h a l f b a k e r yMy hatstand runneth over
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Heating the air in this blimp is accomplished by three sources
of energy:
1. A Kernmantle rope with an electric wire in or attached to
it, tethering the blimp and powering its heating (and
propulsion) system.
2. Solar heat - designed with a clear top and lightweight dark
leaf inside, during
sunny days the blimp is heated directly.
3. Wind power - once up in the air, an AWES (airborn wind
turbine) will supply power, either back through the tether to
be consumed back down on earth, or to be stored in airborne
batteries and used when needed.
An extended version of the blimp would have an ionizer or a
Van-De-Graaff generator (grounded through the tether), so
that the air is thinned even further.
With batteries made from this
http://www.thestar...._for_batteries.html
Only meanwhile, until the "lighter than light" version promised at the end of the article is out [pashute, May 14 2015]
Clement Ader (Thanks [MB] !)
https://en.wikipedi...i/Cl%C3%A9ment_Ader
includes links to webpages of his flying machines [pashute, May 20 2015]
Disc loading
http://en.m.wikiped...g/wiki/Disk_loading
[EnochLives, May 20 2015]
[link]
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Put water inside the blimp envelope, coat the inside of the
blimp with an appropriate reflector, and then use the
tethered electric power to make
microwaves to efficiently convert the water to steam, and
keep it hot. The steam
then inflates the blimp (and is significantly lighter than
ordinary hot air, too). |
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Because of the tether, the propulsion system will propel it around in a circular, or perhaps dome shaped path. That would be perfect for football games, less good for transatlantic crossings. |
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In 1903-04, the French aviation pioneer Clément Ader
conducted trials of several electrically-powered
aeroplanes which flew at the end of a long power-
carrying tether up to 2km in length. Electric motors
in those days were heavy, but were still lighter than
the available liquid-fuelled engines and had the
advantages of reliability and easily-controllable
speed. |
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Ader successfully flew his aircraft (the Electron, the
Magnéte and the Voltaire Bis - the last of which had
two motors) on a number of occasions, in circuits
around a central tower which provided the power and
payed out the cable using a sprung reel. His longest
flight was just over three hours, during which he
covered some 120 miles - easily beating the current
distance and time records. |
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Ader's aim was not to develop electric aircraft, but to
use his system as a dependable test-bed for studying
the performance of various aircraft designs, in
preparation for what he predicted would be the
development of lightweight, reliable liquid-fuelled
engines. |
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To minimize the weight and drag of the tether, he
used only one conductor; the return path was made
with a much shorter cable which ended in a series of
copper chains. This shorter cable dragged along the
ground directly below the aircraft to provide an earth
connection. |
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His diaries record over 700 flights in these three
aircraft, making him the most experienced aviator of
the day. |
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[Max] I appreciate how you always find the most
obscure and interesting historical facts. I usually
feel that I have to look them up to verify and to
learn more, which often ends up being very
difficult. |
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Regarding the electric airplane, what really
interests me (but I wasn't able to find more details
on) was how he got a solid ground connection
with dragging copper chains. If there is enough
chain dragging to allow for altitude changes and to
provide enough contact for a low resistance
electrical connection, it seems like it would
provide way to much drag and have an
unacceptable risk of snagging something. |
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Interesting about the electrical plane Max. I think
this Ader guy had a bad press agent as it's definitely a part
of
aviation history that doesn't get much mention. I'd
never heard of him. |
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//how he got a solid ground connection// I believe
he used high voltage (and low current), both for this
reason and to keep the tether cable as light as
possible. I don't know if his motors ran off the high
voltage, or if there was a transformer (which, given
the transformer technology of the time, would have
been quite heavy). |
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Incidentally, although the idea of an electric plane
running off
an extension lead is generally considered risible
nowadays,
there may be a recreational market. |
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Consider those water-jet packs, that run off a hose
from the
floating base unit. They're considered great fun
despite being
tethered. |
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So, I wonder how feasible it would be to build a man-
carrying
twin-motor, twin-rotor backpack machine that took
its power
from a ground tether of, say, 100ft. It'd be great fun,
and
potentially useful for (for instance) inspecting high
structures. |
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Reliability would be pretty high. Stability could be
fly-by-wire
(based on existing drone technology). A backup
battery, either
onboard or at the base station, would provide a few
seconds of
power for a safe descent in the event of a power
loss. |
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Any ideas on the power needed to keep a man
hovering? |
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//Any ideas on the power needed to keep a man
hovering?// |
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See link for a simple description of actuator disc theory.
The penultimate equation suggests about 5kW is required
to lift a vehicle of 150kg using a lightly loaded rotor. You
should probably double this to account for aerodynamic
inefficiencies. |
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Hovering is difficult, but I was actually expecting the power
to be somewhat more than this. |
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5kW is OK, in fact even 10kW would be doable from a
domestic supply, via a reasonably-sized cable. I too
would have expected it to be higher. |
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So, based on 10kW, it's feasible to build an electric
hovering thing that's tethered to a domestic supply.
I'd buy one. |
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