Hi,

This is just a thought...

I’ve recently been extremely interested in the FES (Front Electric Sustainer) sailplanes. They are becoming quite popular. Even very high-performance racing sailplanes like the Ventus 3 are being sold with FES systems installed.

I am the U.S. dealer for DG/LS and they offer the LS8e neo with FES and the new DG-1001e neo with FES prototype will fly very soon. It will be the first 2-seat sailplane with FES. I would love to trade my DG-1000S in for a DG-1001e neo with FES, but so far my DG-1000S co-owners aren't ready for that upgrade.

I'm not very experienced with winches and certainly not an expert on such matters, but I think there may be a nice market for a very small electric winch designed to get an FES-equipped sailplane just up to 100 feet – high enough to use the FES to climb to the first thermal. Even self-launch capable FES sailplanes would benefit from a small winch because they would save much more of the sailplane's battery for use later in the flight - since the initial takeoff roll requires a lot of power.

You can see an interesting video showing an FES-equipped sailplane taking an autotow to about 100 feet here:
https://youtu.be/pTeNKM2cXQk

I would think that an electric winch could get a glider to 100 feet quite easily and be quite small and relatively inexpensive. The rope needed would be much less, and the drum could be much smaller – I imagine.

A "level ground bungee launch" to 100 feet would be another interesting option. But I would think that would have risks from by the bungee snapping or coming loose and hurting someone.

Any thoughts...? I'm just dreaming about the future of gliding...

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

The "mini winch" could also be a car and an air tow (200 foot or so) rope. Keeps you from having to buy and maintain additional equipment.

Steve Leonard

At 06:03 04 March 2020, Steve Leonard wrote:
>The "mini winch" could also be a car and an air tow (200 foot
or so) rope.
>Keeps you from having to buy and maintain additional
equipment.
>
>Steve Leonard
>
Yes, hard to know why you would want to go to the trouble of
an electric winch? Presumably you are thinking of a battery
powered electric winch? Unless you fly from a site with no
winch or aerotow facilities why bother?
If you are at a normal gliding club just take a proper launch to
a sensible height and keep what little power you have in your
tiny batteries for the retrieve?
Dave W

A truck and a compound pulley system could get you up to a minimum safe turn back altitude easily enough and no new engineering would be necessary.

https://youtu.be/Q0rv1zOmyWg

Paul A.
Jupiter, Fl

Hi Steve,

An auto launch is a great option on a hard-surface runway, but not ideal on a grass runway like we have at our lovely little gliderport. The airport management and owners wouldn't want us tearing-up the grass.

Best Regards,

Paul Remde
______________________________

On Wednesday, March 4, 2020 at 12:03:43 AM UTC-6, Steve Leonard wrote:
> The "mini winch" could also be a car and an air tow (200 foot or so) rope. Keeps you from having to buy and maintain additional equipment.
>
> Steve Leonard

On Tuesday, March 3, 2020 at 11:38:57 PM UTC-6, Paul Remde wrote:
> Hi,
>
> This is just a thought...
>
> I’ve recently been extremely interested in the FES (Front Electric Sustainer) sailplanes. They are becoming quite popular. Even very high-performance racing sailplanes like the Ventus 3 are being sold with FES systems installed.
>
> I am the U.S. dealer for DG/LS and they offer the LS8e neo with FES and the new DG-1001e neo with FES prototype will fly very soon. It will be the first 2-seat sailplane with FES. I would love to trade my DG-1000S in for a DG-1001e neo with FES, but so far my DG-1000S co-owners aren't ready for that upgrade.
>
> I'm not very experienced with winches and certainly not an expert on such matters, but I think there may be a nice market for a very small electric winch designed to get an FES-equipped sailplane just up to 100 feet – high enough to use the FES to climb to the first thermal. Even self-launch capable FES sailplanes would benefit from a small winch because they would save much more of the sailplane's battery for use later in the flight - since the initial takeoff roll requires a lot of power.
>
> You can see an interesting video showing an FES-equipped sailplane taking an autotow to about 100 feet here:
> https://youtu.be/pTeNKM2cXQk
>
> I would think that an electric winch could get a glider to 100 feet quite easily and be quite small and relatively inexpensive. The rope needed would be much less, and the drum could be much smaller – I imagine.
>
> A "level ground bungee launch" to 100 feet would be another interesting option. But I would think that would have risks from by the bungee snapping or coming loose and hurting someone.
>
> Any thoughts...? I'm just dreaming about the future of gliding...
>
> Best Regards,
>
> Paul Remde
> Cumulus Soaring, Inc.

Paul, what makes you think a "mini winch" is less complex and less expensive than one that gets you all the way to 1,500' plus? You still need to accelerate the same mass to flying and climbing speed and do it quickly. You still need a guillotine on the winch, a winch driver, cable retrieve, parachute on the cable etc.etc. Going to only 100' has you rely on your motor to get out of that most dangerous place we have while launching.

Herb

For the volume of launches you'd be doing auto tow would work just fine for FES. I also agree with Herb. A mini winch would be of limited utility. Why not go whole hog and take advantage of a full size winch for normal or non-FES launches? You would be helping your club and others and not just adding to your overhead. Maybe if you took on a mini winch as a self educational project for a boutique opperation and didn't care about additional utility or resale value it could be fun but again its hard to compete with auto tow with low launch numbers.
There's good and bad info about winching circulating in the U.S. I suggest looking to Europe for answers. Ask many questions and don't try to fill in the blanks yourself, that's why Americans have such a poor record on the matter.

-DT

Agree with other posters, not sure how much you'd save in terms of
money/effort/time with a mini winch vs a regular one.

Speaking of that, what ever happened to the great electric winch project
up at Bend OR that set the internet on fire not so long ago?


On 3/3/20 10:38 PM, Paul Remde wrote:
> Hi,
>
> This is just a thought...
>
> I’ve recently been extremely interested in the FES (Front Electric Sustainer) sailplanes. They are becoming quite popular. Even very high-performance racing sailplanes like the Ventus 3 are being sold with FES systems installed.
>
> I am the U.S. dealer for DG/LS and they offer the LS8e neo with FES and the new DG-1001e neo with FES prototype will fly very soon. It will be the first 2-seat sailplane with FES. I would love to trade my DG-1000S in for a DG-1001e neo with FES, but so far my DG-1000S co-owners aren't ready for that upgrade.
>
> I'm not very experienced with winches and certainly not an expert on such matters, but I think there may be a nice market for a very small electric winch designed to get an FES-equipped sailplane just up to 100 feet – high enough to use the FES to climb to the first thermal. Even self-launch capable FES sailplanes would benefit from a small winch because they would save much more of the sailplane's battery for use later in the flight - since the initial takeoff roll requires a lot of power.
>
> You can see an interesting video showing an FES-equipped sailplane taking an autotow to about 100 feet here:
> https://youtu.be/pTeNKM2cXQk
>
> I would think that an electric winch could get a glider to 100 feet quite easily and be quite small and relatively inexpensive. The rope needed would be much less, and the drum could be much smaller – I imagine.
>
> A "level ground bungee launch" to 100 feet would be another interesting option. But I would think that would have risks from by the bungee snapping or coming loose and hurting someone.
>
> Any thoughts...? I'm just dreaming about the future of gliding...
>
> Best Regards,
>
> Paul Remde
> Cumulus Soaring, Inc.
>

