Boeing's Electric Taxi Motor

RST Engineering wrote:
And those of us on usenet seeing a possible breakthrough in engineering
technology saying, "why the hell did I spend all that time in engineering
school when these uninformed idiots comparing 1950s technology on usenet
have all the answers".



I'm not dissing their breakthrough on motor technology at all.

What I see from their publicly released design information is a system
that will add at least several hundred pounds of weight to the aircraft
and add significant maintenance problems to the gear as well as makeing
it even more complicated than the nose gear of the B-58 and the mains
on the F-111. Fixing the drive motor within the fuselage and then
having to transmitt the energy from there to the landing gear, down
the gear leg itself and then tee it to both wheels really drives up the
complexity. The test rig is a giant strap on box hanging off of the
back of the gear and uses belt drive to power one wheel. Even they
admit that they encountered significant engineering problems with the
test rig and the 767.

One of the things they don't seem to address anywhere is how or if they
are going to decouple the drive system for takeoff and landings. Also,
there is no mention of the actual speeds accomplished with the system.

When they get their motor package down the the point where it can be
mounted within the front wheel assmeblies and keep the installed weight
under a couple of hundred pounds and be able to taxi the bird at
10-15mph for several miles, then they will have a really viable product
that will have everyone clamoring for it.

BTW..Lufthansa tried a program for a number of years where the tugs
supplied motion to the aircraft as well as airconditioning and
eletrical power. The aircraft were towed ammost all the way to the hold
line prior to engine start. If I remember right, what they saved in
fuel and engine time costs was surpassed by labor and turn around time
costs and they dropped the program.

Craig C.

On 19 Aug 2005 15:41:47 -0700, wrote in
.com::

Fixing the drive motor within the fuselage and then
having to transmitt the energy from there to the landing gear, down
the gear leg itself and then tee it to both wheels really drives up the
complexity.

If this is the system Boeing is installing:

http://www.wheeltug.gi/technology.php
http://www.chorusmotors.gi/technology/

What makes you think the motor will be installed within the fuselage?

Larry Dighera wrote:
On 19 Aug 2005 15:41:47 -0700, wrote in
.com::

Fixing the drive motor within the fuselage and then
having to transmitt the energy from there to the landing gear, down
the gear leg itself and then tee it to both wheels really drives up the
complexity.

If this is the system Boeing is installing:

http://www.wheeltug.gi/technology.php
http://www.chorusmotors.gi/technology/

What makes you think the motor will be installed within the fuselage?

By what they have released to the press, such as the following:

http://www.flightinternational.com/A...oeing+767.html

I'm not sure how to make it a hotlink from the browser and system that
I'm using right now, but you should be able to copy and get to the
article, mainly the last paragraph.

Craig C.

On 19 Aug 2005 16:32:27 -0700, wrote in
.com::

Larry Dighera wrote:
On 19 Aug 2005 15:41:47 -0700, wrote in
.com::

Fixing the drive motor within the fuselage and then
having to transmitt the energy from there to the landing gear, down
the gear leg itself and then tee it to both wheels really drives up the
complexity.

If this is the system Boeing is installing:

http://www.wheeltug.gi/technology.php
http://www.chorusmotors.gi/technology/

What makes you think the motor will be installed within the fuselage?

By what they have released to the press, such as the following:

http://www.flightinternational.com/A...oeing+767.html


Thank you for the link. This is interesting information indeed:

To get more torque out of an electric motor, it is necessary to
increase the current handling capabilities of the inverter.
However, this usually requires a larger, more expensive inverter,
not all the capacity of which is usable because of limits on the
total power available. The Meshcon system gets round this by
regulating the voltage required by the inverter at various speeds,
allowing the inverter to deliver all its power at reduced motor
speeds.

Carman says the Meshcon system has been developed specifically for
traction and increased low-speed torque loads, and applications
for which starting torque requirements are higher than the
continual torque requirements. The system uses multi-phase motors
in which the windings are connecting several inverter terminals to
each other, and not the ground. The different connectors act like
different gear rates, and the motor can electronically change
"gears" by operating the inverter at the harmonics of the drive
frequency.

The system therefore uses harmonic drive to essentially fool the
drive electronics into thinking they are operating at a higher
speed. The net benefit is that the motor drive can achieve five
times the torque speed of a similarly sized machine and is
therefore much smaller and lighter.

"We believe the ability to integrate it into a weight-sensitive
application is totally feasible," adds Carman. The demonstration
is not representative of a flight-worthy system, suggesting that
the drive system is being temporarily integrated into the nose
gear bay and undercarriage leg rather than into the fuselage. The
concept dovetails with Boeing's move to a more-electric aircraft
philosophy, as is being pursued with the 787.

