Bug ? Supercharger auto

[JG13Wulf]

Hello,

 

I think there is a little bug with supercharger.

 

I wanted to test the auto activation. But I can't see it activate from 1500 to 3500 m.

No track again sorry. But my test :

 

Starting at 1500 and don't touch throttle while increasing altitude.

At 3500 a stop trying and touch the throttle and at this exact moment the supercharger seems to turn on.

 

Then I fly with this beast and it seems that the supercharger get on at correct altitude (arround 2000 m) but only if I'm moving throttle. If I don't touch it, it don't seem to start.

 

Don't know if it's normal or if I make a mistake with it.

:pilotfly:

[grafspee]

Hello,

 

I think there is a little bug with supercharger.

 

I wanted to test the auto activation. But I can't see it activate from 1500 to 3500 m.

No track again sorry. But my test :

 

Starting at 1500 and don't touch throttle while increasing altitude.

At 3500 a stop trying and touch the throttle and at this exact moment the supercharger seems to turn on.

 

Then I fly with this beast and it seems that the supercharger get on at correct altitude (arround 2000 m) but only if I'm moving throttle. If I don't touch it, it don't seem to start.

 

Don't know if it's normal or if I make a mistake with it.

:pilotfly:

are you testing it at full power full throttle ??

[JG13Wulf]

I was around 1.2 Ata at start (1500 m) and was moving RPM manually to stay à 2400 - 2500 (forget to tell that sorry).

 

I could see Ata going down when increasing altitude (going to about 1.1 or a bit less). Supercharger should give me back more ata when getting on. And it get on only when I move throttle again (3500 m).

 

So I think the supercharger work fine but it feels like there is an interaction with throttle to start it. I don't have the same feeling with Bf 109 and Fw 190 D9.

 

Edit : I can maybe make a short video later (maybe not today).

I'm at work :p

[grafspee]

I was around 1.2 Ata at start (1500 m) and was moving RPM manually to stay à 2400 - 2500 (forget to tell that sorry).

 

I could see Ata going down when increasing altitude (going to about 1.1 or a bit less). Supercharger should give me back more ata when getting on. And it get on only when I move throttle again (3500 m).

 

So I think the supercharger work fine but it feels like there is an interaction with throttle to start it. I don't have the same feeling with Bf 109 and Fw 190 D9.

 

Edit : I can maybe make a short video later (maybe not today).

I'm at work :p

 

i dont know exact numbers but 2500rpm is quite high for 1.2 ata so when you rev engien high and set ata low you moving switching point for supercharger speed up

its happening automatic so when supercharger can maintain 1.2 ata it wont change its speed

when you add throttle than you can instantly triger auto supercharger speed by demanding more boost which is not avilable for 1st speed then you get instant switch

i think that throttle is linked with boost control unit if there is something like that dont know exactly how it is done in bmw 801.

but one thing is certain if at difrent rpm at difrent thottle position speed switch alt will change.

auto mode for supercharger speed is done that supercharger speed switch happen only when it give benefits. so if you fly 1.1ata at 1st speed and you switch supercharger to 2nd speed you will get 1.2 but it doesnt mean that you have more power becouse 2nd speed will waist a lot of engine power. so second gear should kick in when it will give benefits.

you can compare low and high blower power curves for v-1650-7 and you can see where switch will give benefits

you can see that low blower hit crit alt at around 2500ft but from high blower power curve its completly pointles to go for high speed 7000-8000ft is where you want low to high speed switch for mthis point you will get more power and probably same thing happening in your case

Edited June 7, 2019 by grafspee

[JG13Wulf]

Maybe, I'll make more try when I can :)

 

But the fact i get it working at 3500 m at the exact moment I move throttle make it weird to me.

When moving throttle in other test I get supercharger on around 2000 m (with similar parameters).

 

Don't know exactly how the automatisation work so that why I write "Bug ?" ^^

 

Thanks ;)

[Ala13_ManOWar]

Starting at 1500 and don't touch throttle while increasing altitude.

At 3500 a stop trying and touch the throttle and at this exact moment the supercharger seems to turn on.

You are supposed to throttle up when MP decreases with altitude, that's not any estrange behaviour but what it's meant to be IRL (and the other modules as well). I believe supercharger behaviour from what I've read in the other posts about that, is supposed to be like that.

 

 

S!

[saburo_cz]

You are supposed to throttle up when MP decreases with altitude

This does not work for planes with united engine control, like A-8, D-9...

If you move with throttle, you will change whole engine setting, RPM...etc. Not only manifold pressure.

 

It works for planes like P-51 or Spitfire where throttle is separated from RPM control.

In this case you can (and should do) move up with throttle lever to maintain MP as required.

[Ala13_ManOWar]

This does not work for planes with united engine control, like A-8, D-9...

If you move with throttle, you will change whole engine setting, RPM...etc. Not only manifold pressure.

Well, in Dora it's obvious as throttle is supposed to be sort of "rpm selector" and everything works automatically, but that's in a Jumo engine, not sure about BMW behaviour. 109 also features Komandogerat and still you have to compensate MP with altitude.

 

S!