Boeing's Electric Taxi Motor

[Larry Dighera]

BOEING CO. has tested an electric motor that could allow
commercial jets to taxi around airports without using their
engines or ground-based towing vehicles, the company said.
Boeing said its Phantom Works unit had used the nose-wheel
motor, built by Chorus Motors Plc, to move around an Air Canada
Boeing 767 jet in tests simulating various runway conditions in
June. The system could offer a glimmer of hope to U.S.
airlines, which have been scouring for ways to boost economies
amid record fuel prices, by directing pilots to taxi with
single engines, among other steps. It was unclear how soon the
motor would be ready or how much it would cost. Boeing said the
companies are working to overcome various technical issues that
had surfaced during the tests. The motors could save airlines
money by eliminating the use of airport tow tugs and boost
efficiency by running their jets less, as well as reduce
emissions, the companies said.
(Reuters 11:44 AM ET 08/01/2005)

More:
http://q1.schwab.com/s/r?l=248&a=1115480&m=1006242eea2f800022036a&s=rb050801

----------------------------------------------------------------

[Ben Hallert]

So... do you still log the taxi time as PIC? : )

Ben Hallert
PP-ASEL

[Jose]

> So... do you still log the taxi time as PIC? : )

Sure. There are no regs on what is supposed to be powering the
aircraft. :)

What I wonder is which weighs more - the fuel that would have been used,
or the motor that the airplane has to carry around for the whole flight.

Jose
--
Quantum Mechanics is like this: God =does= play dice with the universe,
except there's no God, and there's no dice. And maybe there's no universe.
for Email, make the obvious change in the address.

[Peter Duniho]

"Jose" > wrote in message
t...
> [...]
> What I wonder is which weighs more - the fuel that would have been used,
> or the motor that the airplane has to carry around for the whole flight.

Doesn't really matter. The weights are probably comparable (and the fuel
may well weigh more), but more important is that the airline has to keep
buying the substance that makes up the weight of the fuel (that is, the fuel
itself), while they can buy the electric motor once (or some very small
number of times over the lifetime of the airframe).

Unless the electric motor were vastly heavier than the fuel (and that seems
unlikely), this seems like a pretty good idea to me. It wasn't clear at all
from the press release what the nature of the motor would be. Is it a
permanent installation, or is it attached to the airplane only while at the
airport? Does it have an internal battery, or does it run off of some kind
of external power source (like the airplane's APU).

I don't think the answers are all that critical to the success of the
device, but they are things I wonder about. Ironically, the link Larry
labeled as "More" simply repeats the exact text he posted. Duh. I guess
"More" just means "more formatted and other extraneous crap".

Pete

[Happy Dog]

"Peter Duniho" >
> "Jose" > wrote in message
>> What I wonder is which weighs more - the fuel that would have been used,
>> or the motor that the airplane has to carry around for the whole flight.
>
> Doesn't really matter. The weights are probably comparable (and the fuel
> may well weigh more), but more important is that the airline has to keep
> buying the substance that makes up the weight of the fuel (that is, the
> fuel itself), while they can buy the electric motor once (or some very
> small number of times over the lifetime of the airframe).
>
> Unless the electric motor were vastly heavier than the fuel (and that
> seems unlikely), this seems like a pretty good idea to me. It wasn't
> clear at all from the press release what the nature of the motor would be.
> Is it a permanent installation, or is it attached to the airplane only
> while at the airport? Does it have an internal battery, or does it run
> off of some kind of external power source (like the airplane's APU).

How many kilowatts does a passenger jet consume to run all the other stuff
that must be powered whilst taxiing? A/C, lighting, avionics etc.
Batteries seem an unlikely solution for all that. Additional batteries plus
the power from an idling engine? Third rail?

moo

[Bucky]

Happy Dog wrote:
> How many kilowatts does a passenger jet consume to run all the other stuff
> that must be powered whilst taxiing? A/C, lighting, avionics etc.
> Batteries seem an unlikely solution for all that.

