Wheeltug - the novel answer to marginal airline profitability

[TheShadow]

http://www.designnews.com/article/CA6494612.html?nid=2321&rid=1302801725
Based on a patented ac-induction motor from Chorus Motors, this WheelTug system takes its power from the plane’s APU and directly drives the nose wheel. It’s designed to move regional and larger aircraft on the ground at speeds up to 20 mph without running their turbines or hooking them up to an airport tug.
The resulting savings could be huge, which has enticed Delta Airlines to invest in the new technology, initially for its Boeing 737s. “Even a moderately sized fleet could save tens of millions of dollars per year,” says Walt Klein, Delta’s director of engineering, quality and training. WheelTug’s projections put the savings at $60,000 per month on a typical 737 involved in regional runs, according to Isaiah Cox, CEO of WheelTug, which is a subsidiary of Chorus Motors.
All those savings come from a variety of sources. One big one is the direct savings of burning less fuel when the turbines no longer have to push the aircraft to the runway. And there’s an indirect fuel savings, too. To account for taxi time, airlines often have to load more fuel onto the plane then they need for the flight itself. The weight of that extra fuel, if it’s not all burned on the ground, potentially poses a secondary drag on fuel economy.

see the link above for more detail and imagery/graphics/graphs

[OVERTALK]

http://www.designnews.com/articles/images/DN/20071026/CA6494612_B.jpg
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[WHBM]

Good morning Rahosi

http://www.flyertalk.com/forum/showthread.php?t=718298

[Hand Solo]

Does wheeltugs designer have any figures for the fuel penalty involved in lugging around all that extra weight for the many hours the aircraft is in the air as opposed to the time it spends taxying?

[Capt Pit Bull]

To account for taxi time, airlines often have to load more fuel onto the plane then they need for the flight itself.

say what?

pb

[llondel]

Hand Solo:
Does wheeltugs designer have any figures for the fuel penalty involved in lugging around all that extra weight for the many hours the aircraft is in the air as opposed to the time it spends taxying?
Who says it's a penalty? If you've got to load fuel for the engines to do the same job, it's quite possible that the efficiency of the wheeltug is such that it's still more economical to lug it around than it is to have to burn fuel in the engines to move the aircraft on the ground. However, it would be interesting to see figures for a full flight profile gate to gate with typical taxi delays.

[Dave Gittins]

Sounds fine on first look but ....

As pilots are notoriously unable to see behind them, this will still need somebody on the ground to either direct or control the equipment and steering at pushback. How complex could that be ? Or are we going to put video cameras in tail and wingtips ??

There is a weight penalty for every aeroplane which needs to be offset against fuel. Will one pushback be more expensive than lugging the equipment (say 500 kg inc batteries as I somehow doubt an APU providing enough amps to drag the aeroplane about) on a 12 hour plus sector ?

This will need to be fited on every aeroplane to be effective but a tug can push ... what ? a plane every half hour ??

Just musings ......

[Rainboe]

Very unconvinced. The engines provide motive energy whilst the APU is shut down. They also provide electrical power and airconditioning through compressors. So this system uses APU alone to provide all that electrical energy (considerable!), enough to get a heavy aeroplane up slopes, as well as providing compressed air for cabin conditioning. Going to take a far beefier APU with an enormous alternator to provide that energy...which will burn far more fuel than APUs currently do. Then, we're going to put those electrical motors in the same space that brakes currently occupy in wheel hubs, where they will not only get roasted to oven temperatures from -60 degrees C, but regularly doused with large quantities of water and dirt. And the downside, apart from first cost and complexity of maintenance, is significant extra weight of these large motors being carried throughout flight.

I'll believe it when I see it working reliably. Which it won't.

[rahosi]

Good afternoon
(Sorry for the delay, been down Costco doing the shopping.)

Wonderful thing Google alerts...

[Rainboe]

The discussion point is not Google alerts it's electrical push devices. Concentrate will you!

[WHBM]

Rainboe, old chap, it's an in joke. Do please keep up ...... :)

[Rainboe]

Pray let me in on it please? Maybe don't bother.......

[Intruder]

Then, we're going to put those electrical motors in the same space that brakes currently occupy in wheel hubs
AFAIK, the proposals are for nosewheel installation, where there are no brakes.

OTOH, your concerns about electrical loads are valid...

[BRAKES HOT]

Unread Today, 13:51 #7
Dave Gittins

There is a weight penalty for every aeroplane which needs to be offset against fuel. Will one pushback be more expensive than lugging the equipment (say 500 kg inc batteries as I somehow doubt an APU providing enough amps to drag the aeroplane about)


ermm, am i missing something? How could batteries be more powerful than an APU gen?

[ChristiaanJ]

What's this APU thing?
I thought you normally started both engines before pushback, to power systems, aircon, etc. And did a proper checklist.

If we're now talking again about starting the engines just before line-up and take-off.... we're back to an earlier thread about taxying with tugs (does "RB" remind you of something?).
With all the consequences, like huge bottlenecks on the entry point to the runway, when sumptin goes belly-up?

And, as said here, has anybody done a proper balance sheet?

[west lakes]

Interesting electrically, weight is quoted as 200lb.

In theory as it is thyristor driven it could also be used as a regenerative braking system (as long as the power produced can be absobed by the a/c systems)

[Rainboe]

AFAIK, the proposals are for nosewheel installation, where there are no brakes.

This now becomes a joke! Like those 2 dinky nosewheel tyres (on anything, even a 747) are going to have enough traction? Even pushback tugs with oversize tyres and weighing anything up to 20 tons or more can be slipping and sliding. And when wet- no traction at all! You would still need investment in all the pushback tugs (and their groundstaff) for windy or wet days.

It's a joke. It won't work. It's those bloody greens again. Don't listen to them.

[rahosi]

For those that don't know me, I am associated with the company, Borealis it's parent, and all the other subsidiaries. Not an employee, but under NDA (Non Disclosure Agreement). I am a BOREF shareholder as in most of the subs too. Rainboe, you are not the only one that thinks I am a dork (and worse). Be assured I will never lie.

I usually post on Raging Bull (BOREF). However do not expect me to break the NDA because I WON'T.

For those that doubt the whole thing, look at the video of the PROOF OF CONCEPT tests WT ran with Air Canada & Boeing back in 2005 (Actually before my time under NDA). That clunky (v0.1, my terminology) rig was NEVER intended to fly only to prove the concept, which it did.

Here, most of the questions and points of view could be answered by doing some simple research on the WT web site. Since I am not paid to field questions here, please don't expect me to be a search tool for you. At times it is hard for me to remember what isn't public; often that is what takes me time.

