Vitormouraa Veteran



Join Date: Oct 2014 Location: SC, Brazil Posts: 3,198

How to calculate your current flight time and fuel flow oscillations



Today I just wanted to show you a quick, easy way to have a rough idea of your current Flight Time. But first of all, I'd like to say that these methods, aren't by any means, professional ways to calculate your exact time available in the air, instead, it's just a quick way to find out your current flight time.



But why current flight time? because your current flight time (let's call it CFT) varies quite a lot depending on the atmosphere such as temperature, altitude, flight conditions such as speed and finally, PLA (Power Lever Angle).



There are two methods to find out your CFT;



1° Method: Take your total fuel, subtract from your bingo, then the result is divided by your current Fuel Flow (FF - pph), after this, you should multiply the result by 60 (60x). The result should be your CFT in minutes.



2° Method: Take your total fuel, subtract from your bingo to find out your usable fuel, divide by your current FF (Fuel Flow - but this time, it should be in pounds per minute of fuel ppm, instead pounds per hour pph). The result should be your CFT in minutes just like the 1° Method. This method is actually used in real life operations (TOT-BINGO)/FFppm. Also special thanks to Chicken from our Discord To find out your PPM is very simple, take your PPH and divide it by 60. Do the opposite to find out your PPH.





Atmosphere conditions: +15°C, 29.92 inches of mercury (standard pressure).



1° Scenario using the first method:



My flight conditions are as follows:



250 KIAS, 220ft altitude (let's call it Sea Level - SL)



FF: 8,760PPH Total usable fuel: 3,800= 3,800/8,760= 0.433*60= 26 minutes of flight.



Spoiler :



2° Scenario using the second method:



My flight conditions are as follows:



250 KIAS, 15,000ft altitude



FF: 123PPM Total usable fuel: 3,800= 3,800/123= 30 minutes of flight.



Spoiler :



3° Scenario using the second method again:



My flight conditions are as follows:



250 KIAS, 25,000 ft altitude



FF: 0.99PPM Total usable fuel: 3,800= 3,800/0.99= 38 minutes of flight.



Spoiler :



-----------------



Important notes: As I said above, your CFT will vary as soon as you increase/decrease your Indicated airspeed, change your altitude or increase/decrease your throttle. Also, I was using Infinite fuel in order to have the same value at all times, so doing that you are actually able to see the differences. 26 minutes, 30 and 38.



Why does the fuel flow vary so much? Well that's because the engine has to adjust its FF in order to work properly, as you increase your altitude, the pressure decreases, and air density decreases as well, so the engine has to "trim out" the fuel flow in order to keep the engine under normal conditions, temperatures and others.



I did this based on the Harrier engine, but you can do this for any aircraft, as long as you have Fuel Flow meter and your usable fuel or total fuel subtracted from the bingo.



Never forget to calculate the Bingo fuel, you need to go home after you finish your mission!



Thank you guys, I hope that was useful. If you have any suggestion or correction, please let me know. Hey guys,Today I just wanted to show you a quick, easy way to have a rough idea of your current Flight Time. But first of all, I'd like to say that these methods, aren't by any means,ways to calculate your exact time available in the air, instead, it's just a quick way to find out your current flight time.But why current flight time? because your current flight time (let's call it CFT) varies quite a lot depending on the atmosphere such as temperature, altitude, flight conditions such as speed and finally, PLA (Power Lever Angle).There are two methods to find out your CFT;Take your total fuel, subtract from your bingo, then the result is divided by your current Fuel Flow (FF - pph), after this, you should multiply the result by 60 (60x). The result should be your CFT in minutes.Take your total fuel, subtract from your bingo to find out your usable fuel, divide by your current FF (Fuel Flow - but this time, it should be in pounds per minute of fuel ppm, instead pounds per hour pph). The result should be your CFT in minutes just like the 1° Method. This method is actually used in real life operations (TOT-BINGO)/FFppm. Also special thanks to Chicken from our DiscordTo find out your PPM is very simple, take your PPH and divide it by 60. Do the opposite to find out your PPH.Atmosphere conditions: +15°C, 29.92 inches of mercury (standard pressure).1° Scenario using the first method:My flight conditions are as follows:250 KIAS, 220ft altitude (let's call it Sea Level - SL)FF: 8,760Total usable fuel: 3,800= 3,800/8,760= 0.433*60= 26 minutes of flight.2° Scenario using the second method:My flight conditions are as follows:250 KIAS, 15,000ft altitudeFF: 123Total usable fuel: 3,800= 3,800/123= 30 minutes of flight.3° Scenario using the second method again:My flight conditions are as follows:250 KIAS, 25,000 ft altitudeFF: 0.99Total usable fuel: 3,800= 3,800/0.99= 38 minutes of flight.-----------------As I said above, your CFT will vary as soon as you increase/decrease your Indicated airspeed, change your altitude or increase/decrease your throttle. Also, I was using Infinite fuel in order to have the same value at all times, so doing that you are actually able to see the differences. 26 minutes, 30 and 38.Why does the fuel flow vary so much? Well that's because the engine has to adjust its FF in order to work properly, as you increase your altitude, the pressure decreases, and air density decreases as well, so the engine has to "trim out" the fuel flow in order to keep the engine under normal conditions, temperatures and others.I did this based on the Harrier engine, but you can do this for any aircraft, as long as you have Fuel Flow meter and your usable fuel or total fuel subtracted from the bingo.Never forget to calculate the Bingo fuel, you need to go home after you finish your mission!Thank you guys, I hope that was useful. If you have any suggestion or correction, please let me know.

SplashOneGaming

Discord



https://splashonegaming.com __________________ Last edited by Vitormouraa; 03-01-2018 at 08:42 PM . Reason: Small fix