Electrically Powered Ultralight Aircraft

Larry Dighera wrote:
On Tue, 07 Aug 2007 19:14:59 GMT, wrote in
:

If you go to http://xtronics.com/reference/energy_density.htm you
find the energy densities of a lot of things.


Propane (liquid) 13,900 Wh/kg
Diesel 13,762 Wh/kg
gasoline 12,200 Wh/kg
Ethanol 7,850 Wh/kg
Methanol 6,400 Wh/kg
Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
Primary Zinc-Air 300 Wh/kg
Lead Acid Battery 25 Wh/kg

So batteries have to improve by a factor of 10 to match gasoline.

When you compare the efficiency of internal combustion Otto Cycle
engines (30% - 40%) against electric motors (80% - 95%), it appears
that a factor of five might be a more realistic comparison of their
relative merits. Then there is the issue of power plant weight...

Electric motors don't lose power in thin air either. With regard to
reliability, electric motors have only one moving part compared to
scores of moving parts for IC engines, their failure rate should be
substantially greater than IC engines.

Here is a 100hp electric motor. I don't know if it is typical for an
electric motor but damn the thing weighs over half a ton. I might make the
601XL a little nose heavy. But it's priced right up there with a Lyc of
equal power.

http://www.baldor.com/products/detai...neralPur pose

Catalog Number: D50100P
Description: STOCK MOTOR,368AT,100HP,1750/2000RPM,DPFG
Ship Weight: 1,118 lbs.
List Price: $21,195
Multiplier Symbol: N2

Gig 601XL Builder wrote:
Larry Dighera wrote:
On Tue, 07 Aug 2007 19:14:59 GMT, wrote in
:

If you go to http://xtronics.com/reference/energy_density.htm you
find the energy densities of a lot of things.


Propane (liquid) 13,900 Wh/kg
Diesel 13,762 Wh/kg
gasoline 12,200 Wh/kg
Ethanol 7,850 Wh/kg
Methanol 6,400 Wh/kg
Secondary Lithium - ion Polymer 130 - 1200 Wh/kg
Primary Zinc-Air 300 Wh/kg
Lead Acid Battery 25 Wh/kg

So batteries have to improve by a factor of 10 to match gasoline.
When you compare the efficiency of internal combustion Otto Cycle
engines (30% - 40%) against electric motors (80% - 95%), it appears
that a factor of five might be a more realistic comparison of their
relative merits. Then there is the issue of power plant weight...

Electric motors don't lose power in thin air either. With regard to
reliability, electric motors have only one moving part compared to
scores of moving parts for IC engines, their failure rate should be
substantially greater than IC engines.

Here is a 100hp electric motor. I don't know if it is typical for an
electric motor but damn the thing weighs over half a ton. I might make the
601XL a little nose heavy. But it's priced right up there with a Lyc of
equal power.

http://www.baldor.com/products/detai...neralPur pose

Catalog Number: D50100P
Description: STOCK MOTOR,368AT,100HP,1750/2000RPM,DPFG
Ship Weight: 1,118 lbs.
List Price: $21,195
Multiplier Symbol: N2



Just a wild guess, but wouldn't this make for a very, very safe airplane??

George

George wrote:


Just a wild guess, but wouldn't this make for a very, very safe
airplane??
George

None would be safer, though you might find some people who would have a
problem with calling it an airplane if it couldn't get off the ground.

Gig 601XL Builder wrote:
George wrote:
Just a wild guess, but wouldn't this make for a very, very safe
airplane??
George

None would be safer, though you might find some people who would have a
problem with calling it an airplane if it couldn't get off the ground.


That was my point, if it can't fly, how can it crash?? vbg

George

On Tue, 7 Aug 2007 16:12:16 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

Here is a 100hp electric motor. I don't know if it is typical for an
electric motor but damn the thing weighs over half a ton. I might make the
601XL a little nose heavy. But it's priced right up there with a Lyc of
equal power.

http://www.baldor.com/products/detai...neralPur pose

Catalog Number: D50100P
Description: STOCK MOTOR,368AT,100HP,1750/2000RPM,DPFG
Ship Weight: 1,118 lbs.
List Price: $21,195
Multiplier Symbol: N2


Right. Those are the type I used to install in the early '70; that
was about forty years ago. Today the situation is a bit different.

