Engine OFF during flight, prop causing drag ?

[Phil]

Gents...
I know that when the engine is turned "off" in flight, the blades become a wind drag....

Will this do same in the game ?

Fought a 109 the other day and heard his engine going "off" and back "on"...
Turning the engine "off", will it help you slow down ?
Does it really work in this game ?

Phil / OPP7755

[TequilaChaser]

NO it only hinders your ability when needing to throttle back up, because takes longer for engine to start.

no difference in Throttle off and engine off

[FLOTSOM]

i dont know it for a certainty, but when i shut off the engine it seems to act differently than just throttling back.

but it could just be a mental thing, you expect it to so you percieve that it does type of thing

[Delirium]

i dont know it for a certainty, but when i shut off the engine it seems to act differently than just throttling back.

In your Hurricane, suddenly you will not have any torque. Other than that, it is more of a hindrance than a help...

[BaldEagl]

i dont know it for a certainty, but when i shut off the engine it seems to act differently than just throttling back.

but it could just be a mental thing, you expect it to so you percieve that it does type of thing

Widewing has tested this and posted in another thread.  The differences were so minimal as to be non-existant.

[Phil]

Thank you Gentlemen !
 
Phil / OPP7755

[Murdr]

Gents...
I know that when the engine is turned "off" in flight, the blades become a wind drag....

Will this do same in the game ?

Phil / OPP7755

As indicated in previous replies, there is little difference in drag penalty between idle throttle and engine off.  But to answer this part of the question, yes prop drag is modeled.  The example you gave was with a goal of slowing down quickly.  Either way, power on or off, at max RPM settings, your blades are as flat angled to your direction of travel as they can get, producing a maxium amout of prop drag. 

On the flip side if your goal was to create as little drag as possible in a situation like trying to glide back to base, you can effect your prop drag by reducing your rpm's to minimum.  This will have the effect of angling your blades edge on to your direction of travel and create less drag.  This can greatly increase the distance you can glide from a given altitude.

[A8TOOL]

On the flip side if your goal was to create as little drag as possible in a situation like trying to glide back to base, you can effect your prop drag by reducing your rpm's to minimum.  This will have the effect of angling your blades edge on to your direction of travel and create less drag.  This can greatly increase the distance you can glide from a given altitude.

Interesting.
I wonder if using the reduce RPM's button would help the Ki-84 get home when the engine is out...or for that matter any plane that's had it's engine shot out.

The Ki-84 glides like it's pulling a sign that says "you'll never make it home"

One of the best gliders is the N1K1 and the 51 is pretty good too.

[Murdr]

Interesting.
I wonder if using the reduce RPM's button would help the Ki-84 get home when the engine is out...or for that matter any plane that's had it's engine shot out.

The Ki-84 glides like it's pulling a sign that says "you'll never make it home"

One of the best gliders is the N1K1 and the 51 is pretty good too.

It will if you reduce RMP's before your engine seizes.  Once your engine locks up on a single engine fighter, it appears that you are no longer able to adjust the RPM settings, which in turn feathers the prop. 


As an example though, here are screenshots showing the difference in glide capibility max vs min rpm settings.  With ki-84 from AHTA08 A12 NE runway, using auto take off, engaging auto level when gear retracts, cutting power at 200 mph indicated, and letting auto level fly it as far as it will go.

This is where the plane glides to with minimum RPM...



This is where it glides to with normal (max) RPM setting.  Had to take the screenshot in the air since the impact was fatal.

[A8TOOL]

Well thats appears to be almost 2 and a 1/4 times the distance!

I realize you had your engine running then but if I was to reduce my RMP's just before i ran out of oil lets say, I should then be able to travel much farther and quicker. Once the eng is out I'm screwed unless I reduced it before hand, which probably will never happen since i never know when it will be shot out.

Thanks for the Info Murdr

 

[BaldEagl]

If I'm not mistaken reducing RPM to improve glide time/distance only works as long as the prop is windmilling.  That means that you have to shut down the engine just before you run out of oil or overheat due to lack of water.  If the engine siezes for any reason and the prop stops it won't help anymore, even if you reduced rpm prior to the siezure.

[Murdr]

but if I was to reduce my RMP's just before i ran out of oil lets say, I should then be able to travel much farther and quicker.

Correct!

When you are not under enemy threat, you can nurse a damaged powerplant several sectors by managing your RPM settings and watching your guages to reserve powered flight for when it's absolutely needed.  With an oil leak, if you shut your engine off, when you turn it back on, the oil pressure will return to the level it was when you shut down (ie. you leak little or no oil when it's not running).  With a radiator leak, you can go through cycles of running it until the tempature nearly redlines, then shut it down and let it cool off.  

If you spend your power on time gaining as much energy as possible at max RPM and MIL power (level speed or climb), and glide time minimizing drag (minimum RPM and default alt-x auto speed, you can get many times the range of just flying at power until the engine quits.

[Murdr]

If I'm not mistaken reducing RPM to improve glide time/distance only works as long as the prop is windmilling.  That means that you have to shut down the engine just before you run out of oil or overheat due to lack of water.  If the engine siezes for any reason and the prop stops it won't help anymore, even if you reduced rpm prior to the siezure.

That does not apply to multi-engine planes as they auto-feather when they shut down or fail.  As far as max vs min RPM prior to an engine failure on a single engine plane, from experience I think it does make a difference in drag, though it is difficult to simulate a test.  I do know the AH model goes so far that damaged (bent over) props yeild about 8% less total parasitic drag than a prop windmilling at minimum RPM.

[morfiend]

 Here's a simple test: climb to 10k and dive to 5k full throttle max rpm,then do same full throttle with rpm at min. you will see the plane actually go faster with rpm reduced.

 Do same test,no throttle max rpm and no throttle and min rpm,again you'll see min rpm have a higher speed.

 This shows prop drag is modeled,Phil the 109 driver didnt know what he was doing,using the engine stop/start is a sign he doesnt know how to use throttle,or he was listening for GV's with engine off,not likely in 109 tho.... opps did I say that out loud!!

[StuB]

Cutting throttle in an a/c that has lots of horsepower and torque (like the 109-K4) helps increase it's roll rate when rolling oposit the engines torque.

When you are in a scissors fight, trying to force (or prevent) an overshoot, the extra degree/second you can get by cutting throttle can really help.

If the other a/c was actually shutting down and then restarting, I would wager that they didn't have a throttle and were toggling the motor on/off in order to help maintain corner speed or increase roll rate..

Gents...
I know that when the engine is turned "off" in flight, the blades become a wind drag....

Will this do same in the game ?

Fought a 109 the other day and heard his engine going "off" and back "on"...
Turning the engine "off", will it help you slow down ?
Does it really work in this game ?

Phil / OPP7755