$1 billion BMS Ooops...

2G wrote on 3/5/2021 8:29 AM:
On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
2G wrote on 3/3/2021 6:11 PM:
....

ICO glider engines have been developed over the last 70 years or so. And, then, many of them have come from the 2-cycle engine applications such as snowmobiles and ultralights. The electric glider market is much more immature..

That immaturity means they have a lot of promise, compared to the ICE gliders. We know in 5
years the performance of the electrics will increase significantly; the fossil fueled ones -
not nearly so much. Even at the current immature stage, they are so desirable, all the major
manufacturers, and some of the second tier, offer at least two electric models in mast or FES
varieties.

I suggest that in maybe 5, but certainly in 10 years, the discussions will no longer be about
gas vs electric, but which electric to buy.
--
yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1

Wishful thinking duly noted. The development, deployment and long-term flight experience of aircraft takes time. Ten years is a good estimate for a single model such as the Antares. Its first flight was in 2003, so development must have started about 20 years ago. I think that in 5 to 10 years we will be thinking "Boy, those electric gliders looked promising at the time, but if we knew then what we know now I would never have bought one." Successful product development just can't be rushed.

It's not wishful thinking when there are four companies selling electric glider power systems:
Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers do not have to design
their own system, like Antares had to. That speeds development (even eliminates it in some
cases), reduces their cost, and increases reliability.

While the glider market is very small, the main component - batteries - is under intense
development by major corporations around the world. We will benefit from this investment,
without investing a dime in it.

As for glider pilots feeling sorry for their current electric choices in 5 or 10 years, well,
I'm going to suggest many glider pilots will be feeling sorry for their current gas engine
choices ;^)
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

Predicting the future is ALWAYS wishful thinking. If you could actually do it reliably you would be a billionaire. Having four companies doing it doesn't mean the development is 4 times as fast, you just get 4 possible failures instead of one.

There are already some pieces of "common wisdom" that have been debunked. One is that electric is inherently more reliable than ICE. The fire incidents are of greatest concern. Dave's issues with his Antares are also troubling - systems that are dependent on complex software can have failure modes that are only found by extensive testing. I know of another Antares owner who had to fly a technician over from Germany to fix the problems with his glider. And the small numbers of electric gliders means that buyers will ultimately do most of the testing themselves. Long term support of these complex systems is yet another question.

I apologize to all readers for the repetition: The Antares was a pioneering effort, and you can
recognize a pioneer by the arrows in his back. Schleicher, Schempp-Hirth, Jonkers, and others,
are not following the Antares path. They are not pioneers, but cautious "settlers" that follow
after the pioneers have showed them where to go.

There are far more FES gliders flying than Antares, and very successfully. The problems that
occur are solved by LZ Design, not the glider manufacturers. The eglider segment of gliding has
reached the "specialization" stage, and to talk about Dave's Antares problems is to miss the
future because you are focusing on a pioneering glider designed and built almost two decades ago.

The future, which is now, includes mast-mounted options from several manufacturers. The "old"
manufacturers got old by not being too bold: they are cautious, risk-adverse companies that see
a burgeoning opportunity they have to join. There will not be fleets of egliders from these
companies 5 or 10 years from now, sitting on the ground, unused.

I've seen this happen before, with the ASH26E (my current glider), which was quite bold in
1994: the first retracting self-launching sailplane from Schleicher, using a Wankel engine, and
- horrors - only a 18m wingspan when there was no 18M class! There were problems, especially in
the first 5 years, but they made it work, didn't they? You've owned one! And they (and the
other manufacturers) will make the egliders work, and work well.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

Kenn,

Can you add me to that group too?
emirsherbi at g m ail

Regards

"Having four companies doing it doesn't mean the development is 4 times as fast, you just get 4 possible failures instead of one."

“Crash programs fail because they are based on the theory that, with nine women pregnant, you can get a baby a month.�

(Wernher von Braun)

On Friday, March 5, 2021 at 9:16:58 AM UTC-8, Eric Greenwell wrote:

I apologize to all readers for the repetition: The Antares was a pioneering effort, and you can
recognize a pioneer by the arrows in [their] back.

In the Silicon Valley, we say:

"The early bird gets the worm. The second mouse gets the cheese."