For those that doubt the whole idea, it is not easy to get the likes of Boeing, Delta & Air Canada to agree to their names being publicly associated with another company. Newport Aeronautical is other. Other 'names' will be made public soon.

Financing the project is taking time. Meanwhile progress is being made towards the ultimate certification hurdle. There are numerous patents covering the IP.

In my 1st post I should have titled it Good Afternoon WHBM, who evidently posts under another ID on Raging Bull, but I know not which. Evidently he guessed right (or maybe lured me...) that I would show up here. I was previously aware of this forum (and a few others) where WT is discussed. However I hadn't previously posted. (Please excuse my 1st brief post; my family was just arriving for dinner.)

(I'm away for a couple of days.)

[CAT II]

Just so you know, all 18 wheels on the 747 (all series) are the same size and interchangeable.

[Rainboe]

I believe the traction problem is insurmountable. Aprons have fuel spillages, de-icing residues, oil spillages. Put a little covering of water on that, and traction using just 2 nosewheel tyres (no tread) is not possible, especially when there is an upslope, as taxiways often have. Parking positions are usually depressed making initial movement difficult. Even with a heavyish 737, in the rain, a large pushback tug with a big engine can have trouble to the extent that the groundcrew occasionally ask for the start to be delayed to avoid having to push against the aircraft engines. 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.

Good luck if you can pull it off, but I cannot see it working.

[CAT II]

Rainboe,

Agreed, there might be situations that this device as stated might not be able to ovbercome, But, for the vast majority of flights worldwide, I can see the advantages.

[chksix]

I hope there will be some blue smoking burnouts ;)

Nothing like the smell of burning rubber in the morning :}

[Rainboe]

CATII- I don' think for the vast majority. There will still be a high proportion of flights where because of weather, wind, unservicability or taxiway slope, full pushback facilities (and staff to go with it) will still have to be available, therefore it's difficult to justify the alleged savings.

[WHBM]

I should have titled it Good Afternoon WHBM, who evidently posts under another ID on Raging Bull, but I know not which.No, I've no idea what this is.

[NSEU]

Just so you know, all 18 wheels on the 747 (all series) are the same size and interchangeable.

Optionally, the nosewheel can be smaller (20" instead of 22"). Also, the 744ER has larger wheels/tyres.

Imagine the burnouts you can achieve by parking the brakes (or is there an interlock?).

Rgds.
NSEU

[rahosi]

WHBM - sorry, I posted in a hurry, our paths previously crossed on a different forum. Raging Bull is the principal forum home for the ultimate parent company, Borealis Explorations Ltd.

The WT system is intended for the nose wheels without brakes, not the main bogeys.

The traction 'problem' isn't. The whole point of the system is that the main engines won't be started until warm up / the penultimate minutes before take off. Weighty (largely offsetting the weight of WT) and expensive fuel savings are substantial. The fuel burn difference between a main engine & an APU is significant. Other savings can be made in main engine servicing & wear & tear on the engines. Then there is the redundancy of most of the tug fleet & crew, who are also responsible for a large percentage of ground collisions. There will be significant reductions if air pollution noise and jet blast around apron. There are other features yet to be made public.

The heart of the system, the Chorus Motor, is what makes the whole concept possible. It has an amazing power density and efficiency. The available APU power is fundamental.

The system would be utilised the vast majority of the time.

The dimensional constraints along with customers requirements will vary between aircraft models and airlines.

WT will initially only pursue certification for one type of aircraft.

Sophisticated software will run the system, avoiding the possibility of contradictory operational situations.

On the WT site, the details of some of the staff and companies hired are available. The finest in the industry. WT will not fail as a result of elementary oversight.

[NSEU]

"The whole point of the system is that the main engines won't be started until warm up / the penultimate minutes before take off."
Interesting thought: Most airlines have the ground engineers monitor engine startup(e.g. if flames are shooting out the back of the engine, they alert the flight crew). Are the engineers expected to chase the airplane to the threshold to monitor startup? :p
Also, I agree with ChristiaanJ.... For example, if startup fails and the airplane is already in a long queue of aircraft taxying to the runway.... I can see there will be problems getting the aircraft back to the gate if there is nowhere for the aircraft to turn around.

Has this company really thought of everything?

Sorta reminds me of the in-air wheel spinup devices designed to save wear and tear on tyres on landing (see forum for further info).

Rgds.
NSEU

[Rainboe]

Remote hold startups are common- you don't need external monitoring these days. However I think we are dismissing the traction problem to easily. Moving 80 tons of aeroplane through 2 untreaded nosewheel tyres on wet, oily aprons and taxiways with some quite significant slopes (I saw on the north side of AMS yesterday a significant slope up to a bridge)? I really can't see it. I don't think we can dismiss all the pushback crews yet- so if we have to retain them for wet , windy days, the savings are not really there- or we accept on those days, operations will be disrupted.

I know the pressure is on to make sales, but we really need to see this thing prove itself instead of hearing all the hype. If it works, it will sell itself. The only answer is to get a system working and demonstrate it.

What taxi speeds is this thing anticipated to produce?

[rahosi]

Quote:Just so you know
Hence WT's tie up with Delta, Newport Aeronautical & employing Gilbert Thompson - nothing but the finest.

Has this company really thought of everything?
Everything is an unreal expectation, but WT are striving for that! It is expected that, on balance, WT will be a 'no brainer'.

demonstrate it.
See the video. If it wasn't feasible at the simple terrain obstacle level, WT wouldn't be at the development stage it currently is. Inclines etc were part of the joint WT/Boeing proof of concept test.

For example, if startup fails.
The system will have a very long service life / MTBF. Besides if it were to fail (to a 100% safe condition), the fall back is to the traditional methods. The only issue might be a shortage of fuel. If you mean a main engine fails to start, that situation would occur some ~5 minutes before take off and (sorry if my terminology is wrong, I'm in business development) usually there is an escape route away from the runway. It is most unlikely that WT & BOTH engines would fail at the same time. (Such craft would have no business being anywhere near a runway anyway!)

Taxi Speeds.
That is a variable design parameter. Trade offs between speed, acceleration, motor weight, available power and the requirements of the customer.

Dismiss all the pushback crews
Certification will be handled one model at a time. Installation will take time to roll out too. Thus even with a satisfactory development outcome, it will not be an overnight changeover.

in-air wheel spinup
except that that would then be a flight system, for which WT are not currently planning the system to be so certified.

