Mini-Winch for FES

On Wed, 04 Mar 2020 15:54:48 -0700, kinsell wrote:

Yep, that's been making the rounds again recently. Announced in 2016,
supposed to be commercially viable in another 5-10 years. The good
thing is Goodenough is 97 years old, and unlikely to be around to take
criticism if it doesn't pay off.

Only four years? So what?

Need I remind you that work started on lithium-ion cells in 1977,
Goodenough and Mizushima demonstrated a rechargeable Li-ion cell in 1979
and Yazami demonstrated the carbon anode in 1980, but it still took
another 11 years before Sony released the first commercial battery in
1991. Thats 14 years in development.

The first device I owned with a Li-ion battery was a Compaq iPAQ 3630 -
iPAQs weren't released until 2000, with the 3630 appearing in 2001 - a
mere 24 years after the first Li-ion battery was demonstrated.

So, I think we need a teensy bit more evidence than "its taken 4 years
already and still not on the shelves" to discount glass-technology
lithium batteries as vapour-ware.

I see the Germans burned up their Lilium eVTOL "jet" prototype a few
days ago, 36 ducted fans on something targeted as an electric flying
taxi cab. If they're going to keep burning up prototypes, maybe they
should do it in Greta Thundberg's back yeard, so she can experience what
a fully involved lithium battery fire actually smells like.

If you store a lot of energy in a battery containing a flammable
electrolyte, mistreat it in some way (short, overheat or puncture -
doesn't matter which) you shouldn't be surprised if bad things happen:
several crashed Teslas have caught fire hours after the crash happened.


--
Martin | martin at
Gregorie | gregorie dot org

Have you ever seen an FES propeller extended?Â* There's no way I'd
attempt a launch either by air, auto, or winch with that prop spinning!Â*
Now, a catapult launch might just work and it might just rip the landing
gear off the ship.

I wonder if Mark would post that video of the solar electric prototype
glider model catapult test launch.Â* Hint:Â* The fuselage flew a short
distance but the wings remained at the takeoff point.

On 3/4/2020 11:22 PM, son_of_flubber wrote:
I'd rather take my chances on something that would accelerate the glider 0-50 knots in 50 meters with the FES running from the very start of the roll. This would increase available runway ahead for launch failure and conserve a bit of battery power. Fully automated with pilot pushing the go button.

How much runway do you need to self-launch a heavy two place FES when there is sink and windshear present?


--
Dan, 5J

Well with the right hill and some head wind...
https://youtu.be/zdCGb9-vjck

Seems like the Wright Brothers had a solution to accelerate their craft to flight speed...

Perhaps Willie Coyote can give us some ideas...

Bungees?Â* We don't need no stinking bungees!
https://www.youtube.com/watch?v=lbRAqPxd49E

On 3/5/2020 8:47 AM, Mike N. wrote:
Well with the right hill and some head wind...
https://youtu.be/zdCGb9-vjck

--
Dan, 5J

At 15:47 05 March 2020, Mike N. wrote:
Well with the right hill and some head wind...
https://youtu.be/zdCGb9-vjck

Slightly more on Paul's original topic, at the site where the bungee clip
was shot (Long Mynd in UK) on slightly less windy days, they winch launch
to around 300' straight onto the hill.

No 'Mini-Winch' though - they use a standard, full power Skylaunch winch,
which the also use on their longer runs when the wind is not on the hill.

https://www.youtube.com/watch?v=tGeUFJUQlaQ

As a snow skier, I think that is quite cool. All that site needs is a rope tow back to the top of the hill... �

More on topic, Paul's original post seems to have the most practical solution.

Auto towing of an FES glider to a safe height to either fly out on FES power or allowing a safe return to the field, seems a great and practical solution.

Consider soaring sites at small airfields with neither tow plane or winch available.

Bring your glider to the site with your tow vehicle, then auto tow using the same vehicle. Think of the potential for flying from small sites.

No offense Paul, but maybe a mini winch for FES launching is a solution looking for a problem.

On Wednesday, March 4, 2020 at 3:04:34 PM UTC-5, wrote:
How hard could it be?
Sigh
UH

Yep! How hard could it be?
https://www.youtube.com/watch?v=R--m0NDR0j8

I did watch a live demo of a high-performance jet sustainer glider using an auto tow on a short rope (IIRC, a conventional aerotow rope) to get the sailplane moving fast enough to spin up the jet and get off the ground, at which point (less than 100 feet) the pilot released and climbed away, with plenty of room to land straight ahead on the [hard surface] runway if necessary. Pretty impressive. But no interference with an FES prop to worry about.

I also watched an FES ASW 27 self launch a few years ago from a hard surface runway. Also pretty impressive.

Chip Bearden
JB