Yeah, I agree. Maybe the engines drive an alternator, which powers the
electric motor.

[Peter Duniho]

"Happy Dog" > wrote in message
. ..
> How many kilowatts does a passenger jet consume to run all the other stuff
> that must be powered whilst taxiing? A/C, lighting, avionics etc.
> Batteries seem an unlikely solution for all that. Additional batteries
> plus the power from an idling engine? Third rail?

IMHO, the most likely solution is to simply run it off the APU. Or maybe
just the regular generator on the engine (which can probably produce enough
power with the engine at idle, which is still a savings over taxiing with
all but one engine shut down). Someone at Boeing was probably driving their
Prius to work and had an epiphany.

My point was simply that the press release is incredibly vague; we really
have no idea *what* this device is, how it works, or how practical it will
be. I suspect it will turn out to be a good idea, but it's hard to know
without any actual information.

Pete

[[email protected]]

It's probably some kind of ultra high voltage DC pancake motor that
would require it's own special APU to power it. It would have to
develope on the order of three to four hundred horsepower to be able to
reliably move a fully loaded jet around under all the taxi conditions
that a jet might see. In addition it would either have to be able to
spool up at a fast enough rate as to not rip the nose gear tires off
the rims on landing or be disconnected from the nose wheels on landing.
Either way it's a lot of extra crap to carry around on the aircraft as
well as go through the certification process over using a tug.

Craig C.

[Dave S]

I wonder what the cost is gonna be in battery life over time.

Dave

[Eduardo K.]

In article >,
Happy Dog > wrote:
>
>How many kilowatts does a passenger jet consume to run all the other stuff
>that must be powered whilst taxiing? A/C, lighting, avionics etc.
>Batteries seem an unlikely solution for all that. Additional batteries plus
>the power from an idling engine? Third rail?

APU.

--
Eduardo K. | Some say it's forgive and forget.
http://www.carfun.cl | I say forget about forgiving just accept.
http://e.nn.cl | And get the hell out of town.
| Minnie Driver, Grosse Point Blank

[Kyler Laird]

"Peter Duniho" > writes:

>My point was simply that the press release is incredibly vague; we really
>have no idea *what* this device is, how it works, or how practical it will
>be. I suspect it will turn out to be a good idea, but it's hard to know
>without any actual information.

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

--kyler

[N93332]

Just brainstorming so this may be a completely wrong idea.

If these electric motors are more effecient than running the engines on the
jets for taxi purposes and will save the airlines 'considerable' fuel costs
for the taxi operations, do the electric motors need to be 'installed' on
the jets? How about using these efficient electric motors on the tugs, use
the tugs to push/pull the jet from the gate all the way to the hold short
line while the jet is just idling. Then have the electric tugs 'race' down a
taxiway to take the arrivals back to a gate. This would mean more tugs and
personnel to drive them.

Just an (dumb?) idea....

[sfb]

Where will you find the BTUs to charge the tugs? Isn't the theory that
the plane has free amps to spare either from an APU that must be running
anyway or batteries charged off the main engines while flying much like
free heat to warm your automobile.

"N93332" > wrote in message
...
> Just brainstorming so this may be a completely wrong idea.
>
> If these electric motors are more effecient than running the engines
> on the jets for taxi purposes and will save the airlines
> 'considerable' fuel costs for the taxi operations, do the electric
> motors need to be 'installed' on the jets? How about using these
> efficient electric motors on the tugs, use the tugs to push/pull the
> jet from the gate all the way to the hold short line while the jet is
> just idling. Then have the electric tugs 'race' down a taxiway to take
> the arrivals back to a gate. This would mean more tugs and personnel
> to drive them.
>
> Just an (dumb?) idea....
>

[N93332]

"sfb" > wrote in message news:NcHMe.7384$rR4.2590@trnddc08...
> Where will you find the BTUs to charge the tugs? Isn't the theory that the
> plane has free amps to spare either from an APU that must be running
> anyway or batteries charged off the main engines while flying much like
> free heat to warm your automobile.
>
> "N93332" > wrote in message
> ...
>> Just brainstorming so this may be a completely wrong idea.