The pressure is on
True. The pressure is on the industry to green up. WT really is something the industry can offer that lobby AND save itself an awful lot of money..
Quote, Aviation Week and Space Technology, August 20/27, Page 60
"Tough Road" Pressure builds on Industry as calls for greener aviation increase Robert Wall/Paris
"....Taxing without engines running could also yield substantial savings that Airbus estimates at 10,000 metric tons of fuel during the life of an A320...."

[NSEU]

It is most unlikely that WT & BOTH engines would fail at the same time. (Such craft would have no business being anywhere near a runway anyway!)

Who said both engines? Please don't insult our intelligence here. The aircraft would have to return to the gate if one engine failed to start.

usually there is an escape route away from the runway.

Is "usually" good enough for the airline industry? I don't see any escape routes at our international airport (a failure would require the aircraft to taxy along long sections of an active runway).

Rainboe said:
You would still need investment in all the pushback tugs (and their groundstaff) for windy or wet days.

Most airports involve some kind of pushback (will the pilots be steering blind away from the gate?). Don't expect Occupational Health and Safety to approve this..... They've already thrown our airport back to the dark ages in terms of efficiency.

Rgds.
NSEU

[ChristiaanJ]

"....Taxing without engines running could also yield substantial savings that Airbus estimates at 10,000 metric tons of fuel during the life of an A320...."Can we have this translated into the total fuel consumption of an A320 during its life time? 0.1%, 0.01% ?

OK, I'll be honest.
I see this as somebody trying to make another quick buck from the aviation bashing lobby.

Selling better smoke stack cleaning equipment to the Chinese coal firing power stations (one going on-line every week) would seem a better idea than selling an unproven gadget to reduce arcraft "emissions" (currently at about 2%) by 0.01%.

[rahosi]

Firstly I did say I wasn't technical, I'm in business development. I bow to your superior operational knowledge. Having declared my association to WT, why would I want to insult anybody?

Of course it would have to return to gate with a single engine failure. I covered the hypothetical unlikelihood of a multiple engine failure blocking a taxiway. I had already detected negativity here & I was trying to answer questions before they were asked. For the first time a pilot will truly be in control of his flight from gate to gate.

I didn't detail the departure sequence. Naturally everything will have to be done safely. There will be NO blind or unsafe procedures. I fly too you know! I cannot see the point of me doing a cut & paste of the entire WT web site. If interested, DYOR. All being well, roll out is planned to commence in a couple of years or so.

It was an Airbus quote not a WT quote.
What ever any saving, no matter how small, airlines quite rightly will chase it down. For a large airline, say 100 aircraft, The cost of 1 million metric tons of fuel is serious money.

If universally adopted by major US airlines, it equates to about 320M gallons of fuel per year. It also equates to 3M metric tons of CO2 a year. Then there are the other emissions including noise. Just by modifying the take off & landing. Some while ago, single engine taxiing became fairly standard fuel saving procedure. WT takes it one step further. On the single engine taxi point, how often does an aircraft have to abort take off when the pilot discovers, on powering up the hitherto idle engine, that it has a problem? What procedure does the pilot then follow? I guess the utilisation of WT will double this frequency on a 2 engine a/c.

Of course WT is trying to make money. Lots of it. But for fair return. (Does anybody here work for free?) If WT were attempting to bash the industry, why would Boeing, Delta & Newport Aeronautical, all prestigious companies in the industry, allow their names to be publicly associated with WT? Other names will go public as & when. WT also had an article in The Times and numerous other prestigious publications. Googling WheelTug scores 540. A lot of info can be found.

Who would honestly believe an unproven gadget, could interest airlines, be allowed to be fixed to aircraft, or be allowed to fly by the FAA/CAA? In case you hadn't noticed, aircraft are already rather complicated 'gadgets'. When the Boeing test was run in Arizona, not even a single screw was permitted to be fitted to the test aircraft.

Its strange the mention of better smoke stacks. Did you read up on one of the parent companies other projects? PowerChips. Direct conversion of (waste) heat into electricity, at high efficiency. Similarly CoolChips. They will be employed on aircraft. When the R&D is complete. When the certification is complete.

The companies scientific projects each try and stand up in their own right both economically & environmentally.

And we have an iron ore mine (in development) too. Roche Bay in Canada. No we don't intend on building cast iron aircraft.


(Disclosure. I am a shareholder in all the companies mentioned)

[Rainboe]

The engine start problem at the holding point is a complete red herring (ie not a factor at all). Remote holds are common now, with aeroplanes starting engines unmonitored by ground staff. Engine start failures are extremely unusual. I don't see why that was raised. Aeroplanes can go around breakdowns, and those breakdowns can easily be taxied eventually out of the way. Not a problem to this system.

I would be interested in seeing if the system can work. By all means it should be installed in a test aircraft and prove itself on different types and in different weather conditions. I'm still sceptical, but from the number of times I have been totally wrong in the past, that is certainly no disadvantage to Wheeltug! Let's see it work, and do its thing, even in the wet, without overheating or causing a hazard of its own. If it works, it will sell.

[rahosi]

Let's see it work, and do its thing... If it works, it will sellAgreed - except that WT will be leasing the system. Thus little up front cost to the airlines.

More news soon.

[Short_Circuit]

The concern should be that if one or indeed both fail, ie motors, batteries, power supply, whatever, on push back and the A/C is already moving backward, how will you stop the aero? Use the main gear brakes and you will lift the nose off the deck and possibly sit in on its tail. Now that will cost ya.

[NSEU]

Aeroplanes can go around breakdowns, and those breakdowns can easily be taxied eventually out of the way.QUOTE]
That's not to say that there are international airports where you can't taxy out of the way/go around aircraft easily. e.g. Sydney 16R/34L departures.
Seems like a great idea for taxy-ins... no worries about jet blast. Those single engine taxys on 777's scare the hell out of me (especially where there is a slope up to the gate).
[QUOTE]Remote holds are common now, with aeroplanes starting engines unmonitored by ground staff.
You just have to convince every airline and aviation authority that this is as safe as monitored starts.
I'd be interested to know if they've done a proper study on the wear and tear of the nose wheel/tyres and supporting structure.
Rgds
NSEU

[Rainboe]

I don't see all this as a problem. This is a taxi device. If an aeroplane has a failed engine on start, it can simply taxi under ATC control using this device until it is out of the way and making its way back to the apron. What is the problem? If it fails on push, presumably friction of the motor will provide braking, or automatic safety devices? It will only be pushing back at walking pace- what's the problem? You may as well ban pushbacks in case the towbar fails. You can easily stop gently- just brake very lightly.

I see a problem in getting it out of the apron depressions at the parking spots in the first place!

[Short_Circuit]

"If it fails on push, presumably friction of the motor will provide braking, or automatic safety devices?"

