Low engine output thrust

I've done a low speed ground acceleration test at close to sea level airfield (Sochi), temperature = 15 C

During the test I measured low speed acceleration (flaps up), watching the track at time slowed to 1/8 

m = 26821 kg (full fuel no load)

max AB acceleration was 5,8 m/s2

after that I measured deceleration at low speed, engines off

deceleration engine off (59-45 kts range) average 0,7 m/s2

Using these 2 values:

Drag :   18 775N

Thrust: 174 337N (174,3 kN)   

Thrust per engine : 87,15 kN   <-------> according to the chart it should be more than 110 kN

Did another test with a low mass of 18206kg (10% fuel)

That acceleration showed 85,6 kN per engine, so changing the weight does not produce anything funny, it is just the thrust is less than expected.

Does that chart account for the intake fence in take off config? That could reduce thrust quite a bit by blocking some of the air.

Tried to make an in-flight test at 2000 m same conditions around M 0,5

This is much less accurate because I did not turn the engines off when trying to measure deceleration in level flight.

Anyway I got around 92 kN / engine, while the chart shows around 102 kN, so closer.

This difference could be there because I did not calculate with the idle thrust.

is this chart mentioned for an installed engine?  the amount it is low sounds like basic installation losses (intake friction and gearbox power extraction).

On 1/16/2021 at 11:56 PM, HWasp said:

Did another test with a low mass of 18206kg (10% fuel)

 

That acceleration showed 85,6 kN per engine, so changing the weight does not produce anything funny, it is just the thrust is less than expected.

 

Does that chart account for the intake fence in take off config? That could reduce thrust quite a bit by blocking some of the air.

 

замерь разгон масса самолета 20000кг высота 1000м разгон от 600км до 1100км/ч

Could this be the source of the poor transonic acceleration in game compared to the Su-30MK2 video?

http://www.mycity-military.com/uploads2/154453_865801817_Cy27_F15.pdf
 

this is the tsAGI report mentioned earlier, it’s been posted before and the devs are aware of it.

also of interest