

So I did some testing.

I started the P38 at 2000m with the engines off and timed how long it took to hit the ground at 135mph glide.

 

Prop Pitch: 0, Throttle: 0, Time to crash: 6.44

Prop Pitch: 0, Throttle: 100, Time to crash: 6.26

Prop Pitch: 100, Throttle: 0, Time to crash: 4.36

Prop Pitch: 100, Throttle: 100, Time to crash: 4.12

 

 

There is likely at least a 1:00 error or more in these results until someone can set up a tool assisted test or repeat the test many times.

[Lusekofte]

Hmm with first option did you at any point stall or close to stall. But it make sense since the propellers would produce mire srag

[Retnek]

1 hour ago, 216th_LuseKofte said:

Iam not sure if you are able to maintain high rpm with no manifoil pressure on a older manual pitch system. I do not think so

Afaik this has been one of the most often used critics against hydraulic driven prop-automation. Usually the prop-hydraulics pressure was coupled to the engines power, so loosing engine cut prop-hydraulics pressure immediately, too. While the engine dying one had to be quick to set the props pitch a last time for the final setting.

 

A lot of German planes and at least some build in the US used electric prop-pitch setting. Lovely Peshka, too. Here the engine power-off was no problem, as long as there's some electric energy left. Different P-47 models used props with one or the other type of pitch regulation. P-38 L according to wikipedia used "Curtiss Electric" constant-speed propellers.

 

PS: quickly going through the planes I'm somewhat familiar with in IL2 ... all those with some kind of electric switches use (surprise-surprise) electric pitch setting, all those with a mechanical lever near the throttle act with hydraulics. Not that difficult ... except there's an exception. Are there strange setups using electric buttons for finally regulating a hydraulic driven prop pitch? Or (even more irritating) a lever arm delivering discrete prop-pitch settings via electrics?

 

Edited April 26, 2020 by Retnek

[Retnek]

2 hours ago, Retnek said:

 ... except there's an exception. Are there strange setups using electric buttons for finally regulating a hydraulic driven prop pitch? Or (even more irritating) a lever arm delivering discrete prop-pitch settings via electrics?

Standing in the shower, ... sure there are, that P-38 has electric switches, but has a lever, too. P-47 the same, f.e. - flown her often enough, never realized that detail. Looks like that lever not directly steers a the prop-pitch, it's feeding a Constant-Speed-Unit. How I love this website:
http://www.enginehistory.org/Propellers/Curtiss/curtissprop.shtm

 

Nice story: http://www.enginehistory.org/Propellers/propstories/propstories.shtml
 

Edited April 26, 2020 by Retnek

[Art-J]

 

3 hours ago, [DBS]Browning said:

So I did some testing.

I started the P38 at 2000m with the engines off and timed how long it took to hit the ground at 135mph glide.

 

Prop Pitch: 0, Throttle: 0, Time to crash: 6.44

Prop Pitch: 0, Throttle: 100, Time to crash: 6.26

Prop Pitch: 100, Throttle: 0, Time to crash: 4.36

Prop Pitch: 100, Throttle: 100, Time to crash: 4.12

 

By "0" do you mean minimum RPM? Sorry, I'm not familiar with technochat percentages, as I don't use it.

 

If so, I'm curious how both props feathered would compare with your results.

Edited April 26, 2020 by Art-J

[[DBS]Browning]

0 is course pitch.

I will experiment with feathered props

6:40 with feathered props

[Retnek]

For keeping the flight conditions under control, there's Joe, the autopilot to keep her straight and level. I think this might be a good way to test the retardation. If we arrange some standard settings there's a nice library soon.
Mine conditions here were Kuban-Map, summer, over sea, 1000 m above sea-level, no wind etc. I got myself the P-38 (slick plane, props resistance should show), air-start, 100 % throttle, 100% mixture and pitch set via pitch-setting-unit. After some time she's up to maximum speed of 340 mph (seen by instrument panel, next time I'll activate that data-display panel, too). Now the time from changing the conditions from all-out-high-speed until the autopilot is forced to drop the nose somewhere below 120 mph:

1) throttle to idle, full pitch ("coarse", high rpm) - prop settings become more and more improper to low speed

63 s +/- 1

2) throttle to idle and pitch to minimum ("fine", low rpm) - prop settings more and more fit to low speed

131 s +/- 1

3) engine off and props feathered

103 s +/- 2

 

That's just some test data, for exact measurements I should have set both coolers and pitch to manual. Anyhow, the results are explicit. Most interesting to me was the energy input the engines on idle still deliver in series 2) - the speed was reduced in a somewhat "high" retardation-rate from 340 to maybe 150 mph, then the idle engines input plus proper pitch settings remarkably prolonged the time until the nose finally dropped.

 

 

[41Sqn_Skipper]

 

 

Quote

(...)full pitch ("coarse", high rpm)"

(...)

pitch to minimum ("fine", low rpm)

(...)

I should have set both coolers and pitch to manual

 

I'm confused about the nomenclatur. Did you switch to manual prop pitch to explicitly set fine/coarse pitch or did you only moved RPM lever forward/backward?

Edited April 27, 2020 by 41Sqn_Banks

[Retnek]

45 minutes ago, 41Sqn_Banks said:

I'm confused about the nomenclatur. Did you switch to manual prop pitch to explicitly set fine/coarse pitch or did you only moved RPM lever forward/backward?

