FSX Thrust acceleration

[super64]

Is it possible (and how) to reach faster reaction with thrust?
I think it's must be possible somehow, because for example an aircraft reaches full thrust from 50% straight away, but another needs to reach full thrust 5-10 seconds.

 

[jx_]

increase the upward curve of the high RPM in table 1505.

 

[super64]

Thank you, it works. Because of this (or not - I don't know) it's too fast on low altitude. Can I decrease the speed (and how) on low altitude (on high altitude it's all right).

 

[jx_]

Always set your tables based on Sea Level performance first. Set 1505 to be correct at a sea level airport with the brakes locked.

Then you need to set your CN1 & CN2 by mach, and CN2 by altitude correctly in tables 1502-03-04.

Those tables interact based on sea level mach and correct to altitude.

It 'sounds' like your high altitude CN2 is lower than your low altitude CN2. This could be causing the problem.

 

[super64]

Thank you, but it's exceeds my modest knowledge.

 

[Flusirainer]

aircraft.cfg

[TurbineEngineData]
fuel_flow_gain=0.002500
inlet_area=9.420000
rated_N2_rpm=11750.000000
static_thrust=14555.000000
afterburner_available=0
reverser_available=1



This value controls the spool up time rate. The bigger, the faster.

 

[hgschnell]

where can we find data of real jet engines?

 

[vololiberista]

aircraft.cfg

[TurbineEngineData]
fuel_flow_gain=0.002500
inlet_area=9.420000
rated_N2_rpm=11750.000000
static_thrust=14555.000000
afterburner_available=0
reverser_available=1

This value controls the spool up time rate. The bigger, the faster.

I'm using the modified 1505 table recommended by JX which avoids the engine surge on start-up. fuel_flow_gain has to be set to =1

The only problem with this model is that engine respose to lower throttle settings is too slow

vololiberista

 

[jx_]

aircraft.cfg

[TurbineEngineData]
fuel_flow_gain=0.002500
inlet_area=9.420000
rated_N2_rpm=11750.000000
static_thrust=14555.000000
afterburner_available=0
reverser_available=1



This value controls the spool up time rate. The bigger, the faster.

This doesn't answer the question. It only addresses overall response and not specific RPM or altitude.

The only problem with this model is that engine respose to lower throttle settings is too slow

I still haven't had a chance to get to it. Have you tried a steeper curve on the high end?

 

[vololiberista]

I still haven't had a chance to get to it. Have you tried a steeper curve on the high end?

I did have a go, but it didn't seem to make any difference.
vololiberista

 

[jx_]

Not the vertical line I told you to try. That was just a test.

Try reducing each x line above 70CN2 by an increasing percentage.

For example

* 0.9
* 0.8
* 0.7
* 0.6
etc...

Should make the radius of the upward curve shorter and help with the throttle capture.

 

[vololiberista]

Those numbers made no differeence at all I'm afraid. I would have to increase them by a substantial amount such that the curve would not be smooth.
vololiberista

 

[jx_]

okay i will keep working on it

 

[vololiberista]

These are my numbers if that helps:-
x=0 y=23
x=250 y=25
x=450 y=28.5
x=600 y=36.5
x=680 y=43.6999
x=758 y=50.8
x=828 y=59.7
x=893 y=68.2998
x=980 y=82
x=1050 y=105

From the point of view of fuel to idle it's close enough being about a second and a half slow.
Also from idle to max throttle is around a second too slow. Only pilots that fly these engines for real might notice that.

Idle to 68% (breakaway thrust) takes a week
as does idle to 96%
To get the correct engine response: In case one advance the throttle to 85% and pull it back to 68%
And case two full throttle on the brakes. As it passes 85% release brakes and throttle back to 96%
vololiberista