Here's a small electric motor manufactured by the same fellow, Bob
Boucher, who designed the Sonex motor:


http://www.astroflight.com/store/sto...y3CKHwWtA02470

Cobalt 90 Direct Drive Motor
Cobalt 90 Direct Drive Motor, 30 to 40 cells, 1500W

Astro 90 Cobalt Motor p/n 690
Model No. p/n 690
Name 90 Cobalt
Armature Winding 10 turns
Armature Resistance 0.111 ohms
Magnet Type Sm Cobalt
Bearings Ball Bearings
Motor Speed /volt 256 rpm/volt
Motor Torque/amp 5.3 in-oz /amp
Voltage Range 24 to 48 volts
No Load Currrent 3 amps
Maximum Continuous Current 35 amps
Maximum Continuous Power 1200 watts
Motor Length 3.7 inches
Motor Diameter 2.1 inches
Motor Shaft Diameter 0.25 inches
Prop Shaft Diameter 5/16 inch
Motor Weight 32 oz


Expected Performance of Cobalt 90
Battery Prop Amps Watts Rpm
36 Nicads 14x7 20 amps 800 watts 9,000 rpm
36 Nicads 14x10 25 amps 1000 watts 8,500 pm
36 Nicads 15x10 30 amps 1200 watts 8,000 rpm
36 Nicads 16x10 35 amps 1400 watts 7,500 rpm


This is a small motor, as you can see, but it uses ~1,500 watts, so at
720 watts per horsepower, that's about two horsepower, and it weighs
32 oz, or about two pounds. That works out to about one horsepower
per pound for this type of motor. I have no idea if a one hundred
horsepower motor of this type would weigh 100 lbs or not, but it seems
reasonable.

Larry Dighera wrote:



I have no idea if a one hundred
horsepower motor of this type would weigh 100 lbs or not, but it seems
reasonable.

That's why I showed the first 100HP electric motor I could find. They
obviously don't make a 100HP motor of the type you showed or you would have
quoted it's specs.

I doubt they add the extra 1000 lbs just for the fun of it.

On Wed, 8 Aug 2007 08:12:37 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

They obviously don't make a 100HP motor of the type you showed or you would have
quoted it's specs.


Take a look at the ~75 HP electric motor installed in the Sonex Waiex:
http://www.sonexaircraft.com/news/im...light_5947.jpg

Exclusive of the two black boxes, the Sonex motor sure doesn't appear
to weigh any where near the 1,118 lbs motor you found. My guess would
be under 100 lbs. It is custom built for/by Sonex, so I'm not able to
quote its specifications.

You don't really believe Sonex is using an electric motor that weighs
any where near 1,118 lbs, do you. The entire empty weight of the
Waiex is only ~620 lbs with a gross weight of 1150 lbs.

Larry Dighera wrote:
On Wed, 8 Aug 2007 08:12:37 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

They obviously don't make a 100HP motor of the type you showed or
you would have quoted it's specs.


Take a look at the ~75 HP electric motor installed in the Sonex Waiex:
http://www.sonexaircraft.com/news/im...irventure07/e-
flight_5947.jpg

Exclusive of the two black boxes, the Sonex motor sure doesn't appear
to weigh any where near the 1,118 lbs motor you found. My guess would
be under 100 lbs. It is custom built for/by Sonex, so I'm not able to
quote its specifications.

You don't really believe Sonex is using an electric motor that weighs
any where near 1,118 lbs, do you. The entire empty weight of the
Waiex is only ~620 lbs with a gross weight of 1150 lbs.

Of course I don't. But they might as well be at this point becuse the
electric motor they have has never been off the ground.

I wish the Sonex guys well and will praise the hell out of them if they do
what they are trying to do. But, as I said in a earlier post, I just don't
see this big of a technological leap coming from a company whose last major
enginnering feat was converting a VW engine for aircraft.

If and when it happens it will be either a bunch of guys from MIT or Cal
Tech or as the offshoot of a much more profitable electric motor project.

On Wed, 8 Aug 2007 10:48:40 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

Larry Dighera wrote:
On Wed, 8 Aug 2007 08:12:37 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

They obviously don't make a 100HP motor of the type you showed or
you would have quoted it's specs.


Take a look at the ~75 HP electric motor installed in the Sonex Waiex:
http://www.sonexaircraft.com/news/im...irventure07/e-
flight_5947.jpg

Exclusive of the two black boxes, the Sonex motor sure doesn't appear
to weigh any where near the 1,118 lbs motor you found. My guess would
be under 100 lbs. It is custom built for/by Sonex, so I'm not able to
quote its specifications.

You don't really believe Sonex is using an electric motor that weighs
any where near 1,118 lbs, do you. The entire empty weight of the
Waiex is only ~620 lbs with a gross weight of 1150 lbs.

Of course I don't. But they might as well be at this point becuse the
electric motor they have has never been off the ground.

The motor was apparently designed by Bob Boucher. He also designed
the motors Dr. Paul MacCready used to fly across the English channel
solely under power from the sun, and other successful AeroVironment
electrically powered aircraft commissioned by NASA. If anyone can
design a proper electric motor for aviation, Mr. Boucher should be
able to; he has the past successes to prove it.

I wish the Sonex guys well and will praise the hell out of them if they do
what they are trying to do. But, as I said in a earlier post, I just don't
see this big of a technological leap coming from a company whose last major
enginnering feat was converting a VW engine for aircraft.

If and when it happens it will be either a bunch of guys from MIT or Cal
Tech or as the offshoot of a much more profitable electric motor project.


Perhaps.