Engine Power/Aircraft Speed

[Gunfreak]

1 hour ago, felixx75 said:

Here is a picture of how I reach 260kt+ without any problems, with max. cont. (Manifold 44, 2550rpm, Blower: neutral)

All coolers closed.
Why others only ever reach low speeds, I don't seem to have these problems. 

How long can you fly with all coolers closed? 

[felixx75]

1 hour ago, Gunfreak said:

How long can you fly with all coolers closed? 

So far, without limit. Since the blower is off, you don't need an intercooler. And cylinder head and oil temperature is ok, as you can see. From about 200kt at 44 manifold pressure you can easily close the coolers. Similar to the P-47, where you also have to close the radiator from 200 (mph).

[Gunfreak]

I've never been able to close the cowlflaps. I need at minimum some cowl flaps no matter what speed and power. 

It also an extremely slow climber. At max continuous I can only do 500 feet a minute at 120knots. It should be able to do well over 2000 a minute with 120 knots as ideal climb speed. 

[Hayrake YE-ZB]

9 hours ago, Nealius said:

What's the weather in your mission like, and how do you have your cowl flaps/oil cooler/intercoolers, and supercharger set? Trying a typical 29C Marianas day 29.92 I'm stuck at a 210knt wall for some reason.

Had another go after work. Marianas WW2 map, 29C/29.92

Sea Level, skimming the waves, ball in the center, trimmed to hands off -

2700rpm/~28.5MP

Auto Rich Mixture

All cooling flaps closed - 301 Kias 

Oil and Intercoolers flapsfull Open - 285

Oil and Intercoolers Closed, Cowl flaps Open (they stop in trail due to airloads)- 292

The real F4U manual talks about using 2550 rpm to save the engine with very minor speed loss at altitude, but these settings kept the engine CHT’s in parameters during my 2 minute runs.

Make sure you are trimmed so you don’t have excess surfaces sticking out in the breeze.

 

2 hours ago, Gunfreak said:

I've never been able to close the cowlflaps. I need at minimum some cowl flaps no matter what speed and power. 

It also an extremely slow climber. At max continuous I can only do 500 feet a minute at 120knots. It should be able to do well over 2000 a minute with 120 knots as ideal climb speed. 

What altitude are you only getting 500fpm, what’s your mixture, supercharger and engine rpm/mp?

Try 130-135 for a climb speed.

Edited June 24 by Hayrake YE-ZB

[Gunfreak]

10 minutes ago, Hayrake YE-ZB said:

Had another go after work. Marianas WW2 map, 29C/29.92

Sea Level, skimming the waves, ball in the center, trimmed to hands off -

2700rpm/~28.5MP

Auto Rich Mixture

All cooling flaps closed - 301 Kias 

Oil and Intercoolers flapsfull Open - 285

Oil and Intercoolers Closed, Cowl flaps Open (they stop in trail due to airloads)- 292

The real F4U manual talks about using 2550 rpm to save the engine with very minor speed loss at altitude, but these settings kept the engine CHT’s in parameters during my 2 minute runs.

Make sure you are trimmed so you don’t have excess surfaces sticking out in the breeze.

 

What altitude are you only getting 2000fpm, what’s your mixture, supercharger and engine rpm/mp?

Try 130-135 for a climb speed.

I'm never get 2000. I'm getting 500 to mabye 1000.  At max continuous (44mp 2500rpm) 

[Rhayvn]

I did a test for a few different aircraft that I have at 5000, 12000 and 24000 feet.  The speeds listed are TAS and what you can sustain pretty much indefinitely in level flight.  For the clean aircraft, if there is a '/' the number before is without water injection and the number after is with water.  For the GA lines, that is Ground Attack and are the speeds with a full load of rockets and bombs with the number after the / as the speed after dropping all the ordnance.

It's pretty close to the P-51 in overall speed, depending on the specific altitude (Due to SC gearing most likely) and beats the 47 and D9 handily.  They can only match it with water/mw90 active.

Edited June 24 by Rhayvn

[Hayrake YE-ZB]

1 hour ago, Gunfreak said:

I'm never get 2000. I'm getting 500 to mabye 1000.  At max continuous (44mp 2500rpm) 

I meant 500fpm. You can’t get more than 1000 fpm at SL? What’s your fuel load and ext stores config and airspeed?

Edited June 24 by Hayrake YE-ZB

[Nealius]

Something is definitely very weird. People doing the same thing yet one group getting stonewalled at 200-210kts and the other getting normal airspeeds. 

One thing I noticed in reviewing my flights is that the ball in the gunsight and the ball in the dashboard aren't always in agreement. When the ball is centered in the gunsight, the ball in the dash is showing slightly left, however it is still within the bounds of the center brackets. I doubt such minimal slip or discrepancy in the balls (heh) would cause a 90kt penalty. 

[lawndartleo]

There are shenanigans going on.  A bunch of us are sitting in an MP server getting the tricks to work on the prop lever and sending the RPMs way up and the boost up to near 100... and 210 kias.