On Wednesday, March 4, 2020 at 12:38:57 AM UTC-5, Paul Remde wrote:
> Hi,
>
> This is just a thought...
>
> I’ve recently been extremely interested in the FES (Front Electric Sustainer) sailplanes. They are becoming quite popular. Even very high-performance racing sailplanes like the Ventus 3 are being sold with FES systems installed.
>
> I am the U.S. dealer for DG/LS and they offer the LS8e neo with FES and the new DG-1001e neo with FES prototype will fly very soon. It will be the first 2-seat sailplane with FES. I would love to trade my DG-1000S in for a DG-1001e neo with FES, but so far my DG-1000S co-owners aren't ready for that upgrade.
>
> I'm not very experienced with winches and certainly not an expert on such matters, but I think there may be a nice market for a very small electric winch designed to get an FES-equipped sailplane just up to 100 feet – high enough to use the FES to climb to the first thermal. Even self-launch capable FES sailplanes would benefit from a small winch because they would save much more of the sailplane's battery for use later in the flight - since the initial takeoff roll requires a lot of power.
>
> You can see an interesting video showing an FES-equipped sailplane taking an autotow to about 100 feet here:
> https://youtu.be/pTeNKM2cXQk
>
> I would think that an electric winch could get a glider to 100 feet quite easily and be quite small and relatively inexpensive. The rope needed would be much less, and the drum could be much smaller – I imagine.
>
> A "level ground bungee launch" to 100 feet would be another interesting option. But I would think that would have risks from by the bungee snapping or coming loose and hurting someone.
>
> Any thoughts...? I'm just dreaming about the future of gliding...
>
> Best Regards,
>
> Paul Remde
> Cumulus Soaring, Inc.

Stupid question: since FES (Front Electric Sustainer) sailplanes have a propeller in the front, with very little ground clearance, how would you attach a tow rope without interfering with the propeller? Perhaps you mean a winch launch with the propeller stowed, turning on the FES after releasing from the rope. Seems like doing that at 100 feet is not a great idea, even though FES startup is a lot simpler and quicker than with other sailplane motor arrangements. So at the least you'd want to go to 300 feet or so - high enough to try and start the FES, and land safely if that does not work.

And as Herb said, for a good acceleration at the start, you'd still need a lot of power (at least 100 KW), nothing "mini" about that.

Yeah I'd like to hear more about (full-size) electric winches in development. With the progress being made on electric cars (and trucks) and their batteries that seems like the future of winches.

On Wednesday, March 4, 2020 at 1:03:43 AM UTC-5, Steve Leonard wrote:
> The "mini winch" could also be a car and an air tow (200 foot or so) rope. Keeps you from having to buy and maintain additional equipment.
>
> Steve Leonard

I know a guy who has done this when a towplane was not available. Flying off grass.
UH

At 17:06 04 March 2020, wrote:
>On Wednesday, March 4, 2020 at 12:38:57 AM UTC-5, Paul
Remde wrote:
>> Hi,
>>=20
>> This is just a thought... =20
>>=20
>> I=E2=80=99ve recently been extremely interested in
the FES (Front
>Electri=
>c Sustainer) sailplanes. They are becoming quite popular.
Even very
>high-=
>performance racing sailplanes like the Ventus 3 are being
sold with FES
>sys=
>tems installed.
>>=20
>> I am the U.S. dealer for DG/LS and they offer the LS8e
neo with FES and
>t=
>he new DG-1001e neo with FES prototype will fly very
soon. It will be the
>=
>first 2-seat sailplane with FES. I would love to trade my
DG-1000S in for
>=
>a DG-1001e neo with FES, but so far my DG-1000S co-
owners aren't ready for
>=
>that upgrade.
>>=20
>> I'm not very experienced with winches and certainly not
an expert on
>such=
> matters, but I think there may be a nice market for a very
small electric
>=
>winch designed to get an FES-equipped sailplane just up to
100 feet =E2=80=
>=93 high enough to use the FES to climb to the first
thermal. Even
>self-la=
>unch capable FES sailplanes would benefit from a small
winch because they
>w=
>ould save much more of the sailplane's battery for use later
in the flight
>=
>- since the initial takeoff roll requires a lot of power.
>>=20
>> You can see an interesting video showing an FES-
equipped sailplane
>taking=
> an autotow to about 100 feet here:=20
>> https://youtu.be/pTeNKM2cXQk=20
>>=20
>> I would think that an electric winch could get a glider to
100 feet
>quite=
> easily and be quite small and relatively inexpensive. The
rope needed
>wou=
>ld be much less, and the drum could be much smaller
=E2=80=93 I imagine.
>>=20
>> A "level ground bungee launch" to 100 feet would be
another interesting
>o=
>ption. But I would think that would have risks from by the
bungee
>snapping=
> or coming loose and hurting someone.=20
>>=20
>> Any thoughts...? I'm just dreaming about the future of
gliding...
>>=20
>> Best Regards,
>>=20
>> Paul Remde
>> Cumulus Soaring, Inc.
>
>Stupid question: since FES (Front Electric Sustainer)
sailplanes have a
>pro=
>peller in the front, with very little ground clearance, how
would you
>attac=
>h a tow rope without interfering with the propeller?
Perhaps you mean a
>wi=
>nch launch with the propeller stowed, turning on the FES
after releasing
>fr=
>om the rope. Seems like doing that at 100 feet is not a
great idea, even
>t=
>hough FES startup is a lot simpler and quicker than with
other sailplane
>mo=
>tor arrangements. So at the least you'd want to go to 300
feet or so -
>hig=
>h enough to try and start the FES, and land safely if that
does not work.
>
>And as Herb said, for a good acceleration at the start,
you'd still need a
>=
>lot of power (at least 100 KW), nothing "mini" about that.
>
>Yeah I'd like to hear more about (full-size) electric winches
in
>developmen=
>t. With the progress being made on electric cars (and
trucks) and their
>ba=
>tteries that seems like the future of winches.

Really? You think "progress being made on electric cars and
their batteries"? Sure there are a lot of them out there but
the battery technology they use has been around for years.
Lots of fancy batteries in development labs and in
Universities but none in any commercially available vehicle.
>

On 3/4/20 7:38 AM, Paul Remde wrote:

> Any thoughts...? I'm just dreaming about the future of gliding...

Speaking as a winch instructor. One requirement for a safe winch launch
is for the glider to always be in a position to make a safe landing in
the event of a launch failure. Thus the launch profile must be such that
by the time that you are too high to land straight ahead you have
sufficient height to fly a small circuit and land back on the runway.
You also want some overlap between the two options to take the stress
out of decision making. If you winching into zero or low winds, a 180
deg turn and landing "downwind" is also an option.