Now I am beginning to understand you concern about weight and
complexity.

I wonder if the electric motor could be integrated into the nose wheel
hubs and drive them through ring gear reduction. That might save some
weight and complexity at the expense of completely redesigning the
nose wheels. Alternatively the motor could be mounted at the top of
the gear leg and its shaft directed down between the wheels to a worm
gear. Of course some sort of clutch would be necessary to disengage
the electric drive system during landing I suppose.

writes:

Larry Dighera wrote:

What makes you think the motor will be installed within the fuselage?

By what they have released to the press, such as the following:

http://www.flightinternational.com/A...oeing+767.html

"We believe the ability to integrate it into a weight-sensitive
application is totally feasible," adds Carman. The demonstration
is not representative of a flight-worthy system, suggesting that
the drive system is being temporarily integrated into the nose
gear bay and undercarriage leg rather than into the fuselage.
I think the reporter took some liberties with "suggesting that..."

Perhaps this press release will clarify their intentions.
GIBRALTAR -- (MARKET WIRE) -- 09/11/2005 -- Chorus Motors plc (OTC:
CHOMF) and WheelTug plc confirmed today that they have designed an
initial version of a WheelTug drive that can fit within the existing
nose wheel hub of a 767-class aircraft, with the goal of largely
eliminating the use of tow tugs and jet engines in moving aircraft on
the ground.

--kyler

On Tue, 13 Sep 2005 03:17:02 GMT, Kyler Laird
wrote in ::

Perhaps this press release will clarify their intentions.
GIBRALTAR -- (MARKET WIRE) -- 09/11/2005 -- Chorus Motors plc (OTC:
CHOMF) and WheelTug plc confirmed today that they have designed an
initial version of a WheelTug drive that can fit within the existing
nose wheel hub of a 767-class aircraft, with the goal of largely
eliminating the use of tow tugs and jet engines in moving aircraft on
the ground.

--kyler


Many thanks for the updated information.

A motor in the hub design is the most elegant solution. I wouldn't
have thought the motor would have sufficient torque to drive the
wheels without adequate gear reduction.

Larry Dighera writes:

A motor in the hub design is the most elegant solution. I wouldn't
have thought the motor would have sufficient torque to drive the
wheels without adequate gear reduction.

Exactly - the much higher than usual (5x) low-speed torque of the
Chorus motors are what make them so appropriate for this application.
I wish I had a kit for my Aztec!

I got interested in BOREF for their licensing of Cool Chips
http://www.coolchips.gi/
to keep avionics and turbine engines(!) cool. I think that's going
to take awhile to develop. The motors are much more immediately
exciting.

--kyler

On Tue, 13 Sep 2005 16:17:02 GMT, Kyler Laird
wrote in ::

Larry Dighera writes:

A motor in the hub design is the most elegant solution. I wouldn't
have thought the motor would have sufficient torque to drive the
wheels without adequate gear reduction.

Exactly - the much higher than usual (5x) low-speed torque of the
Chorus motors are what make them so appropriate for this application.
I wish I had a kit for my Aztec!

Even at 5X torque, it would seem that some gearing would be necessary
for a small motor to move an airliner. But there may be a way to
build that into the hub also.

I got interested in BOREF for their licensing of Cool Chips
http://www.coolchips.gi/
to keep avionics and turbine engines(!) cool. I think that's going
to take awhile to develop. The motors are much more immediately
exciting.

--kyler

Wow! That is a breakthrough. Thanks for the information.

On 2005-09-13, Larry Dighera wrote:
Even at 5X torque, it would seem that some gearing would be necessary
for a small motor to move an airliner. But there may be a way to
build that into the hub also.

Probably a planetary gear set. The motor's casing (if the armature is
held still and the case allowed to rotate) could form the sun gear.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

Larry Dighera writes:

Even at 5X torque, it would seem that some gearing would be necessary
for a small motor to move an airliner. But there may be a way to
build that into the hub also.

http://www.wallstreetcorner.com/stockpick.html

I signed a non-disclosure agreement, & was therefore able to
view actual tests on the product -- all I can say is that it
is amazing.

The WheelTug(TM) drive can fit within the existing nose wheel
hub of a 767-class aircraft, with the goal of largely
eliminating the use of tow tugs & jet engines in moving
aircraft on the ground.

[...]

An economic analysis by WheelTug plc estimates that a typical
WheelTug System would have a net present value to airlines of
over $6 million per airplane

Yeow!

--kyler