P3D V3 Ground Turn Radius

[BIGSKY 316]

Hi all,I don't seem to be getting full nose wheel deflection on a turn,until I depress a brake.I am getting full rudder deflection on the lower ICAS controls page.

 

Thanks Jim

[scandinavian13 5,192]

Hi all,I don't seem to be getting full nose wheel deflection on a turn,until I depress a brake.I am getting full rudder deflection on the lower ICAS controls page.

 

Let it roll forward and then try to turn the wheel (no brake). Does it animate then? I don't recall P3D animating the nosewheel until you started rolling first.

[BIGSKY 316]

Hi, not talking about the animation,but the psychical turn radius. When I have the rudder or (tiller) maxed, I get less of a radius than when I do a brake pivot.

[scandinavian13 5,192]

Hi, not talking about the animation,but the psychical turn radius. When I have the rudder or (tiller) maxed, I get less of a radius than when I do a brake pivot.

 

I believe that's typical of just about any aircraft, honestly. Based on your thrust, the aircraft wants to move tangentially. The only way to force a tighter turn is to add some brake.

[BIGSKY 316]

The hydraulics should drive the nose wheel all the way to the stop.

[Wotaplonker 1]

Is autorudder enabled in the sim?

[scandinavian13 5,192]

The hydraulics should drive the nose wheel all the way to the stop.

 

Correct, but:

1. This is the sim (see above limitation mentioned); and
2. Driving it to the stop doesn't mean you're going to get the maximum turn rate out of it.

The only way you can get the max turn rate is to apply the brakes to make it pivot on the wheel. It's a physics thing. The wheel is freely spinning. The thrust is pushing the aircraft forward. The only thing trying to turn the plane is the nosewheel, which is trying to add a lateral dimension to the forward thrust vector. The only way to reduce the forward thrust's effect is to lock the wheel (or diminish the forward rotation thereon), which requires brakes.

 

Is there some reference you're using or is this just a gut feeling?

[BIGSKY 316]

Thanks for the reply's Kyle, upon further digging,it seems that in the 777 FCTM, it states that using inboard braking will tighten a turn,sorry. : )

[77west 139]

Thanks for the reply's Kyle, upon further digging,it seems that in the 777 FCTM, it states that using inboard braking will tighten a turn,sorry. : )

 

In any airplane, with a conventional gear setup, using the brakes differentially will tighten the turn. In fact, some small airplanes are designed to only use brakes to steer!

 

You can also use a bit more power on the outboard engine(s) although I don't know if Boeing approves this method. I have seen a 744 takeoff video and the pilot pushes No.1 thrust lever up to about halfway when doing a tight right turn onto the runway.

[scandinavian13 5,192]

Thanks for the reply's Kyle, upon further digging,it seems that in the 777 FCTM, it states that using inboard braking will tighten a turn,sorry. : )

 

No worries - no apology necessary.

 

 

You can also use a bit more power on the outboard engine(s) although I don't know if Boeing approves this method. I have seen a 744 takeoff video and the pilot pushes No.1 thrust lever up to about halfway when doing a tight right turn onto the runway.

 

I'm not sure what the Boeing recommendation is, but I use differential thrust where I can. If I recall correctly, the only thing I've seen in any form of documentation is that it's "not necessary."

[BIGSKY 316]

It states In 777 FCTM that you can use outboard thrust in the turn as required.

[777simmer 117]

Using outboard thrust does help a bit in real life and is used.

But the nose wheel steering (plus main gear steering) is so good that differential breaking is not normally used.

 

In FSX this is a different story though.

I find myself skidding all over the place in FSX....not enough grip it seems.

If I taxi with more than 15kt or so, and then try to make a turn with the tiller, it (777-200) simply keeps going straight ahead (pretty much).

Differential braking helps a lot in FSX in my opinion and I use it all the time.