Light Electric Rotorcraft

wrote:
And hydrogen is a lightweight fuel too, for lower fuel load.
But suppose you want some extra juice sometimes, for more
maneuvering/lifting power.

Hydrogen is only a lightweight fuel in its uncompressed, gaseous form.
In fact, in terms of energy per Kg, hydrogen is not a good fuel. Storing
hydrogen in sufficient density to be useful requires strong (read heavy)
tanks.

Well, some research group is claiming to have come up with a new way to
store hydrogen, which may make it more feasible as a vehicular fuel:

http://www.sciencedaily.com/releases...0907102549.htm

http://denmark.dk/portal/page?_pagei..._schema=PORTAL

http://www.amminex.com/

http://www.thewatt.com/modules.php?n...rticle&sid=763

http://www.investindk.com/visNyhed.asp?artikelID=13670

But admittedly, it's very new and as yet untried in the marketplace.

Frank van der Hulst wrote:

wrote:

And hydrogen is a lightweight fuel too, for lower fuel load.
But suppose you want some extra juice sometimes, for more
maneuvering/lifting power.


Hydrogen is only a lightweight fuel in its uncompressed, gaseous form.
In fact, in terms of energy per Kg, hydrogen is not a good fuel. Storing
hydrogen in sufficient density to be useful requires strong (read heavy)
tanks.

Unless you are driving an anti-static engineered lifting body shaped
dirigible, in which case, compressing or decompressing a little of
the surplus fuel / bouyancy medium using a "bouyancy bladder" device
allows ascent and descent without actual fuel expenditure, except
that required to compress the gas when descending. Quite the
inverse of a normal flying vehicle, where energy is expended to ascend.

Has anybody analyzed that in terms of fuel efficincy?

Terry K