$1 billion BMS Ooops...

[Dave Nadler]

https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
Discus amongst yourselves...

[Darryl Ramm]

On Wednesday, February 24, 2021 at 1:42:01 PM UTC-8, d...@nadler.com wrote:
> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> Discus amongst yourselves...

Dave, it's time for you to stop complaining and just admit electric is simple.

[Dave Nadler]

On 2/24/2021 4:51 PM, Darryl Ramm wrote:
> On Wednesday, February 24, 2021 at 1:42:01 PM UTC-8, d...@nadler.com wrote:
>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/

>> Discuss amongst yourselves...

>
> Dave, it's time for you to stop complaining and just admit electric is simple.

You're absolutely right Darryl!
After all, how hard could it be???

[kinsell]

Simple and ultra reliable. You gonna be dragging your old faithful
Antares down to the Seniors this year?

[Dave Nadler]

After it failed during the last two comps I took it to?
Drive for days, fly a few times, then drive for days home after it breaks?
I don't think so...

Anyway, no vaccination yet so no travel in any case.

[Eric Greenwell]

The Antares was a bold effort, perhaps too bold, and by now, it's an old effort. No point in
holding it up as an example anymore. Now, all the manufacturers have electric gliders, and Solo
has added electric systems to their sailplane power business. Electric isn't the coming thing
any more: it's here. The next milestone will be passed when they start selling more electrics
than ICEs.

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

[kinsell]

I see another Silent 2 just popped up on the market, that makes four
plus one recently sold. Garret suggests you might want to aerotow or
winch launch to conserve battery power. When I see these things with a
dozen hours on them up for sale, it suggests that the owners aren't that
thrilled with what they got for their money.

[Dave Nadler]

On 2/25/2021 9:49 AM, kinsell wrote:
> I see another Silent 2 just popped up on the market, that makes four
> plus one recently sold.  Garret suggests you might want to aerotow or
> winch launch to conserve battery power.  When I see these things with a
> dozen hours on them up for sale, it suggests that the owners aren't that
> thrilled with what they got for their money.

The Silent 2 is an interesting bird.
I've got friends that love it, and others that have sold it on.
Some owners have had to replace battery packs, newer packs
are reported OK - but this is 2nd or 3rd hand info.
More importantly, its got very limited energy, so if you
self-launch, not much in the tank to get home.
Because of its limited performance, you can't just skip
over gaps that higher performance machines take for granted,
and a bit of headwind is a big obstacle.

So, if it can do what you need with your weather and site
constraints, great! But work through carefully whether it
meets your needs.

FWIW...
Best Regards, Dave

[Hank Nixon]

On Wednesday, February 24, 2021 at 4:42:01 PM UTC-5, d...@nadler.com wrote:
> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> Discus amongst yourselves...

The market wants:
Fast charge for convenience
Safety
Long life for low cost of ownership
It is possible to get the send two if one compromises on the first.
Can't have all.
Balancing packs requires time.
Unbalanced packs fail or die sooner.
Reality
UH

[Eric Greenwell]

It would be instructive to discuss the reasons with the people selling the Silents. My only
contact with one is Jeff Banks' Silent. We flew together for a week out of Richfield, UT, last
year. He likes it, self-launched every flight, and had good flights. He also flew out of Heber,
Nephi and Dick Stout airfields in 2020. You can check the OLC for his flights in 2018, 2019 and
2020. Also, 2021 - first flight of the year at Seminole.

[kinsell]

Just reading about the Lilium electric air taxi in Forbes, they want to
draw 1.2 megawatts from the batteries for 60 seconds for vertical
takeoff and transition to forward flight.

You can do that sort of thing for 3 seconds in a Tesla for Ludicrous
mode, but 60 seconds can fry the batteries in the air taxi.

Tesla has 4000 small cylindrical cells, with a manifold in contact with
all of them, with pumped liquid cooling to allow high charge and
discharge rates.

Most electric gliders just use big pouch cells, a lot of people just
don't understand the implications of that.

