Enable/disable water injection working?

[LeCuvier]

I have bound a switch to these commands, but see no effect. I'm wondering if they work at all. Can somebody please tell me where this switch is in the cockpit?

[Saxman]

There's no switch in the cockpit. Water injection was activated automatically when the throttle was maxed out. There was a stop wire that would block off the final 3/8in of the throttle and the pilot would have to push through it to turn on injection.

The consensus right now is that injection doesn't appear to be working properly.

[LeCuvier]

13 minutes ago, Saxman said:

There's no switch in the cockpit. Water injection was activated automatically when the throttle was maxed out. There was a stop wire that would block off the final 3/8in of the throttle and the pilot would have to push through it to turn on injection.

The consensus right now is that injection doesn't appear to be working properly.

Thanks for the swift reply!

[felixx75]

However, I assume that the water injection actually works, whether it is correct or not is of course not for me to judge.

Water injection is activated by pushing the throttle all the way forward. There is an animated detent in our F4U, which corresponds to the Mil Power (about 53 MP @2700 RPM). If you now go over this detent and push the throttle full forward (the safety wire is unfortunately not animated and always cut) you get exactly the 57.5-60 MP, depending on the altitude @2700 RPM, which corresponds to WEP.

My understanding is that mil power + water injection = WEP. Therefore, I assume that water injection is implemented and working.

Edited June 27 by felixx75

[LeCuvier]

Interesting! If all that is true, why do we have a binding to enable or disable water injection? 

[Saxman]

33 minutes ago, felixx75 said:

However, I assume that the water injection actually works, whether it is correct or not is of course not for me to judge.

Water injection is activated by pushing the throttle all the way forward. There is an animated detent in our F4U, which corresponds to the Mil Power (about 53 MP @2700 RPM). If you now go over this detent and push the throttle full forward (the safety wire is unfortunately not animated and always cut) you get exactly the 57.5-60 MP, depending on the altitude @2700 RPM, which corresponds to WEP.

My understanding is that mil power + water injection = WEP. Therefore, I assume that water injection is implemented and working.

That would still indicate its implementation is wonky.

If maxing the throttle already gives the additional power as it should, there's no need for a separate WEP button. But I've only ever seen the Injection light turn on a few minutes after pressing the "WEP Button."

[GUCCI]

6 minutes ago, LeCuvier said:

Interesting! If all that is true, why do we have a binding to enable or disable water injection? 

I will go on a limb and say, that keybind is not meant to be there and was leftover- as has been the case for a few keybinds (auto-pilot/attitude hold Kb's in mind.)

Maybe they had it in there for dev and testing purposes  

[felixx75]

24 minutes ago, LeCuvier said:

Interesting! If all that is true, why do we have a binding to enable or disable water injection? 

This might be similar to the afterburner button in the F-18, or the wep button in the P-51

22 minutes ago, Saxman said:

That would still indicate its implementation is wonky.

If maxing the throttle already gives the additional power as it should, there's no need for a separate WEP button. But I've only ever seen the Injection light turn on a few minutes after pressing the "WEP Button."

As I said, I don't know if it works properly, but it's definitely explainable.

The fact that there is a binding for it will probably have a similar reason why, for example, the F-18 has an afterburner button, or why the P-51 has a wep button.

[Mike Busutil]

I have had 61" Manifold at 20,000' MSL and did get the green water injection light indicating 3 minutes of water remains. 

[felixx75]

19 minutes ago, GUCCI said:

I will go on a limb and say, that keybind is not meant to be there and was leftover- as has been the case for a few keybinds (auto-pilot/attitude hold Kb's in mind.)

Maybe they had it in there for dev and testing purposes  

That sounds absolutely plausible 

[GUCCI]

8 minutes ago, felixx75 said:

This might be similar to the afterburner button in the F-18, or the wep button in the P-51

As I said, I don't know if it works properly, but it's definitely explainable.

The fact that there is a binding for it will probably have a similar reason why, for example, the F-18 has an afterburner button, or why the P-51 has a wep button.

That is also an excellent point, several modules have this feature for those who don't have detents or fingerlifts, some have it as a 1 button toggle. 

I guess we shall wait and see Rudels input!  

[NavalPilot35]

I did some research, and from what I can see right now water injection isn't working at all. Yes the trottle detent visually is working but the injection system is automatic, and should place the manifold pressure in the 60-61 range. Even if you bind up the "water injection" controlls, there is no difference made. Im certain I have the aircraft in the correct configuration for max power, but my manifold caps out at 49-50.

