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I want to depict my Fujimi A-7 while taxiing on the carrier deck. While searching the internet I found only a few pics which show the A-7 taxiing with the nosewheel deflected. And this is where my question came up. The one pic I found of a A-7 taxiing with wings folded up and nosewheel deflected to turn a corner, does not show any deflection of the rudder, while the few pics with wings extended show the rudder deflected in correspondence to the nosewheel.

My question is if there was some kind of mechanism which prevented the rudder from deflecting while the wings were folded up. Usually the rudder deflects during taxiing when using the rudder pedals and only the nosewheel steering had to be manually activated by a knob on the control stick, at least for aircraft of that era.

Thanks

Michael

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Here’s a guess and only a guess...we can look it up easily enough in NATOPS but when NWS was energized with wings folded, all the flight controls were overridden to prevent aileron/spoiler deflection. This topic now requires I go and find the right answer!

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Here's how it worked, the rudder only deflected when the rudder pedals were depressed, not when the nose gear was off centered (turned). The nose gear would not automatically center if the aircraft was not moving so if the aircraft was in the middle of a turn and stopped. The nose gear would remain deflected even if the rudder pedal was not depressed, you had to have forward movement for the nose gear to center. The only time the nose gear would center without the aircraft moving is when the tail hook was dropped, which could damage the nose gear steering depending on the deflection of the nose wheels. The nose gear would also center (if deflected) when the gear is raised.

 

So, if the aircraft is just sitting there after doing a turn, the nose gear will be deflected but the rudder would be in the neutral position unless the pilot is depressing the rudder pedal.

 

On the A-7E, the flight controls were not disabled with the wings folded, we would do pre-flight flight control checks with the wings folded as part of the pre-flight procedures.

 

In the pic linked by Finn, the reason why the rudder is deflected with the nose gear entered is because once the aircraft is shut down it wouldn't take long for hydraulic pressure to bleed off and the wind would cause the rudder (and ailerons) to deflect a few degrees. Once hydraulic pressure bleeds off, the speed brake would droop a few inches, the rudder and ailerons would defect few degrees (with the help of the wind) and you could move the UHT's (horizontal stabs). The only real flight controls that you couldn't move were the trailing/leading edge flaps. Hell, the wings would droop and making it a pain to get the wing locks in, half the time we had to use the hydraulic hand pump to pump the wings back up in order to get the wing locks in.

 

To my knowledge all (except the F-18) Navy aircraft nose gear steering worked the same way, the rudder(s) only turned when the rudder pedal was depressed, that's how you know the bird was turn when moving (walking/running) around on the flight deck. If the rudder didn't move, then the bird was taxing straight, if they deflected to the left, it's going to turn left and the same if it deflected to the right. You had to have your head on a swivel and know what the bird was going to do because if you didn't, you could have a bird turn on you and you will get an aerial tour of the flight deck which usually ended in a 85 foot drop to someplace very wet.:thumbsup:

 

Bottom line, you can have the nose gear deflected with the rudder in the neutral position, it just shows that the last motion the aircraft made was a turn and now it's stationary.

 

hth

GW

VA-82 84-87

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Thanks a lot. All makes sense. I did not factor in carrier operations were the plane might stop and wait without having the spaceto move a few inches. The F-4 had the same concept but being used to land ops only, we parked/stopped the jet with nose gear and rudder straightened out 99,9% of the time. I actually remember only one case of seeing a Phantom parked with the nose gear deflected.

Thanks again

Scout (former F-4F WSO with FW-72"W" & FW-71"R" of the Luftwaffe)

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My pleasure, it's always nice to be able to pass along things I learned while banging on airplanes and fumbling with explosives.:thumbsup:

 

It was not unusual for a bird to be sitting waiting to taxi up to the cat or into spot with the nose gear turned and the rudder in neutral position. We tried to center the nose gear but there were times were if we did it would have resulted in the metal benders (Airframers) having to do a lot of extra work.

 

Releasing the rudder pedal while sitting still helped keep the hydraulic system from overheating since there was very little airflow going to the hydraulic pump to cool it while the bird was sitting on deck.

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  • 4 weeks later...

And another Question. Does anybody have a clear picture of the slot for the catapult launch bar which is located on the underside of the forward fuselage just in front of the nose gear bay.

Thank you

Michael

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a-7a_153135_045_of_109.jpg

The pivot point for the nose landing gear was just below where the launch bar attached to the nose strut. The upper drag link attachment point and below turned. The bar that attaches to the launch bar was the launch bar actuator, it raised and lowered the launch bar, with the launch bar lowered the nose gear could only swivel (IIRC) 10 degrees.

 

hth

GW

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You would not want the launch bar to rotate like or with the nose gear.  It would ALWAYS need to be aligned with the aircraft centerline.  If it were not there would be a lot of cracked helmets and canopies and nose gear struts when launching....

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13 hours ago, habu2 said:

You would not want the launch bar to rotate like or with the nose gear.  It would ALWAYS need to be aligned with the aircraft centerline.  If it were not there would be a lot of cracked helmets and canopies and nose gear struts when launching....

 

F/A-18 and most aircraft with nose gear launch bars do rotate with the lower strut. Back when I was in school (aerospace engineering) I we had a presentation by McDonnell Douglas engineer on the original F/A-18.  He had slow motion videos from carrier qualification trials of intentionally lined up crooked cat shots and rolled or yawed arrested landings. It was all about figuring out the limits.

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The A-6, EA-6, E-2, F-14, F-18 launch bars all turn with the nose gear.

 

If you look at pictures of F-14 Nose Landing Gear Doors and see a small chip out of inboard edge, that is from the launch bar hitting the door while the aircraft was turning (See Pic Below)

 

VF-31003-1.jpg

 

Also, if an aircraft is launched (catapulted) more then a degree off center of the cat, that deck crew is really eff'ed up. It's damn near impossible to launch a bird off center since the aircraft has to taxi at least 5 feet with the launch bar in the "zipper" and 10 feet prior to that to the shuttle.

 

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  • 5 years later...

Anyone know how the main landing gear works on the sluf?

 

What actually articulates the gear struts. The ends of the main strut and shock absorber are mounted to the fuse with hinges.  

 

Where is the prime mover that moves those struts and how does it move them?

 

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On the A-7 the main gear is moved by a hydraulic cylinder aft of the main gear. The cylinder pulls the main struts aft to lower the gear and pushes the main struts forward to retract. A smaller separate door behind the main gear doors covers this actuating cylinder in retracted/in flight position.  This aft view of the port gear shows the strut and smaller door (top right photo). 

 

s-l1200.webp

.

 

Edited by habu2
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