Toe Brakes and NWS

[zamboni]

I'm a bit unsure on how things are supposed to work, but after doing a search on forums and elsewhere I haven't seen this addressed anywhere.

After landing on a couple of missions, I have had the plane start to pull off the side of the runway. Trying to correct with rudder didn't help. I slid off the runway and after hitting NWS I was able to get back on and taxi back to parking.

After I got out of the way I went to the external view and started messing around. This is what I found:

1) with NWS on, rudder left/right seems to work right with the nosewheel steering

2) with NWS off.  If I press the right toebrake, the nose wheel turns right. If I release the toe brake the nose wheel remaisn right and I can only turn it back to the left using the left toe brake. Should the toebrake be causing the nose wheel to turn at all?

I'm guessing my problem with skidding off to the side of the runway was a result of hitting the toebrake with NWS off before landing. and when I landed it caused it to slide off. This doesn't seem to be right. But not seeing it show up as a problem for others, I am wondering if it only happens to me, or if it is a "feature" and I am not careful with my toe brakes.

[MAXsenna]

This sounds very strange, and is not supposed to happen. I do not get this behavior, so you might want to check your settings for conflicts. 

Cheers! 

[ASAP]

On landing roll the rudders should be efective until about 50 knots at which point you should turn on the NWS to keep runway center line. But really if you can’t maintain runway centerline with just rudder on landing roll, engage NWS. That is usually around 50 knots, but with a heavy crosswind could be closer to 60-70 knots,

The behavior you described makes sense and is the way I’d expect an aircraft to handle. With NWS off using the toe brake isn’t moving the nose wheel directly. It’s slowing one of the main wheels more than the other which causes the aircraft to turn. The nose wheel is pretty much acting like a castor wheel and turning because that’s what the aircrafts motion is forcing it to do. NWS off doesn’t lock the nose wheel in place it actually allows it to rotate freely.  Taking your feet off the brakes doesn’t force the aircraft to automatically recenter itself so it’s going to stay cocked to the side until you apply brakes on the opposite side. 
 

 

[MAXsenna]

Come to think of it. Another user had a similar problem in another module. Make sure your toe braker set as sliders in the axis tune settings.

[zamboni]

Ya, I do have it as a slider. When I was testing. I was basically standing still when turning NWS on and off and checking things., that Is why I don't think the caster wheel thing fits. Its almost like pressing the wheel brake is turning the nosewheel by itself. Will have to play around with it some more.  Also should mess with the plane in the air, gear down, NWS off and see if the toe brakes also cause the nose wheel to move (that is how I think I ended up off the runway to begin with.....i.e. nosewheel was pointed to the left on touchdown).

[zamboni]

I've figured it out.

I have wheel brakes on an axis of my VKB stick. I also have toe brakes configured on the rudder.  I brought up the control overlay and watched things. On landing, I hit the wheel brakes on the VKB. When slowing enough I hit NWS (but still have the wheel brake going).  I drifted to the left a little and hit the right toe brake. That straightened me up. The problem is that if you hit the toe brake and the wheel brake axis at the same time.....when you release the toe brake it also releases the brake on that side. Net effect in the end is full left toe brake and me sliding off the runway cuz I couldn't figure it out.

Lesson learned, don't use toe brakes + full wheelbrake at the same time, you may not like the end result.

Also, you are right about the caster effect on the nosewheel. It will turn even if the plane is moving only slightly. Its almost like the nosewheel turns more than it should for the movement. At least I figured out what not to do

[MAXsenna]

Cool you figured it out. But rather lesson learned. Do not configure the single wheelbrake, which is not realistic, and is just a place holder for people without rudders with toebrakes.

Cheers! 

[jaylw314]

8 hours ago, ASAP said:

On landing roll the rudders should be efective until about 50 knots at which point you should turn on the NWS to keep runway center line. But really if you can’t maintain runway centerline with just rudder on landing roll, engage NWS. That is usually around 50 knots, but with a heavy crosswind could be closer to 60-70 knots,

The behavior you described makes sense and is the way I’d expect an aircraft to handle. With NWS off using the toe brake isn’t moving the nose wheel directly. It’s slowing one of the main wheels more than the other which causes the aircraft to turn. The nose wheel is pretty much acting like a castor wheel and turning because that’s what the aircrafts motion is forcing it to do. NWS off doesn’t lock the nose wheel in place it actually allows it to rotate freely.  Taking your feet off the brakes doesn’t force the aircraft to automatically recenter itself so it’s going to stay cocked to the side until you apply brakes on the opposite side. 
 

 

When the plane is rolling slowly the nosewheel will caster freely.  At more than taxi speed, though, aircraft with free-castering nosewheels are stable and will self-center, since the main gear is behind the center of gravity.  As long as the main gear are not sliding a la Initial D, letting go of the brakes while rolling out really should center the nosewheel.

@zamboni FWIW, you can use the free castering nosewheel to your advantage while parking.  If you press one toebrake while NWS is off, the plane will turn much tighter than when NWS is on.

[ASAP]

19 minutes ago, jaylw314 said:

When the plane is rolling slowly the nosewheel will caster freely.  At more than taxi speed, though, aircraft with free-castering nosewheels are stable and will self-center, since the main gear is behind the center of gravity.  As long as the main gear are not sliding a la Initial D, letting go of the brakes while rolling out really should center the nosewheel.

True at high speeds the inertia of the aircraft moving forward will force the wheel to straighten out.  But you shouldn’t use wheel brakes to steer the aircraft at anything higher than a slow taxi speed, and he didn’t say how fast he was going so I assumed he was creeping along slowly which is when I’d expect that behavior. In a real aircraft using differential braking on a takeoff and landing roll will put a lot of stress on the brakes and shouldn’t be done or necessary under any normal conditions. 
 

the only wheel brakes the A-10 has are the toe brakes. The control binding for wheel brakes is just both toe brakes being applied equally. If you have foot petals with toe brakes I wouldn’t even bind the wheel brakes. Just bind the individual toe brakes. And hold both down at the same time