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Post by johnhinson on Mar 12, 2024 12:26:44 GMT -5
In all the life of FS2004 there has been, for me, one thing that has never been fixed (and is a major irritant to me) - the taxi behaviour of 90% of turboprop aircraft. It is impossible to keep a constant speed of around 15 knots, even using a taxi speed control gauge.
I can only think of two turboprops that behave anywhere near realistically on the ground - the Vickers Vanguard and the Bristol Britannia. This implies there is a solution, but . . . what is it?
John
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Post by Tom/CalClassic on Mar 12, 2024 12:33:37 GMT -5
One of the problems is that many of the planes use constant speed engines, and those are not modeled well in FS.
One thing you can try is to move the prop lever from full fine to full coarse, sometimes that slows them down.
Another thing to do is after landing shut down two engines (varies with the plane, look at videos) so the plane will taxi slower.
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Post by johnhinson on Mar 12, 2024 19:53:48 GMT -5
Thanks, Tom. Slowing them down is not really the issue, it is maintaining a steady speed (with the massive engine surges) that seems impossible to achieve. When we have dealt with so much that is "not modelled well" over the 20 or so years of FS2004, I'm surprised this issue hasn't been given a lot of attention.
John
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Post by mrcapitalism on Mar 12, 2024 20:16:25 GMT -5
Do you have this problem with the default C-208B?
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Post by Tom/CalClassic on Mar 12, 2024 22:20:36 GMT -5
It hasn’t gotten a lot of attention because no one has come up with a reasonable solution. I try to find a low power level that provides a reasonable speed (usually idle and coarse pitch) and then use only brakes to control the speed, never touching the engines.
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Post by johnhinson on Mar 13, 2024 9:39:05 GMT -5
It hasn’t gotten a lot of attention because no one has come up with a reasonable solution. I try to find a low power level that provides a reasonable speed (usually idle and coarse pitch) and then use only brakes to control the speed, never touching the engines. That's broadly what I do (although idle won't move any of my aircraft but I have suitable power figures noted for each one), but typically I find if I stop, the aircraft won't move again without a further burst of power. It is so unbelievably un-prototypical! I think perhaps the US made the transition to jets so quickly there weren't that many TPs kicking around but there were a huge range of them in Europe which is why I find them so frustrating. Best regards, John |
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Post by johnhinson on Mar 13, 2024 10:36:03 GMT -5
Do you have this problem with the default C-208B? I had never tried it before, but yes, it seems to taxi quite nicely. J |
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Post by Tom/CalClassic on Mar 13, 2024 10:42:38 GMT -5
One reason for that is that MS modeled the plane’s PT6 engine as the turboprop model. Unfortunately it is not one typical in our era…
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Post by mrcapitalism on Mar 13, 2024 12:15:46 GMT -5
I had never tried it before, but yes, it seems to taxi quite nicely. J Okay good, next question: How do the CalClassic CV-580 and F-27 taxi? |
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Post by johnhinson on Mar 13, 2024 20:26:37 GMT -5
I had never tried it before, but yes, it seems to taxi quite nicely. J Okay good, next question: How do the CalClassic CV-580 and F-27 taxi? Dreadfully! As I previously described. John |
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Post by johnhinson on Mar 21, 2024 4:29:49 GMT -5
Considering the apparent lack of interest here, I am doubting many are concerned about realistic taxying, but I have been systematically going through the turbo-prop aircraft I have on my setup to compare behaviour. All perform nicely once airborne, but most can only be described as "awful" whilst on the ground. These are my findings:
Taxi reasonably well, controllable:
Bristol Britannia
Canadair CL44
Ilyushin IL-18
Tupolev Tu114
Vickers Vanguard
Taxi poorly, tiny throttle adjustments cause delayed surges in power:
Armstrong-Whitworth Argosy
Fairchild F-27/FH-227
Focker F27 Friendship
Handley Page Herald
Hawler Siddeley HS748
Convair 580
Convair 640
NAMC YS-11
Vickers Viscount (all varieties)
Accelerates on idle
Lockheed Electra
It seems from the above that larger, four-engined planes perform best, but the key interest to me is to find out how to fix the delayed surge in the smaller examples (mostly twin-engined, but not all). If the delay to the winding up of the engines could be made instantaneous, I'm sure they would be far more controllable on the ground. I'm happy to do my own meddling if anybody can point me at the setting - I have tried over many, many years without success.
John
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Post by Defender on Mar 21, 2024 5:31:40 GMT -5
John,
The solution might lie in the airfile table 511 which controls prop thrust levels through the range of prop pitch settings. I've used Aircraft Airfile Manager to shorten the DC-7C's take off run and to enable the Stratocruiser to taxi on 2 engines by adjusting full fine pitch thrust and so not affecting cruise etc.
Trouble is I know nothing about turbo prop settings but you could compare each aircraft's 511 table to see if there's a pattern that could be followed. Also it's possible to copy and paste 511 from aircraft to aircraft but it then affects all aspects of the flight.
Bill
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Post by johnhinson on Mar 21, 2024 8:37:32 GMT -5
Thanks, Bill, I will certainly look at that.
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Post by Defender on Mar 21, 2024 9:51:08 GMT -5
I loaded up the V810 to see what happens and the problem seems entirely due to the delayed throttle response which may or may not be realistic, I don't know. Table 511 doesn't look too different from the stock King Air's.
It takes 24% throttle to start rolling on concrete but when reducing to say 18% the actual engine thrust keeps on falling and so the aircraft eventually stops. There's another useful tool which allows you to observe the throttle/thrust relationship and the settings that table 511 is using. Look for AFSD_portable.exe. It only runs when an aircraft is loaded and it needs a separate window from FS.
I note Tom's comments but I'll try to find out what controls that power delay.
Bill
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Post by Tom/CalClassic on Mar 21, 2024 9:52:58 GMT -5
FSAviator concentrated on flight/takeoff/landing behavior and pretty much ignored taxi. He would change it, but only if it didn’t change flight behavior in any way.
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