Nosewheel Nosedive on Braking

[Fleet Canuck]

I realize the brakes on FS2004 are either off or on, so there's no way to brake slightly. Different aircraft seem to have different levels of braking programmed in.

I find some aircraft, like Tim Conrad's top notch AA5B Grumman Tiger or Bill Lyon's excellent PA-22 Tripacer have extreme amounts of pitch down upon applying the brakes, even at slow speeds. Is there a way in the cfg file to "stiffen up" the spring on the front gear?

[srgalahad]

there will be several answers with mods to fix the issue, depending on the aircraft, but if you are using pedals with toe brakes you can adjust the sensitivity. In FS, Options/Controls/Sensitivities. If you have any interest in realism a good set of pedals are worth the $$ (real planes don't have push-button brakes).

Some real a/c do 'bob' on braking anyway as they have 'soft' shock struts on the nose gear.

[srgalahad]

there will be several answers with mods to fix the issue, depending on the aircraft, but if you are using pedals with toe brakes you can adjust the sensitivity. In FS, Options/Controls/Sensitivities. If you have any interest in realism a good set of pedals are worth the $$ (real planes don't have push-button brakes).

Some aircraft actually do 'bob' on braking anyway... more than most people expect as they actually have 'soft' shock struts.

[Z-claudius24]

Hi,

Must ajust damper in the contact points !
Give some of the aircrafts you have problems (exact file name) and I can take a look when time allow

[fliger747]

Pedals allow modulated braking, button braking, such as with the trigger or period key etc is eith er full on or off. Imagine driving your car that way! The braking scalar in the cfg file could be adjusted by substituting a smaller value, reducing the brake effectiveness, or the contact point for the nose gear could be adjusted. However the stiffening of the nose gear is not a easy one number adjustment as all parameters are carefully set to work ith each other to keep the visual effects correct, wheel sitting on the pavement and not submerging or riding above the surface etc.

Good luck! T

[Lionheart]

For me, as a Dev, its a nightmare to set them as Tom hit it on the target. They are inter-twined. Dampening can be adjusted without having to mess with the other two, but the other two will effect everything, even by just messing with one... (especially if you mess with one... ).

You could do this... Backup the config file somewhere, then copy /paste other nose wheel 'settings' into yours and see if you can find one that works best. That is a quick way of doing it. You can even do it with FS running, and reboot your plane to see the new settings take effect, though after a few reboots, it may start sticking and stop updating, of which you can reboot the sim and start testing over again.

There is a formula for this, but I have found it rarely works (for me). Milton knows the formula well and he can get it to work quite well.

Bill

[Tom Clayton]

I once had a plane (really wish I could remember which one) that had a "Brake Pressure" gauge in the panel. I noticed that it actually took a second or two for full pressure to come up when I hit the trigger on my controller. Because of that, I learned that I could modulate the trigger to keep the pressure down to a moderate level so that I didn't come to a screaching halt - which in real-life would likely result in a brake fire.

I've several planes that have reduced values in the toe brake line in the cfg in order to comensate for the lack of modulation in a trigger brake. But the problem with that is you lose the ability to abort takeoff in an emergency. Pedal owners also are then required to apply full toe-braking force just to do a normal stop.

Try leaving the brake scalar at 1.0 and tapping the brake trigger - with practice you can learn just how long to hold each tap to get the right amount of braking force.

BTW, anybody else remember ever seeing that brake force gauge anywhere?

[Sunny9850]

Rick Piper's HS-748 and HS-780 are two examples that have a brake pressure gauge as I recall.

Stefan

[idancesafetydance]

Rick Piper's HS-748 and HS-780 are two examples that have a brake pressure gauge as I recall.

Stefan

I don't know if it was just me, but the last time I used my CH Pro pedals, the sim would actually react to my pressure inputs, so I could brake as hard as I wanted to. However it could've just been me.

[Milton Shupe]

I realize the brakes on FS2004 are either off or on, so there's no way to brake slightly. Different aircraft seem to have different levels of braking programmed in.

I find some aircraft, like Tim Conrad's top notch AA5B Grumman Tiger or Bill Lyon's excellent PA-22 Tripacer have extreme amounts of pitch down upon applying the brakes, even at slow speeds. Is there a way in the cfg file to "stiffen up" the spring on the front gear?