In my practical experience, the second mouse also often eats the first mouse.

--Bob K.

On 3/5/21 10:16 AM, Eric Greenwell wrote:
2G wrote on 3/5/2021 8:29 AM:
On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
2G wrote on 3/3/2021 6:11 PM:
...

ICO glider engines have been developed over the last 70 years or
so. And, then, many of them have come from the 2-cycle engine
applications such as snowmobiles and ultralights. The electric
glider market is much more immature..

That immaturity means they have a lot of promise, compared to the
ICE gliders. We know in 5
years the performance of the electrics will increase significantly;
the fossil fueled ones -
not nearly so much. Even at the current immature stage, they are so
desirable, all the major
manufacturers, and some of the second tier, offer at least two
electric models in mast or FES
varieties.

I suggest that in maybe 5, but certainly in 10 years, the
discussions will no longer be about
gas vs electric, but which electric to buy.
--
yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1


Wishful thinking duly noted. The development, deployment and
long-term flight experience of aircraft takes time. Ten years is a
good estimate for a single model such as the Antares. Its first
flight was in 2003, so development must have started about 20 years
ago. I think that in 5 to 10 years we will be thinking "Boy, those
electric gliders looked promising at the time, but if we knew then
what we know now I would never have bought one." Successful product
development just can't be rushed.

It's not wishful thinking when there are four companies selling
electric glider power systems:
Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers
do not have to design
their own system, like Antares had to. That speeds development (even
eliminates it in some
cases), reduces their cost, and increases reliability.

While the glider market is very small, the main component - batteries
- is under intense
development by major corporations around the world. We will benefit
from this investment,
without investing a dime in it.

As for glider pilots feeling sorry for their current electric choices
in 5 or 10 years, well,
I'm going to suggest many glider pilots will be feeling sorry for
their current gas engine
choices ;^)
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1


Predicting the future is ALWAYS wishful thinking. If you could
actually do it reliably you would be a billionaire. Having four
companies doing it doesn't mean the development is 4 times as fast,
you just get 4 possible failures instead of one.

There are already some pieces of "common wisdom" that have been
debunked. One is that electric is inherently more reliable than ICE.
The fire incidents are of greatest concern. Dave's issues with his
Antares are also troubling - systems that are dependent on complex
software can have failure modes that are only found by extensive
testing. I know of another Antares owner who had to fly a technician
over from Germany to fix the problems with his glider. And the small
numbers of electric gliders means that buyers will ultimately do most
of the testing themselves. Long term support of these complex systems
is yet another question.

I apologize to all readers for the repetition: The Antares was a
pioneering effort, and you can recognize a pioneer by the arrows in his
back. Schleicher, Schempp-Hirth, Jonkers, and others, are not following
the Antares path. They are not pioneers, but cautious "settlers" that
follow after the pioneers have showed them where to go.

There are far more FES gliders flying than Antares, and very
successfully. The problems that occur are solved by LZ Design, not the
glider manufacturers. The eglider segment of gliding has reached the
"specialization" stage, and to talk about Dave's Antares problems is to
miss the future because you are focusing on a pioneering glider designed
and built almost two decades ago.

The future, which is now, includes mast-mounted options from several
manufacturers. The "old" manufacturers got old by not being too bold:
they are cautious, risk-adverse companies that see a burgeoning
opportunity they have to join. There will not be fleets of egliders from
these companies 5 or 10 years from now, sitting on the ground, unused.

I've seen this happen before, with the ASH26E (my current glider), which
was quite bold in 1994: the first retracting self-launching sailplane
from Schleicher, using a Wankel engine, and - horrors - only a 18m
wingspan when there was no 18M class! There were problems, especially in
the first 5 years, but they made it work, didn't they? You've owned one!
And they (and the other manufacturers) will make the egliders work, and
work well.


Don't think anybody is going to predict the future five years out.
Maybe there will be some big breakthrough in batteries, maybe not.

FES gliders have been out almost 10 years now, what is clear is their
history. Underpowered back then, underpowered still today. Makes you
wonder where these huge improvements in capacity are hiding. Some are
being sold as self launchers, even when flown as sustainers they're
still landing out.