Lilium has raised 400 odd million bucks in funding, looking more like a
pipe dream all the time. Ditto for that Alice thingie, but they've only
burned 200 mil.

[Tango Eight]

On Thursday, February 25, 2021 at 11:50:46 AM UTC-5, kinsell wrote:
> Just reading about the Lilium electric air taxi in Forbes, they want to
> draw 1.2 megawatts from the batteries for 60 seconds for vertical
> takeoff and transition to forward flight.

1.21 Gigawatts for 60 microseconds and you can go back in time. Or you'll be history. Or something like that.

Now, where did I leave my Segway...

There's no law saying that investors have to be smart.

T8

[Herbert Kilian]

Right on, Dave. I want to see just one of these pipe-dream machines get a standard airworthiness cert. with the OK for carrying passengers, just one. Just like fusion power (and Trump's healthcare plan), it's only a short few years away, I guess.

[Dan Marotta]

Oh that is so last decade. I've got an InMotion V11 instead, and the
bruises to prove it!

Dan
5J

[Darryl Ramm]

Electric unicycle that's adventurous as one of us old folks.... oh remembers Dan has a gyrocopter... :-)

[Dave Nadler]

On 2/24/2021 11:22 PM, Eric Greenwell wrote:
> ...Electric isn't the coming thing any

> more: it's here. The next milestone will be passed when they start
> selling more electrics than ICEs.

Eric, you've been drinking the Cool-Aid.
As I did once.
You're bringing your new electric machine to the Seniors, right?
And I do mean THIS year...

[kinsell]

I noticed one of the other Silent 2 Electro owners was fishing around to
buy an ASH31Mi, a gas guzzling Schleicher product. Grass is always
greener on the other side.

Maybe Eric and that guy could work out a swap, then they'd both have
their dream ships :-)

[G K]

> Right on, Dave. I want to see just one of these pipe-dream machines get a standard airworthiness cert. with the OK for carrying passengers, just one.

- I know of one being close. Look up Joby.

Just like fusion power (and Trump's healthcare plan), it's only a short few years away, I guess.

- Kamala has a health plan for you Herb.
Unfortunately, You and Me as white males only get to pay for it, but Hey now!
It's a true realization of Marx&Engel's dreams and it covers the entire Central America.

Best,
GK

[Eric Greenwell]

Even on the original, pre-Covid schedule, it would not have been ready for the Seniors. And
consider this: my current motorglider, the ASH26E, was delivered a year late by Schleicher, so
by that standard, GP still has until Feb. 2022 to get the new glider to me :^)

There are a lot of FES gliders out there now, and with all the manufacturers offering them,
there will be many more. The more powerful electrics with mast mounted propellers are also
offered by all the manufacturers, and many pilots that think the FES gliders are appealing but
marginal will be ordering these new gliders.

I think you will see a lot of Kool-Aid drinkers behind the Schleicher, Schempp-Hirth, and
Jonkers booths at the SSA convention in 2022, all offering what you saw - and desired - in the
Antares years ago. They won't make the same mistakes that Lange made.

[Dan Marotta]

Yes, and I've been laid up for the past week after a horrific spill. My
helmet and pads protected skin and skull, but not the ribs from a good
bruise. Now it hurts to laugh (really) and I'm impatiently waiting for
the pain to subside so I can mount up again. Pretty sure I can fly the
gyro without problems, but getting in and out of the thing will hurt...

Dan
5J

[Dan Marotta]

Went to the airport today. Wind was 40 degrees off at 27 gusting 33
kts. The gyro POH says 60 kmh is the max so I just helped my wife train
on her unicycle.

