Engine Diagnostics Script

[GTFreeFlyer]

Here you go guys.  A quick SP air start with a script I made to view real time fuel burn, fuel efficiency, airspeed and more.  
 

Spoiler alert:  It is actually pretty close to the published charts. 

Also FYI, the image below is just a cover image.  Diagnostics in the mission are not as pretty.  It's just the standard text overlay you are used to seeing.
 

https://www.digitalcombatsimulator.com/en/files/3346516/

Edited August 22 by GTFreeFlyer

[Rudel_chw]

Thanks, really nice for using when exploring the aircraft limits.

 

I'm currently on the first stages of editing a training mission for Engine management, using a Climb to 25,000 feet as a fixed situation to be able to monitor it using triggers. My purpose is to learn the proper use of all controls: Super Charger, cooling flaps, throttle, mixture, with the mission reminding me of operating the blower properly as we climb, learn to keep an eye on temps, etc. To give a worthwhile mission objective and add a sens of urgency, I intend to record the time it takes to get to 25,000, the less time the higher the score  

 

because of this, I wonder if you could add to the script some engine management parameters, like cyl temp, oil temp, etc  ... it would help me a lot while I develop my mission, as reading the gauges while flying makes me kind of lose focus on my aircraft handling  

 

best regards,

 

Eduardo

[GTFreeFlyer]

1 hour ago, Rudel_chw said:

Thanks, really nice for using when exploring the aircraft limits.

 

I'm currently on the first stages of editing a training mission for Engine management, using a Climb to 25,000 feet as a fixed situation to be able to monitor it using triggers. My purpose is to learn the proper use of all controls: Super Charger, cooling flaps, throttle, mixture, with the mission reminding me of operating the blower properly as we climb, learn to keep an eye on temps, etc. To give a worthwhile mission objective and add a sens of urgency, I intend to record the time it takes to get to 25,000, the less time the higher the score  

 

because of this, I wonder if you could add to the script some engine management parameters, like cyl temp, oil temp, etc  ... it would help me a lot while I develop my mission, as reading the gauges while flying makes me kind of lose focus on my aircraft handling  

 

best regards,

 

Eduardo

Great idea!  However, I don't know how to look up those values with lua at the moment.  If you can provide that info I can try to integrate it.

Also, I'm a big fan and advocate for pilots conducting instrument scans properly, especially in this warbird.  I think moving some of the data from the instrument panel to the upper corner will teach bad habits, and might be a "cheat" for the mission you want to make which includes scoring.  You might end up climbing quickly, but what good is the pilot if they never had to look at the instruments and handle the aircraft properly at the same time?  Just my 2 cents.  Cheers.

Edited August 22 by GTFreeFlyer

[Rudel_chw]

2 hours ago, GTFreeFlyer said:

Also, I'm a big fan and advocate for pilots conducting instrument scans properly, especially in this warbird. 

 

You are correct, didn't think of that

  .. on my mission I intend to use X:COCKPIT triggers to inspects these parameters that the Module offers:

 

 

Eduardo

 

 

[gdx65]

On 8/22/2025 at 6:37 PM, Rudel_chw said:

 

You are correct, didn't think of that

  .. on my mission I intend to use X:COCKPIT triggers to inspects these parameters that the Module offers:

 

 

Eduardo

 

 

I have noticed with the Corsair that once one engage in a dogfight or action (2700RPM and throttle as required), in order to avoid the engine trip, I open the cowling flaps somehow half way or by monitoring the cylinder head temperature, then the oil cooler and intercooler open half way or even fully open. Less than that the engine will trip. 

[Cool-Hand]

Nice I'll definitely have a look at this thanks for putting this together! I'm kinda scripting illiterate, would this be possible to do for other warbirds like the p-47? 

[GTFreeFlyer]

40 minutes ago, Cool-Hand said:

Nice I'll definitely have a look at this thanks for putting this together! I'm kinda scripting illiterate, would this be possible to do for other warbirds like the p-47? 

Absolutely. There’s a note about that in the mission description.  In short, you’ll need to pull the script out of the .miz and modify the fuel tank capacity, save, reload into the .miz.  The script is well-documented and you’ll see exactly what to do once you open it. 

