Turboprop flight dynamics

[Guest andyb]

Hi Folks. I hope I'm in the right forum. Since moving to FS2004 I cannot seem to get many turboprop-engined aircraft to react quickly to power lever settings. There is an unrealistic lag from idle to 90% plus in the order of 5-10 secs. Are there any air file parameters that I can revise to speed up the reaction to power lever changes?AndyB

[kanogek 0]

Well, my guess is that 5 sec from idle to say a 90% is not that unrealistic.10 sec would be, but i suppose that also depends on the type of engine.I am a ground engineer and regularly do ground runs on aircraft with turboprop engines and in my experience it is ok.For instance the PW 125 takes some 5 sec to go from ground idle to take off power and that is during a slam accellerate test.One other engine, the RR dart (which is old, but still going strong being conceived at the end of WW 2) takes longer to accellerate. If you would slam the throttles on this one, you find yourself sweeping the tarmac in order to remove the pieces of turbine blades you just burnt out.Apart from that, i think it should be editable in some cfg file but i cannot assist you on that unfortunately.grtzWillemwww.f27-project.tk

[Guest Milton]

Take a look at the *.air file, table 1501/Spool up rate.

[Guest andyb]

Hi Willem!The aircraft is a J32 Jetstream and its response is sluggish unlike, say, the KingAir. I was on a J32 the other day right down at the front so I could see everything the crew were doing. When they pushed the prop levers the response was almost immediate and quite torque-y. When they pushed the power levers the engines responded within a few seconds and when brakes were released a few seconds later the kick was amazing. I suspect the air file has a few problems.Cheers!AndyB

[Guest andyb]

Thanks for that. I have been looking at that particular parameter but I cannot seem to make it have any effect. Is it coupled with another and if so how would you revise them to make an effect?RegardsAndyB

[Guest Douglas K]

You should edit the following entry in aircraft.cfg:fuel_flow_gain=0.011It

[Guest andyb]

Hi Douglas.Thanks for the info. No wonder 1501 changes seemed to make precious little difference. I'll look into that link when I get a bit more time - it might save a lot of heartache.Cheers!AndyB

[Guest Douglas K]

No problem!:)Douglas

[Guest IanK]

Actually he meant T15051505=*!Turbine Corrected Fuel Flow vs CN2,tbldb1505h=Corrected Fuel Flow (x) vs CN2% (y)|FF(pph) = Thrust_Reference * F1505(CN2) * Delta_t/sqrt(Theta_t)|Shape affects spool rate|Not in TurboProps (KingAir)Ian

[Guest Douglas K]

>>>>Actually he meant T15051505=*!Turbine Corrected Fuel Flow vs CN2,tbldb1505h=Corrected Fuel Flow (x) vs CN2% (y)|FF(pph) = Thrust_Reference * F1505(CN2) * Delta_t/sqrt(Theta_t)|Shape affects spool rate|Not in TurboProps (KingAir)<<<

[Guest IanK]

Hello Douglas,yes you are right and I did forget about fuel_flow_gain but with all these propulsion systems I sometimes get confused.It was the 1501 thing I noticed. If you search aired.ini for turboprop there are lots of things to tweak such as friction, gear ratios. Also prop MoI etc.Thanks for this opportunity to correct my self.Ian

[wsieffert 0]

Has anyone tried adding T1505 to a turboprop air file to see what would happen?W. Sieffert

[Guest Douglas K]

>>>>Hello Douglas,yes you are right and I did forget about fuel_flow_gain but with all these propulsion systems I sometimes get confused.<<<