Parking a 727

[jeff raines]

Hello

Federal Express very kindly donated a 727 to the local college here for use in training aircraft mechanics. The college has asked me to design the foundation for it which isn't a problem. However, I need to get it from Point A to Point B without doing a lot of grading and without getting the airplane stuck in the mud up to it's belly. I'm going to lay down steel plates along the route and then we're going to tow the plane into place. At some point, the nose gear will have to turn 65 degrees to make a 54 degree turn.

Is that doable? Will the plane hydraulics need power from the engines?

Here's a sketch of what we're planning

ENGINEERING.com | File Downloads (http://files.engineering.com/getfile.aspx?folder=7c0d56c5-589d-4307-aa0e-2bc9a636022c&file=727_track.JPG)

The geometry of the site limits me to a 65 degree angle on the nose wheel. If I want less than that, I need to do some pretty extensive grading for which there is no budget.

Thanks in advance for any advice.

[JLWSanDiego]

I believe a "dolly" (with plates) under the nose gear will allow you to pivot on either main.

[captjns]

You can almost caster the nose gear with the scissors disconnected. If you have an operatable APU, you can power the System "B" Hydraulic pumps, as they are both electric. However, you need a minimum amount of about 1560 lbs of fuel in the right wing to ensure cooling, the alternative is to hook up a mule to the hydraulic system so the brakes can be ridden too.

[MarkerInbound]

The Boeing maintenance manual says there are no restrictions on the angle you can can use a tow bar to move a 727. At about 140 degrees you're driving back into the wing. If you go 90 degrees plus/minus 10 you have to disconect the nose gear electrical conduit. You can go 75 degrees plus/minus 3 without disconecting the nose gear torque links.

Freighters are notoriously tail heavy empty. The MM has a couple cautions about insuring the aircraft is in CG. It references an aft towing CG limit that I've never heard of (I just flew em.) And it says if you're going to tow over rough ground, go slow.

If you charge the brake accumulator (get AC power on the plane, run a B hydraulic pump until the system pressure is 3000 pounds) Boeing says the accumulator has enough fluid and pressure for 5 brake applications. So you may not need power on the plane while moving it. If you can get the APU running, so much the better. Plus you'll have air conditioning. There's a brake pressure gauge, normally in front of the co-pilot's knee, sometimes found on the FE panel.

[grounded27]

You are actually better off not using Hydraulics, place safety pins in the gear, disconnect the nose wheel scissors and you can actually position by hand the noseweel with the towbar for complex maneuvers. Are you at KOAK? PM me, if you wish I may have some resources for you. The hydraulic system is dangerous on that aircraft, I would suggest having a professional around. When the NLG is fully extended there is a cam that center's the gear, you want this aircraft as light as possible w/o worrying about the aircraft tipping on it's tail. . Steel plates may be overkill.

[nitpicker330]

Surely FedEx can loan you a couple of type qualified Engineers to help with any technical stuff...

Or just ask their Engineers directly, I'm sure they would be more than glad to help out if asked.