[Super Wabbit]

Question about drop tanks.  The documentation says to set the FUEL_TANK_CAPACITY to the internal fuel tank total including external tanks.  So if I run the Corsair with 2x 150 Gal drop tanks, I should set this to 537.  When I do this it's now reading that I have 1227 gallons with the drop tanks equipped.  If I unequip the drop tanks in the same mission, the script displays 537 gallons.  If set the fuel capacity in the script back to 237, the internal fuel level, and then attach 2 150 gallon tanks, it reads 541 gallons.  That's still not exactly correct but it's close.

So should that value only be set to the internal tank capacity?

 

[GTFreeFlyer]

8 hours ago, Super Wabbit said:

Question about drop tanks.  The documentation says to set the FUEL_TANK_CAPACITY to the internal fuel tank total including external tanks.  So if I run the Corsair with 2x 150 Gal drop tanks, I should set this to 537.  When I do this it's now reading that I have 1227 gallons with the drop tanks equipped.  If I unequip the drop tanks in the same mission, the script displays 537 gallons.  If set the fuel capacity in the script back to 237, the internal fuel level, and then attach 2 150 gallon tanks, it reads 541 gallons.  That's still not exactly correct but it's close.

So should that value only be set to the internal tank capacity?

 

 Interesting.  The script uses the built in function to get the fuel, which is returned as a percentage (value zero to one).  What I’m doing with the script is simply multiplying that with the total capacity that you set in the script.  I’ll have a look to see what’s going on later, but what I’ll do is simple and you can try if you want.  Set fuel capacity to zero in the script and then I’ve coded it to show the text in the mission as percentage instead of gallons, and it will give you an idea what’s happening.

It almost sounds like DCS is giving a value of more than 100% fuel remaining if you are carrying the drop tanks, which I did not expect.  I didn’t test for this, as my speed trials were with a clean configuration.   

 If you get to it before I do, let us know what you’ve found.  Thanks for the feedback

Edited 17 hours ago by GTFreeFlyer

[Super Wabbit]

Haven't had a chance to test yet.  I'm wondering if the drop tanks and fuel system aren't quite finished yet on the Corsair.  I had the 2 150 gallon drop tanks equipped, set the fuel selector to the right drop tank and waited for the engine to quite.  It appears that it pulled from both drop tanks even though I never selected the left drop tank.  That's why I wonder if there is there is something not quite finished yet.  If I get to it, I'll also test this on the P-51 and the P-47 for reference.

[Super Wabbit]

TL:DR - I think the script works perfectly if you define the internal fuel capacity only.

Tested the script in the P-47 by setting the fuel capacity to 370.  Rearmed the P-47 to 100% fuel and the script displays 369 gallons which is pretty close to the theoretical max (I wonder if they are accounting for usable fuel amounts).  Added drop tanks and the total gallons goes up by each drop tank capacity.

Fuel percentage may be calculated differently based on tanks attached.  I've noticed in the rearming menu, if you put empty tanks on an aircraft, like the F-14, your current fuel percentage will change because you've increased your capacity.  If you've ever landed an F-18 with empty drop tanks, refueling takes longer and when you move the fuel slider in the rearming menu to 100%, that 100% now represents internal fuel plus drop tanks.  

Tangent/Story time:

I rearmed the P-47 down to 0% without drop tanks.  The script then displayed 1 gallon.  When that gallon was used up the engine shut off.  From the rearm menu, I left the fuel slider at 0% and added two 150 gallon drop tanks.  Script now reads 300.4 gallons and the rearm menu now shows that I'm at 81% fuel.  81% of 370 is roughly 300.  But, going from 81% to 100% fuel in the rearm menu from this configuration now displays 669.2 gallons by the script.  This is the correct value for fuel in gallons.  But I have no idea what the game is doing with its percentages calculation.  If 81% = 300 gallons, adding 19% more fuel then adds 370 gallons.   That math isn't correct so I'm assuming that DCS calculates that fuel percentage based on internal tank capacity and cannot display over 100% in the rearming menu.  Setting the script to use percentages agrees with this.  The script will show over 100% with drop tanks equipped and the amounts are accurate (with in a small margin of error).  With the script set to 370 gallons (full internal) for a P-47, with full internal fuel plus two 150 gallon drop tanks, the script displays 180.9% fuel.  181% is the calculated value.