That said the gauge could be glitched and just saying it is at 49-50, but I have seen the gauge reach 70+ when first spawning into a free flight then dropping down and an audible difference in engine sound pitch so who knows...

 

Overall, this aircraft is still WIP so not much complaining can be made... yet

 

[MIDWAY]

The on and off buttons do work.  You'll not see a difference in MP tho.   

At sea level I'm 305kts indicated without,  but showing mp that should be on.   

 

Hitting the on button changes nothing in the cockpit,  but my speed will go up to 312kts indicated.  

 

Goes back to 305kts when the switch is back off. 

 

Not saying that's correct (it's not)  just reporting my findings.  

[PL_Harpoon]

On 7/3/2025 at 7:20 PM, NavalPilot35 said:

but the injection system is automatic, and should place the manifold pressure in the 60-61 range

Where did you find that number?

[rob10]

On 6/27/2025 at 1:25 PM, Saxman said:

 But I've only ever seen the Injection light turn on a few minutes after pressing the "WEP Button."

As someone indicated above, that light should only turn on when you have 3 minutes of WEP remaining, so it appears to be working at least roughly as intended if it took a bit to come on.

[Saxman]

On 7/3/2025 at 1:09 PM, MIDWAY said:

The on and off buttons do work.  You'll not see a difference in MP tho.   

At sea level I'm 305kts indicated without,  but showing mp that should be on.   

 

Hitting the on button changes nothing in the cockpit,  but my speed will go up to 312kts indicated.  

 

Goes back to 305kts when the switch is back off. 

 

Not saying that's correct (it's not)  just reporting my findings.  

MP changes seem to be hit or miss. Sometimes I'll see an increase in MP, others not. There's also times where the MP doesn't change until I shift the Supercharger, even if I'm below critical altitude for that gear.

[felixx75]

On 7/3/2025 at 7:20 PM, NavalPilot35 said:

I did some research, and from what I can see right now water injection isn't working at all. Yes the trottle detent visually is working but the injection system is automatic, and should place the manifold pressure in the 60-61 range. Even if you bind up the "water injection" controlls, there is no difference made. Im certain I have the aircraft in the correct configuration for max power, but my manifold caps out at 49-50.

That said the gauge could be glitched and just saying it is at 49-50, but I have seen the gauge reach 70+ when first spawning into a free flight then dropping down and an audible difference in engine sound pitch so who knows...

 

Overall, this aircraft is still WIP so not much complaining can be made... yet

 

The highest MP listed in the tables is 59.5 @20000ft. There may be something wrong with your keybindings, because I can easily reach the MP values that should be achieved with water injection.

(without using a button, because it should be triggerd automatically with throttle full forward)

 

9 hours ago, PL_Harpoon said:

Where did you find that number?

It's not 60-61, but max 59,5 @20000ft

 

Edited 9 hours ago by felixx75

[PL_Harpoon]

I was asking because at 20k ft I was easily getting 61" at 2700 RPM. I find it strange especially since in the manual provided by M3 there's even lower MAP

What's also interesting is the recommended 2550 RPM which corresponds with another Engine Flight Chart I found:

Why 2550 RPM? Should the engine not be able to sustain 2700 RPM (which to me seems odd since it's a matter of pitch angle)? Or does 2550 provide more thrust (in which case I also don't quite understand how)?

[felixx75]

In fact, our two tables differ if you look closely. For example, I have 2700 RPM @20k ft. 

I'm pretty sure M3 used the wrong table for their own manual as a source. Namely for the R-2800-8 and not for the R-2800-8W (with water injection). Another indication of this is the likewise incorrect plate on the left cockpit wall, which actually lists the wrong engine type (R-2800-8).

They must have actually simulated the correct type with water injection, as the correct MP values are achieved pretty much at the corresponding altitudes.

Edited 5 hours ago by felixx75

[PL_Harpoon]

1 hour ago, felixx75 said:

as the correct MP values are achieved pretty much at the corresponding altitudes

Since I'm getting 61" at 20k I'm not so sure about that.

[felixx75]

As the needle wobbles back and forth anyway, 61 is certainly within the error tolerance. In addition, the values in the table are the maximum values that you are allowed to call up in order to fly with it, not the maximum that can be achieved.