For the test data presented above I did "pitch set via pitch-setting-unit" - so the results depend on what that automatic unit is doing with the pitch if I draw the lever back (low rpm, fine) or push forward (high rpm, coarse). You're right, "for exact measurements I should have set both coolers and pitch to manual".

Edited April 27, 2020 by Retnek

[Mikoyan74]

I think some people are confused about Prop Pitch and Prop RPM.

 

Coarse Pitch - bigger blade angle - bigger bite of the air - lower engine RPM - used to Cruise

Fine pitch - small blade angle (relevant to airflow) - small bite of the air - high engine RPM - used to Takeoff, Climb and generally at Landing

 

A very fine pitch can also be used like a brake on landing - like on the 1950s airliner Fokker F27 - where you reduce the prop pitch below the flight fine limit to a ground fine limit.

 

There also seems to be confusion regarding constant speed and variable pitch propellers - they are the same thing.  Currently the manual description is incorrect but is being corrected.

 

If you set a speed - the pitch will be varied to maintain that speed - if you dived - the prop would start to speed up - the pitch would increase to slow the prop, if you climbed the prop rpm would decrease - the prop pitch would be reduced (finer angle) to increase the speed of the prop - ergo the speed (RPM) remains constant.

 

The engine prop governor varies the pitch to maintain the (constant) speed you selected - the automatic system fitted to some German aircraft in the war was an automatic propeller control system designed to maintain optimal RPM based on engine speed selected with the throttle.  It also maintained a constant speed by varying the pitch but the pilot did not select the speed (unless in manual mode - where they actually controlled the pitch directly - as a backup system in case the auto system failed) but an automatic governor controlled the optimal prop speed.

 

In a power off situation the prop constant speed governor would try to maintain the RPM selected as best as it could as long as oil pressure allowed it to, once it reached it's limit the prop would be stuck at that angle as each prop has a minimum (fine) stop and a maximum (coarse) stop.  You can't control a prop pitch over 0-90°.  You might only get a range of 25-75° - only reaching 90º (or thereabouts) if you can feather that prop.

Edited April 27, 2020 by Mikoyan74

[[DBS]Browning]

3 minutes ago, MattS said:

So can someone put this in a nutshell for me? What I think I'm reading here is:

 

Upon losing an engine...

 

...in a twin with prop feathering, feather the dead engine.

 

...in a twin without feathering (Pe-2), set the Prop RPM of the dead engine to the lowest setting (and close radiator).

 

...in a single with a controllable propeller, set the Prop RPM to the lowest setting.

 

True?

 

For the game, this is true. Can't comment about IRL.

[ZachariasX]

4 minutes ago, MattS said:

True?

Yes.

[41Sqn_Skipper]

23 minutes ago, MattS said:

So can someone put this in a nutshell for me? What I think I'm reading here is:

 

Upon losing an engine...

 

...in a twin with prop feathering, feather the dead engine.

 

...in a twin without feathering (Pe-2), set the Prop RPM of the dead engine to the lowest setting (and close radiator).

 

...in a single with a controllable propeller, set the Prop RPM to the lowest setting.

 

True?

 

If there is a CSP or other automatic system and have the possiblity to disable it and manually set propeller pitch (e.g. Bf 109, Fw 190, P-40) do so and set "coarse pitch", which should be lowest % prop pitch setting.

[Bremspropeller]

54 minutes ago, MattS said:

Upon losing an engine...

 

...in a twin with prop feathering, feather the dead engine.

 

...in a twin without feathering (Pe-2), set the Prop RPM of the dead engine to the lowest setting (and close radiator).

 

...in a single with a controllable propeller, set the Prop RPM to the lowest setting.

 

True?

 

First is always "fly the airplane". Sounds funny, but a lot of people (IRL and in game) died, because they flew their engines first.

The rest is correct.

 

However, keep in mind:

Putting the airplane down into an optimal field right below you and not trying to stretch the glide by trying to go coarse pitch is better than trying to go as far as possible and crash into a less than optimal spot. That's kind of also a part of "flying the airplane first".

Edited April 28, 2020 by Bremspropeller

[216th_Jordan]

1 hour ago, MattS said:

So can someone put this in a nutshell for me? What I think I'm reading here is:

 

Upon losing an engine...

 

...in a twin with prop feathering, feather the dead engine.

 

...in a twin without feathering (Pe-2), set the Prop RPM of the dead engine to the lowest setting (and close radiator).

 

...in a single with a controllable propeller, set the Prop RPM to the lowest setting.

 

True?

 

True but AFAIK in hydraulically operated blade pitch systems you have to do it before the engine fails for it to work.

[JG13_opcode]

13 minutes ago, 216th_Jordan said:

 

True but AFAIK in hydraulically operated blade pitch systems you have to do it before the engine fails for it to work.

 

Depends on the prop.  Some systems have mechanical pitch stops/locks that engage in the event of a loss of hydraulic pressure and essentially turn the prop into a fixed-pitch prop.  Others will auto-feather.

 

No idea if any of the aircraft we're simulating included this feature in real life but I don't know a lot about the Bf 110 or the Peshka.

Edited April 28, 2020 by JG13_opcode

[216th_Jordan]

16 minutes ago, JG13_opcode said:

 

No idea if any of the aircraft we're simulating included this feature in real life but I don't know a lot about the Bf 110 or the Peshka.

 

Yep, the devil is in the detail, I don't even know if this is modelled at all ingame (hydraulic dependency). But better safe than sorry. 

Edited April 28, 2020 by 216th_Jordan