Don't worry, it was meant as an accolade.... :ok: They were around when I started my "career", and that was a long long time ago.

Ignoring the obvious insult....
Maybe I should just leave the job to baggage handlers... or become a baggage handler and buy shares in this company? :ugh:

If there is no comms, how does the marshaller know
1) when to push
2) which way to point the aircraft (where there is a choice). Or does he look for a windsock?
3) which aircraft has priority if there is an aircraft pushing at the same time (behind him at parallel terminal fingers)? Sometimes manoeuvering aircraft at our terminal is akin to solving a chinese puzzle.

This forum is for disseminating information.. If I don't ask questions or make comments, how am I to learn how things work in your part of the world?
Also, just because this system works at your airport/in your country, it doesn't mean it will work at ours.

18 Wheeler.. thanks... but it was a mostly rhetorical question about lead length... I'll be sure to build up my neck muscles to take the weight of the cord (until I learn how to do the required hand signals).

Swedish Steve... I don't like hanging around the nosewheel either, but our company is trying to improve its ontime performance by keeping engineers from various trades on standby in the vicinity of the airplane. If we are there, we may as well do the pushback. Also, excuse my feeble attempt to save my job.

I've removed two posts which discussed the commercial good/bad/whatever of the company concerned. Not appropriate to PPRuNe, I suggest. While this thread continues down the "does it"/"doesn't it" and similar technical paths, we'll let it run ...

I watched a single marshaller reverse a 737 out of a gate at YMSY and then drive it forward to the edge of the apron using a long headset lead for communications to the aircraft with the single tug under the port main wheels operated by remote control by this single marshaller. Both engines were started whilst being maneuvered on the tug.

This leaves the issue of traction. Out of interest how much weight is supported by the nose gear of jet (say a 737 or A320 or a heavy such as a 747) under static conditions on the ground? It is this weight that will determine the amount of traction available.

W

rainboe :
If a large aircraft tug with a big diesel e.ngine can struggle sometimes, how can a small electric motor cope? I would have thought it would require a larger APU to be certified.


I know the 787 will have 2 250kva genny's on the apu, that would help.
i think your right on the traction front though.
tk

Lots of WheelTug info
 

Electric WheelTug System to Move Planes on the Ground, article in Design News

WheelTug Pushback
 

I just read through this old thread and I don't see what the problem with WheelTug pushback is.

Pilots are also not in control of aircraft movement when there is a tug for pushback. Pilot just signals to ground crew when to pushback and in what direction. Touching brakes when moving backwards is a big no-no, tug or no tug. As long as main wheel brakes are not used then no problem. Nose wheel braking cannot tip over the aircraft. Even if tug motor locks up the plane can not tilt over because nose wheel gets lighter and simply skids to a gentle stop. More so I believe procedures should not be changed from now. Target should be to just remove the tug when conditions allow. Ground crew should normally control the wheel tug via manual controls connected to a short cable and see both wing walkers for best reaction time. Pilot should only have an override control for both soft and hard stop. This tug motor is also great for airports with limited number of gates and airlines will need less ground crew too. Flights can leave the gate at scheduled time because taxi time is not a problem. It is only a problem for airlines that pay the pilots for actual taxi time...

Edited for clarity. Original was a bit messy. See below. :uhoh:

I am confused :confused:

Story published yesterday in the Times:

http://www.timesonline.co.uk/tol/new...cle3516551.ece

Presumably the same problem would apply if the a/c is 'towed' by motors in the nose wheels as proposed by Wheeltug....

I'm slightly bemused by that. Surely every time an aircraft is pushed/pulled off gate by a tug that is exactly what happens? I concede that the greater distance could mean greater stress cycles, but surely the nosewheel leg is designed to withstand such stress cycles within elastic limits?

I still think it's about the same as the marvelous idea of having blimps hovering at the ramps, lifting the aircraft.

No more taxying
No more runway friction.
No more runways, come to that.

No more runway length limitations, the aircraft can continue to accelerate until it reaches flying speed, and only then disconnect from the blimp, which returns to pick up the next aircraft.

Oh, you never heard of the idea? No wonder, I just thought of it....... honestly.

CJ

WheelTug Update
 

How is WheelTug doing with their development program? The story, link below, is around six month’s old, and it states: “Delta Airlines will get the first WheelTug-equipped 737s by late 2009, and at least one automaker is talking with Chorus as we go to press.”

http://www.motortrend.com/features/editorial/112_0901_flying_hybrids_technologue/index.html

I am curious if this installation is a new 737 delivery involving Boeing installing the WheelTug, or a retrofit to an existing Delta 737. It reads like certification will be done by then too. If so, has there been an installation done yet using production parts? Rahosi, are you still monitoring this forum? If so, can you bring us upd to date?