BTW - the fuel capacity, when set to the internal fuel amount, is super accurate.  I think DCS is doing all its work based on usable fuel only, which might explain some of the math not lining up exactly.  When the script reads 0.1 gallons left, the engine is running.  As soon as it ticks to 0.0 the engine shuts down.  

 

Sorry I haven't said this before GTFreeFlyer, but thank you for this script.  It is a great tool.

As an aside, it's funny to see the Fuel Consumption and efficiency when you refuel the aircraft.  Also, pointing the script at AI aircraft gets some very interesting results.  The AI seems to be supernaturally fuel efficient.  Cruise at 15k feet for a human player sees roughly 70-75 gal/hr at ~200 knots IAS in the Corsair.  An AI flying that profile gets ~36gal/hr in the same configuration.  No combination of RPM, Throttle, Blower, cooling flaps can match that for a human player.

[GTFreeFlyer]

1 hour ago, Super Wabbit said:

TL:DR - I think the script works perfectly if you define the internal fuel capacity only.

Tested the script in the P-47 by setting the fuel capacity to 370.  Rearmed the P-47 to 100% fuel and the script displays 369 gallons which is pretty close to the theoretical max (I wonder if they are accounting for usable fuel amounts).  Added drop tanks and the total gallons goes up by each drop tank capacity.

Fuel percentage may be calculated differently based on tanks attached.  I've noticed in the rearming menu, if you put empty tanks on an aircraft, like the F-14, your current fuel percentage will change because you've increased your capacity.  If you've ever landed an F-18 with empty drop tanks, refueling takes longer and when you move the fuel slider in the rearming menu to 100%, that 100% now represents internal fuel plus drop tanks.  

Tangent/Story time:

I rearmed the P-47 down to 0% without drop tanks.  The script then displayed 1 gallon.  When that gallon was used up the engine shut off.  From the rearm menu, I left the fuel slider at 0% and added two 150 gallon drop tanks.  Script now reads 300.4 gallons and the rearm menu now shows that I'm at 81% fuel.  81% of 370 is roughly 300.  But, going from 81% to 100% fuel in the rearm menu from this configuration now displays 669.2 gallons by the script.  This is the correct value for fuel in gallons.  But I have no idea what the game is doing with its percentages calculation.  If 81% = 300 gallons, adding 19% more fuel then adds 370 gallons.   That math isn't correct so I'm assuming that DCS calculates that fuel percentage based on internal tank capacity and cannot display over 100% in the rearming menu.  Setting the script to use percentages agrees with this.  The script will show over 100% with drop tanks equipped and the amounts are accurate (with in a small margin of error).  With the script set to 370 gallons (full internal) for a P-47, with full internal fuel plus two 150 gallon drop tanks, the script displays 180.9% fuel.  181% is the calculated value.

BTW - the fuel capacity, when set to the internal fuel amount, is super accurate.  I think DCS is doing all its work based on usable fuel only, which might explain some of the math not lining up exactly.  When the script reads 0.1 gallons left, the engine is running.  As soon as it ticks to 0.0 the engine shuts down.  

 

Sorry I haven't said this before GTFreeFlyer, but thank you for this script.  It is a great tool.

As an aside, it's funny to see the Fuel Consumption and efficiency when you refuel the aircraft.  Also, pointing the script at AI aircraft gets some very interesting results.  The AI seems to be supernaturally fuel efficient.  Cruise at 15k feet for a human player sees roughly 70-75 gal/hr at ~200 knots IAS in the Corsair.  An AI flying that profile gets ~36gal/hr in the same configuration.  No combination of RPM, Throttle, Blower, cooling flaps can match that for a human player.

Love this.  Thank you.  I will update the instructions in the script later today based on your findings, and you’ll get a special mention in the credits as well