If you are winch launching a sustainer, the requirement must be for the
glider to launch, release, attempt an engine start and then still be in
a position to make a safe landing if the engine fails.

What you do not want, is to make a habit of releasing over the downwind
threshold, to low to fly a circuit back over the runway. (Yes this is
accepted for aerotow. But the launch failure rate is much lower and
simulated launch failure training is done in light winds which allow
landing downwind.)

One option is a conventional ground launch, car or winch to say 1000'
AGL. Glider can then fly a circuit, start the engine on downwind and be
in a position to land if the engine does not start. This would work for
any sustainer technology. The ground launch is an "existing art" and you
can get training and ratings for it. There are also established clubs
with the means to provide the launch.

Next option is the "launch to 100'". This must be done such that you can
release, attempt an engine start and still be able to land straight
ahead if it fails. A variation involves deploying and even starting the
engine before launch, with a pylon mounted engine, like a jet, but not
possible with FES. This saves some time for the engine start and reduces
the risk of a start failure. These launches have been done, but you wont
easily find an "approved procedure" accepted by manufacturers and
authorities etc.

Last comment, is do not assume that FES cannot suffer a launch failure.
They have safety control systems and all it would take is one contact
breaker "trip" to spoil your day. Also remember that any battery energy
you use to get from 100' to "start of soaring" will not be available for
a retrieve later in the day.

But yes, this could be the future of gliding ...

Ian

On Wednesday, March 4, 2020 at 10:40:53 AM UTC-5, kinsell wrote:
> Agree with other posters, not sure how much you'd save in terms of
> money/effort/time with a mini winch vs a regular one.
>
> Speaking of that, what ever happened to the great electric winch project
> up at Bend OR that set the internet on fire not so long ago?
>
>
There was a paper given at the last SSA convention by Bill Daniels about his electric winch development - at least it was on the roster. I couldn't make it to the convention; does anyone know if this talk was recorded and will be made available?
Uli
'AS'

How about taking the running gear from a salvaged Tesla or similar? A
quick look found several in the $10K range and I'm sure you could find
something for less.Â* Also, simple research (looking at one website) says
that the Tesla's battery provides around 400 VDC which is fed to an
inverter to provide the AC voltage to run the motor(s).Â* Surely someone
could put together a battery bank (assuming the car's batteries are not
functional) or even have a 480 V 3-phase service installed to run the
motors.

Now, we just need someone to build the hardware to connect the motor(s)
to the drum.

Or buy a ready-made winch.

On 3/4/2020 12:21 PM, ian wrote:
> On 3/4/20 7:38 AM, Paul Remde wrote:
>
>> Any thoughts...?Â* I'm just dreaming about the future of gliding...
>
> Speaking as a winch instructor. One requirement for a safe winch
> launch is for the glider to always be in a position to make a safe
> landing in the event of a launch failure. Thus the launch profile must
> be such that by the time that you are too high to land straight ahead
> you have sufficient height to fly a small circuit and land back on the
> runway. You also want some overlap between the two options to take the
> stress out of decision making. If you winching into zero or low winds,
> a 180 deg turn and landing "downwind" is also an option.
>
> If you are winch launching a sustainer, the requirement must be for
> the glider to launch, release, attempt an engine start and then still
> be in a position to make a safe landing if the engine fails.
>
> What you do not want, is to make a habit of releasing over the
> downwind threshold, to low to fly a circuit back over the runway. (Yes
> this is accepted for aerotow. But the launch failure rate is much
> lower and simulated launch failure training is done in light winds
> which allow landing downwind.)
>
> One option is a conventional ground launch, car or winch to say 1000'
> AGL. Glider can then fly a circuit, start the engine on downwind and
> be in a position to land if the engine does not start. This would work
> for any sustainer technology. The ground launch is an "existing art"
> and you can get training and ratings for it. There are also
> established clubs with the means to provide the launch.
>
> Next option is the "launch to 100'". This must be done such that you
> can release, attempt an engine start and still be able to land
> straight ahead if it fails. A variation involves deploying and even
> starting the engine before launch, with a pylon mounted engine, like a
> jet, but not possible with FES. This saves some time for the engine
> start and reduces the risk of a start failure. These launches have
> been done, but you wont easily find an "approved procedure" accepted
> by manufacturers and authorities etc.
>
> Last comment, is do not assume that FES cannot suffer a launch
> failure. They have safety control systems and all it would take is one
> contact breaker "trip" to spoil your day. Also remember that any
> battery energy you use to get from 100' to "start of soaring" will not
> be available for a retrieve later in the day.
>
> But yes, this could be the future of gliding ...
>
> Ian

--
Dan, 5J

On Wednesday, March 4, 2020 at 2:39:29 PM UTC-5, Dan Marotta wrote:
> How about taking the running gear from a salvaged Tesla or similar? A
> quick look found several in the $10K range and I'm sure you could find
> something for less.Â* Also, simple research (looking at one website) says
> that the Tesla's battery provides around 400 VDC which is fed to an
> inverter to provide the AC voltage to run the motor(s).Â* Surely someone
> could put together a battery bank (assuming the car's batteries are not
> functional) or even have a 480 V 3-phase service installed to run the
> motors.
>
> Now, we just need someone to build the hardware to connect the motor(s)
> to the drum.
>
> Or buy a ready-made winch.
>
> On 3/4/2020 12:21 PM, ian wrote:
> > On 3/4/20 7:38 AM, Paul Remde wrote:
> >
> >> Any thoughts...?Â* I'm just dreaming about the future of gliding....
> >
> > Speaking as a winch instructor. One requirement for a safe winch
> > launch is for the glider to always be in a position to make a safe
> > landing in the event of a launch failure. Thus the launch profile must
> > be such that by the time that you are too high to land straight ahead
> > you have sufficient height to fly a small circuit and land back on the
> > runway. You also want some overlap between the two options to take the
> > stress out of decision making. If you winching into zero or low winds,
> > a 180 deg turn and landing "downwind" is also an option.
> >
> > If you are winch launching a sustainer, the requirement must be for
> > the glider to launch, release, attempt an engine start and then still
> > be in a position to make a safe landing if the engine fails.
> >
> > What you do not want, is to make a habit of releasing over the
> > downwind threshold, to low to fly a circuit back over the runway. (Yes
> > this is accepted for aerotow. But the launch failure rate is much
> > lower and simulated launch failure training is done in light winds
> > which allow landing downwind.)
> >
> > One option is a conventional ground launch, car or winch to say 1000'
> > AGL. Glider can then fly a circuit, start the engine on downwind and
> > be in a position to land if the engine does not start. This would work
> > for any sustainer technology. The ground launch is an "existing art"
> > and you can get training and ratings for it. There are also
> > established clubs with the means to provide the launch.
> >
> > Next option is the "launch to 100'". This must be done such that you
> > can release, attempt an engine start and still be able to land
> > straight ahead if it fails. A variation involves deploying and even
> > starting the engine before launch, with a pylon mounted engine, like a
> > jet, but not possible with FES. This saves some time for the engine
> > start and reduces the risk of a start failure. These launches have
> > been done, but you wont easily find an "approved procedure" accepted
> > by manufacturers and authorities etc.
> >
> > Last comment, is do not assume that FES cannot suffer a launch
> > failure. They have safety control systems and all it would take is one
> > contact breaker "trip" to spoil your day. Also remember that any
> > battery energy you use to get from 100' to "start of soaring" will not
> > be available for a retrieve later in the day.
> >
> > But yes, this could be the future of gliding ...
> >
> > Ian
>
> --
> Dan, 5J

How hard could it be?
Sigh
UH

On Wed, 04 Mar 2020 18:46:18 +0000, Dave Walsh wrote:

> Really? You think "progress being made on electric cars and their
> batteries"? Sure there are a lot of them out there but the battery
> technology they use has been around for years. Lots of fancy batteries
> in development labs and in Universities but none in any commercially
> available vehicle.
>>

A new technology has just been announced, which uses sodium anodes and a
lithium-glass electrolyte. It claims greater durability, much less
flammability, and a considerably longer life than Lithium-ion.