Nothing can go wrong ..... go wrong ..... go wrong ... go wrong....:suspect:

[ChristiaanJ]

I know I sounded critical earlier.
So far WT has done a proof-of-concept test, and that's about it.

Let's leave them to get on with it.
They've probably already been through all the arguments we can come up with.

If they end up being able to demonstrate a useable system and propose a valid business case, everybody will be using it in a few years from now.

If not.... nice idea. Next idea?

[NSEU]

If it fails on push, presumably friction of the motor will provide braking?

If it fails, wouldn't that be the last thing you would want it to do??? You want the nosewheel to revert to.. a plain and simple nosewheel (at least when the aircraft is moving forward).

I can't imagine this system would ever be used for pushbacks. The pilot would have no idea what is going on behind/under him/her. The engineers are not going to be able to guide a pilot out (l can just imagine the engineer saying... left hand down a bit, right hand down a bit....).

The risks seem to be too great:

1) Engineer getting run over (happened recently)
2) Headset lead getting stuck under the nosewheel (=lost comms). Wireless headsets have been trialed here.. and they failed the initial tests.
At least with a tug pushback, the tug driver can see the engineer and respond immediately.
3) Ground vehicles ignoring rotating beacons (common)

"WT Trial... cleared for powerback after Bugsmasher123 has taxied behind you... "

On some aircraft types, you are lucky to be able to see the wingtips, let alone directly behind you.

Rgds.
NSEU

[rahosi]

Spot on Rainboe. Slowly does it. There is very sophisticated software running the system to avoid various problems. WT will not turn an aircraft into a dragster!

I think Short Circuit blew a fuse...

Logical thinking Christiaan. Except WT have done quite a bit since the Proof of Concept. Your right about numerous scenarios, usable system, valid business case. We do have many more 'ideas'. Some equally as advanced as WT, which is a specific end use for one of many in house technologies. The Chorus Motor has much potential.

Tow bars are a constant source of maintenance woes. Hard linking a strut to a tug exposes the strut, mounting and airframe to the full jarring force of the tug. WT is much more gentle.

WT eliminates Jet blast and many FOD issues. Jet engines run on the ground act as giant vacuum cleaners for grit etc. NOT desirable. Some urban airports are now brining in limits as to the total ground noise envelope. Others have noise limits with early & late landings; a 10 minute taxi in creating 5 minutes of unnecessary noise (after cool down). Then there is air pollution emanating from airports. Using tugs is expensive too. However traditionally airports don't make a separate charge for their use - yet. Gate & taxiway operations will speed up considerably. WT will be a godsend.

When it comes to dips indentations and ramps etc, these have been factored in. Power usage can be momentarily increased to cope.

NSEU, WT's intent is to eliminate the day to day need for tugs. I shan't be addressing the commercially sensitive issue of pushback method here. Are you aware of the number of accidents directly caused by the use of tugs. Not risks, actual events. It was a proof of concept. The video is Boeing's.
Quite rightly WT were not allowed to interfere with ANY on-board systems. Hence the need for a separate power supply. V0.1 was never intended to be remotely close to V1.0. Boeing / Air Canada were satisfied with the method used to prove the concept. As were/are Delta and numerous others. To visually satisfy lay viewers of the video, the Proof of Concept test would have cost many millions more. Money WT just doesn't have to splash about.
When it comes to the real thing, none of your concerns will be issues. If they were, the project would have ceased by now.
The concept isn't new. There were experiments with hook on diesel motors in the 50's. I guess they floundered because the cost of fuel, noise, and environmental concerns weren't topics in those days.

Have any of you pilots experienced Virgin's towing a/c round airports? It seems to have ceased....

[NSEU]

Using tugs is expensive too.

So you are saying that this system WILL be used for pushbacks?

If so, I think this biggest company's hurdle will be Occupational Health and Safety.... then company beancounters after a few million dollar-wingtips have sliced through lightpoles, other aircraft, etc...

[rahosi]

Sorry NSEU after I posted I saw your last. Please see my previous edited post.
WT do know nobody would take up the system. That is IF your concerns were to crystallise.

H&S. First there is the FAA & CAA with certification and an STC. This is where Newport Aeronautical come in. They do such work for the big boys. They know what is feasible.
Airlines are quite protective of their fleets too.

Winglets managed it and that was a flight system!
WT are not amateurs.

[Rainboe]

NSEU- you're an avionics engineer? You are arguing a bit out of your sphere of knowledge!
<<If it fails on push, presumably friction of the motor will provide braking?>>
If it fails, wouldn't that be the last thing you would want it to do??? You want the nosewheel to revert to.. a plain and simple nosewheel (at least when the aircraft is moving forward).

I can't imagine this system would ever be used for pushbacks. The pilot would have no idea what is going on behind/under him/her.

If such a device failed on push, the first thing you would want it to do is gently provide automatic braking. What you must not do is brake the main wheels- that could tip the aeroplane back. We rely on such safety braking systems every time we get in an elevator!

Why would it not be used for pushbacks (if it can hack it)? We used to do powerbacks- starting engines on stand, idle reverse and let it go- steering to ground controllers visual instructions. It works OK, but training required, and the engines tend to ingest debris. The pilot has to follow exact visual instructions from the marshaller. I sat at Dallas and watched AA MD82s doing powerback after powerback most skillfully.

If this company wants to prove itself- good luck to them, let them try. They may just do it. But all the ideas are established procedure at some time or other. It's a complete red herring harping on about failed starts at holding points- everyday aeroplanes have trouble at various places. Just today I took off behind a 757 that abandoned take-off at Stockholm. It happens...people deal with it.

[ChristiaanJ]

Rainboe,
I agree.
Let them try.
I can't see a 200 lbs add-on to the nosewheels provide enough traction in all but the most ideal cases.
I can't see saving a few hundred pounds of taxy fuel as compensating for carrying the equivalent of another passenger or two across the Atlantic.
I'd like to see the sums.
But if we're talking 0.1% or so, the changes in procedures, the necessity to still have push-back trucks on standby, and all that, may well negate any advantages.

See you in 2010.

[west lakes]

Bear in mind that most electric motors can be used to provide a braking action as well as traction,
Either as a resistive brake i.e. motor used as a generator and power disapated in resistors, though not practical on an a/c through weight,
Or regenerative braking where the generated power is returned to the supply bus, this could work from touch down so it would not remove the braking action from the nose wheels.
As a last ditch an electric motor can go from forward to reverse, again to provide braking action.

