Dumb jetliner question of the day...

I don't know about the 737 but the 747, 767 & 777 have a hand crank gizmo below the #2 window on both sides. For taxiing only!
I don't have an answer on how the brakes are applied but I know that they are input assisted activation with ABS.
I see no pedals above the rudder controls but I do see hand activated brake levers on the center console that I assume are for parking.

 

This guy can answer the brake question, 1UAL777, http://www.thebestemployee.com/forum/member.php?u=31542

 

Some airliners don't have steering in the nose wheel, the wheels are set in a trailing type of geometry. The larger airplanes have two hydraulic steering cylinders that are connected to lugs mounted on the nose wheel strut inner cylinder that swivels when one or the other cylinder is actuated from movement of the tiller or other steering device in the flight deck. Brakes are most times integrated with the rudder pedals, I can't speak about all the airplanes 'cause I'm not knowledgeable about them.very good questions, though.
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I have seen ground handling with main gear differential braking but not on current airliners, more like DC3's..

 

The 737 steering is similiar to what was on the 727 and wasn't really changed much from the classic (100-200-300) to the next gen aircraft (700-800-900). Basically added prox switches for air/ground replacing the old style mechanical switches and now energizing the air/ground relay through a signal from the prox switch electronic unit (PSEU) Here is a discription from a company training manual:

Steering inputs are from the steering wheel or the rudder pedals. When you
move the steering wheel full travel, the nose wheels turn a maximum of 78
degrees in the left or right direction. When you move the rudder pedals full
travel on the ground, the nose wheels turn a maximum of 7 degrees in the left or
right direction. Steering inputs from the steering wheel or rudder pedals go to
the metering valve through a cable loop.

 

Basically all large aircraft use some sort of "tiller" on the captains side (or both sides) to steer on the ground. The rudder pedals also allow steering but with less range of movement and are used during take off and landings. The brake pedals are the top part of the rudder pedals and are activated separately (left foot brakes left main wheels, right foot right main wheels) although most modern aircraft use "auto brakes" on landing where the computer manages the brakes.

 

Jedi, there are no dumb questions when the questioner has the good sense to ask about things about which he does not know. The asking of questions is how all of us learn. The dumb part comes from those who feel that they are competent to answer questions about which they know nothing. Ask away, Pal.
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In the DC-10 it uses two hydraulic systems from the #1 and #3 systems. With these two systems operating the plane is steered by the tiller with nosewheel movement up to 68 degrees left or right. With a single hydraulic failure it fails to 25 degrees nosewheel movement on the side that failed. #1 is left #3 is right.

Rudder pedals provide 15 degrees of steering. The tiller is mainly used for large turns.

The 757 and 767 uses similar technogoy with limits of 65 degrees.

Here is my office!

You can see the First Officers tiller below the clipboard. This is a 767 with the option of having two tillers. Steering a jumbo jet is alot of fun especially when u can move her smoothly and precisely without spilling the champagne in the back. The DC-10 tiller is a much better design IMO. The DC-10 tiller is the second picture. Much easier to be smooth and precise.

Cheers
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Going backwards a bit in regards to directional control, I got to thinking about messing around in the Pietenpol Air Camper. We discovered that putting one's hand out to signal a turn would actually make the airplane turn. Not quickly or elegantly but the darn thing would slowly go into a turn. My friend, Chuck, while flying a TV cameraman had to use corrective rudder when the big 16mm movie camers was stuck out the side to film the engine and carb ice build-up. A little different than a DC-10.
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So rightly said Bob. I just found this thread and what a great tool for explanation of others to learn. For those of us who had the opportunity, lets not forget the DC-8 series of aircraft and navigating those birds.

 

Smaller aircraft such as fighters steer with the nose wheel. F-4's had a paddle switch on the stick you hit with your pinkie finger which disengaged the auto pilot in the air and when on the ground activated the nose wheel steering. The F-16 and F-22 use a button to do the same thing, via a hydraulic steering actuator.

The rudder pedals move fore and aft for rudder actuation by pressing mostly with your heels and the pedals are able to pivot at the bottom so pressing on the top portion or simply pressing it like a gas pedal applies the brakes. The pedals don't have a seperate hinged pad to step on at the top to apply brakes as in some general aviation applications.

 

Tim, I jumped a bit when I saw your location as Dallas, Ga. My grandfather was wounded at New Hope Church near Dallas in the Battle of the Hell Hole during the Civil War, May,1864. He took a 55 cal. Minnie' in the chest and survived it. I still have the bullet and the button that it smashed. They didn't probe for the bullet and left him to die but he didn't. 15 months later the bullet appeared in a boil on his lower back.
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On the F-111, the nose-wheel steering switch on the aircraft commander's stick was also the air-refueling contact switch. If you landed and could not select nose-wheel steering on roll-out below 60 knots after aerial refueling, recycling the air refueling doors cured the problem nearly 100% of the time. Only took you once to figure that out.