Ok, some way to electrically connect the tug to the jet to use the jet's
'free' amps? Charge the tug while it is tugging?

[Garner Miller]

I'm quite sure the device will be powered by the APU, which will
produce electricity and air conditioning for all the equipment, and the
pressurized air needed to start the engines later.

An idling jet engine uses a TON of fuel and makes quite a bit of
thrust; aside from initially getting the plane moving, taxiing is
normally done at idle thrust anyway. But it's that high idle fuel
consumption that this will eliminate for the taxi-out, and I think it's
a terrific idea.

Just to throw some numbers out, an older 737's engine (I don't have
specs in front of me for the newer ones) burns about 1200 pounds of
fuel per hour, per engine, at idle.. The APU burns about 300 pounds
per hour. A savings of 900 pounds, or about 135 gallons of fuel per
hour over a single-engine taxi. (315 gallons less than a more-common
two-engine taxi!)

Jet fuel's costing the airlines upwards of $1.75 a gallon. For every
minute the airplane could taxi using only the APU instead of one
engine, an airline would save about $4. A typical 15-minute taxi-out
at a semi-busy airport would save $60. An hour-long taxi on a bad
weather day? $240.

Obviously the economics will be different for each airplane type, and
for some airlines like Southwest that don't normally fly into
delay-prone airports, it might not make financial sense to install this
device.

But an airline that flies to LaGuardia, Chicago O'Hare, Atlanta, etc.,
all day long? It could save a ton of money if they can make it work.

--
Garner R. Miller
ATP/CFII/MEI
Clifton Park, NY =USA=

[john smith]

wrote:
> It's probably some kind of ultra high voltage DC pancake motor that
> would require it's own special APU to power it. It would have to
> develope on the order of three to four hundred horsepower to be able to
> reliably move a fully loaded jet around under all the taxi conditions
> that a jet might see. In addition it would either have to be able to
> spool up at a fast enough rate as to not rip the nose gear tires off
> the rims on landing or be disconnected from the nose wheels on landing.

I was pondering a similar question earlier this week as I watched
gasoline prices increase.
The conversion from horsepower to kilowatts is 1:0.75, so a 400 hp
engine is 300 kw.
I was curious as to how large a 300 kw motor is and how massive the
power cables are to provide the requisite voltage and current.
1000 V and 300 A?
How much energy is lost to heating?
How does one reduce this heating loss?
How many kw does it take to start a given mass moving?
I am guessing there is an initial surge current, followed by reduction
in current once the mass is in motion and to keep it moving.

[JohnH]

Larry Dighera wrote:
> BOEING CO. has tested an electric motor that could allow
> commercial jets to taxi around airports without using their
> engines or ground-based towing vehicles, the company said.

Other pluses for this is increased worker safety (running jet engines can be
a tad dangerous and noisy), and improved passenger comfort as the terminal
would no longer smell like a leaky tank of kerosene.

I like it. Or something like it anyway.

[[email protected]]

john smith wrote:
> I was pondering a similar question earlier this week as I watched
> gasoline prices increase.
> The conversion from horsepower to kilowatts is 1:0.75, so a 400 hp
> engine is 300 kw.
> I was curious as to how large a 300 kw motor is and how massive the
> power cables are to provide the requisite voltage and current.
> 1000 V and 300 A?
> How much energy is lost to heating?
> How does one reduce this heating loss?
> How many kw does it take to start a given mass moving?
> I am guessing there is an initial surge current, followed by reduction
> in current once the mass is in motion and to keep it moving.