CNN proclaimed back in 2017 that lilium was just around the corner.
Four years later, they have one burned up prototype, another one that
hasn't flown, and now they're saying they didn't really intend to
certify that design anyway. Huge shock for Herb, but not everything you
hear on CNN is true.

The electric beaver folks have been awful quiet after demonstrating a
single three minute flight. They claimed they were going to be in
commercial operation in 2022. Uh-huh. Not sure why you'd certify a
passenger plane that has no room left for passengers. Made for lots of
phony press releases though.

The Alice in Wonderland folks burned up their prototype last year, now
they're back with a radically different airframe design, and claiming
first flight will be in 2021. You betcha. Maybe they burned that proto
because the knew it never was going to fly? They did have a fire engine
standing by.

The electric Caravan folks fried their inverter during their big demo
flight, put the turbine back on it and are trying to sell it.

Maybe electrics will make huge progress, wouldn't that be great? But
I'm not going to lose any sleep over it. Nor am I excited about the
current offerings.

Comparisons of commercial air transport with self launched gliders are specious, very different energy use profile. Same with cars vs. self launched gliders. In either case though, the energy density difference between 100LL and state-of-the-art batteries is hard to ignore - at least 30:1 at this moment, and still 10:1 even considering relative efficiencies. I've no doubt electrics will eventually take over, the question is only if you buy one now, how early are you in the development cycle? Once the cycle is mature, there should be a market for a drop in electric replacement for aging ICE powerplants on popular gliders.

On Friday, March 5, 2021 at 8:28:29 PM UTC-8, kinsell wrote:
On 3/5/21 10:16 AM, Eric Greenwell wrote:
2G wrote on 3/5/2021 8:29 AM:
On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
2G wrote on 3/3/2021 6:11 PM:
...

ICO glider engines have been developed over the last 70 years or
so. And, then, many of them have come from the 2-cycle engine
applications such as snowmobiles and ultralights. The electric
glider market is much more immature..

That immaturity means they have a lot of promise, compared to the
ICE gliders. We know in 5
years the performance of the electrics will increase significantly;
the fossil fueled ones -
not nearly so much. Even at the current immature stage, they are so
desirable, all the major
manufacturers, and some of the second tier, offer at least two
electric models in mast or FES
varieties.

I suggest that in maybe 5, but certainly in 10 years, the
discussions will no longer be about
gas vs electric, but which electric to buy.
--
yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1


Wishful thinking duly noted. The development, deployment and
long-term flight experience of aircraft takes time. Ten years is a
good estimate for a single model such as the Antares. Its first
flight was in 2003, so development must have started about 20 years
ago. I think that in 5 to 10 years we will be thinking "Boy, those
electric gliders looked promising at the time, but if we knew then
what we know now I would never have bought one." Successful product
development just can't be rushed.

It's not wishful thinking when there are four companies selling
electric glider power systems:
Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers
do not have to design
their own system, like Antares had to. That speeds development (even
eliminates it in some
cases), reduces their cost, and increases reliability.

While the glider market is very small, the main component - batteries
- is under intense
development by major corporations around the world. We will benefit
from this investment,
without investing a dime in it.

As for glider pilots feeling sorry for their current electric choices
in 5 or 10 years, well,
I'm going to suggest many glider pilots will be feeling sorry for
their current gas engine
choices ;^)
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1


Predicting the future is ALWAYS wishful thinking. If you could
actually do it reliably you would be a billionaire. Having four
companies doing it doesn't mean the development is 4 times as fast,
you just get 4 possible failures instead of one.

There are already some pieces of "common wisdom" that have been
debunked. One is that electric is inherently more reliable than ICE.
The fire incidents are of greatest concern. Dave's issues with his
Antares are also troubling - systems that are dependent on complex
software can have failure modes that are only found by extensive
testing. I know of another Antares owner who had to fly a technician
over from Germany to fix the problems with his glider. And the small
numbers of electric gliders means that buyers will ultimately do most
of the testing themselves. Long term support of these complex systems
is yet another question.

I apologize to all readers for the repetition: The Antares was a
pioneering effort, and you can recognize a pioneer by the arrows in his
back. Schleicher, Schempp-Hirth, Jonkers, and others, are not following
the Antares path. They are not pioneers, but cautious "settlers" that
follow after the pioneers have showed them where to go.