Normally I'd go off muttering abouyt pipe-dreams except that the lead
researcher is John Goodenough. He has an excellent track record in this
field since he was in the team that developed the lithium-ion battery,
and shared the Nobel Prize for Chemistry for that. Says this tech could
be commercially successful in 5 - 10 years. The story is here:

https://www.theregister.co.uk/2020/03/02/
canadian_firm_to_develop_goodenoughs_new_glass_bat tery/


=====

But, back to electric winches.

Here's the website for what looks to be the most successful German
electric winch maker:

http://www.startwinde.de/

The main site is in German, so if you don't read German, start here
instead:

https://onkelmaggus.beepworld.de/index.htm

This winch is basically a purpose-designed trailer containing a couple of
cable drums, a 200 kW electric motor and a big pile of lead-acid truck
batteries to act as a buffer between it and a 12-20 kW mains connection.

We looked at this system a few years back and decided that running cables
to the various places where we park our winch depending on the wind
direction was too expensive to justify going electric, so now we have a
Skylaunch and a Tost they refurbished, both running on LPG.


--
Martin | martin at
Gregorie | gregorie dot org

On 3/4/20 3:12 PM, Martin Gregorie wrote:
> On Wed, 04 Mar 2020 18:46:18 +0000, Dave Walsh wrote:
>
>> Really? You think "progress being made on electric cars and their
>> batteries"? Sure there are a lot of them out there but the battery
>> technology they use has been around for years. Lots of fancy batteries
>> in development labs and in Universities but none in any commercially
>> available vehicle.
>>>
>
> A new technology has just been announced, which uses sodium anodes and a
> lithium-glass electrolyte. It claims greater durability, much less
> flammability, and a considerably longer life than Lithium-ion.
>
> Normally I'd go off muttering abouyt pipe-dreams except that the lead
> researcher is John Goodenough. He has an excellent track record in this
> field since he was in the team that developed the lithium-ion battery,
> and shared the Nobel Prize for Chemistry for that. Says this tech could
> be commercially successful in 5 - 10 years. The story is here:
>
> https://www.theregister.co.uk/2020/03/02/
> canadian_firm_to_develop_goodenoughs_new_glass_bat tery/
>
>

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.

In the mean time, we've got lithium-sulfer, lithium-carbon dioxide,
lithium graphene, the mysterious IBM seawater battery, semi-solidstate
lithium, and others to look forward to. Which one will deliver the
miraculous increase in capacity in a couple years that the electric
plane makers keep talking about?

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.

On one level I think this is an interesting idea. The concept of a low
level launch and climb away on FES is one that I've
heard others raise, but always in relation to aerotow.

The norm in a winch launch is to gently transition to a 45 degree climb in
a way which ensures you can always recover to a safe attitude and
subsequent landing. This transition typically happens at 30' - 100'. In
principle, if there was enough demand, I think it would be possible to
develop a lower powered winch, and a shallower climb to release, but from a
safety perspective, you would need to be able to ensure that if the FES did
not start, you could always land safely. Given the likely release height,
this would need a long enough run to land ahead safely from any failure.
The dynamic would be very site specific.

While any 'lower powered winch' might be slightly cheaper than one which
could launch to higher heights, most of the engineering would be very
similar, and my guess is not much cheaper. The days of low cost, self help
winches have largely gone in Europe, with the reality being that while
these were cheap(ish) to build, they could be quite dangerous. The modern
equivalent are much, much safer to operate (ground operations and flying
wise) but expensive. IIt;s an interse think for most US operations with
limited winch experience, the learning curve for even the most modern kit
would be steep.

Also factor in that most high performance gliders will want to get airborne
fully ballasted. This increases the likelihood of a launch failure, and
might make a safe landing from a failure much more interesting. I have
thousands of winch launches, and train others to recover from failures, but
always choose to fly my ballasted Ventus from aerotow. It's just about the
risk balance.

It's an interesting idea, and is certainly possible in my view, but I don't
really think it's commercially viable option where there is no existing
infrastructure. At our club, with all of the winch launching
infrastructure in place, the small number of FES equipped gliders choose to
go to the top of the winch launch (we would charge the same anyway). Lower
launches would save some fuel, but mixing lower launched with higher ones
would be a pain, and save no time.

Overall, I think a low level aerotow might be a much better option.


While winch launching is very common in Europe,

At 05:38 04 March 2020, Paul Remde wrote:
>Hi,
>
>This is just a thought... =20
>
>I=E2=80=99ve recently been extremely interested in the FES (Front
Electric
>=
>Sustainer) sailplanes. They are becoming quite popular. Even very
>high-pe=
>rformance racing sailplanes like the Ventus 3 are being sold with FES
>syste=
>ms installed.
>
>I am the U.S. dealer for DG/LS and they offer the LS8e neo with FES and
>the=
> new DG-1001e neo with FES prototype will fly very soon. It will be the
>fi=
>rst 2-seat sailplane with FES. I would love to trade my DG-1000S in for
a
>=
>DG-1001e neo with FES, but so far my DG-1000S co-owners aren't ready for
>th=
>at upgrade.
>
>I'm not very experienced with winches and certainly not an expert on such
>m=
>atters, but I think there may be a nice market for a very small electric
>wi=
>nch designed to get an FES-equipped sailplane just up to 100 feet
>=E2=80=93=
> high enough to use the FES to climb to the first thermal. Even
>self-launc=
>h capable FES sailplanes would benefit from a small winch because they
>woul=
>d save much more of the sailplane's battery for use later in the flight -
>s=
>ince the initial takeoff roll requires a lot of power.
>
>You can see an interesting video showing an FES-equipped sailplane taking
>a=
>n autotow to about 100 feet here:=20
>https://youtu.be/pTeNKM2cXQk=20
>
>I would think that an electric winch could get a glider to 100 feet quite
>e=
>asily and be quite small and relatively inexpensive. The rope needed
>would=
> be much less, and the drum could be much smaller =E2=80=93 I imagine.
>
>A "level ground bungee launch" to 100 feet would be another interesting
>opt=
>ion. But I would think that would have risks from by the bungee snapping
>o=
>r coming loose and hurting someone.=20
>
>Any thoughts...? I'm just dreaming about the future of gliding...
>
>Best Regards,
>
>Paul Remde
>Cumulus Soaring, Inc.
>

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?