To give you a couple of size references, we had a 25 hp DC motor that
was set to move a carriage that could weigh as much as 1500 pounds up
and down a column. The engineering requirement was for the motor to be
able to accelerate the carriage from a stop to the furthermost position
(12 feet up)in something under 4 seconds and the placement be within
..1". The power was provided by a high voltage DC unit producing 900 VDC
and up to 100 amps current. The motor case was about 10" in diameter
and about 20" long and weighed over 75 pounds. The power supply was a
little bigger than a 21" monitor but required 220/3Phase to operate.

An air compressor that I used to run had a 1750 hp open frame motor
for the main drive. It was 10 feet in diameter and 3 feet thick. It
took a special 1700 VAC/3P feed and took nearly 2 minutes to come up to
steadystate speed.

What they are going to find in the end, is that putting some kind of
electric taxi system on the individual aircraft is going to backfire
and cost them seat and cargo capacity that outweighs the supposed saved
fuel costs.

Craig C.

[Larry Dighera]

On Wed, 17 Aug 2005 14:24:27 -0400, "JohnH" >
wrote in >::

>Larry Dighera wrote:
>> BOEING CO. has tested an electric motor that could allow
>> commercial jets to taxi around airports without using their
>> engines or ground-based towing vehicles, the company said.
>
>Other pluses for this is increased worker safety (running jet engines can be
>a tad dangerous and noisy), and improved passenger comfort as the terminal
>would no longer smell like a leaky tank of kerosene.
>

Additionally, light aircraft taxiing to the rear of airliners would
not be so precariously subject to upset by jet blast.

But the best improvement will be to decrease the 17,523-million*
gallons of jet fuel the airlines consume annually. Any reduction in
petroleum emissions will benefit the environment, the economy and
reduce US dependence on foreign oil.



* http://www.aopa.org/whatsnew/factcard.pdf

[Bucky]

wrote:
> It's probably some kind of ultra high voltage DC pancake motor that
> would require it's own special APU to power it.

What powers an APU? diesel fuel or something?

[RST Engineering]

Just another tit on the aircraft's Jet-A tanks.

Jim



"Bucky" > wrote in message
oups.com...
> wrote:
>> It's probably some kind of ultra high voltage DC pancake motor that
>> would require it's own special APU to power it.
>
> What powers an APU? diesel fuel or something?
>

[Blueskies]

"N93332" > wrote in message ...
> "sfb" > wrote in message news:NcHMe.7384$rR4.2590@trnddc08...
>> Where will you find the BTUs to charge the tugs? Isn't the theory that the plane has free amps to spare either from
>> an APU that must be running anyway or batteries charged off the main engines while flying much like free heat to warm
>> your automobile.
>>
>> "N93332" > wrote in message ...
>>> Just brainstorming so this may be a completely wrong idea.
>
> Ok, some way to electrically connect the tug to the jet to use the jet's 'free' amps? Charge the tug while it is
> tugging?
>

Or the other way around; power the plane from the tug until engine start...

[Morgans]

> wrote

> What they are going to find in the end, is that putting some kind of
> electric taxi system on the individual aircraft is going to backfire
> and cost them seat and cargo capacity that outweighs the supposed saved
> fuel costs.

I suspect that the electric taxi concept is to be used in precision taxi
movements, and pushbacks, to avoid jet blast issues. I don't think that
they would plan on doing long distance and/or higher speed taxi movements.
Smaller motors with much gearing could mean a pretty small unit, and wires.
It would mean that they could delay engine start, and also shut down
earlier. The APU will already be running anyway, right?

Unless someone knows more than has been mentioned here, all we are doing is
speculating on the configuration, and use. What results is bound to be a
WAG.

The whole idea of Boeing's new generation of planes, is to use the jet
engines for propulsion; only, and eliminate bleed air being used for a
bazillion other uses, thus stealing thrust and efficiency. It makes great
sense to me. It boggles my mind to see how much bleed air is used to run an
air cycle machines.
--
Jim in NC

[Morgans]

"Bucky" > wrote
>
> What powers an APU? diesel fuel or something?

