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Post by elmar on May 11, 2013 11:52:51 GMT
Hello HJG members!
I recently downloaded the B717, but the drag of the wheels or what ever while taxiing is so much, that I need continuously more than 50% of thrust, that's far too much. Does anybody know how to reduce the rolling resistance?
I also checked the weight, so it's not overweight.
Best regards!
Elmar
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Post by aerofoto - HJG Admin on May 11, 2013 22:06:21 GMT
A number of factors can come into play here .... BUT .... in the case of most simulations (to which this may apply .... and to some more than others) it's the natural FS "GROUND FRICTION" phenomenon that becomes the imposition and results in precisely what you're describing/experiencing .... and there's usually "bugger-all" one can do about it without, potentially, risking screwing-up other things.
In most cases .... this particular phenomenon forces the use of an abnormal amount of engine thrust just in order to be able to commence ground rolling, but, in most cases, this may be reduced, progressively, once taxiing/momentum has been gained .... so .... shouldn't be a major/too much on an imposition really.
Some FS add-on scenery can also impose their own ground friction issues too .... again greater or lesser effect.
It's quite a difficult situation for FS aircraft developers to try to triumph over .... simply because, in many cases, when a simulation is programed to ground roll "with relative ease", then this often results in "overly-excited/overly-eager" flight performance (often to rediculous extremes) .... and .... as attempts are made to try to arrest this tendancy it often risks in screwing up the fidelity of other flight performance parameters.
HJG generally prioritizes flight performance over ground performance. This's quite a common compromise in FS .... meaning .... in the case of some HJG simulations (not alll of them) one will need to apply a bit more power than is realistic in order to start ground rolling, but, once in flight, the simulations performance should be "fairly close" to reality .... within the boundaries of certain FS limitations.
I note you say your B717-200 simulation wasn't overweight, but, aircraft weight .... even "near full" .... can/will impose a little resistance to ground rolling.
I conducted some brief tests this morning .... using the HJG B717-200. I loaded the simulation as follows ....
LEFT TANK = 90%
CENTER TANK = 68.5%
RIGHT TANK = 90%
NO PAYLOAD (PAX FREIGHT) ADJUSTMENT
The above fuel (only) adjustment resulted in an overload of just 21 LBS. Engine power required .... just to commence ground rolling was as follows ....
N1 57%
N2 73%
.... and then reducing to
N1 49%
N2 70%
.... in order to maintain a near constant ground roll speed of some 15-18 KTS.
PLEASE NOTE: The engine parameters I'm quoiting are applicable to the HJG hosted SOUTHEY version MDX/B717-200 panel.... but .... these values could differ "considerably" with the gauge programming of other non-HJG offered panel options.
Engine power could then be further reduced .... which would, then, obviously, result in a slowly decaying ground speed, butthen, be boosted slightly, as necessary, in order to restore/maintain a descent and almost constant ground taxiing speed of around 10-15 KTS.
Mark C
AKL/NZ
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