> 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.

You just need to an old aircraft carrier catapult!

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

On Friday, March 6, 2020 at 4:20:40 PM UTC-8, wrote:
> 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

Chip,

I talked to a JS pilot at Little Rock that does that regularly. He and his wife have it pretty well dialed in.

As I understood the initial discussions, I didn't hear anyone proposing launching with FES running. They would just use the belly hook on the aircraft for the initial launch and then start the FES. Not a bad option if you have enough runway to leave options.

Waiting for spring...

Craig Funston
JN

On 3/5/20 3:44 PM, Mike N. wrote:
> 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.

Not a great solution. Fes gliders aren't known for having any large
reserves of power, so using a chunk of it to reach a reasonable height
is going to leave little for a self-retrieve.


>
> 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.
>

Here's an idea, how about buying an actual self-launch glider, something
that was designed, tested, and certified for the job??

On Wednesday, March 4, 2020 at 8:40:53 AM UTC-7, kinsell wrote:
> Agree with other posters, not sure how much you'd save in terms of
> money/effort/time with a mini winch vs a regular one.
>
> Speaking of that, what ever happened to the great electric winch project
> up at Bend OR that set the internet on fire not so long ago?
>
Still a work in progress. Whether it will operate this year remains to be seen.

On Wednesday, March 4, 2020 at 10:06:50 AM UTC-7, wrote:
> On Wednesday, March 4, 2020 at 12:38:57 AM UTC-5, Paul Remde wrote:
> > Hi,
> >
> > This is just a thought...
> >
> > I’ve recently been extremely interested in the FES (Front Electric Sustainer) sailplanes. They are becoming quite popular. Even very high-performance racing sailplanes like the Ventus 3 are being sold with FES systems installed.
> >
> > I am the U.S. dealer for DG/LS and they offer the LS8e neo with FES and the new DG-1001e neo with FES prototype will fly very soon. It will be the first 2-seat sailplane with FES. I would love to trade my DG-1000S in for a DG-1001e neo with FES, but so far my DG-1000S co-owners aren't ready for that upgrade.
> >
> > I'm not very experienced with winches and certainly not an expert on such matters, but I think there may be a nice market for a very small electric winch designed to get an FES-equipped sailplane just up to 100 feet – high enough to use the FES to climb to the first thermal. Even self-launch capable FES sailplanes would benefit from a small winch because they would save much more of the sailplane's battery for use later in the flight - since the initial takeoff roll requires a lot of power.
> >
> > You can see an interesting video showing an FES-equipped sailplane taking an autotow to about 100 feet here:
> > https://youtu.be/pTeNKM2cXQk
> >
> > I would think that an electric winch could get a glider to 100 feet quite easily and be quite small and relatively inexpensive. The rope needed would be much less, and the drum could be much smaller – I imagine.
> >
> > A "level ground bungee launch" to 100 feet would be another interesting option. But I would think that would have risks from by the bungee snapping or coming loose and hurting someone.
> >
> > Any thoughts...? I'm just dreaming about the future of gliding...
> >
> > Best Regards,
> >
> > Paul Remde
> > Cumulus Soaring, Inc.
>
> Stupid question: since FES (Front Electric Sustainer) sailplanes have a propeller in the front, with very little ground clearance, how would you attach a tow rope without interfering with the propeller? Perhaps you mean a winch launch with the propeller stowed, turning on the FES after releasing from the rope. Seems like doing that at 100 feet is not a great idea, even though FES startup is a lot simpler and quicker than with other sailplane motor arrangements. So at the least you'd want to go to 300 feet or so - high enough to try and start the FES, and land safely if that does not work.
>
> And as Herb said, for a good acceleration at the start, you'd still need a lot of power (at least 100 KW), nothing "mini" about that.
>
> Yeah I'd like to hear more about (full-size) electric winches in development. With the progress being made on electric cars (and trucks) and their batteries that seems like the future of winches.

400ft would be the minimum safe working altitude IMVHO.

On Wednesday, March 4, 2020 at 12:34:32 PM UTC-7, AS wrote:
> On Wednesday, March 4, 2020 at 10:40:53 AM UTC-5, kinsell wrote:
> > Agree with other posters, not sure how much you'd save in terms of
> > money/effort/time with a mini winch vs a regular one.
> >
> > Speaking of that, what ever happened to the great electric winch project
> > up at Bend OR that set the internet on fire not so long ago?
> >
> >
> There was a paper given at the last SSA convention by Bill Daniels about his electric winch development - at least it was on the roster. I couldn't make it to the convention; does anyone know if this talk was recorded and will be made available?
> Uli
> 'AS'

Hello winch head. Missed seeing you. Bill's talk updated progress on the electric winch and some design changes going forward with the design. I suppose Bill might provide a copy w/audio like he did previously. I'll ping him abotu that. He desktop died after returning from Little Rock, so he's working on a laptop at the moment, until he finds a replacement. AFAIK, the live session was not recorded.

Frank Whiteley

On Friday, March 6, 2020 at 10:44:25 PM UTC-5, Frank Whiteley wrote:
> On Wednesday, March 4, 2020 at 12:34:32 PM UTC-7, AS wrote:
> > On Wednesday, March 4, 2020 at 10:40:53 AM UTC-5, kinsell wrote:
> > > Agree with other posters, not sure how much you'd save in terms of
> > > money/effort/time with a mini winch vs a regular one.
> > >
> > > Speaking of that, what ever happened to the great electric winch project
> > > up at Bend OR that set the internet on fire not so long ago?
> > >
> > >
> > There was a paper given at the last SSA convention by Bill Daniels about his electric winch development - at least it was on the roster. I couldn't make it to the convention; does anyone know if this talk was recorded and will be made available?
> > Uli
> > 'AS'
>
> Hello winch head. Missed seeing you. Bill's talk updated progress on the electric winch and some design changes going forward with the design. I suppose Bill might provide a copy w/audio like he did previously. I'll ping him abotu that. He desktop died after returning from Little Rock, so he's working on a laptop at the moment, until he finds a replacement. AFAIK, the live session was not recorded.
>
> Frank Whiteley

Thanks for the update, Frank!
Uli
'AS'

On Wednesday, March 4, 2020 at 12:38:57 AM UTC-5, Paul Remde wrote:
> Hi,
>
> This is just a thought...
>
> I’ve recently been extremely interested in the FES (Front Electric Sustainer) sailplanes. They are becoming quite popular. Even very high-performance racing sailplanes like the Ventus 3 are being sold with FES systems installed.
>
> I am the U.S. dealer for DG/LS and they offer the LS8e neo with FES and the new DG-1001e neo with FES prototype will fly very soon. It will be the first 2-seat sailplane with FES. I would love to trade my DG-1000S in for a DG-1001e neo with FES, but so far my DG-1000S co-owners aren't ready for that upgrade.
>
> I'm not very experienced with winches and certainly not an expert on such matters, but I think there may be a nice market for a very small electric winch designed to get an FES-equipped sailplane just up to 100 feet – high enough to use the FES to climb to the first thermal. Even self-launch capable FES sailplanes would benefit from a small winch because they would save much more of the sailplane's battery for use later in the flight - since the initial takeoff roll requires a lot of power.
>
> You can see an interesting video showing an FES-equipped sailplane taking an autotow to about 100 feet here:
> https://youtu.be/pTeNKM2cXQk
>
> I would think that an electric winch could get a glider to 100 feet quite easily and be quite small and relatively inexpensive. The rope needed would be much less, and the drum could be much smaller – I imagine.
>
> A "level ground bungee launch" to 100 feet would be another interesting option. But I would think that would have risks from by the bungee snapping or coming loose and hurting someone.
>
> Any thoughts...? I'm just dreaming about the future of gliding...
>
> Best Regards,
>
> Paul Remde
> Cumulus Soaring, Inc.