[ChristiaanJ]

Sorry westlakes.......regenerative braking...That makes sense on trams and trains, especially high-speed trains.
It makes no sense whatsoever on aircraft taxying at a few miles an hour.....

[rahosi]

Great debate. It hasn't taken long for this think tank to arrive at many of the salient points.

The financial (http://www.wheeltug.gi/financial.php) and environmental (http://www.wheeltug.gi/environmental.shtml) numbers can be calculated. Simply, on a 737-700 the savings will be something under $½M per year.....

Safety (http://www.wheeltug.gi/safety.shtml) issues are here.

Many Technical & Corporate (http://www.wheeltug.gi/WTSAE-A5final.ppt) issues can be studied on this PowerPoint slide show, as presented at the SAE A-5 Toronto, Towbarless Towing Panel, May 2, 07.


Oh & sooner than 2010. Plus there will be a constant stream of news along the way.

Prime objectives, Get it working, certified & installed. Deluxe features can wait.

Next time you pilots find yourself twiddling your thumbs during a tug related issue, you'll be thinking, 'roll on WT'.

[NSEU]

NSEU- you're an avionics engineer? You are arguing a bit out of your sphere of knowledge!

True, I am an avionics maintenance engineer, but I'm actively involved in pushbacks of aircraft of many different types. Sure, I understand about braking during pushback... but my biggest concern is the motor locking up on takeoff/landing....I assume the system is NOT fitted with antiskid? Most airplane systems, if they lose electrical power, go into the safest mode. What happens if this nosewheel drive system loses power? Sure, you can put interlocks on this system, but how many will there be? (with reversers and spoilers, they seem to keep re-evaluating the number every 10 years after the existing interlocks have failed and caused major accidents).

BTW, if communications break down between the ground and flight deck during a critical part of pushback, what is the procedure to stop the aircraft? (at least with a tug, you can signal the tugdriver to stop... or even if you are in difficulty and are unable to signal the driver, he can see what you are doing at all times). Pushing back a 747, how long would the headset lead have to be before the pilots can see me? (Note: the longer the lead, the more likely it is put strain on the wiring, leading to failure... or to get caught under the wheels)... And just ask me how many times I have called the cockpit only to be told to "standby".... :mad:

[Short_Circuit]

Sorry All
I believe I introduced to words ”during push back” in attempt to
highlight one disadvantege of the system. :uhoh:
I guess the system is not designed for that phase of departure,
it is to allow “Taxi” with no engines or possibly 1 of 4 running to and from
the runway to save gas. But, hey, it has produced some good dialogue.;)

[rahosi]

Some great dialogue & insight as to the numerous hurdles. Nobody is pretending it is going to be a walk in the park. If it were, I wouldn't be here because the system would already exist! Conversely if there were elementary show stoppers, by now the project would have ceased.

Many of the basic questions can be answered by spending 10 minutes on the web site.

From the preamble
System Overview

Introduction

WheelTug® is a fully integrated ground propulsion system for aircraft. Built into the hubs of the nose wheels, it will give aircraft of all sizes full ground mobility (forward & reverse with steering) without turbines or external tugs. It will not require airframe modifications. It will be powered by the Auxiliary Power Unit (APU) which, while technically a turbine, is designed for this sort of application.

To the:-
Join the team, Involvement can be full or part-time, and does not require relocation or frequent travel.

[west lakes]

regenerative braking


Christiaan

Yes I know, the only time it could possibly be used would be during touch down (or rejected take off) as part of the overall braking effort.
I was more trying to show that the presence of an electric motor (and no independant brakes on nose wheels) does not mean there is no possibility of "braking" those wheels, again as part of the overall braking action of the aircraft.

[rahosi]

Regenerative BrakingConsider how many electrical Joules would be required to heat the multiple brakes red hot in say 30 seconds. (This is what happens with traditional friction braking on landing). Then there is the increased size/weight of the (motor /) generator required to utilise said energy, mounted on the relatively flimsy front strut.... This energy has to be either very rapidly stored (weighty & bulky) or dumped as heat (might as well dump it without going through the transformation to electricity!). Back up brake systems would still be needed too!

Another issue. The concentration and redistribution of all those braking forces, instead of from the main bogeys, from the front strut, up into the airframe. Would 1st class & flight deck crew object to being used as friction material?

(You might have guessed from my terminology, although I have rudimentary understanding of the issues, it doesn't go much further.)

[Swedish Steve]

Well speaking as an LAE I think it sounds like a good idea. We have a lot of ATC slot delays here (flights to LHR) and the thought of being able to release the ground crew at depature time so they can go and do another job, instead of hanging around waiting for the slot sounds like a good idea. We have straight push backs so I see no problem with the crew doing it themselves. But our problem is ice in the winter. The parking stands are also the last places to be swept in the snow, mainly because there are aircraft parked there! We use TBL tractors for pushback, which have a very low mass, and quite often in winter they cannot get enough friction to get the pushback started. Often I am shovelling grit under their wheels so they can get a grip. Some gates have underfloor heating and these are much better, we need it on the other gates.
I see no problem with unsupervised engine starts. Nearly all pushbacks are performed by loaders, not LAEs, and I can't remember the last time we had an incident which would have been handled better with an LAE on the headset.
I think that airlines that operate to crowded airports where you have to wait in line for departure will find this a must have.
I am definitely for it, hope we can afford the leasing costs!

[west lakes]

Braking

In theory only!

The use of regenerative braking on the rail system depends on being able to return the power to the supply network. In an a/c, despite the large electrical loads, I agree it could be a non-starter.

Any braking action would be in concert with the main bogeys and forces would be no larger than already imparted on the structure than conventional brakes.
As an example (this would not work in the a/c case) most high speed trains whan braking, first use the regenerative brakes and gradually blend in the conventional brakes as speed reduces - it's about how clever the automation is!

Most electrical motors can operate as a generator with no weight penalty, again it's all in the control equipment
(some windfarms are motors, when required to generate they run up to nearly synchronous speed as a motor the wind then accelerates them to synchronous speed which turns them into a generator)

Not very detailed but I hope this gives an idea of the principle.

The heat dump idea would be the resistive braking mentioned by me earlier - a non-started (or stopper!!!)

The design sketch in the early part of the thread is reminisent of the basic design of a linear motor (I could be way off beam here) that has been rolled up

http://en.wikipedia.org/wiki/Linear_motor

The Maglev trains use electrical braking as their sole means of stopping by control of the motor.