It is just a small jet engine, running a shaft for auxiliary power use, and
power generation. I can't imagine why an additional dedicated APU would be
necessary for the electric taxi motor.
--
Jim in NC

[[email protected]]

Morgans wrote:
> "Bucky" > wrote
> >
> > What powers an APU? diesel fuel or something?
>
> It is just a small jet engine, running a shaft for auxiliary power use, and
> power generation. I can't imagine why an additional dedicated APU would be
> necessary for the electric taxi motor.
> --
> Jim in NC

Most APU's are already loaded up to nearly their max output. I have yet
to be on a jet with an APU that provide enough electrical power for
everything on the aircraft as well as enough air for the air
conditioner packs.

[Jay Beckman]

"Larry Dighera" > wrote in message
...
>
> BOEING CO. has tested an electric motor that could allow
> commercial jets to taxi around airports without using their
> engines or ground-based towing vehicles, the company said.

<SNIP>

Kinda OT, but IIRC, the XB-70 Valkerye (sp?) had electric motors that "spun
up" the mains just before touchdown so that they didn't shear the tires off
the wheels upon landing.

I don't think these motors helped it taxi however.

Jay Beckman - PP/ASEL
Arizona Cloudbusters
Chandler, AZ

[Kyler Laird]

wrote:
> It's probably some kind of ultra high voltage DC pancake motor

No, the Chorus motors are far from being DC. They use phase manipulation
to get substantially higher torque (than traditional technologies) at low
speeds. Taxiing seems like a very good fit.

--kyler

[alexy]

wrote:

>What they are going to find in the end, is that putting some kind of
>electric taxi system on the individual aircraft is going to backfire
>and cost them seat and cargo capacity that outweighs the supposed saved
>fuel costs.

Silly Boeing, paying all those engineers, when the answer is freely
available on Usenet. ;-)
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

[RST Engineering]

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".

Jim


"alexy" > wrote in message
...
> wrote:

>
> Silly Boeing, paying all those engineers, when the answer is freely
> available on Usenet. ;-)

[john smith]

Well, if you went to school in the 50's, that was the current technology
then, so that is what you were taught. Some might say, old habits die hard!

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".

wrote:
>>Silly Boeing, paying all those engineers, when the answer is freely
>>available on Usenet. ;-)

[[email protected]]

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.

[Larry Dighera]

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?

[[email protected]]

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/Articles/2005/05/17/197975/Electric+taxi+concept+gets+test-drive+on+Boeing+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.

[Larry Dighera]

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/Articles/2005/05/17/197975/Electric+taxi+concept+gets+test-drive+on+Boeing+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.

[Kyler Laird]

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/Articles/2005/05/17/197975/Electric+taxi+concept+gets+test-drive+on+Boeing+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

[Larry Dighera]

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.

[Kyler Laird]

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

[Larry Dighera]

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.

[Dylan Smith]

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"

[Kyler Laird]

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

[[email protected]]

Looks to be very encouraging despite the acknowledgement on the site
that they still have some engineering hurtles to overcome. When they
get a flight ready test package put together I'll be real curious as to
how they do the final integration and structural installation, as well
as powering it.

Craig C.

[John Gaquin]

> wrote in message

>
> ......I'll be real curious as to
> how they do the final integration and structural installation, as well
> as powering it.

Power it from the onboard APU.

[Larry Dighera]

On Tue, 06 Dec 2005 22:17:02 GMT, Kyler Laird >
wrote in >::

> 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!

Thanks for the updated information.

In the last year CHOMF has been selling between $5 and $20, and is
currently $7/share. It looks like a good investment to me.

[[email protected]]

John Gaquin wrote:
> > wrote in message

> > ......I'll be real curious as to
> > how they do the final integration and structural installation, as well
> > as powering it.
>
> Power it from the onboard APU.

Yeah, that much I had figured out....what I was meaning is, are the
drives going to be run off of some high voltage AC or DC or run from
already common 28 VDC or 115/400 3p that the APUs can already develope.