Then there is the Colditz Cock solution.
A hole in the ground,a rope, a pulley , a weight and clean gravitational energy
Oh , and a horse to rewind the weight.
JMF

Actually, that is not the worst of the ideas. Safer than other ideas for sure.
Mixed with the idea of the compound pulley and truck the hole does not need to be too deep

On Saturday, March 7, 2020 at 4:29:58 PM UTC+13, kinsell wrote:

> Here's an idea, how about buying an actual self-launch glider, something
> that was designed, tested, and certified for the job??

Dave Nadler's SSA Convention presentation disabused me of that notion.

On Saturday, March 7, 2020 at 10:20:05 AM UTC-6, Emir Sherbi wrote:
> Actually, that is not the worst of the ideas. Safer than other ideas for sure.
> Mixed with the idea of the compound pulley and truck the hole does not need to be too deep

As I mentioned before, anyone heard of the Wright Brothers and their 1903 Flyer? Pretty quick acceleration to flight speed over a short distance.

Another aspect would make such a winch not very useful: a climb from 300 ft would cut the range considerably. I know pilots with FES planes that have hard deck of 1200 ft for the activation of the engine (same as turbos with gasoline engnes) when running out of thermals. Simply because climbing is much more absorbing than flying level with a FES (at least with the current battery generation)

On Friday, March 13, 2020 at 7:20:34 PM UTC-4, wrote:
> Another aspect would make such a winch not very useful: a climb from 300 ft would cut the range considerably. I know pilots with FES planes that have hard deck of 1200 ft for the activation of the engine (same as turbos with gasoline engnes) when running out of thermals. Simply because climbing is much more absorbing than flying level with a FES (at least with the current battery generation)

If there is no other tow option available, and the difference is flying or not, it becomes very useful.
UH

At 14:53 08 March 2020, wrote:
>On Saturday, March 7, 2020 at 10:20:05 AM UTC-6, Emir Sherbi
wrote:
>> Actually, that is not the worst of the ideas. Safer than other
ideas for
>sure.
>> Mixed with the idea of the compound pulley and truck the hole
does not
>need to be too deep
>
>As I mentioned before, anyone heard of the Wright Brothers and
their 1903
>Flyer? Pretty quick acceleration to flight speed over a short
distance.
>
Well as it's raining: the idea of a (large) hole in the ground with
high speed wire motion around it on an active airfield doesn't seem
to have much going for it. Be an interesting 'Health & Safety'
problem. It would be a non starter in the UK - it would be full of
water by now.

On Saturday, March 14, 2020 at 9:00:06 AM UTC-4, Dave Walsh wrote:
> At 14:53 08 March 2020, wrote:
> >On Saturday, March 7, 2020 at 10:20:05 AM UTC-6, Emir Sherbi
> wrote:
> >> Actually, that is not the worst of the ideas. Safer than other
> ideas for
> >sure.
> >> Mixed with the idea of the compound pulley and truck the hole
> does not
> >need to be too deep
> >
> >As I mentioned before, anyone heard of the Wright Brothers and
> their 1903
> >Flyer? Pretty quick acceleration to flight speed over a short
> distance.
> >
> Well as it's raining: the idea of a (large) hole in the ground with
> high speed wire motion around it on an active airfield doesn't seem
> to have much going for it. Be an interesting 'Health & Safety'
> problem. It would be a non starter in the UK - it would be full of
> water by now.

The idea of dropping a weight into a hole - i.e. a dried-up oil-well in Texas - was discussed ad nausea in the winchdesign forum a couple of years back. The biggest issue is the control-ability of such a setup.
Personally, I find the idea of building a small winch to launch FES-equipped gliders just off the ground only to push precious electrons through the motor to gain altitude, a pretty bad one. Use a manly winch and do a normal winch launch and keep them precious electrons on one side of the battery!

Uli
'AS'

All fine and good, Uli, but think of the height you could get by
dropping a huge weight down a 7,000' vertical shaft.Â* Then you could
have all the greenies in the area crank it back up by hand so that
there's zero carbon footprint.Â* Except for the labored breathing... :-D

On 3/14/2020 8:50 PM, AS wrote:
> On Saturday, March 14, 2020 at 9:00:06 AM UTC-4, Dave Walsh wrote:
>> At 14:53 08 March 2020, wrote:
>>> On Saturday, March 7, 2020 at 10:20:05 AM UTC-6, Emir Sherbi
>> wrote:
>>>> Actually, that is not the worst of the ideas. Safer than other
>> ideas for
>>> sure.
>>>> Mixed with the idea of the compound pulley and truck the hole
>> does not
>>> need to be too deep
>>>
>>> As I mentioned before, anyone heard of the Wright Brothers and
>> their 1903
>>> Flyer? Pretty quick acceleration to flight speed over a short
>> distance.
>> Well as it's raining: the idea of a (large) hole in the ground with
>> high speed wire motion around it on an active airfield doesn't seem
>> to have much going for it. Be an interesting 'Health & Safety'
>> problem. It would be a non starter in the UK - it would be full of
>> water by now.
> The idea of dropping a weight into a hole - i.e. a dried-up oil-well in Texas - was discussed ad nausea in the winchdesign forum a couple of years back. The biggest issue is the control-ability of such a setup.
> Personally, I find the idea of building a small winch to launch FES-equipped gliders just off the ground only to push precious electrons through the motor to gain altitude, a pretty bad one. Use a manly winch and do a normal winch launch and keep them precious electrons on one side of the battery!
>
> Uli
> 'AS'

