Nose wheel Steering: D, Dawson?

[fliger747]

Doug:

Question as to possibilities for nose wheel steering; Currently it is possible in FS9 and FSX to have a steerable nosewheel, or a castoring one. The biggest problem with this is a steerable nose wheel for ramp manuvering is totally too sensitive for takeoff if it is given a realistic steer angle.

Are there any possibilities to get around this and tie steerability to say a groundspeed of 10-15 knots or perhaps a throttle setting?

Also anyway of reducing the wheel skid effect in FSX, it greatly hampers braked turns, especially on dirt and grass.
Regards: Tom

[ddawson]

Doug:

Question as to possibilities for nose wheel steering; Currently it is possible in FS9 and FSX to have a steerable nosewheel, or a castoring one. The biggest problem with this is a steerable nose wheel for ramp manuvering is totally too sensitive for takeoff if it is given a realistic steer angle.
Are there any possibilities to get around this and tie steerability to say a groundspeed of 10-15 knots or perhaps a throttle setting?
Also anyway of reducing the wheel skid effect in FSX, it greatly hampers braked turns, especially on dirt and grass.
Regards: Tom

Jeez... You act like you know what you're doing and people actually start to believe that you do! :costumes:
I had a look at the variables available through FSUIPC and through SimConnect directly. Didn't see anything that looked like it would help. I was hoping that we could effectively lock the nosewheel by forcing a variable. It would appear that this approach is not possible...

I suppose we could watch the velocity and/or acceleration around the yaw axis. If the value exceeded X, it could be reduced with an FSUIPC write. If you had some values in mind here, I could try putting something together.

As to doing any of this gracefully, rather than with blunt force, I have to confess I really don't know!!

Cheers,

Doug

[fliger747]

Thanks Doug!

Ya never know till you ask. Some of the resident FS Boffin's have done amazing workarounds through various sorts of legerdemain. Actually a lock is not what is desired, rather a cease and desist order issued for steering commands and a reversion to castoring.

Below say 20 knots for example, some degree of nose steering might be usefull, but above that speed on takeoff it's sensitivity leads to overcontrolling if it has enough low speed authority.

In the real Life 747-400 we have a seperate tiller for low speed turns, (up to 70 deg!)and a seperate body gear steering of the inboard main trucks that turn them (opposite) when the nose gear gets beyond a predetermined value, but only if the speed is below 15 knots. For takeoff the rudder pedals only steer 7 deg left or right.

Anyway you can see that there would be a realism advantage in many cases if nose stearing was only availble at lowspeeds for tight turns.

Or if there was any way to allow a limited degree of steering angle, beyond which the gear would break free into a castor for the slow speed turns with power, rudder and brake. This is how many steerable tailwheels on Gen Av taildragger function, steerable within a limit and then breakfree.

Interesting possibilities anyway!!

Best regards: tom...

[P3_Super_Bee]

After reading this a couple times, not sure what you are actually looking for. Are you talking actual aircraft movement within FS? or just the animation of NWS and/or a tail draggers castering tail wheel?

If the former, sorry will go back to my corner as I haven't a clue...
If the later...

Project Opensky does it through XML coded animations. Their new B747SP has this...

Nose gear steering works between 1kt and 60kts
Body gear steering works between 1kt and 15kts
Rudder doesn't move between 1kt and 60kts.
ground spoilers only work on the ground << go figure
low speed ailerons lock at high speed.

[fliger747]

I saw the POSKY stuff but haven't tried it out as yet. On the SP ailerons are supposed to be tied to flap position, on the 400 series they are speed related. Hard to do workarounds for everything for FS!

What I was asking of doug was for aircraft control parameters. With any kind of nose wheel steering in FS, the takeoff tends to suffer a bit from overcontrolling.

Regards: T.

[Milton Shupe]

Excellent idea Tom ... one I've wanted a solution for over time.

I believe the Dash 7 is limited to 7.5 degrees on takeoff.

I guess if the max deflection variable in contact point 0 could be changed given the magic speed, that would work. Not sure of the variables available for XML but if it's controllable there, then Doug could certainly do it under gauge control. :-)

The A-26 also has this need.

[Corpus_1971]

Why not throw a few values in this table

Record: 0519 Rudder Deflection vs Q
Points: 5
0.000000 1.000000
20 0.750000
120 0.330000
320 0.000000
1420 0.000000

I'm not sure how long you can make the table, and from memory Q is not something nice like Knots or MPH, but it is proportional to them.

This would allow 'extra' throw at 0-20 (use a value greater than 1 perhaps) and limited throw 21-200 or whatever you want

[fliger747]

What we are trying to do is in effect seperate nose gear and aerodynamic rudder steering over most of the speed regiem. Aircraft that use a tiller for low speed nose wheel steering (seperate control for nose wheel from rudder) can steer at angles up to 70 deg without moving the rudder at all.

The current FS setup of always connecting the two, tends to cause overcontroling of nose steering when it isn't needed (above 40 knots) and still providing too little range at low speed.

[errmail]

What we are trying to do is in effect seperate nose gear and aerodynamic rudder steering over most of the speed regiem. Aircraft that use a tiller for low speed nose wheel steering (seperate control for nose wheel from rudder) can steer at angles up to 70 deg without moving the rudder at all.

The current FS setup of always connecting the two, tends to cause overcontroling of nose steering when it isn't needed (above 40 knots) and still providing too little range at low speed.

Tom, I think I have very good news for you. FSX has apparently completely separated these two items and the nose wheel can be steered independently of the rudder movement, I mean, as in a completely separate controller input. You should be able to steer the nosewheel either by keystrokes (as you would if you used the keyboard to fly), mouseclicks, or -- and I am not utterly certain of this -- a controller axis. That means a TILLER...yes, a tiller in FSX.

This was ostensibly confirmed to me by an FSX developer today.:jump:

[Corpus_1971]

What I failed to emphasise in prior post was that modding the rudder or nosegear throw via a guage/xml will have no effect on the actual turning radii determined by input from the 'rudder' axis. You can achieve a sensitive nosewheel (and therefore tight turn radii) by fiddling with the values in the aforementioned table - exaggerate them for taxi/parking speeds and early takeoff roll speeds, suppress them for takeoff roll speeds where you are happy there would be no rudder effect (and therefore you need a low-rate nosewheel to keep straight without veering), and then transition to normal rudder effectiveness at a speed by which the nosewheel would be off the ground anyway. Of course, the visible rudder throw will be changed (for the worse) by all this, but that can be corrected via a stepwise function in xml. As I said, Q is not in nice units, so some calibration will be needed.

If this isn't helpful I am sorry, but is just the approach I would take to the nosewheel steering rate problem in question here :iidea: I guess it only applies in FS9 now anyway, M$ keep us running to stand still :running:

[fliger747]

I'll have to take a look at the FSX implimentation, that would be a big help for the heavy iron. Unfortunatly rudder is still needed at medium to high speeds, especially in case of engine failure (I work with this a lot) and crosswind tko/lndg.

In most modern Boeing aircraft, the rudder pedals are connected to nosewheel steering only for the first seven degrees of travel, which simplifies life a bit over aircraft which are not connected at all, such as the C-130 where one has to work with both till about 40 knots.

Thanks all for the continued input!

[fliger747]

just been trying the POSKY 747SP which ties various features to airspeed, including body gear steering etc. Haven't made any conclusions as yet!.
thanks!! T.