Again only theory from an electrical view point



Of course, to comply with best practice, will a/c fitted with this system also be fitted with reversing lights & an audible warning "CAUTION THIS AIRCRAFT IS REVERSING"
That's a joke by the way;)

[Rainboe]

NSEU:
BTW, if communications break down between the ground and flight deck during a critical part of pushback, what is the procedure to stop the aircraft? (at least with a tug, you can signal the tugdriver to stop... or even if you are in difficulty and are unable to signal the driver, he can see what you are doing at all times). Pushing back a 747, how long would the headset lead have to be before the pilots can see me? (Note: the longer the lead, the more likely it is put strain on the wiring, leading to failure... or to get caught under the wheels)... And just ask me how many times I have called the cockpit only to be told to "standby"....

It's all done on hand signals only! It's too dangerous to connect up for it. You have just run through why we used hand signals only for it. Can't you leave the practicalities about pushing to those that know about it, and stick to the technical side?

[18-Wheeler]

Pushing back a 747, how long would the headset lead have to be before the pilots can see me?


About 25 metres.

[rahosi]

Humour first
Communications - cordless phones are pretty cheap
Regenerative - Hook it up like a trolley bus
-----------

The Chorus Motor is one very clever piece of kit. Virtual windings (http://www.wheeltug.gi/technology.shtml) (bit like the Company (http://www.borealis.com/investor/faq.shtml#virtual)) that actually harness the normally detrimental harmonics. On the fly it can perform as if many different style of motor, in one, and with greater efficiency than each regular motor/generator. Phenomenal power density. One of the big problems with traditional A/C motors is the size / capacity of the controller to handle the relatively large transient peak power requirements at start up. Industry leading Semikron (http://www.semikron.com/) are handling that side of things. Neat is a word that springs to mind.

Safely too. A DC motor has a failure mode akin to an arc welder. (Thought they banned smoking on flights some while ago). An AC motor fails to a non resistive open circuit state. An AC Chorus® Motor is the nextgen.
If I'm not mistaken, what held Maglev back for a long while, was the complexity of the electronics managing the magnetic field. All electric motors manage magnetic fields. Thus there will always be similarities. Mathematically a linear motor is simply an infinite rotating motor.

Come what may, WT technology has to safely, practically, economically reconcile itself with operations at airports.


I must thank you all for your continuing valued input.

[ChristiaanJ]

Re reversing lights and "beep, beep, beep".
May well become mandatory.... normally you're alerted, by running engines and a big noisy tug, that something is due to happen. Now you'll have aircraft suddenly and quietly creep up on you !
Maybe we'll see the return of the "man with the red flag" !

rahosi,
On a more serious note, went back to the website and the ppt presentation.
If it works on a 767 it should work on a 737.
And I see WT has Semikron on board... not exactly a fly-by-night company (no pun intended).

[rahosi]

Drove a new Toyota Prius the other day. Similar problem with the silence in reverse. For a laugh, whilst it was parking itself, I leant out the window and deliberately talked to someone gesticulating with both hands. It rather unnerved him seeing the steering wheel spinning this way & that.

Technology has a way of solving problems.

The 767 was supplied by Air Canada. The 737 will be WTs 1st target.

Re Semikron. Not sure if your comment was an accolade or not. They are worthy.

Fly by night or wire? :ouch:

[ChristiaanJ]

Re Semikron. Not sure if your comment was an accolade or not. They are worthy.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.

[NSEU]

Can't you leave the practicalities about pushing to those that know about it, and stick to the technical side?

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.

[john_tullamarine]

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 ...

[werbil]

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

[Tyre kicker]

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

[rahosi]

Electric WheelTug System to Move Planes on the Ground, article in Design News (http://www.designnews.com/index.asp?layout=article&articleid=CA6494612&industryid=43651)

[P1L0T]

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:

[Dave Gittins]

I am confused :confused:

[supercarb]

Story published yesterday in the Times:

http://www.timesonline.co.uk/tol/news/environment/article3516551.ece

Virgin Atlantic has quietly abandoned a plan to tow Boeing 747 jumbo jets to special “starting grids” at the end of runways after the aircraft manufacturer found that pulling the landing gear would seriously weaken it.

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

[matt_hooks]

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?

[ExSimGuy]

WT will be leasing the system.

I think that's what's called "putting $$$ where mouth is!

If it works, and the APU can provide the power, and it is proved safe . . . . I'll be in Row 12!

Good luck guys and looks forward to flying with you:ok:

[ChristiaanJ]

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

[repariit]

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 (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?

[repariit]

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

“Delta Air Lines (http://en.wikipedia.org/wiki/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 (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/ (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.

[Intruder]

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?

[repariit]

The public info indicates "right after certification" to be 2010. I take that to mean that they will not have production hardware on a test airplane for a while yet, hence no STC. I wonder how far along they are with manufacturing and working out the issues of fitting it to the nose gear and having shaft seals that will stand up to environmental conditions.

[airfoilmod]

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.

[Loose rivets]

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.

[rahosi]

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 (http://www.timesonline.co.uk/tol/news/environment/article3516551.ece) quite soon after commencement. Mind you some of the green lobby may well have felt a bit off colour after their wrongful accusations (http://www.timesonline.co.uk/tol/news/environment/article3516551.ece) on that abandonment. Ground tugs are quite aggressive.
-------

Following through on your link to MotorTrend, (+ today's interest) you might find Chorus™ for Cars (http://www.choruscars.com/index.shtml) 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 (http://www.motortrend.com/features/editorial/112_0903_whacking_moles_technologue/index.html) 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.

[LeslieAltoSax]

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?

[airfoilmod]

This promotion is inappropriate.

[rahosi]

I only replied to other's posts. It is hardly likely that a sale would occur as a result. Neither I or another company person instigated the revival of this thread. I replied out of courtesy.

Hello Leslie...

(Nonplussed) Loose Rivets. The plan is the hub on the front strut. It worked in the 'non flying' proof of concept. See the Boeing video on the web site or YouTube. I shan't give links in case anyone thinks I'm advertising. Last time I looked the (hot) brakes were on the main gear. The motor is indeed very compact yet powerful.

Our wire harness kit suppliers does not perceive the cabling problems you do.

I shall not enter into discussion on your potential investments.

[repariit]

“Last time I checked, PPRuNe was an aviation forum so why the discussion of hybrid technologies for cars?”

The WheelTug subject is an innovation that purports to increase operational efficiency. We can’t yet know if it will work or not. The technology that needs to be proven is whether the extremely high energy density of this Chorus motor will work at all. It may be that the auto industry puts it to use before it makes it through the rigors of the aircraft certification process. How it does in that venue may well have at least partial significance to airborne application.

Some have also objected to the apparent “promotion” of this product by one who has apparently invested in its development. I think it is of value to take in all available information. Efficiencies gained through such innovations are critical to survival in this industry.