--
Dan, 5J

On Sunday, 15 March 2020 02:50:45 UTC, AS wrote:
> On Saturday, March 14, 2020 at 9:00:06 AM UTC-4, Dave Walsh wrote:
> > At 14:53 08 March 2020, wrote:
> > >On Saturday, March 7, 2020 at 10:20:05 AM UTC-6, Emir Sherbi
> > wrote:
> > >> Actually, that is not the worst of the ideas. Safer than other
> > ideas for
> > >sure.
> > >> Mixed with the idea of the compound pulley and truck the hole
> > does not
> > >need to be too deep
> > >
> > >As I mentioned before, anyone heard of the Wright Brothers and
> > their 1903
> > >Flyer? Pretty quick acceleration to flight speed over a short
> > distance.
> > >
> > Well as it's raining: the idea of a (large) hole in the ground with
> > high speed wire motion around it on an active airfield doesn't seem
> > to have much going for it. Be an interesting 'Health & Safety'
> > problem. It would be a non starter in the UK - it would be full of
> > water by now.
>
> The idea of dropping a weight into a hole - i.e. a dried-up oil-well in Texas - was discussed ad nausea in the winchdesign forum a couple of years back. The biggest issue is the control-ability of such a setup.
> Personally, I find the idea of building a small winch to launch FES-equipped gliders just off the ground only to push precious electrons through the motor to gain altitude, a pretty bad one. Use a manly winch and do a normal winch launch and keep them precious electrons on one side of the battery!
>
> Uli
> 'AS'

To me as well, it makes more sense to use the whole winch launch. And even for longer retrieves too, drop in on and relaunch at a couple of clubs, cruise level, depending on wind could get back from 120 to 150 away.

On Sunday, 15 March 2020 16:14:24 UTC, wrote:
> On Sunday, 15 March 2020 02:50:45 UTC, AS wrote:
> > On Saturday, March 14, 2020 at 9:00:06 AM UTC-4, Dave Walsh wrote:
> > > At 14:53 08 March 2020, wrote:
> > > >On Saturday, March 7, 2020 at 10:20:05 AM UTC-6, Emir Sherbi
> > > wrote:
> > > >> Actually, that is not the worst of the ideas. Safer than other
> > > ideas for
> > > >sure.
> > > >> Mixed with the idea of the compound pulley and truck the hole
> > > does not
> > > >need to be too deep
> > > >
> > > >As I mentioned before, anyone heard of the Wright Brothers and
> > > their 1903
> > > >Flyer? Pretty quick acceleration to flight speed over a short
> > > distance.
> > > >
> > > Well as it's raining: the idea of a (large) hole in the ground with
> > > high speed wire motion around it on an active airfield doesn't seem
> > > to have much going for it. Be an interesting 'Health & Safety'
> > > problem. It would be a non starter in the UK - it would be full of
> > > water by now.
> >
> > The idea of dropping a weight into a hole - i.e. a dried-up oil-well in Texas - was discussed ad nausea in the winchdesign forum a couple of years back. The biggest issue is the control-ability of such a setup.
> > Personally, I find the idea of building a small winch to launch FES-equipped gliders just off the ground only to push precious electrons through the motor to gain altitude, a pretty bad one. Use a manly winch and do a normal winch launch and keep them precious electrons on one side of the battery!
> >
> > Uli
> > 'AS'
>
> To me as well, it makes more sense to use the whole winch launch. And even for longer retrieves too, drop in on and relaunch at a couple of clubs, cruise level, depending on wind could get back from 120 to 150 away.

I seem to have missed out km

On Thursday, March 5, 2020 at 1:22:48 AM UTC-5, 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.
>

This is really the idea right here. As we increasingly embrace self-launch eGliders, I think we'll see more and more gliders operating out of small airports without the benefit of a club. Thus, what's missing in the conversation is a consideration of the CONOPS (CONcept of OPerationS) for single-person launching.

Gliders have a major limitation in requiring a team to get a single pilot airborne. Having a catapult, which terminates before the runway begins, would get the plane airborne without requiring outside help. It could be semi-permanently installed and not require setup or teardown. The energy needed to accelerate a 300kg plane to 25m/s fits in a battery the size of a tangerine.

When the planes are reported as typically using only 20% of their packs to go fly, I feel this tells us that the major risk isn't climb out, it's takeoff.

Ignoring the risk imparted by the catapult, there are several consequent risk reductions:

1) At a 10% climb grade, a catapult on a 3000' runway would allow a plane to reach 100' with 2000' of runway to spare. An engine failure suddenly becomes a very easy straight-ahead recovery. Contrast this to a more leisurely ground roll on grass which eats up 1000' and where an engine failure at 100' is a real cause for sphincter puckering.
2) For FES-style systems, the prop can be started once off the ground, eliminating the possibility of a ground strike
3) No chance of ripping the wings off the plane due to an over-exuberant winch operation
4) Reduced chance of ground-looping on roll-out, esp. in cross-wind scenarios.
5) Everything that goes wrong goes wrong at low altitude at low speeds
6) Does not impact the runway or leave anything on or near the runway

Relatedly, any kind of automated winch or autotow system requires serious thought about what to do with the launch system once the pilot flies away. A catapult doesn't have this problem since it is installed before the threshold.

I'm not saying getting the catapult right would be easy, but it definitely has a different operational spec than a winch or autotow.

> I'm not saying getting the catapult right would be easy, but it definitely has a different operational spec than a winch or autotow.

Heck, let's go for altitude also! Try the Trebuchet. Judging by the altitude Monty Python got using a cow, you ought to be able to fling a 1-26 at least Silver Distance!

On Thursday, June 4, 2020 at 6:55:24 PM UTC-4, wrote:
> > I'm not saying getting the catapult right would be easy, but it definitely has a different operational spec than a winch or autotow.
>
> Heck, let's go for altitude also! Try the Trebuchet. Judging by the altitude Monty Python got using a cow, you ought to be able to fling a 1-26 at least Silver Distance!

Register that glider in the Isle of Man so it can have the registration M-OOOO.

On Thursday, June 4, 2020 at 6:38:23 PM UTC-4, Kenz Dale wrote:

> 3) No chance of ripping the wings off the plane due to an over-exuberant winch operation

That possibility is reliably eliminated by a calibrated weak link in the winch launch rope.

On Thu, 04 Jun 2020 21:07:02 -0700, son_of_flubber wrote:

> On Thursday, June 4, 2020 at 6:38:23 PM UTC-4, Kenz Dale wrote:
>
>> 3) No chance of ripping the wings off the plane due to an
>> over-exuberant winch operation
>
> That possibility is reliably eliminated by a calibrated weak link in the
> winch launch rope.

Good modern winches monitor and adjust cable tension rather than blindly
using throttle position. Skylaunch units have a basic (analog?) computer
which accepts the glider type and surface wind speed before each launch.
I've yet to have a bad launch off one.


--
Martin | martin at
Gregorie | gregorie dot org

On Thursday, June 4, 2020 at 5:38:23 PM UTC-5, Kenz Dale wrote:
> On Thursday, March 5, 2020 at 1:22:48 AM UTC-5, 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.
> >
>
> This is really the idea right here. As we increasingly embrace self-launch eGliders, I think we'll see more and more gliders operating out of small airports without the benefit of a club. Thus, what's missing in the conversation is a consideration of the CONOPS (CONcept of OPerationS) for single-person launching.

Cool idea, however, it has sort of been tried before. One of our club members posted this link to a film documenting initial tests with a semi-autonomous auto-launch system. Seemed to work, but with significant wear on the launch vehicle.

https://youtu.be/wwsa4PVYMJY

>
> https://youtu.be/wwsa4PVYMJY

Excellent.

