Gentlemen,
Hope no one minds my two cents worth since I am new to the group.
(1)
The battery is the usual second source of electrical power.
Addition of a second alternator adds weight and complexity.
Kind of defeats one advantage of the rotary, (simplicity) when complicating
the supporting systems.
Making complex systems reliable is rather expensive.
As Tracy Crook recommends, keep tabs on battery health and have a low
voltage
warning light on your engine monitor or as part of your charging system
design.
(2)
I do LOVE the concept of a flywheel / starter / alternator to complement
the
natural compactness of the rotary.
I would bet that Tracy would be interested is having it as an accessory to
his gear drive.!
Has anyone asked him?
Sort of a Honda IMA concept.
Not many out in the world yet but perhaps the Insight IMA assembly could be
adapted.
Sorry to get so long winded !
Tom Henry
Duncan Aviation Avionics System Engineer
LNK, NE
Tom
It seems lot of people are interested in a compact flywheel alternator
concept. Only needs about 1kw in the alternator mode. I believe a little
more is needed in motor mode to start the RE. There is plenty of room in
the bell housing for a motor/gen. generator of 12KW or more if needed.
To use the IMA system effective, we would need a power source and controls
that weigh less and produces more net energy than the RE burning hydro
carbon based fuels.
Sailplane yes it has been done with flexible solar cell bonded with the wing
skins.
Like Russell implied, having a spare source of electrical generation, will
save our butt if we are stuck up in IFR conditions, or over big ponds for
hours at night. A 100amp/hour battery despite their stated rating may not
deliver all of those 100 amp/hrs. when you need them. Hey but you know
that. I guess it depends on what type of flying you want to do. Short
cross country? Perhaps you want to risk it. None of us (if any??) will be
adapting magnetos to our rotaries so to depend on only one battery and one
alternator. Hmmmmmm???
Yea I am a fan of hybrid cars electrical motors as well.
Here a quote about the new Honda V-6. I can hear Paul sighing already:)
The IMA [Integrated Motor Assist] system's 12-kilowatt, high-output,
electric motor contributes more than 100 lb.-ft. of torque to the Accord
Hybrid's 3.0-liter V-6 engine during hard acceleration and recaptures
kinetic energy generated during deceleration and braking for storage in the
IMA system's advanced nickel-metal hydride battery pack. When cruising at
steady speeds where less engine power is required, the VCM system
deactivates the V-6 engine's rear bank of cylinders, closing both the intake
and exhaust valves for reduced fuel consumption.
Under light acceleration from a cruising state, the IMA motor can provide
power assistance to the engine in three-cylinder mode. When coming to a
stop, the IMA system shuts off the vehicle's engine at speeds below 10mph to
reduce fuel consumption and exhaust emissions. At the moment the driver
releases the brake pedal, the IMA motor instantaneously restarts the
gasoline engine.
Doug in Japan
You don't need a large diameter 100 pound motor/generator to start and
stop the engine at street lights. GM is doing the same thing with a 7 pound
starter/alternator that looks just like the current alternator. Mazda has
taken
a first step in this direction by controlling the field current in the RX8
alternator using the main computer.
There are two ways to get HP out of an electric motor or generator. You can
use
a big old clunky large diameter motor/generator or you can use a much smaller
motor generator operating at high RPM. The small high RPM motor/generators
have a much higher power to weight ratio. Since the current alternator is
already
of the last variety it doesn't take much to convert it to a starter motor and
make it
do double duty. GM fully intends to stop and start their engines at stop
lights
yielding half the fuel savings of a hybrid car with a seven to ten pound
decrease
in overall weight. Patience! You will be able to buy one of these
things any day now.
Hybrid cars are 500 to 700 pounds heavier than an equivalent car therefor they
consume precious natural resources in the form of copper and other exotic
material in their batteries. Since the manufacturing cost of cars is
proportional
to the weight they cost up to 25% more to manufacture. Also up to 25% more
energy
is required to manufactures the materials. This is a hidden additional stress
on the
environment never talked about. Toyota admits they are subsidizing the cost
and
selling the hybrid cars at a loss merely to appear to be concerned about the
environment.
This cynical practice enables them to sell many more conventional, much more
profitable cars and therefore make more money over all. (Don't make me scan
the
article in Automotive News and send it to you :))
From an engineering point of view it makes no sense whatsoever as additional
weight translates to more HP required particularly when climbing hills. Hybrid
cars are also marginally more efficient when cruising on the freeway at high
speed.
That is probably the reason they don't sell well in Europe. They are primarily
effective in stop and go city traffic but so two would be a car equipped with
a
low tech, large diameter flywheel to store energy. Actually rubber bands
store
more energy per pound than just about anything else one can find.
The correct engineering approach is to improve the horribly inefficient
internal
combustion engine and reduce the weight and aerodynamic drag of the vehicle.
Putting
an electric hybrid system in an SUV is totally INSANE!!!!!
The current tiny and low drag Honda Incite (it incites and excites me :))
hybrid
would be just wonderful if all the excess weight would be removed and a
slightly larger turbo compound engine used instead.
I commend Doug on his willingness to improve the efficiency of the internal
combustion engine by his work on turbo compounding.
BTW Doug I made contact with my old friend at Garret, David Elpern (He is
still
there. Now Honeywell). See SAE paper 821149 The "Effects of Turbocharger
Design
and Installation on Gasoline Vehicles Transient Response". He is working on
gathering
HP data on the turbo chargers but don't hold your breath as that is not what
they
are really interested in. You might have to build a turbo dyno. (Not as hard
as
it sounds.)
Paul
I had a hunch that the word 'hybrid' would excite you. My interest in hybrid
cars is that they will drive the development of more efficient electrical
motors and smaller controllers and pave the way for fuel cell driven cars.
Perhaps somewhere along the way we will benefit from a simpler smaller
energy storage device.
Meanwhile I happen to agree with you that the current design philosophy for
hybrid cars does overall more damage to the environment when you tally in
the environmental impact of resources used never mind cost performance.
Toyota Inc are experts at greenwashing. I've been following their tactics
for 24 years now. They are good at marketing and manufacture well made
machines. Again they have created the market perception that buying a hybrid
is a good thing.
BTW, EXPO 2005, starting this March, was promoted by Toyota Homes (divison
of Toyota) and Meitetsu railroad/department store chain as a cover for the
development of a mega suburban city out in natural surroundings.
Toyota pays a lot of taxes and they have a lot of influence in Aiichi
Prefecture near Nagoya. Interesting enough the EXPO's theme is called
"Nature's Wisdom" but because they literally cut down the forests to design
a 'natural' landscape, the motto perhaps should be called Nature's Wisdumb"
I refused to design any systems for them or have my name associated with
that fiasco. I did agreed to be one of the 100 speakers they have called
upon from around the world to speak at the EXPO. My speech will be about
how to use technology appropriately. I think might they may regret it asking
me:)
Paul two questions.
1. Do you have an idea how I could make a test stand for my turbo compound
gear box? Air motor can test it under speed unloaded of course. Getting the
13B I have running is going to take longer than I thought as it looks like
it needs total rebuilding.
2. Turbocharger: I believe the turbine is pressed on the shaft. How about
the compressor wheel, keyed and retaining nut?
Doug in Japan
Any forty HP electric motor running at 60,000 RPM can test the gear box as long
as you have a corresponding load on the output shaft :)
The turbine is spin welded to the shaft. Yes on the compressor wheel.
Paul Lamar
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