Too much air in the gas tank??

On 5/5/2021 9:22 AM, Eric Greenwell wrote:
On 5/5/2021 12:20 AM, Martin Gregorie wrote:
On Tue, 04 May 2021 19:29:42 -0700, Guy Acheson wrote:

Same with cars.Â* Solar panels covering the surface will recharge the
batteries continuously for free.

Sure have - but lightweight, single seat vehicled with large, flat top
surfaces covered with solar cells. Specially designed to race across
Australia.

Airplanes have already demonstrated powered flight with all power coming
from solar panels.

Yep, and one even flew round the world on solar power. But lets not
forget that it was huge, a single seater, flew at 35-40 kts and took
weeks to finish the journey.

Just like unlimited power from fission...it is only 10 years away.

Thats the problem with the kids who should know better - they're unable
to distinguish between a hobby/proof of concept vehicle and something you
can buy right now and drive to Vegas for a weekend.

Isn't it wonderful to read about all those VTOL electric cars that will
be available for anybody to buy and fly in four years time, but right now
only exist as shiny graphics plus a price on some website?Â* Not!

Sometimes, I wonder what was said when automobiles were one-offs and
horses provided the local transportation for people and goods and trains
for long distances. Imagine how impractical they were in the beginning:
poor roads, no fueling or repair stations, very expensive. And not safe
to use while drunk because you'd crash, while a horse would keep you
safe, maybe even get you home.


Ah yes, back then we even had "self driving cars" (horses)! :-)

On Wednesday, 5 May 2021 at 15:39:57 UTC+1, Martin Gregorie wrote:
On Wed, 05 May 2021 06:22:15 -0700, Eric Greenwell wrote:

On 5/5/2021 12:20 AM, Martin Gregorie wrote:

These are the projects that deserve critical examination, not rave
reviews in glossy magazines.

One that comes close to this is the Alauda Airspeeder
https://alaudaracing.com/

This was a 1/3 scale prototype was built and flown, but crashed, thanks
to poorly thought systems which were also badly implemented. There's an
AAIB report about it, which is worth reading as an object lesson on how
not to develop a prototype aircraft:

AAIB investigation to Alauda Airspeeder Mk II, (UAS, registration n/a)
040719
https://www.gov.uk/aaib-reports/aaib...da-airspeeder-
mk-ii-uas-registration-n-slash-a-040719
--
Martin | martin at
Gregorie | gregorie dot org

Interesting. My only previous knowledge of this accident was a regional TV news item, with a brief description, and including a photo from ~8000' in controlled airspace.

It brings to mind an old semi-famous comment by a gliding instructor about a certain aircraft: Fly it? I wouldn't walk under it..

On Wed, 05 May 2021 08:46:35 -0700, Eric Greenwell wrote:

On 5/5/2021 7:39 AM, Martin Gregorie wrote:
On Wed, 05 May 2021 06:22:15 -0700, Eric Greenwell wrote:

On 5/5/2021 12:20 AM, Martin Gregorie wrote:
On Tue, 04 May 2021 19:29:42 -0700, Guy Acheson wrote:

Same with cars. Solar panels covering the surface will recharge the
batteries continuously for free.

Sure have - but lightweight, single seat vehicled with large, flat
top surfaces covered with solar cells. Specially designed to race
across Australia.

Airplanes have already demonstrated powered flight with all power
coming from solar panels.

Yep, and one even flew round the world on solar power. But lets not
forget that it was huge, a single seater, flew at 35-40 kts and took
weeks to finish the journey.

Just like unlimited power from fission...it is only 10 years away.

Thats the problem with the kids who should know better - they're
unable to distinguish between a hobby/proof of concept vehicle and
something you can buy right now and drive to Vegas for a weekend.

Isn't it wonderful to read about all those VTOL electric cars that
will be available for anybody to buy and fly in four years time, but
right now only exist as shiny graphics plus a price on some website?
Not!

Sometimes, I wonder what was said when automobiles were one-offs and
horses provided the local transportation for people and goods and
trains for long distances. Imagine how impractical they were in the
beginning: poor roads, no fueling or repair stations, very expensive.
And not safe to use while drunk because you'd crash, while a horse
would keep you safe, maybe even get you home.

I think you're missing my point: there are a couple of eVTOL aircraft
that have been flying for several years, not yet certified but planned
to be on sale in four years or so.

I'm not talking about the Terrafugia either - that does fly - or even
the Moller Flying cars, which Paul Moller has been building for getting
on 50 years: these have flown, though never without a safety tether and
never, AFAICT, with anybody on board.

As I said, I'm not talking about them. What I AM pointing the finger at
are several whose entire existence seems to art on a glossy website
with no news about financing, construction, or test flying development
progress yet with promises to be on sale on four years time at already-
announced prices.

These are the projects that deserve critical examination, not rave
reviews in glossy magazines.

One that comes close to this is the Alauda Airspeeder
https://alaudaracing.com/

This was a 1/3 scale prototype was built and flown, but crashed, thanks
to poorly thought systems which were also badly implemented. There's an
AAIB report about it, which is worth reading as an object lesson on how
not to develop a prototype aircraft:

AAIB investigation to Alauda Airspeeder Mk II, (UAS, registration n/a)
040719
https://www.gov.uk/aaib-reports/aaib...ion-to-alauda-
airspeeder-
mk-ii-uas-registration-n-slash-a-040719

My apologies: my remarks weren't intended as criticism of your comments,
but more generally about the difficulty of predicting the future. I
think there are some parallels with horses/autos and now autos/evtol
that are at least interesting, maybe useful to know. I suspect there
were also entities back then making promises about their autos and the
future of automobiles that were too optimistic, and some of those were
charlatans looking for investors to fleece.

As for flying cars, I think airport loaner cars, Hertz, and Uber are
better solutions to a pilot's ground transportation needs.

No problem!

BTW, did you ever see those videos circulating a year or two back about
electric flying taxis that small Chinese outfits were developing? They
were designed to carry 1-2 people in what looked like urban areas. They
all looked like giant drones with four unshielded rotors, but the scary
feature was that the cabin sat in the middle above the rotors, which were
at roughly knee level when on the ground. The riders had to walk between
the rotors to get in or out, and they didn't look exactly safe for
pedestrians on a windy, gusty day either.

I think I'd prefer a rickshaw pulled by a robot, especially if it was one
of the clanking, coal-powered, steam driven variety from a Harry Harrison
Stainless Steel Rat novel. That would be fun even if I did get cinders in
my eye.


--
Martin | martin at
Gregorie | gregorie dot org

On 5/5/21 1:20 AM, Martin Gregorie wrote:
On Tue, 04 May 2021 19:29:42 -0700, Guy Acheson wrote:

Same with cars. Solar panels covering the surface will recharge the
batteries continuously for free.

Sure have - but lightweight, single seat vehicled with large, flat top
surfaces covered with solar cells. Specially designed to race across
Australia.

Airplanes have already demonstrated powered flight with all power coming
from solar panels.

Yep, and one even flew round the world on solar power. But lets not
forget that it was huge, a single seater, flew at 35-40 kts and took
weeks to finish the journey.


You're speaking of the Solar Impulse 2? Took a year and a half, a large
support team of meteorologists, a cargo plane following them carrying a
huge inflatable hangar, and lots of supplies. They fried their
batteries and had to replace in the field.

A noble experiment, proved it could be done, but also proved it's a hell
of a long ways from being practical.

https://www.youtube.com/watch?v=4qbROmxxIOU