For an FES ground assist, you need enough energy for a rope break like return to the field when the FES does not work.

I there a safe and economical way to make a winch that can just get you to 300 feet?

Might be some minor issues with the design example in the video.

On Friday, June 5, 2020 at 8:59:21 AM UTC-6, wrote:
> >
> > https://youtu.be/wwsa4PVYMJY
>
> Excellent.
>
> For an FES ground assist, you need enough energy for a rope break like return to the field when the FES does not work.
>
> I there a safe and economical way to make a winch that can just get you to 300 feet?
>
> Might be some minor issues with the design example in the video.

Good and cheap are mutually exclusive. A good, safe machine won't be cheap.

> Good and cheap are mutually exclusive. A good, safe machine won't be cheap.

Right, but I thought the idea of the original question was to see if sacrificing some good (higher than 300 foot tow?) might make cheap and safe possible.

Seems like a small corner case until there are lots more FES, but still fun to think about.

On Friday, June 5, 2020 at 12:26:21 PM UTC-5, wrote:
> > Good and cheap are mutually exclusive. A good, safe machine won't be cheap.
>
> Right, but I thought the idea of the original question was to see if sacrificing some good (higher than 300 foot tow?) might make cheap and safe possible.
>
> Seems like a small corner case until there are lots more FES, but still fun to think about.

A light duty winch to get you to 300 feet would still require all the same components as a heavy duty winch designed to get a Duo to 2000'. Assuming you will climb at a relatively shallow angle, you could get away with somewhat less power than a typical glider winch because you won't need to climb steeply as is done in a regular winch launch. Also, because line tension will be less in the shallow climb, your winch drum can be lighter. Brakes are critical on a winch to manage inertia of the drum/line and to put some tension on the in when reeling it out. A lighter system could have correspondingly lighter brakes. Your winch line will be under less tension, and with a low launch rate, wear would not be a big issue. You could forego expensive Dyneema line and just use polypropylene (might be a false economy eventually). These would all be small increments of "lighter, smaller, cheaper". Probably not enough to justify building it. My guess is it would be better to buy/build a regular winch or go with auto launch. Hard to get cheaper and simpler than an old car, a bucket of rope, and a tow release on a trailer hitch.

On Friday, June 5, 2020 at 1:26:21 PM UTC-4, wrote:
> > Good and cheap are mutually exclusive. A good, safe machine won't be cheap.
>
> Right, but I thought the idea of the original question was to see if sacrificing some good (higher than 300 foot tow?) might make cheap and safe possible.
>
> Seems like a small corner case until there are lots more FES, but still fun to think about.

Agreed! It's a fun thought experiment for a growing sector of the sport.

For me, the issue is that if I have a setup which can get me to 300', it can get me a lot higher for minimal extra effort. 300' would mean about 600' of linear space, which is unlikely to fit in the area before a runway. So once I'm using any part of the runway, I might was well use the entire length.

From a mechanical perspective, the only substantial difference between 300' and 3000' is the length of rope and the total energy required. The angles, forces, and power stays the same.

Some crucial distinctions of a 100' long catapult-style launch are that there's no hardware on the runway so it can plausibly be completely autonomous; the angles are purely horizontal so the spooling system is simplified and the hook cannot drift down onto the runway; a 3 second launch means that motor cooling is not an issue due to the thermal mass of the motor; and a launch failure is very graceful, with a worst case result of rolling down the runway at a leisurely 30-40kts.

WB
Thats a good Vid!
Do you know what movie that was taken from?
Nick
T

On Friday, June 5, 2020 at 1:50:59 PM UTC-4, WB wrote:
> On Friday, June 5, 2020 at 12:26:21 PM UTC-5, wrote:
> > > Good and cheap are mutually exclusive. A good, safe machine won't be cheap.
> >
> > Right, but I thought the idea of the original question was to see if sacrificing some good (higher than 300 foot tow?) might make cheap and safe possible.
> >
> > Seems like a small corner case until there are lots more FES, but still fun to think about.
>
> A light duty winch to get you to 300 feet would still require all the same components as a heavy duty winch designed to get a Duo to 2000'. Assuming you will climb at a relatively shallow angle, you could get away with somewhat less power than a typical glider winch because you won't need to climb steeply as is done in a regular winch launch. Also, because line tension will be less in the shallow climb, your winch drum can be lighter. Brakes are critical on a winch to manage inertia of the drum/line and to put some tension on the in when reeling it out. A lighter system could have correspondingly lighter brakes. Your winch line will be under less tension, and with a low launch rate, wear would not be a big issue. You could forego expensive Dyneema line and just use polypropylene (might be a false economy eventually). These would all be small increments of "lighter, smaller, cheaper". Probably not enough to justify building it. My guess is it would be better to buy/build a regular winch or go with auto launch. Hard to get cheaper and simpler than an old car, a bucket of rope, and a tow release on a trailer hitch.

>> You could forego expensive Dyneema line and just use polypropylene (might be a false economy eventually). <<

I would advise against using polypropylene line since it has a much higher elongation compared to UHMWPE lines. It would most likely lead to a very unsteady launch with a lot of surging - like hanging on a bungee cord. Spectra or Dyneema have an elongation very close to what a steel cable has but at about 1/10 of the weight. That also plays into the overall equation for accelerating the line and then stopping everything with your drum brakes.
Rather than building something on the 'Hold my beer - watch this' principle, spend the money and get the right stuff.

Uli
'AS'

On Fri, 05 Jun 2020 11:00:11 -0700, sebesta wrote:

> On Friday, June 5, 2020 at 1:26:21 PM UTC-4, wrote:
>> > Good and cheap are mutually exclusive. A good, safe machine won't be
>> > cheap.
>>
>> Right, but I thought the idea of the original question was to see if
>> sacrificing some good (higher than 300 foot tow?) might make cheap and
>> safe possible.
>>
>> Seems like a small corner case until there are lots more FES, but still
>> fun to think about.
>
> Agreed! It's a fun thought experiment for a growing sector of the sport.
>
> For me, the issue is that if I have a setup which can get me to 300', it
> can get me a lot higher for minimal extra effort. 300' would mean about
> 600' of linear space, which is unlikely to fit in the area before a
> runway. So once I'm using any part of the runway, I might was well use
> the entire length.
>
The rule of thumb over here is that you get to 1/3 of the cable length,
not 1/2, but it depends on wind too. Our Skylaunch (around 400 hp from V8
on LPG and 1000m (3270 ft) of cable gets me to 1200ft on a light breeze
and 1400 ft plus in more normal summer weather with a reasonable wind
gradient (Std Libelle, not pulling hard, so around 1/2.5 of line length
on average.

A low power winch won't do nearly as well.



--
Martin | martin at
Gregorie | gregorie dot org

On Friday, June 5, 2020 at 1:10:12 PM UTC-5, Nick Kennedy wrote:
> WB
> Thats a good Vid!
> Do you know what movie that was taken from?
> Nick
> T

La Grande Vadrouille.