Hitech- Question.

[Urchin]

Howdy, I was having this discussion with Nomde in the DA, and we couldnt really come to a satisfactory conclusion.  Forgive the length of this post in advance, because I'm just a layman and I have trouble explaining what I mean.  

Quite a few people turn their engines on and off in combat.  They'll turn their engine off to slow down real fast, to prevent or cause an overshoot.  It does seem to slow you down more than just putting the throttle in 'idle' (think full throttle, what I call 'idle' is full on the opposite side).  What I was curious to know is WHY it slows you down faster?  

I can't see any difference, from a 'drag' standpoint, between an unfeathered prop connected to an engine that is off and an unfeathered prop connected to an engine that is ON, but sitting at idle (hopefully producing no thrust).  If your prop was automatically feathered, like how it does when you take damage, that would actually REDUCE the drag on the prop, and wouldn't slow you down as much as just leaving the throttle at idle.  

There is no difference in RPMs (according to the guage at least) when you either reduce throttle or shut the engine off during flight.  So I don't see how just shutting off the engine would slow you down faster than chopping the throttle to idle.  Can you explain to me how it works?  

Also, Nomde brought up an interesting point towards the end of our discussion.  He said there may be ONE way turning the engine off would increase drag.  He said it might disconnect the transmission from the prop, allowing the wind to turn it.  Theorically, the wind could turn it faster than the engine was, leading to more RPMs and greater drag.  The RPM needle doesn't go up or down when you turn the engine off.  Is this the way it is modelled in AH, except the RPM guage doesn't move?

[Dago]

I don't know how it's modeled in AH, but in real life, a windmilling prop on a dead engine creates much more drag than an engine at idle.

When a prop is windmilling on a dead engine, it is in fact driving the engine to turn.  This means it has to overcome resistance and to do so requires energy.  Energy that is robbed by way of drag.

An idling engine is producing its own power, thereby not having to rob energy from the forward motion of the aircraft.

I am not an expert on this, and there are probably many who can explain it better, but that is the basic concept.

dago

[Wotan]

imho turning off your eng in combat is as gamey as the folks in il2 who use flaps and gear at any speed to cause an overshoot.

But it happens and I cant make folks fly my way.

I do know that when my oil or rad is hit I watch the temp gauge and turn my eng on off and lower and increase rpms to get a better glide.

So I am as "gamey" as the next guy.

[hitech]

Dago is correct. But only some of the force required to produce the current prop rpm is comming from the eng when at ideal, the other is comming from "reverse thrust", when you shut off the eng all power required to keep the current rpm is comming from the "reverse thrust".


HiTech

[Mitsu]

HT here is another question...

In AcesHigh, The plane which has a windmilling prop can roll quickly from airfield or CV at takeoff.

I feel it is not realistic.
Is it just a gameplay feature?

For example, in A6M5, you can roll immediately by pushing E key 3 times and adding throttle. It skips engine start action.

[Dago]

For example, in A6M5, you can roll immediately by pushing E key 3 times and adding throttle. It skips engine start action

Maybe HT needs to change the action, so that hitting E 3 times quickly duplicates your bail out key struck 3 times quickly?  

dago

[MrLars]

Originally posted by Mitsu

For example, in A6M5, you can roll immediately by pushing E key 3 times and adding throttle. It skips engine start action.

Now I suspect everyone that reads this will attempt to circumvent what few start-up procedures AH imposes...time for random < not random if the start-up procedure is abreviated > engine malfunctions maybe?

Or maybe we can have a megaphone to stick out of the cockpit so we can yell "Hold still on the runway so I can vulch you you silly gamer you".

[Urchin]

ok, thanks HT.

[Turbot]

Originally posted by Mitsu
For example, in A6M5, you can roll immediately by pushing E key 3 times and adding throttle. It skips engine start action.

Hmm learn something everyday

[WldThing]

For example, in A6M5, you can roll immediately by pushing E key 3 times and adding throttle. It skips engine start action.

Hmm... Well i know if you hit your engine key only 2 times it wil skip the engine start action.  I think it is only 2 buttons on the zeke too.  I know P38 doesnt skip the start action.  Maybe a couple others, that im not aware of.

[SKurj]

Guys.. the hit E key thing 3x has existed since practically the zeke was introduced, and it happens on many more aircraft than just that one.


SKurj

[dtango]

Awww!  That answers many questions.  

I had performed glide tests in AH for drag evaluation purposes but couldn't figure out how to negate the effects of prop drag as a variable.  I was cutting the engine and reducing RPM as low as it could go thinking that this would do the trick but alas I think I had all my prop aerodynamic assumptions all screwed up around this.

This leads to another question for HT.  Does idling the engine and reducing RPM to it's lowest set up the "zero-thrust" configuration I'm looking for to negate prop drag during a glide?

Tango, XO
412th FS Braunco Mustangs

[hitech]

No dtango. It just minimizes it the prop drag.

[mjolnir]

I've been playing for a little over 2 years, and hitting E 3 times to start rolling immediately has always been how most people take off, from what I can tell.  It works on almost all USAF and RAF planes, don't know about the German ones because I hardly ever fly them.  It's particularly handy for getting a very heavy F6F off a carrier deck.

[Virage]

Why am I always the last to know about these things?  Ya Lamers!