There are far more FES gliders flying than Antares, and very
successfully. The problems that occur are solved by LZ Design, not the
glider manufacturers. The eglider segment of gliding has reached the
"specialization" stage, and to talk about Dave's Antares problems is to
miss the future because you are focusing on a pioneering glider designed
and built almost two decades ago.

The future, which is now, includes mast-mounted options from several
manufacturers. The "old" manufacturers got old by not being too bold:
they are cautious, risk-adverse companies that see a burgeoning
opportunity they have to join. There will not be fleets of egliders from
these companies 5 or 10 years from now, sitting on the ground, unused.

I've seen this happen before, with the ASH26E (my current glider), which
was quite bold in 1994: the first retracting self-launching sailplane
from Schleicher, using a Wankel engine, and - horrors - only a 18m
wingspan when there was no 18M class! There were problems, especially in
the first 5 years, but they made it work, didn't they? You've owned one!
And they (and the other manufacturers) will make the egliders work, and
work well.

Don't think anybody is going to predict the future five years out.
Maybe there will be some big breakthrough in batteries, maybe not.

FES gliders have been out almost 10 years now, what is clear is their
history. Underpowered back then, underpowered still today. Makes you
wonder where these huge improvements in capacity are hiding. Some are
being sold as self launchers, even when flown as sustainers they're
still landing out.

CNN proclaimed back in 2017 that lilium was just around the corner.
Four years later, they have one burned up prototype, another one that
hasn't flown, and now they're saying they didn't really intend to
certify that design anyway. Huge shock for Herb, but not everything you
hear on CNN is true.

The electric beaver folks have been awful quiet after demonstrating a
single three minute flight. They claimed they were going to be in
commercial operation in 2022. Uh-huh. Not sure why you'd certify a
passenger plane that has no room left for passengers. Made for lots of
phony press releases though.

The Alice in Wonderland folks burned up their prototype last year, now
they're back with a radically different airframe design, and claiming
first flight will be in 2021. You betcha. Maybe they burned that proto
because the knew it never was going to fly? They did have a fire engine
standing by.

The electric Caravan folks fried their inverter during their big demo
flight, put the turbine back on it and are trying to sell it.

Maybe electrics will make huge progress, wouldn't that be great? But
I'm not going to lose any sleep over it. Nor am I excited about the
current offerings.

kinsell wrote on 3/5/2021 8:28 PM:
FES gliders have been out almost 10 years now, what is clear is their history.* Underpowered
back then, underpowered still today.* Makes you wonder where these huge improvements in
capacity are hiding.* Some are being sold as self launchers, even when flown as sustainers
they're still landing out.

The airplane examples you mention don't apply to us, because their goals are very different,
and are much more difficult to achieve. Your judgement that FES gliders are under powered is
just an opinion, one that is obviously not shared by the major manufacturers, who have
increased their FES offerings substantially in the last 10 years, nor is it shared by the
increasing number of glider pilots that are buying them. I'm sure every owner of an FES glider
wishes it had more power; in fact, I've had the same wish for my ASH 26E! But overall, the
26E's attributes are attractive enough that I've flown it for 26 years, and the FES attributes
are attractive enough that many pilots buy them.

It's important to remember many pilots buying an FES glider are coming from an unpowered
glider, so they think the ability to self-launch is an amazing upgrade, and to have a modest
retrieve capability is an outstanding addition!

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

On Friday, March 5, 2021 at 10:28:29 PM UTC-6, kinsell wrote:
On 3/5/21 10:16 AM, Eric Greenwell wrote:
2G wrote on 3/5/2021 8:29 AM:
On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
2G wrote on 3/3/2021 6:11 PM:
...

ICO glider engines have been developed over the last 70 years or
so. And, then, many of them have come from the 2-cycle engine
applications such as snowmobiles and ultralights. The electric
glider market is much more immature..

That immaturity means they have a lot of promise, compared to the
ICE gliders. We know in 5
years the performance of the electrics will increase significantly;
the fossil fueled ones -
not nearly so much. Even at the current immature stage, they are so
desirable, all the major
manufacturers, and some of the second tier, offer at least two
electric models in mast or FES
varieties.

