Classic British Flight Sim

The following obviously made sense to the designers of FS9 but I am finding the following from FS2004 SDK difficult to get to grips with.

Quote from FS2004SDK aircraft: The following factors can be found in the acft cfg.

lift_scalar lift_scalar = 1.0 The percentage of total lift due to flap deflection that this flap set is responsible for at full deflection.

drag_scalar drag_scalar = 1.0 The percentage of total drag due to flap deflection that this flap set is responsible for at full deflection.

pitch_scalar pitch_scalar = 1.0 The percentage of total pitch due to flap deflection that this flap set is responsible for at full deflection.

What does the setting of '1.0' represent?

Take 'Lift Scalar' - How can one calculate or estimate the amount of extra(?) lift produced by a flap at full extension?

Surely the essential job of a flap is to allow the aircraft to fly at a slower speed before it succumbs to a stall. This is achieved by effectively increasing the wing area at the expense of increasing the drag thus requiring a higher throttle setting to maintain a given speed. Once again how does one calculate 'full deflection drag'?

If one sets 'Pitch scalar' at "0.0" does that mean that the nose of the aircraft will NOT pitch up when the flaps are lowered?

I am sure that the FS designers definition makes sense - but not to me at present. Can a forum member please help to clarify these explanations?

'Drag scalar'.

Hi,

From what I have gleaned playing with FDE, the cfg values are a factor of the value in the air file. Set the factor to 1.0 (default mostly) and the figure in the air file is used directly. If you need to increase or decrease the effect then you can alter the factor greater than or less than 1.0 in the cfg file.

Regards

John

Hobby,

As John says, the "1.0" is the default FS scalar which influences the source data in the .air file of the aircraft concerned. These scalars are much easier to make adjustments with than the source data, since this may not be linear in its effects, but the scalars are.

The "lift factor" could be increased, say to 2.0, to give more flaps lift at the same airspeed to reduce the descent rate.

The "drag factor" can be increased to reduce airspeed at a given descent rate

The "pitch factor" can be used to increase or decrease the pitch up or down angle induced by the flaps lowering. Adjusting this can help reduce the amount of manual or trim pitch you need to apply in landing configuration.

If you have real aircraft data you can adjust these factors to have the plane "follow the numbers", but if not I find the best way is to use the flaps to give speed and descent rates appropriate to the type of aircraft and typical approach and landing speed. Descent rate is typically 5 x the airspeed - 100kt=500fpm so use this as the basis of your changes. Try doubling or halving the factor initially then reduce the increments accordingly. Don't forget that the full effect applies to full flaps, although there will be a proportional effect with flap increments but not necessarily linear.

Many thanks Degsy. Your reply has cleared much of the ambiguity of the FS9 developers away. Now back to the hangar.