Braking strength is initially determined in Table 1101 in the .air file. The value range is -32768 to +32768. The formula to calculate appropriate strength is (ft/sec^2*2048). Values typically range from 10000 to 30000. Max braking rate only occurs with full weight on tires.

Now to your question, "Is there a way in the cfg file to "stiffen up" the spring on the front gear?"

Yes, you can stiffen the gear in the aircraft.cfg. There are 3 parameters that affect animation, stiffness, and damping. Parameters are the 9th, 10th, and 11th defined in the SDK as follows:
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9 (0.25) Static Compression This is the distance a landing gear is compressed when the empty aircraft is at rest on the ground (feet). This term defines the “strength” of the strut, where a smaller number will increase the “stiffness” of the strut.

10 (2.5) Ratio of Maximum Compression to Static Compression Ratio of the max dynamic compression available in the strut to the static value. Can be useful in coordinating the “compression” of the strut when landing.

11 (0.90) Damping Ratio This ratio describes how well the ground reaction oscillations are damped. A value of 1.0 is considered critically damped, meaning there will be little or no osciallation. A damping ratio of 0.0 is considered undamped, meaning that the oscillations will continue with a constant magnitude. Negative values result in an unstable ground handling situation, and values greater than 1.0 might also cause instabilities by being “over” damped. Typical values range from 0.6 to 0.95.
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Parameters 9 and 10 are usually set to "match" the oleo compression animation in the model. This means that the distance for modeled compression must be exactly defined by these two parameters or the visuals will not work correctly.

The first parameter (9) defines static compression and represents the distance the oleos should compress while sitting empty sitting on the tarmac.

The second parameter (10) is the ratio of max compression to static compression. Divide the total distance by the static compression distance to get this ratio. The larger this number, the stiffer the suspension. For example, a ratio of 2.5 yields a stiffer suspension than 1.8.

If you wish to change parameters 9 and 10, they must be changed together to maintain the same total animation distance. To do this determine the current distance.
For example if we have .9, 2.0, .7, the total distance represented is .9' X 2.0 or 1.8' distance. If you wish to change this to stiffen the suspension, you must increase the ratio. So, decrease the compression .9 to .6, then compute the new ratio. So, 1.8 divided by .6 equals 3.0. Now the new statement will be .6, 3, .7. Any ratio over 2.5 is pretty stiff.

The third parameter (11) is damping. The higher number gives less or no oscillations (like new shocks). A number like .5 will allow some softness feel with several oscillations. Typical values are .7 to 1.0.

I hope this helps.

[aeromed202]

Milton always has the dope on this area. I would only add that depending on the model, values in section 9 often only need a small change (0.12-->0.16 for example) to make a noticable effect. Values in 10 and 11 will usually need a bit more (0.20-->0.40 for example) to see a discernable change. The aircraft will have to be re-selected and loaded for any change to take effect.

I think I have the Tri Pacer so I'll look and see if I did anything with it.



edit; Yes I did. You can try these first three lines of contact points and see if you like the look. I made other cfg adjustments but I don't think they will matter much. Make a copy of what you have and paste these over the same places.

point.0=1, 5.00, 0.00, -4.82, 9000, 0, 0.60, 47, 0.24, 2.50, 0.50, 0.0, 0.0, 0.0, 0.0,0.0
point.1=1, -0.90, -3.60, -4.52, 5968, 1, 0.60, 0, 0.20, 4.00, 0.60, 0.0, 0.0, 1.0, 0.0, 0.0
point.2=1, -0.90, 3.60, -4.52, 5968, 2, 0.60, 0, 0.20, 4.00, 0.60, 0.0, 0.0, 2.0, 0.0, 0.0

[Fleet Canuck]

Well, thanks for all the input! I'll try the lines that aeromed has posted here for the Tripacer, and I think I'll leave the Grumman Tiger alone. It seems everything is much more complicated than it initially appears. Great (and knowledgeable) community here. And, I've learned there's another advantage to having pedals for simming.

[Z-claudius24]

Hi,

For the Grumman you can try those ....

point.0 = 1, 5.741, 0, -3.75, 1800, 0, 0.5, 40, 0.1, 2.5, 0.8, 0, 0, 0, 0, 0

And

[brakes]
toe_brakes_scale =0.70

[Fleet Canuck]

Wow! Thank you! Time to fly...