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  • Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.

    Post 16 Update

    Post 17 Warning

How To Adjust Speed?

Pips

Pips

Charter Member
No, it's not about throttle use. :) I mean in the file of a particular aircraft.

I fly almost exclusively vintage aeroplanes, eg Bleroit, Antoinette, F2B, Jenny, Curtis Cruze to name just a few. Now while the models are superb, their flight characteristics occassionally leave something to be desired. The most common problem is the they are too fast, sometimes up to 15-20 knots.

Sooo, what do I need to do to change the speed in the aircraft file?
 
It's not easy, the slow-speed flight envelope in FS is one of the weakest areas. However, are you SURE the speed is wrong? Knots was not a common currency in ASI's of the day and you might be confusing miles per hour with knots.

If you are satisfied then you will need to modify BOTH parasite drag and induced drag from the flight tuning section in the aircraft.cfg and then probably the propeller thrust scalar as well. BACK UP the aircraft .cfg before modifying anything.

Be aware that any adjustment CAN have unwanted side effects, as the .cfg modifies what is in the .air file, and many sections there are inter-dependent.
 
Oh yes, the speed is definitely wrong. Two of the aircraft I have in mind are capable of 70 knots in FSX. Whereas in real life they couldn't do more than 45-50 mph. That's a big difference.

Looking at the aircraft cfg for one of them is as follows:
[flight_tuning]
cruise_lift_scalar=1.000
pitch_stability=1.000
roll_stability=1.000
yaw_stability=1.000
parasite_drag_scalar=1.500
induced_drag_scalar=1.201
elevator_effectiveness=1.500
aileron_effectiveness=1.000
rudder_effectiveness=1.000
elevator_trim_effectiveness=1.000
aileron_trim_effectiveness=1.000
rudder_trim_effectiveness=1.000

From what your saying I gather I have to reeduce those values? Is there a rule of thumb for that, or just trial and error?
Cheers. :)
 
Hmmm, been playing around with the 'flight tuning' values, and getting some weird results. No surprising given I'm flying blind in this.

Is there by chance a tutorial that covers this sort of thing? :)
 
Pips said:
Hmmm, been playing around with the 'flight tuning' values, and getting some weird results. No surprising given I'm flying blind in this.

Is there by chance a tutorial that covers this sort of thing? :)
Click to expand...
Try here for a start http://pagesperso-orange.fr/hsors/
whilst there grab a copy of AirEd and the ini file http://pagesperso-orange.fr/hsors/fsairfile.html its a bit dated but will still do 90% of the fsx settings.
Open the airfile in aired and got to section 1101, in the drag section look for Cdo drag coef. zero lift, raising the number slows down the aircraft, lower number speeds up the aircraft.if you need to go outside 20 to 75 to get the correct max speed(make sure all weather is turned off ;) ) then,you will need to look into engine and prop params and that gets complicated :) A number of 20 to 75 isnt a solid rule,Its just a ball park figure and an indication that something is wrong elsewhere.
Cheers
Wozza
 
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