Problem controlling the throttle.

[Gunfreak]

So in the spitfire I have no problems with the throttle.  I can thottle up and down and always get it back to 7+ just on feel and sound, just taking a tiny microsecond to check. 

 

But in the P47 the throttle seems to have a mind of its own. After using the water injection for however long I need, I thottle down and I feel I hit the right thottle for continuous running. But after a few seconds or minutes of playing attention to enemies I look at my gauge and see the thottle is far bellow the maximum of continuous run.  If I push the throttle forward it shoots up way high. And I spend precious seconds finely adjusting the throttle and not looking at what's going on outside. 

I use a winwing tarus F18 thottle.

 

[kablamoman]

In the 47 there's a ram air effect that heavily impacts your manifold pressure, independent of your throttle position.

So if you set it when you're going fast, but then slow down (ie. bleed energy in a climb or turn), you'll end up with less ram air/less manifold pressure and vice versa.

Also, if you're running with the throttle and boost levers interconnected, you probably will get an even less linear relationship between manifold and your throttle position as the turbo spools up and down. Long story short, it's more of a handful.

You can try splitting your boost and throttle levers and using them independently (the boost portion will still lag a bit in response), but you'll always have to watch the changes due to ram air with your speed.

Edited January 14, 2022 by kablamoman

[Gunfreak]

22 minutes ago, kablamoman said:

In the 47 there's a ram air effect that heavily impacts your manifold pressure, independent of your throttle position.

So if you set it when you're going fast, but then slow down (ie. bleed energy in a climb or turn), you'll end up with less ram air/less manifold pressure and vice versa.

Also, if you're running with the throttle and boost levers interconnected, you probably will get an even less linear relationship between manifold and your throttle position as the turbo spools up and down. Long story short, it's more of a handful.

You can try splitting your boost and throttle levers and using them independently (the boost portion will still lag a bit in response), but you'll always have to watch the changes due to ram air with your speed.

 

I just have the RPM at 2500 and only fiddle with the throttle. 

[saburo_cz]

The P-47D does not have a manifold pressure regulator like the Spitfire or the Mustang.

So, any speed/altitude change means engine manifold pressure change.

 

The manifold pressure regulator cover these changes in certain range, but planes without it require constant care.

[Gunfreak]

14 minutes ago, saburo_cz said:

The P-47D does not have a manifold pressure regulator like the Spitfire or the Mustang.

So, any speed/altitude change means engine manifold pressure change.

 

The manifold pressure regulator cover these changes in certain range, but planes without it require constant care.

Is there any special technique?

The problem is I don't get any obvious ques. The engine sound seems almost the same even if the throttle far lower than max continues run. Instead of around 40 I find I've been flying several minutes at 30 or even 25.

And sometimes it sneaks above 40 too and that's bad as it can break the engine. 

[razo+r]

There are many indications as to when your MP is dropping, and they are quite obvious:

 

Change in altitude? MP is changing.

Change in speed? MP is changing.

 

Is there a special technique? Not really, other than you have to check your MP gauge more often. Just do a check from time to time after/during hard/vertical maneuvers

[grafspee]

There are couple things about P-47 which make it totally new experience then spitfire or p-51.

First thing already mentioned, P-47 has no boost regulator, so speed and altitude change will affect your MP.

Second thing is P-47's engine is supercharged and turbocharged.

Throttle control butterfly valve at supercharger intake, and boost lever control how much exhaust gases  goes to turbine via turbo regulator unit.

You can link throttle and boost lever but i recommend to unlink them.

turbocharger rpm unlike supercharger rpm depends on exhaust gases flow through turbine, so when turbocharger starts to boost it create chain reaction, higher boost more exhaust gases then turbo rpm goes even higher and so on so on, so when turbo kicks in be ready to retard throttle, this the reason why you are experiencing this sudden boost spikes.

[Gunfreak]

1 hour ago, grafspee said:

There are couple things about P-47 which make it totally new experience then spitfire or p-51.

First thing already mentioned, P-47 has no boost regulator, so speed and altitude change will affect your MP.

Second thing is P-47's engine is supercharged and turbocharged.

Throttle control butterfly valve at supercharger intake, and boost lever control how much exhaust gases  goes to turbine via turbo regulator unit.

You can link throttle and boost lever but i recommend to unlink them.

turbocharger rpm unlike supercharger rpm depends on exhaust gases flow through turbine, so when turbocharger starts to boost it create chain reaction, higher boost more exhaust gases then turbo rpm goes even higher and so on so on, so when turbo kicks in be ready to retard throttle, this the reason why you are experiencing this sudden boost spikes.

So I'm supposed to control prop RPM, boost and MP to get optimum effect from the plane?

If I disconnect the boost and MP, I'm gonna need a 3rd axis.

That means I'm probably gonna have to use my spitifre throttle as it has 3 axis levers.

[grafspee]

@GunfreakIf you control throttle and boost separately, you can achieve maximum performance out of P-47, by using single axis so throttle and boost lever interconnected you sacrifice some power for easier engine operation, no matter way you use you still experience turbocharger kick in behavior.   

[Tuturuu]

Personally and maybe i'm wrong but i don't change my RPM that often. So i think you are not forced to bind it to an axis, maybe a 2 state button or a pot?

2700 for take off and fighting with water injection (apparently you Can even stay at 2550)

2550 for the rest even climbing at 52 manifold pressure (i noticed Reflected advised that to counter the allied AI climbing behaviour and it doesn't impact the motor even for 1h30 mission)

 

For the throttle/boost i simply use the turbocharger lever slightly behind the throttle as soon as i see It's impact (around 6k at least) in order to stay at 52 or 64 (even few seconds above 64 won't ruin the motor but i don't think it is useful anyway except for escape after a dive at already very high speed) but maybe i'm wrong and i could improve ?

 

What do you guys think ?

Edited January 15, 2022 by Tuturuu

[Bagpipe]

I regularly leave rpm at 2550, interconnect the boost to throttle and fly at 42" MP. 

Once dogfighting it is occasional advances on throttle to full open and adding water injection as required when climbing hard.

Works quite well. I will refine the use of the controls in future but for now I am happy with the performance i get from this approach.

Aside from this it is just about situational awareness and energy management in the turns.