WheelTug has made some progress.
 

Well here I go, apparently talking to myself, on this one. After doing a little poking around, it appears that WheelTug is making progress. They have been granted this patent # US7,469,858 B2, dtd Dec 30, 2008, for the nose gear drive system, issued Dec 30, 2008, with the caption below.



And here is a link to the full patent document.

http://www.wheeltug.gi/patents/US7469858.pdf

“Delta Air Lines is the launch customer and development partner for the first units which will be for the Boeing 737NG, with delivery of the first units slated for 2010 immediately following FAA certification. Delta Air Lines holds the rights to installation and maintenance of WheelTugs.” This sounds like the first installation will be a Delta retrofit, and here is a link to the rest of the related story: http://en.wikipedia.org/wiki/Wheeltug.

It sounds like this might be a real deal, and time will tell, by 2010, according to the current information.

Here is one more link to WheelTug’s own site where you can see more information: http://www.wheeltug.gi/.

Let's keep an eye on this one.

PS: Anyone remember DC9/MD80 operators doing tugless pushbacks using reversers? I am sure that I saw somebody, maybe Continental, doing it in the late 1980's or early 1990's.

I've been in several MD80s in the past few years that did self-pushbacks with reversers. Alaska did them before they got rid of their last MD80s, and I believe a few other airlines still do them.

Does Wheeltug have an STC yet?

Cert Status
 

Bunk
 

Put the "Chorus/MeshCon" units in a ground tug. An A/C is a poor truck, and a hobbled bird with even the bare necessities of "truck stuff" on board while aloft. This is idiocy. If 1/2 the engineering went into ground ops instead of "Innovation" (TM), we'd have more mobile tugs pulling a/c from the ramp to the Hold/Short and from the High Speed back to the Gate.

Also, while you're at it, let's have some Meshcons on my Audi and Prius.

A few years back I was trying to persuade a pal to start a company with me - making powered wheels. This was to be for cars.

There is only one way for the alternative fuel thing to work, and that's to get rid of all complexity. No I. No drive train from conventional motor(s).

The wheel was to be the inappropriately named Stator. No power had to be conveyed to a rotating part. Two, or even four computer-controlled wheels will be the future...though I probably won't be around to see it.

About the only way I could see a sizable aircraft - and that's most of them these days - being self propelled, would be for several of the main wheels being powered. The idea that the squitty nose wheels could do the job leaves me totally non-plussed!

The main-wheel powered hubs wouldn't be the problem, it's the powering of such devices that will be difficult. Hundreds of cycles of gear-hauling, with zero danger of frayed hi-power cables. Light flexible conductors, that offer very little resistance even after they're loaded. Harder to do than you would think.

Even hotter things being stowed in the wheelbays? Breaks get hot during long taxi-runs, so that shouldn't be too problematic, but as for putting a HOT motor into the electrics-busy area up front. I don't like that at all. I defy a motor that's pulled a 747 a mile, to be anything but hot.

Right now I would put my money on a cockpit controlled removable mini-tug. But when that's been fueled by whatever...and the aircraft has been cooled and aired...the net gain is starting to slip away.

Things are progressing, especially on the negotiation front - very busy. Development is also progressing, but the economic climate doesn't help.... Funding is still an issue. The good news is the family of companies have no debt! Lately that looks quite smart.....

Delta is still our launch customer & things are broadly on schedule for 2010.
Look out for a completely revamped website soon. More news ASAP. Maybe some interesting pictures showing the technical progress. Work continues.

And as for towing aircraft all over the place. It doesn't work. As it appears likewise some of the aircraft afterwards.... The high profile tests that were conducted about a year ago were abandoned quite soon after commencement. Mind you some of the green lobby may well have felt a bit off colour after their wrongful accusations on that abandonment. Ground tugs are quite aggressive.
-------

Following through on your link to MotorTrend, (+ today's interest) you might find Chorus™ for Cars interesting. Quite topical at the moment. Series Hybrid is the way to go (literally) - until there is radical advancement on the mobile electrical storage / supply issue.

There is also a more recent MotorTrends article that shows great insight. Anybody & everybody are building prototypes. But where are they going to source the essential elements required to build 10s of millions based on those prototypes? You think those prototypes are expensive now, with a ~$20K surcharge on them, wait until market forces drive up the price of those rare key elements. Forget economies of scale. Parallel Hybrids are VERY complex.
Nothing exotic is required to construct Chorus Motors. Simply a better motor.

I'm having trouble understanding how the above post is not a self-serving advertisement. Last time I checked, PPRuNe was an aviation forum so why the discussion of hybrid technologies for cars?