Climb Performance

[dresoccer4]

Learning the Jug now and had a question about climb performance. 

 

Altitude: 7500ft

Airspeed: 160mph

Throttle: full open (33")

Prop: 2300rpm

Loadout: 2 mk64

Setup: clean (flaps, gear, cowl all in)

Climb: 400fpm

 

Does this seem right? Feel like I'm climbing super slow. When does the turbo kick in? Can I make it kick in sooner? Thoughts?

[razo+r]

You need to control turbo with boost lever. Use it to keep a certain MP.

 

Climb with 46'' and 2550rpm.

Edited March 9, 2021 by razo+r

[grafspee]

If continuous power is still too slow, you can use military power for climb. 52" 2700rpm 10mins with this power should accelerate climb a lot.

[felixx75]

9 hours ago, razo+r said:

You need to control turbo with boost lever. Use it to keep a certain MP.

 

Climb with 46'' and 2550rpm.

 

Btw. continuous power is 42'' / 2550 rpm, military power is 52'' / 2700 (max. 15 minutes, no water) and WEP 64'' / 2750 rpm (max. 5 minutes, with water). 

Edited March 10, 2021 by felixx75

[grafspee]

46" is for P-51

[Rainbowgirl]

On 3/9/2021 at 10:07 PM, dresoccer4 said:

Learning the Jug now and had a question about climb performance. 

 

Altitude: 7500ft

Airspeed: 160mph

Throttle: full open (33")

Prop: 2300rpm

Loadout: 2 mk64

Setup: clean (flaps, gear, cowl all in)

Climb: 400fpm

 

Does this seem right? Feel like I'm climbing super slow. When does the turbo kick in? Can I make it kick in sooner? Thoughts?

Read flight manual. Engine settings fir different stages of flight are there. 2300 rpm with 33 manifold is not ment for climbing. Clip together turbo and throttle levers.

[grafspee]

Definitely not a good idea to interconnect boost and throttle.

Take off 2700rpm throttle wide open or if airfield is short and heavy load, use 15-20 flaps 2700rpm and throttle and boost wide open for take off, just back boost lever once you start passing 52".

Climb: after retracting gear and flaps Boost lever off, throttle to 42" engine rpm 2550. Once you hit max throttle altitude for 42" apply boost from turbo to maintain 42, You will have to back turbo lever with increasing alt because turbo will pump more and more MP with Alt until certain alt then you will need to start moving turbo lever forward to maintain 42".

[Ravent]

Hi wha

5 hours ago, grafspee said:

Definitely not a good idea to interconnect boost and throttle.

Take off 2700rpm throttle wide open or if airfield is short and heavy load, use 15-20 flaps 2700rpm and throttle and boost wide open for take off, just back boost lever once you start passing 52".

Climb: after retracting gear and flaps Boost lever off, throttle to 42" engine rpm 2550. Once you hit max throttle altitude for 42" apply boost from turbo to maintain 42, You will have to back turbo lever with increasing alt because turbo will pump more and more MP with Alt until certain alt then you will need to start moving turbo lever forward to maintain 42".

 

Hi what is MP?

[razo+r]

Manifold Pressure

[grafspee]

50 minutes ago, Ravent said:

Hi wha

 

Hi what is MP?

[Pikey]

The interconnect clips are best used once you can get any boost at all above 5000 in order to avoid bringing the throttle back beneath the boost if you need to chop it as more of a safety feature. They aren't much use pushing forward, you should be more careful in the climb about setting and be checking your MP for when it begins to dorp off with cross checks on the temps and speed. imo anyway.

[grafspee]

When using turbocharger it is very important to watch your MP, it will go up during climb. At climb settings, 2550rpm 42", when i climb 2700rpm 52" i didn't notice any Mp increase in climb.

[Pikey]

1 hour ago, grafspee said:

When using turbocharger it is very important to watch your MP, it will go up during climb. At climb settings, 2550rpm 42", when i climb 2700rpm 52" i didn't notice any Mp increase in climb.

OK, I am pretty sure the manifold  pressure goes down as you climb into thinner air, which is the entire reason there is a boost... am I going mad or did you typo?

[grafspee]

1 hour ago, Pikey said:

OK, I am pretty sure the manifold  pressure goes down as you climb into thinner air, which is the entire reason there is a boost... am I going mad or did you typo?

Its due to nature of turbo regulator. 

[Aernov]

Does turbo lever operates some kind of automated regulator that maintains set MP, or is it just mechanically (via hydraulic/oil piston) closes/opens exhaust waste gate thus regulating amount of gases directed to the turbosupercharger bucket wheel, increasing/decreasing it's speed in near-linear fashion? Is there any info on turbo automatic MP regulation system?

[grafspee]

P-47 in DCS has no automatic MP regulator.

Throttle is directly connected to throttle valve, and boost lever is connected to turbo regulator which govern turbine inlet pressure.

This mean that during climb with constant boost lever position, turbo rpm will increase due to increasing pressure differences between turbine inlet and turbine outlet.

And this will result in increasing MP during climb. So boost lever had to be gradually back off in climb.

This case persist until certain point where supercharger and turbocharger efficiency drops probably to very low ambient pressure, from this point boost lever had to  be advanced again to maintain MP

Edited April 23, 2021 by grafspee