I suggest that in maybe 5, but certainly in 10 years, the
discussions will no longer be about
gas vs electric, but which electric to buy.
--
yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1


Wishful thinking duly noted. The development, deployment and
long-term flight experience of aircraft takes time. Ten years is a
good estimate for a single model such as the Antares. Its first
flight was in 2003, so development must have started about 20 years
ago. I think that in 5 to 10 years we will be thinking "Boy, those
electric gliders looked promising at the time, but if we knew then
what we know now I would never have bought one." Successful product
development just can't be rushed.

It's not wishful thinking when there are four companies selling
electric glider power systems:
Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers
do not have to design
their own system, like Antares had to. That speeds development (even
eliminates it in some
cases), reduces their cost, and increases reliability.

While the glider market is very small, the main component - batteries
- is under intense
development by major corporations around the world. We will benefit
from this investment,
without investing a dime in it.

As for glider pilots feeling sorry for their current electric choices
in 5 or 10 years, well,
I'm going to suggest many glider pilots will be feeling sorry for
their current gas engine
choices ;^)
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1


Predicting the future is ALWAYS wishful thinking. If you could
actually do it reliably you would be a billionaire. Having four
companies doing it doesn't mean the development is 4 times as fast,
you just get 4 possible failures instead of one.

There are already some pieces of "common wisdom" that have been
debunked. One is that electric is inherently more reliable than ICE.
The fire incidents are of greatest concern. Dave's issues with his
Antares are also troubling - systems that are dependent on complex
software can have failure modes that are only found by extensive
testing. I know of another Antares owner who had to fly a technician
over from Germany to fix the problems with his glider. And the small
numbers of electric gliders means that buyers will ultimately do most
of the testing themselves. Long term support of these complex systems
is yet another question.

I apologize to all readers for the repetition: The Antares was a
pioneering effort, and you can recognize a pioneer by the arrows in his
back. Schleicher, Schempp-Hirth, Jonkers, and others, are not following
the Antares path. They are not pioneers, but cautious "settlers" that
follow after the pioneers have showed them where to go.

There are far more FES gliders flying than Antares, and very
successfully. The problems that occur are solved by LZ Design, not the
glider manufacturers. The eglider segment of gliding has reached the
"specialization" stage, and to talk about Dave's Antares problems is to
miss the future because you are focusing on a pioneering glider designed
and built almost two decades ago.

The future, which is now, includes mast-mounted options from several
manufacturers. The "old" manufacturers got old by not being too bold:
they are cautious, risk-adverse companies that see a burgeoning
opportunity they have to join. There will not be fleets of egliders from
these companies 5 or 10 years from now, sitting on the ground, unused.

I've seen this happen before, with the ASH26E (my current glider), which
was quite bold in 1994: the first retracting self-launching sailplane
from Schleicher, using a Wankel engine, and - horrors - only a 18m
wingspan when there was no 18M class! There were problems, especially in
the first 5 years, but they made it work, didn't they? You've owned one!
And they (and the other manufacturers) will make the egliders work, and
work well.

Don't think anybody is going to predict the future five years out.
Maybe there will be some big breakthrough in batteries, maybe not.

FES gliders have been out almost 10 years now, what is clear is their
history. Underpowered back then, underpowered still today. Makes you
wonder where these huge improvements in capacity are hiding. Some are
being sold as self launchers, even when flown as sustainers they're
still landing out.

CNN proclaimed back in 2017 that lilium was just around the corner.
Four years later, they have one burned up prototype, another one that
hasn't flown, and now they're saying they didn't really intend to
certify that design anyway. Huge shock for Herb, but not everything you
hear on CNN is true.

The electric beaver folks have been awful quiet after demonstrating a
single three minute flight. They claimed they were going to be in
commercial operation in 2022. Uh-huh. Not sure why you'd certify a
passenger plane that has no room left for passengers. Made for lots of
phony press releases though.

The Alice in Wonderland folks burned up their prototype last year, now
they're back with a radically different airframe design, and claiming
first flight will be in 2021. You betcha. Maybe they burned that proto
because the knew it never was going to fly? They did have a fire engine
standing by.

