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shumway76
23rd Apr 2013, 23:59
With regard to C172, which has very limited amount of nose wheel steering with rudder pedals, and always requires differential braking when making turns, what is the technique used?

From what I've learned, on the ground while taxiing, the heel of the feet should be resting on the cockpit floor & the balls of the feet on the lower part of the rudder pedal for steering. This prevents "riding" of the brakes.

But on a C172 this rudder pedal steering is only good enough to maintain straight taxiing, but not turns. During turns, on top of full rudder pedal deflection, differential braking is required.

What technique is used in this case?
Slide the feet up to operated the brakes after full rudder pedal is pressed? Or
in anticipation of needing differential braking, put the feet in the "brake pedal operating position" (heel not resting on the cockpit floor) and using the entire feet to operate the rudder pedal to full deflection then brakes?

flyingtool
24th Apr 2013, 04:46
Hi there, when taxiing if I'm not trying to make a tight turn I will only use brake to slow down before turning and then use rudder to make the turn (e.g when I am vacating a runway on to a taxiway or vice versa. If however I am wanting to make a tight, slow turn (into a parking bay or turning at end of runway) then I will use full rudder with ball of foot and brake as required to achieve speed and radius of turn.

You'll get use to it as you fly it more and you'll learn your own technique

westhawk
24th Apr 2013, 04:49
In my own experience, the C-172 nosewheel steering is effective enough during taxi at normal speed or while rolling on the runway during takeoff or landing. I find differential braking is only required for tight taxi turns at low speed or in the rare case when it's necessary to use significant braking pressure to decelerate.

While taxiing, I suggest placing the heels on the lower rudder pedals and holding the toes back from applying pressure to the toe brakes. A common error is to inadvertently apply brakes when not required to slow the aircraft or tighten a taxi turn. This error is recognizable by noting that an abnormal amount of power is being used to maintain taxi speed. Bad form! During takeoff and landing, I've always taught my students that the heels should be on the floor until such time as wheel braking becomes necessary. Then the feet may be slid up the rudder pedals so that rudder is controlled with the heels and the toe brakes can be applied when required. It's important that the carpet be inspected by the pilot prior to flight to ensure that it's properly secured and the heels are able to slide freely throughout the entire travel range of the rudder pedals.

When there is no need to slow down, applying rudder pressure is usually sufficient to keep the airplane rolling straight or to make normal taxiway turns. This of course is presuming that the steering bungees are properly tensioned and that the nose strut is not binding. If rudder pressure is applied soon enough to account for the delay built into the spring operated nosewheel steering system, most normal taxi turns can be accomplished without the need for "inside" braking. When needed, dragging inside brake will of course expedite turning the nosewheel to it's limit.

I cringe every time I see someone standing on inside brake while giving it a big blast of power! So unnecessary. Very gentle use of braking and power is all that is needed to achieve minimum radius turns in properly functioning 172s. Apply rudder pressure first, then gentle inside brake if required. Except for unusual circumstances, it is almost never necessary to use much more than 1,000 - 1,200 RPM to taxi turn on a hard surface. On soft ground the use of brakes should be minimized. In tight parking situations it's better to shut down and use the tow bar to position the airplane rather than blasting pebbles all over the place. (helps avoid fistfights!)

So in summary, heels on floor for takeoff and landing until braking is required. Heels slid up and used to apply rudder pressure during taxi IF one can bend their feet back far enough NOT to drag the brakes while taxiing. This is sometimes problematic for those of shorter stature who must sit high up with the seat far forward as the angle of their legs to the pedals can make moving the rudder pedals while staying off the brakes quite uncomfortable for them. Most pilots just learn to adapt as needed. In the end the level of skill and smoothness displayed while taxiing is often indicative of the level of skill and smoothness with which the airplane will be flown.

While these techniques described above have worked well for myself and for my students, there may well be other techniques which work just as well and achieve the same result of maintaining precise control without abusing the brakes, tires or surrounding aircraft.

Happy flying and enjoy the Skyhawk, one of my favorite airplanes!

westhawk

foxmoth
24th Apr 2013, 09:22
Shumway, if the 172 you are flying is that bad I would suggest it needs looking at by maintainance! The only time I find I need brake as well is if I am making a tight turn, otherwise rudder is sufficient.