Su-25T Climb and Cruise Performance (in-game)

[Cmptohocah]

Hello everyone,

 

here are some Su-25T flight characteristics that I got from flight tests performed in Flaming Cliffs 3 (1.2.16):

 

Climb performance

 

Test for climb performance were conducted under following conditions:

• initial altitude: 200m [MSL]
  
• climb thrust: 97% N1
  
• time of climb: 60s
  
• payload: all pilons with 100% fuel
  
• constant indicated air speed (IAS)
  
• flight time: 60s
  

 

Obtained results are in Fig. 1-0:

Fig. 1-0

 

Curve representing simulator performance (blue) and poly. approximation (dark orange) indicated that optimal climb rate is obtained at speeds ranging from 450km/h to 500km/h IAS.

 

 

Cruise performance

 

Cruise performance data was measured under following conditions:

• constant altitude [MSL]
  
• constant cruise thrust: 95% N1*
  
• bingo (return to base) fuel: 800kg
  
• payload: all pilons with no external fuel tanks
  

 

*- thrust settings below 95% N1 at altitudes above or equal to 3000m are not sufficient to sustain efficient level flight at constant altitude.

 

Flight endurance (time airborne) and range were calculated using the data from table Fig. 1-1:

 

Fig. 1-1

 

Range results were calculated using both the specific fuel consumption and covered distances at different altitudes.

Range data is shown in Fig. 1-2:

Fig. 1-2

 

Data indicates that flight under full load at altitude of 7000m [MSL] and 95% N1 thrust setting, results in longest flight range and longest flight time.

Flying with same thrust settings but at altitude of 3000m [MSL] will result in shortest range, but will produce highest ground speed.

 

Please note that the data provided does not take into account the burn of fuel which results in aircraft weight decreasing. Also no climb to cruise altitude fuel use was considered.

 

Comments and suggestions are more than welcome!

 

Regards,

[DarkFire]

I love flying the Su-25T and have always wondered about those data sets. Thank you very much for taking the time to do the research and posting the results.

 

+1 rep to you!

 

One question: when you specify the payload as "all pylons with no external fuel" do you mean all pylons empty or all pylons carrying a nominal weapon?

[Cmptohocah]

One question: when you specify the payload as "all pylons with no external fuel" do you mean all pylons empty or all pylons carrying a nominal weapon?

 

Sorry I wasn't very clear in my first post: all the pylons were loaded with heavy weapons such as Kh-58 and Kh-25MPU also R-73s and ECM modules.

 

Thank you for your support, I hope you will find it useful. Please leave a comment if you find any discrepancies.

 

Cheers :joystick::pilotfly:

[JNASova]

Thanks for sharing results with us.

[SFAL]

Great!

Please post weapon loadout. Rocket pods have lover drag. KGMU dispensers have high drag...etc..

 

I was wondering about the max altitude. I rarely fly above 5000m with all pylons loaded.

Thanks for the experiment...

[DarkFire]

Sorry I wasn't very clear in my first post: all the pylons were loaded with heavy weapons such as Kh-58 and Kh-25MPU also R-73s and ECM modules.

 

Thank you for your support, I hope you will find it useful. Please leave a comment if you find any discrepancies.

 

Cheers :joystick::pilotfly:

 

Ah right, I thought that might have been the case. Could you post the loadout you used? I hate to think how much fuel one would have to use getting a T-frog up to 7Km altitude. Very interesting idea though, I'll have to test this out...

 

I also agree 100% that throttle settings of below 95% are insufficient to maintain altitudes of above 3000m with a heavy payload.

[159th_Falcon]

Ah right, I thought that might have been the case. Could you post the loadout you used? I hate to think how much fuel one would have to use getting a T-frog up to 7Km altitude. Very interesting idea though, I'll have to test this out...

 

I also agree 100% that throttle settings of below 95% are insufficient to maintain altitudes of above 3000m with a heavy payload.

 

I have quite often flown a fully loaded T above 3000 meters whit a throttle setting between 90 and 95%.

Once you get up there, you don't need a whole lot to stay there.

 

Mind you, this was enroute towards the targets, so straight and level.

[xentxo]

 

Test for climb performance were conducted under following conditions:

• initial altitude: 200m [MSL]
  
• climb thrust: 97% N1
  
• time of climb: 60s
  
• payload: all pilons with 100% fuel
  
• constant indicated air speed (IAS)
  
• flight time: 60s
  

...

 

optimal climb rate is obtained at speeds ranging from 450km/h to 500km/h IAS.

 

Actual i dont know what you mean with "optimal climb rate".

 

There is Vy = best rate of climb (best time) and Vx = best angle of climb (best altitude) and both performances are done with 100% thrust and not with 97% thrust.

 

For example Vy at 1000m is between 530km/h (8000kg load,clean) and 725km/h (1000kg load, clean) at a standard day =15degCel, no wind, 1000m Alt.

Edited May 4, 2015 by xentxo

[Cmptohocah]

Actual i dont know what you mean with "optimal climb rate".

 

There is Vy = best rate of climb (best time) and Vx = best angle of climb (best altitude) and both performances are done with 100% thrust and not with 97% thrust.

 

For example Vy at 1000m is between 530km/h (8000kg load,clean) and 725km/h (1000kg load, clean) at a standard day =15degCel, no wind, 1000m Alt.

 

Vy would be the top of the curve, and Vx would be just after apex.

 

I was refering to Vy as the 'optimal climb rate' since Vx is used to clear obstacles.

[Fri13]

These were very nice informations to know. Especially with the loadouts.

[Cmptohocah]

Great!

Please post weapon loadout. Rocket pods have lover drag. KGMU dispensers have high drag...etc..

 

A little late but never the less:

2 x Kh-58

4 x Kh-25MPU

2 x R-73

2 x ECM

1 x L-081 "Fantasmagoria"