The electric Caravan folks fried their inverter during their big demo
flight, put the turbine back on it and are trying to sell it.

Maybe electrics will make huge progress, wouldn't that be great? But
I'm not going to lose any sleep over it. Nor am I excited about the
current offerings.
Dave, I'm honored to yet a mention from you! You wouldn't believe how little CNN I watch but who cares? Regarding batteries, I have flown RC with most of the available chemistries for the last 20 years and the improvements are mostly in motors, controllers and max discharge amperages as well as slightly more battery cycles vs. earlier times. Still, you are lucky to get 50-100 cycles out of the now listed 50-80C LiPo batteries we fly in RC. Nothing on the horizon that even promises a doubling of capacity. Give me a self-launcher that replaces the tow plane (2k-3k launch) and lets me replace the low cost but fire-safe batteries easily. I'd be interested.

Herb, J7

Herbert Kilian wrote on 3/6/2021 7:13 AM:
Still, you are lucky to get 50-100 cycles out of the now listed 50-80C LiPo batteries we fly in RC. Nothing on the horizon that even promises a doubling of capacity. Give me a self-launcher that replaces the tow plane (2k-3k launch) and lets me replace the low cost but fire-safe batteries easily. I'd be interested.

The glider discharge currents are nowhere near 50-80 times capacity, but more in the 4C range,
so the number of cycles should be much higher; also, you would rarely go to full discharge
(more like 20%-40%) during each flight, which also increases cycle life substantially.

I'm not sure what "replace easily" means: if daily to swap out batteries for charging, then the
fuselage mounted batteries like the FES gliders or Jonkers JS3 RES (mast mounted motor) is what
you need; if it's replacing worn-out batteries every 5-10+ years, I think all of them allow
that in less than a day.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

The glider discharge currents are nowhere near 50-80 times capacity, but more in the 4C range,
so the number of cycles should be much higher; also, you would rarely go to full discharge
(more like 20%-40%) during each flight, which also increases cycle life substantially.

Yes... and no. If you're only going for a single launch, then ideally your pack would be at 20% SoC at the end of the launch. After all, the reserve capacity isn't valuable if you never use it. Assuming 600fpm, and a 2k launch, that yields about 15C as the target discharge rate.

The reason why we have big battery packs in eGliders right now is because 15C is too much discharge for Li-ion technologies. So the pack manufacturers have to make them 3x bigger to get the current to a 4-5C discharge rate. The manufacturers now have a big, heavy, and expensive pack in the plane, but with a lot of reserve capacity. All is not lost, though-- that reserve capacity can be used for sustainer or saves.

Currently, batteries are improving extremely rapidly in ways which are highly relevant to eGliders. The energy density might not be going up very quickly, but we simply don't need it. At 200-250kWhr/kg, we need about 1kg of battery to launch 30kg of glider, so doubling the energy density is only going to shave a few kg off the overall weight. We're already in the realm of diminishing returns at that point.

What we need is power density in a (fire) safe package:

* Li-ions are quite safe, and LiPos are reasonably safe. LiPos are getting safer by the day.
* LiPos far exceed the required power density, and Li-ions are getting there.

As it's not a moonshot to ask for a mild convergence of two sibling technologies, I feel we'll continue to see tangible improvement in the next couple years.We might not see that in the mainstream manufacturers, as they've already locked in their packs and will not be able to change for the foreseeable future, but small projects such as in the aforementioned eGlider group are iterating rapidly.

On Saturday, March 6, 2021 at 10:13:38 AM UTC-5, Herbert Kilian wrote:
Still, you are lucky to get 50-100 cycles out of the now listed 50-80C LiPo batteries we fly in RC. Nothing on the horizon that even promises a doubling of capacity. Give me a self-launcher that replaces the tow plane (2k-3k launch) and lets me replace the low cost but fire-safe batteries easily. I'd be interested.

This is one of the open questions. Do we really want to have an hour cruise left over, or is the biggest value just getting in the air at all?

I predict that people just want to launch. If we can use 8-10kg of 20C LiPos to get to 1k', with 5 minutes of cruise left over, and a freshly charged pack waiting on the ground, then it's basically a winch launch. And as those of us who have flown in the EU know, winch launches are great ways to get flying.