Taz
Terry Phillips

 

Interesting read all this. My only exposure has been with Lockheed C5s. They operated much the same way as the Boeing 747 that was described. My contribution is about the castering rear mains. All four of the main trucks were/are steerable, allowing the aircraft to crab substantially all the way to, during, and after touch down. They would straighten it all out during the roll-out. During sharper taxing turns the rear mains would be allowed to caster, and then powered assisted back to center as the aircraft was straightened up.

The Space shuttle has neither rudder pedals nor a tiller wheel. Yaw both in flight and during roll-out is by rotation of the hand controller only. Note, there is considerable blanking of the rudders until very late in re-entry (end of the de-accel phase), so the yaw thrusters remain the primary yaw control device until the angle of attack decrease for the glide phase. But I digress...

 

The 747 had articulated main truck beams to reduce tire scrubbing and most important, torsion on the oleos. When i saw the huge Russian AN224 Miria at Abbotsford I examined the landing gears and it appeared that they designed one assembly and used it in all 6 or 8 positions. They did not steer and when the airplane was turned they opened up the throttles on one side and skidded the airplane around. When we left and flew over the ramp at the south end of the tarmac there must have been a couple of tons of rubber left on the pavement. An amazing airplane. The Russian crew lived aboard it during the show.
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The rear set of wheels on each six-wheel truck on the 777 articulate as the A/P turns to reduce scrubbing.

Some crosswind testing of the 777 and 747SP, the torsional loads have to be astounding.
Also a KAL "cowboy" landing at Kai Tak and an unknown 747 blowing #1 engine on roll-out.


http://www.youtube.com/watch?v=wmDdQz6QlFs&feature=related

 

I was a static display (well the F-4G I was with, not me) at Abbotsford in 91 I think, first time it ever rained during the airshow. I think it was their 30th anniversary. That was a very interesting account of your Grandfather's ordeal in the war between the states.

Just last week I went to see a local expert on that war who is a bit odd to say the least, as he hangs a banner accross the front of his store on this day every year proclaiming that it's James Earl Ray day. Well, I do live in the deep south you know where the war is still ongoing it seems.

Despite that redneck aspect he is quite the historian of that era evidently and has been hired numerous times by film makers as a consultant for authenticity on uniforms, weapons, etc... I asked about Andersonville prison where my Great Grandfather was marched to after being captured by Confederate troops at the battle of Nashville. He asked "was he a guest or a guard?" He was imprisoned there until the end of the "war of Northern aggression" as they call it here. That is a loooooong way to walk in worn out boots and then barefoot!

Most Union soldiers that went there never lived to tell about it, dying mostly from disease. Your Grandfather and mine were lucky ones indeed. Thanks for sharing that with us, I thrive on insight like that.

 

My grandfather was a sergeant in the 29th Ohio Veteran Volunteer Infantry and fought at Gettysburg and many other battles. He was an Irish immigrant and I have yet to figure out why he not only fought out his original enlistment but re-enlisted for another three years after the daily deprivation and battles. I grew up in the south and went to college in the south but I have never been able to accept the attitudes of the the old southerners who talk about the war "between the states" ( the states weren't fighting each other) or to eulogize R.E.Lee. I personally see it as a rebellion of one economical force based on slavery against an economical force based on industry and an ill-advised attempt to destroy the union. BUT that has no place in today's discussions, I think. I welcome your comments and mean not to force an opinion but to respond. I suppose that I have strong sentiments and express them too energetically at times.
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Does the space shuttle even have a steerable nosewheel? I'd guess not.

Some odd steering systems I've used: the Aerostar had a plastic toggle switch on the pedestal (some of them had it relocated to the glareshield). The Commander series generally has steering on the brake pedals-- yes, that's right, not the rudder pedals, but the brake pedals. The first 1/4" or so of travel is the very, very slow steering, and then you get power brakes. What do those airplanes have in common? They were both originally designed by Ted Smith, who seemed to have a love of odd ground steering systems.

 

I'm digging back into my past and dim memories but I recall that Ted Smith was the designer of the Douglas A-20. Can you see the resemblance between that and the Aerostar ? I wonder what kind of brakes the A-20 had ?
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I tee totally agree, and welcome your comments and or opinions as you see fit to express them. Having lived in 10 different states I have seen good and bad in all of them, this one to me seems more backward than others but better in other ways, like hospitality.

One day I hope to make your aquaintance. We have a fly-in at my old homeplace in Buckley WA the day before Mothers Day every year. My wife is having her Masters commencment that day so I won't make it this year but I may come out early to do an annual, if so I may look you up if that is alright with you. We routinely have antique aircraft, cars, hit or miss engines and other stuff that peaks interests of young and old alike. It would be good to meet and shake your hand.