Somebody PLEASE make a video or a real tutorial. This is frustrating.

OK... a bit of an update.

I can confirm that a few of us hit the magic 300+.

Bring up your controls indicator.  Grab the lever with the mouse. Pick it up, push it down.  The little indicator will now go past the end of the bar and even off the screen if you want.

Edited June 25 by lawndartleo

[Hayrake YE-ZB]

2 hours ago, lawndartleo said:

Bring up your controls indicator.  Grab the lever with the mouse. Pick it up, push it down.  The little indicator will now go past the end of the bar and even off the screen if you want.

I’m not overspending the engine to get 301 Kia’s at Sea Level with half fuel. Full throttle, prop control at max gives me 2700 rpm and ~58” MP using an axis set to slider to obtain proper control of the lever. The default mode causes the prop lever (and engine rpm) to peak and reverse before it reaches full travel. All cooling flaps are closed during the run, which only takes a couple of minutes and won’t overheat anything. No pylons or stores.

I don’t see anything in the real world manual about RPM’s above 2700, perhaps I missed it somewhere.

[lawndartleo]

OK... I am getting really weirded out by this whole thing.

I read some little blurb... maybe in this thread, I don't know where... make sure governor handle is set to slider, not axis.

ok... changed from slider to axis.

2700, 55, 300+ at about 1500 feet.

What the heck?

https://imgur.com/gallery/proof-UBVaFgM

 

Edited June 25 by lawndartleo

[Nealius]

I made the slider change as well. 275kts indicated on the deck, hot day (28C), 53/2700 (mil power), ball centered, all cooling flaps/doors closed or barely cracked open, 70gals fuel loaded.

Roll rate and handling is soooo much better at 250KIAS and above.

Edited June 25 by Nealius

[Kovacs]

3 hours ago, Nealius said:

I made the slider change as well. 275kts indicated on the deck, hot day (28C), 53/2700 (mil power), ball centered, all cooling flaps/doors closed or barely cracked open, 70gals fuel loaded.

Roll rate and handling is soooo much better at 250KIAS and above.

Hey, 

Would you mind explaining to me how you are doing that? What exactly did you change? Throttle axe? 

For me 53/2700 (mil power) is impossible with my current settings.

KR

Edited June 25 by Kovacs

[tekwoj]

14 hours ago, Gunfreak said:

I've never been able to close the cowlflaps. I need at minimum some cowl flaps no matter what speed and power. 

It also an extremely slow climber. At max continuous I can only do 500 feet a minute at 120knots. It should be able to do well over 2000 a minute with 120 knots as ideal climb speed. 

You're doing something wrong if you need cowl flaps all the time. I can usually close them fully when cruising. Experiment with other cooling levers. Also, once you switch to the main fuel tank, turn off the fuel pump.

 

On 6/24/2025 at 11:17 AM, EnzoF98 said:

This is still fine as an option to have though, for us who don't have tactile detents in our throttles.

It's not a really a detent thing like an afterburner, literally the moment you push throttle 100% it should inject the water.

[Hayrake YE-ZB]

7 hours ago, lawndartleo said:

OK... I am getting really weirded out by this whole thing.

I read some little blurb... maybe in this thread, I don't know where... make sure governor handle is set to slider, not axis.

ok... changed from slider to axis.

2700, 55, 300+ at about 1500 feet.

What the heck?

https://imgur.com/gallery/proof-UBVaFgM

 

I’m the person who posted the change to “slider” (although I originally called it “linear” by mistake). The correct label for the checkbox in the axis tuning menu is “slider”.

The default tuning profile leaves this control with an X-Y axis that causes the prop control to peak at max rpm of 2700, then reduce to a value below that as the axis that you have set for prop control is moved to its physical limit. If you play with the axis tuning display, and look at your engine rpm vs propellor control lever in the simulated cockpit, you’ll see the problem. “Slider” removes the peak in the curve to a linear profile instead of an S curve.

Almost all of the people making posts about speed are omitting the altitude that they are flying at for the IAS that they are getting, some are looking at the TAS readings using CTRL-Y. That’s why it’s so confusing. I posted my parameters in this thread. Make sure that you are getting 2700 rpm, 58” of manifold pressure, mixture auto-rich (balls to the wall), half fuel, all cooling flaps closed, no ordnance, canopy closed, weather set to 20º C and see what IAS you are getting at sea level after about a two minute run, skimming the waves.

Edited June 25 by Hayrake YE-ZB

[banjuska92]

Le 23/06/2025 à 02:48, Nealius a dit :

180 on dirait que vous avez eu du drag traîner. 29C jour, équipement, volets vers le haut, refroidisseur d'huile fermé, refroidisseurs d'huile 1/2 à 1/3 ouverts, rabats de capot peut-être 1/4 ouverts, 2550 tr/min 43" et je faisais facilement 210kts indiqué juste en croisière sous 1 000 pieds.