I first got involved in 1964. Most of the airlines that were operating at that time do not exist today. The many that are gone were less efficient than their competitors during a some past period of economic stress and had to capitulate, and failed to live to participate in the following upswing. Delta has invested in the development of this technology precisely because they believe that it will make them more efficient.

We should all have an interest in being a part of an efficient operation that will survive the current economic stress. It does not cost us anything to process the facts, and they may help to know where things are going.

[LeslieAltoSax]

Some facts to process:

The motor which is now part of the WheelTug system has been in existence for more than 15 years. It was originally called the Borealis Electric Motor. It was later rebranded the Chorus motor. A purpose-built motor controller (inverter) was subsequently designed and built. The product has not been commercially successful in any form and so far the company has not found any customers in ground transportation unless you count elevators. The elevator project was a failure.

The ultimate parent company of WheelTug is Borealis which has a long history of other product failures and Canadian regulatory issues. It also hasn't made any money in years instead relying on the continued recruitment of new investors. This recruitment has now come to PPRuNe.

Personally I would rather see this thread limited strictly to a technical discussion, but if the thinly disguised prospecting is going to be tolerated I think it is important for all of the facts to be on the table.

[airfoilmod]

going to sacrifice ANY MG braking to accomodate a MOTOR. That leaves the NG; does anyone take this seriously? 2 years ago a company put four wheel motors into a mini. Each weighed fifty pounds (~20kg.) and produced 150 bhp. The statistics were exciting in a vehicle weighing LESS THAN ONE TON. The site linked to Delta had a pic of a 777 identified as a 737. This is a JOKE. Off to JetBlast with this nonsense.

AF

[repariit]

LeslieAltoSax,

Thank you.

I have processed your information and looked at the limited information that is available on Borealis.

It is quite interesting to read of the Air Canada, Delta, and Boeing involvement in this project, and then not find subsequent documentation of a solid on going technical development program.

The proof of concept video had me convinced that the significant corporations involved would have carried it forward absent encountering technical limitations.


The recent post regarding funding limitation issues is not consistent with a high level of confidence on the part of the large entities that have been involved with the project.

I totally agree that this forum should be focused on any technical merits that might be presented, and not be used to encouraged any readers to make investments of any sort regardless of merits. Also, there may be no public notice given if Delta, Boeing, and Air Canada have ceased to be interested in pursuing it. If there is an active develoment program we will see further publicity from them.

[Loose rivets]

2 years ago a company put four wheel motors into a mini. Each weighed fifty pounds (~20kg.) and produced 150 bhp.

airfoilmod I would be interested in any link if you have one. No other interest now except curiosity.

Back to the self towing aircraft: I frankly don't think this idea would get past the first hurdle.

Does any unbiased person think that an aircraft - size say, from the 737 and bigger - could be usefully pulled by their own nosewheel? By this I mean in a day-to-day working environment, not just a flat and dry ground test.

[Graybeard]

Quite simple, really. If the NG tires don't have enough traction, merely move all the SLF as far forward as possible, standing up, as needed.

Has an independent body studied the efficiency of powering a motor on the nosegear by a generator on an APU, vs. air propulsion from a wing mounted engine? Each power conversion, from air pressure in the APU spinning the generator that converts mechanical energy to electrical, then converting electrical energy to mechanical to turn the nose wheel has losses.

GB

[glum]

Has anyone considered hydraulic drive to the main gear wheels to self propel?

That is after all the way the tugs drive their wheels...

[rahosi]

Re the recent issue of promoting / prospecting / advertising.
I am a shareholder. I am not an employee of the company & other than this, I have no involvement with the air industry. I would make a pretty lousy salesman. I never mentioned the main product / company by name even once, neither did I offer a link to its website. The web link I did offer was in response to other posters off topic comments; more of a technical show piece comparing different approaches to hybrid vehicles. I did not prospect (initiate) ANY topic.

Currently there is no product for sale. Thus 'advertising' is a non issue!

I whole heartedly agree that this thread should be focussed on the technical aspects.

HOWEVER if others stray from this and I do not address that needing clarification, the wrong impression might be conceived by readers. I will not stray, if others don't. I certainly don’t want to write such lengthy replies let alone read one... If a simple question is asked, I’ll try to simply answer within NDA limitations. Other than real news, responding as requested or clarifying, as before, I won’t post. Last was Nov07, so not exactly pushing it. My recent answer was specifically requested of me.

WAY off technical topic.
The technology is heavily patented within the family of companies.

Boeing & Air Canada are not involved in the development program. Never were. (Other than the proof of concept). Boeing selected the company to design, build, and operate said system.

Delta IS our launch customer, but has NOT invested (They hold warrants).

Funding issues are not something I am prepared to discuss at all. I am under an NDA. Current public reporting on this is simply Many negotiations continue worldwide with many parties.This I am personally aware of.

Facts.... (should not always be taken as said. Some gross inaccuracies have been posted here)
The Company had a court case against Lehman Bros for 18 years & managed to collect 70% of what was due to them....
The Canadian regulatory issues are very long & (off) topic. The company’s major iron ore mine exploration has been under way for a 3? years in Canada.
A few projects have gone by the wayside or are effectively dormant. Another ore resource. A microphone & something called Green Steel (I think) (before my time). However ALL current / recent technology projects are still firmly active with good prospects. No products have failed as none have been brought to market – to date. Other subsidiaries have patented technologies that will also have major implications for the aircraft industry. But that is a topic THAT WILL BE addressed here as & when.

All the companies report in a very timely fashion every year.
Borealis reported a retained profit of $7.7M last year and $650K the previous year.
Chorus Motors also showed a profit in both years. Whereas its/the sub in question showed losses due to the expenditure on this project.
The iron ore subsidiary (Legal bit This is subject to a NI 43-101 report. However the company conducting the exploration stated on Jan6 - We believe we are within a few weeks of getting the last of the assays.... Once that process is complete we will be able to finish creating our resource model and the NI 43-101 report.)
Over 100 million dollars have so far been spent on the exploration. Offtake agreements for more than 15 million tons (over 10 years) of refined ore exist.
---

This product will be fully certified.

