A question for 109F4 drivers

[Krusty]

I use a keyboard as well, but I need to shift my attention to it, look at it, move my hand to it, hit the RPM keys while looking at my RPM gague on the screen, and then shift my attention back to whatever I was doing. It's not too efficient, so I don't bother with RPM at times (when I really ought to, I guess).

[bozon]

If I pull the throttle back to idle, so does the RPM.

sounds like a bad idea.

The only reason to reduce throttle from 100% in a fight is to slow down.  If you link your RPM to the trottle, you lower your drag when pulling it back - the opposite of what you want.

Bozon

[MANDO]

Just a small advice about playing with RPM:

Basically, you want max RPM as long as your are at or below your max level speed for your current alt. If you are well faster than your max speed for your current alt, what you want is to reduce drag as much as possible to slowdown the decceleration.

[Tilt]

Originally posted by MANDO

Basically, you want max RPM as long as your are at or below your max level speed for your current alt. If you are well faster than your max speed for your current alt, what you want is to reduce drag as much as possible to slowdown the decceleration.

This would mean that when diving I would accelerate more (once I had passed level max) if I reduced rpm?..............

regardless of loss of boost?

Hmm gaining e this way could be advantagous.......... I'll try that tonight!

[Wilbus]

Yes Tilt it would. While the prop in a prop planes gives the planes it's thrust (pull is forward) it also acts like a brake, specially when going at higher speeds.

I remember a few old guys on my flying club (flying Gliders) discussing this, they said that a prop plane has the prop to slow it down at high speed while us glider pilots have to watch out not to overspeed because we accelerate so fast in a dive due to lack of anything that slows us down.

[MANDO]

Originally posted by Tilt
This would mean that when diving I would accelerate more (once I had passed level max) if I reduced rpm?

No exactly.

When you exceed your max level speed for your current alt you dont want to reduce rpm to minimum (when you dive, you have your engine power + G component - drag). Lets say that when you reach your "maximum controllable" speed in a dive, you want to reduce your RPM to the minimum to keep that speed as long as possible (this is particulary useful when G component is not helping your dive, that is, when you level after the dive). As your plane deccelerates, you keep increasing your RPM slowly, when you reach your maximum level speed for that alt, you should have your RPM set to the maximum.

All this depends on the plane type (drag curve and power) so it is difficult to figure out an accurate optimum general "rpm curve above max level speed" per plane.

[MANDO]

The "secret" of outaccelerating lalas in dives is not a "secret" anymore

Hope no lala drivers are following this thread ...

[Angus]

Just fly the 109F like a Spitty.
It basically performs very much like a Spit IX.

[Krusty]

my bellybutton it does

[Wilbus]

Uhm, problem with reducing RPM at high speed is that it can't be reduced. The faster you go the less you can reduce it. Even if you cut throttle all together in a 500mph dive the RPM stays peaked (actually well above max RPM normally).

[MANDO]

500 mph is (or should be) well above maximum controlable speed for 109F.

[MANDO]

Wilbus, what you are doing is to reduce RPM caused by your engine. The resulting RPM will be mostly caused by your air speed and the fast air should move your propellor in the optimum (dragwise) way (doesnt matter the final resulting RPM as long as you induce minimum interference with the air flow).

[Wilbus]

uhmmmm. Rgr

[Tilt]

Originally posted by MANDO
The "secret" of outaccelerating lalas in dives is not a "secret" anymore

Hope no lala drivers are following this thread ...

Lala driver here..........

I unlinked my rpm last night and started using it (in an La7) to see if I could further enhance dive acceleration above normal level speed.

There is a short band of control approx between 360 and 400 where rpm is still adjustable. At higher speeds the prop rotates at full revs regardless.

I assume that indicated boost is a function of applied thrust so dropping revs in a dive with a resultant boost drop seemed counter productive. If I was in a WEP dive my default disabled my rpm control until WEP was off.

For the La7 this meant it was of little benefit below 8K unless WEP was off.

Unless AH models prop pitch into the prop drag equation.

I do not know if prop drag (in AH) is a function of rpm alone or a combination of rpm and prop pitch. I assume it should be the latter.

If this were the case then reducing the set engine speed (above 400) should tend to feather the prop even tho max rpm is maintained. Hence reducing prop drag.

Combat "feel" alone was insufficient to determine this.

However I started to use the rpm rotary as a sort of E loss adjuster in combat....wierd stuff seemed to occur which needs more checking. On one occasion in an in plain turn competition with another La7 I simply left throttle at full and fettled thrust with the rpm control..........my turn rate "seemed" to increase exponentially without heavy loss of air speed. It may only be that rpm gave me better fidelity of control in the top % band of thrust and I was able to set best corning speed more accurately.

But there is no doubt that I have been missing the prop drag for braking manouvers..........particular ly in dive chasing an oppenent where I would normally over shoot.


Re the Bf109.

Actually the 109G was superior to the La7 in dive. I have copies of tests that record that once initial acceleration had been passed the 109 (G4 in this case) did indeed out dive the La7.

AH does not seem to model this.

[AKFokerFoder+]

Originally posted by Angus
Just fly the 109F like a Spitty.
It basically performs very much like a Spit IX.

Yeh, sure