Oui, mais 210 kts ne sont pas 295/300 kts, le propos est d'arriver à faire 300 kts en palier 

[anlq]

Folks, this aircraft has problem with drag with rockets. It's still draggy even after firing all rockets. |
It's easy to replicate this problem so I will not post a track here.

@BIGNEWY Please take note. 

Edited June 25 by anlq

[Kovacs]

39 minutes ago, Hayrake YE-ZB said:

I’m the person who posted the change to “slider” (although I originally called it “linear” by mistake). The correct label for the checkbox in the axis tuning menu is “slider”.

The default tuning profile leaves this axis with an X-Y axis that causes the prop control to peak at max rpm of 2700, then reduce to a value below that as the axis that you have set for prop control is moved to its physical limit. If you play with the axis tuning display, and look at your engine rpm vs propellor control lever in the simulated cockpit, you’ll see the problem. “Slider” removes the peak in the curve to a linear profile instead of an S curve.

Almost all of the people making posts about speed are omitting the altitude that they are flying at for the IAS that they are getting, some are looking at the TAS readings using CTRL-Y. That’s why it’s so confusing. I posted my parameters in this thread. Make sure that you are getting 2700 rpm, 58” of manifold pressure, mixture auto-rich, half fuel, all cooling flaps closed, no ordnance, canopy closed, weather set to 20º C and see what IAS you are getting at sea level after about a two minute run, skimming the waves.

Great!! Thanks, i'll try. 

[felixx75]

1 hour ago, tekwoj said:

You're doing something wrong if you need cowl flaps all the time. I can usually close them fully when cruising. Experiment with other cooling levers. Also, once you switch to the main fuel tank, turn off the fuel pump.

 

It's not a really a detent thing like an afterburner, literally the moment you push throttle 100% it should inject the water.

You can see the physical detent (and the cut safety wire) on the throttle quadrant. The throttle itself moves beyond this detent, it's animated. The comparison to an afterburner is quite appropriate.

[Saxman]

1 hour ago, tekwoj said:

You're doing something wrong if you need cowl flaps all the time. I can usually close them fully when cruising. Experiment with other cooling levers. Also, once you switch to the main fuel tank, turn off the fuel pump.

 

It's not a really a detent thing like an afterburner, literally the moment you push throttle 100% it should inject the water.

There wasn't a detent, but it did have a stop wire the pilot had to push through the first time he engaged the water injection.

[felixx75]

12 minutes ago, Saxman said:

There wasn't a detent, but it did have a stop wire the pilot had to push through the first time he engaged the water injection

There is one modeled and animated and a not animated, cut safety wire in our F4U. You can see it clearly while moving the throttle forward.

[isotaan]

2 hours ago, Hayrake YE-ZB said:

I’m the person who posted the change to “slider” (although I originally called it “linear” by mistake). The correct label for the checkbox in the axis tuning menu is “slider”.

The default tuning profile leaves this control with an X-Y axis that causes the prop control to peak at max rpm of 2700, then reduce to a value below that as the axis that you have set for prop control is moved to its physical limit. If you play with the axis tuning display, and look at your engine rpm vs propellor control lever in the simulated cockpit, you’ll see the problem. “Slider” removes the peak in the curve to a linear profile instead of an S curve.

Almost all of the people making posts about speed are omitting the altitude that they are flying at for the IAS that they are getting, some are looking at the TAS readings using CTRL-Y. That’s why it’s so confusing. I posted my parameters in this thread. Make sure that you are getting 2700 rpm, 58” of manifold pressure, mixture auto-rich (balls to the wall), half fuel, all cooling flaps closed, no ordnance, canopy closed, weather set to 20º C and see what IAS you are getting at sea level after about a two minute run, skimming the waves.

I cannot reproduce this working with an axis even when I change the mapping to a slider- I max out at 2700RPM regardless of the binding. I am able to reproduce it with only the mouse.

I see a straight line even when not configured into a slider (see the attached image). You are talking about the Prop Governor Handle binding, correct?

null
Can you share screenshots of how you have it tuned and configured? What is your axis (HOTAS? throttle quadrant? manufacturer?)

[Templar560]

Thanks for the engagement chaps it's all very useful, and goes to show the huge discrepancies going on with this aircraft. The slider thing for the prop lever is interesting and I will certainly give it a go! And yes mentioning heights these are being tested at would be useful I think.

[tekwoj]

On 6/24/2025 at 3:08 AM, Saxman said:

 

That needs to be addressed, then, because the 8W was introduced in the 1A and AFAIK none of the 1Ds were produced without water injection.

Well, the manufacturing plate in the model says it's a -8 engine. It's just a texture  but still, the manufacturing number doesn't seem to match any existing model...

[felixx75]

4 hours ago, Templar560 said:

The slider thing for the prop lever is interesting and I will certainly give it a go!

I find it astonishing that hardly anyone seems to use the “slider” option. It is only logical to use “slider” for all axis that do not use a center point and “+” and “-” (Pitch, Roll, Yaw for example) but go from “0” to “100”. Throttle or brakes, for example, are such a case, rotary controls, etc. I have been using the “slider” option for this type of axis for years.