Well renowned companies, individuals & non commercial entities talk to / partner the company. Mostly yet unnamed.
Boeing & Delta. Co-operative Industries (our wire harness partner, offers extensive experience in harness solutions. They design and manufacture electrical wiring harnesses, cables & more. Plus on-site FAA, EASA and CAAC Certified Repair Station),
Luxell (our cockpit controls partner, with a superb track record of providing top-tier Human-Machine Interface (HMI) systems for aerospace, naval and land vehicles),
Newport Aeronautical Development (our certification partner & has an outstanding track record of successfully managing complex certification programs for the world's largest aerospace firms).
The Program Manager - Daniel Barbalata oversaw development, testing, cert and launch of Bombardier Global Express aircraft family (multiple variants). He was also Program Manager at Hispano-Suiza for design, test, cert and launch of L/G and SCU on Dassault Falcon 7X aircraft. Introduced new tools and manufacturing processes in joint program between British Aerospace and Romaero.
The Senior Certification Advisor - Gilbert Thompson has more than 32 years of experience with FAA, including as head of Los Angeles Aircraft Certification Office (ACO). His certification experience includes L-1011, McDonnell Douglas DC8, DC9, DC10, MD-80, MD-90, KC-10A, MD-11, Boeing 717-200, C-17 Globemaster. Winner of AW&ST Laurels Award (1999) for outstanding achievement in aeronautics/propulsion.

I have included the above because some here have poo pooed the feasibility of the product. I hope the credentials of the above are enough to allay such comments previously made.

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Quite a bit of important additional information can be found in last year's article in Flightglobal (http://www.flightglobal.com/blogs/runway-girl/2008/06/tugging-more-than-the-boeing-7.html).
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Re:- Does any unbiased person think that an aircraft - size say, from the 737 and bigger - could be usefully pulled by their own nosewheel? By this I mean in a day-to-day working environment, not just a flat and dry ground test.

Delta does, as did the Air Canada pilots during the test. Boeing put their name to it. Many companies in the industry see its merits too. Along with airports, regulators & environmentalists. You'd be surprised how long the list is...

Test Quote. The Phantom Works/Chorus Motors team, in cooperation with Air Canada, installed an electric motor drive on an Air Canada 767 and conducted a series of successful tests. Air Canada pilots performed ground manoeuvres on slopes and terrains typical of those at airports around the world, including driving in reverse from a gate and taxiing forward to a runway. Tests also were performed at ramp temperatures exceeding 120 degrees Fahrenheit and at loads of up to 94 percent of the maximum takeoff weight for the airplane.

It should be noted that aircraft so fitted retain their previous mode of operation.
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The technology is ideally suited to replace hydraulics. The 'all electric' aircraft is yet another topic!

[Loose rivets]

Let me first say that I realize the importance of stopping taxi fuel waste and pollution. A vital issue.

Also, I should say that I feel like a little old engineer in a flat-hat, shaking his head as he smokes his Woodbine. " It'll never work. "

No knowledge on the subject, just an engineer's gut feeling that the numbers just don't come together.

Decades of sitting in aircraft with a huge tug belting out black smoke to get us rolling. Fear for me nose-gear as the load threatens to buckle something expensive. Relief, as we start to roll, turning to that tight gut again as the whole lot clankels to a stop. Horrible forces on that NG, all to be replaced by a very few square inches of rubber? Mmmm...I've been wrong before. Takes flat'at off to scratch head.

[airfoilmod]

Imagine the power needed to overcome inertia on your type. engines spooled up, sucking fuel. Now imagine all that power needs to come from a teeny APU.

wheeltug? the energy needed is the same. Now throw in a stop or two, and a repeat of inertia capture. No Sale.

AF

[rahosi]

Tugs are responsible for a lot of damage and pollution. The potential savings are substantial. There are numerous benefits.

It is kinder to the NG than existing methods. Much kinder than extended towing....

The electric motor industry has flat-hat tendencies.

As far as traction is concerned, it evidently worked. Main Engines used for taxiing are hopefully (http://www.pprune.org/rumours-news/300539-brand-new-etihad-a340-600-damaged-toulouse-several-wounded.html) running at a fraction of their potential yet unnecessarily gulp copious quantities of fuel. Actually less fuel would then need to be loaded as much less would be required to taxi out AND TAXI IN on landing.

A 737NG APU is orders of magnitude more efficient at generating power and capable of providing the required power for taxiing. The Chorus Motor under design & development is fit for purpose.

Most pilots would be thrilled to be in total control of their craft, gate to gate. Besides they do tend to be more caring than some tug drivers. Certainly more qualified. There are numerous 'incidents' every year in this sphere of operation. More potential for savings.

Main Engines would only be spooled up some minutes before takeoff (as per manufacturers requirements.) Similarly on landing. The previous 'Test Quote' modus operandi was designed to ensure that it is fit for purpose. It satisfied Boeing.

[ChristiaanJ]

Hi all,

As an ancient, I readily admit to no longer having all the figures at hand to do a "back-of-the-envelope" calculation.

My gut reaction is that it will take less fuel to just taxi to the take-off point, and then back from the turn-off after landing, than it will take to carry the (few hundred pounds?) WheelTug across the Atlantic.

Not to mention the WheelTug will still need fuel for the APU.

Does anybody have an envelope handy?

CJ

[Graybeard]

Glum's idea has merit. The hyd pumps are already onboard, and the plumbing is already in the nose gear well. A hydraulic motor is lighter and more compact than equivalent electric motor, especially if gear reduction is needed for the electric motor.

In other words, most of what's needed for hydrostatic nose drive is already onboard and used at other times, and used very little during ground taxi.

Not only do big tugs use hydrostatic drive, but small riding garden tractors as well.

GB

[Luap]

I think the weight on the nosewheel of the aircraft will be less then the wheight on the wheels of a tug. So the wheeltug will have less traction then a tug.

[rahosi]

Weight. There is a net gain in weight (hardly a secret). Fuel v motor and associated kit. This was known very early on & was fully allowed for in the calculations.
There were many such considerations. (Most engineering decisions involve a tradeoff.)

'A few hundred pounds' Considering the NG hub space available, that would imply motors made out of lead. However be assured the production motors will be robust yet relatively light with a very high MTBF.

Hydraulics (expensive, heavy and require a lot of servicing) is one of the systems Boeing is targeting in future designs (http://www.boeing.com/news/frontiers/archive/2004/july/ts_sf7a.html).

I have covered the traction issue before. The plane moved - repeated stops & starts backwards, forwards, left, right, up slopes, down slopes. Traction was sufficient. If it wasn't, Neither the test pilots (One of whom was Air Canada's Chief Test Pilot) or Boeing would not have reported so favourably.

[glum]

Is the addition of a hydraulic drive really that heavy? You already have the pressurising device and pipework, all you would be adding is the drive section to the wheel hubs, and if there was one per hub in the main gear then the motors could be smaller as you would have 8 of them (for example), meaning the individual stresses would be lower, and the redundancy higher.

Maybe this should be a new thread?