Dan
5J

On 2/26/21 9:58 AM, Dan Marotta wrote:
> Yes, and I've been laid up for the past week after a horrific spill.  My
> helmet and pads protected skin and skull, but not the ribs from a good
> bruise.  Now it hurts to laugh (really) and I'm impatiently waiting for
> the pain to subside so I can mount up again.  Pretty sure I can fly the
> gyro without problems, but getting in and out of the thing will hurt...
>
> Dan
>

[Dave Nadler]

On 2/25/2021 9:28 PM, G K wrote:
> - I know of one being close. Look up Joby.

https://www.youtube.com/watch?v=4wbFw165ar0&feature=emb_title

[Dave Nadler]

On 2/25/2021 11:02 PM, Eric Greenwell wrote:
> Dave Nadler wrote on 2/25/2021 5:07 PM:
>> On 2/24/2021 11:22 PM, Eric Greenwell wrote:
>>> ...Electric isn't the coming thing any more: it's here. The next
>>> milestone will be passed when they start selling more electrics than
>>> ICEs.
>>
>> Eric, you've been drinking the Cool-Aid.
>> As I did once.
>> You're bringing your new electric machine to the Seniors, right?
>> And I do mean THIS year...
>

> ...They won't make the same mistakes that Lange made.

Except they already have.
GP delivered and then undelivered to USA a good example.

[Dgtarmichael]

I don't understand the electric bashing. It's still a new and developing technology. By comparison I've never heard of an ICE motorglider that didn't have its own set of problems. Carburetors that don't tune, no parts for certain models, some that occasionally start fire, many that don't start at all. They're so bad that we're warned to NEVER expect them to work for a relight. You have to have them out and running before the pure gliders are even getting serious about looking for the spot to land. I'm a purest by nature and budget, but I'd never count out the future of electrics in soaring. Mr. Nadler hate on Lange all you want it was Schemp-Hirth that almost killed you.

Doug
W24

[Eric Greenwell]

Please note GP wasn't on my list of booths. I do expect the manufacturers that have been
building gliders for decades to have fewer stumbles, and I don't think it is an indictment of
the technology if a startup has problems delivering on time. It is always an extra risk to
order a glider that is not in production yet (also the case when I ordered my ASH26E), and even
riskier when it's a new manufacturer (GP, Lange), but for me, the GP15 is still a more
desirable glider than what the major manufacturers are offering.

So, I will repeat: Schleicher, Schmepp-Hirth, and Jonkers will not make the same mistakes Lange
made (perhaps I should add LAK and Pipistrel to the list).

[Martin Gregorie]

Their timescale, payload and performance looks very similar to Vertical
Aerospace, https://vertical-aerospace.com/ except that VS are aiming for
a bit less range and speed, probably because they are looking at the UK
market rather than the US with its greater ride distances.

Do any of you know what sort of landing/takeoff patch these eVTOL air
taxis are planning to operate from, i.e. helipads to something more al
fresco such as carparks or schoolyards or are they planning to run door
to door operations, which may be a quite limited by availability of
landing areas in cities outside the US - unless, of course, their target
market is just airfield to airfield traffic.

I ask, because, although I've been dimly aware of efforts to build eVTOL
air taxis for a year or two, I've seen absolutely nothing about where
they expect to land when dropping off & picking up fares.


--
Martin | martin at
Gregorie | gregorie dot org

[wtwisn...@gmail.com]

An uncontained battery failure is as bad as an uncontained engine failure (car, airplane, or glider). Any potentially unstable battery like most Lithium chemistries should be in a safety container that will either contain or exhaust the fire, explosion, or heat. I would feel a lot better if the batteries were in a sealed stainless box with appropriate vents to the outside of vehicle.
Wit HZ

[Moshe Braner]

On 2/27/2021 11:25 AM, wtwisn...@gmail.com wrote:
> An uncontained battery failure is as bad as an uncontained engine failure (car, airplane, or glider). Any potentially unstable battery like most Lithium chemistries should be in a safety container that will either contain or exhaust the fire, explosion, or heat. I would feel a lot better if the batteries were in a sealed stainless box with appropriate vents to the outside of vehicle.
> Wit HZ

I feel a bit nervous about carrying a "USB power bank" in the glider,
which includes a not-tiny lithium battery of the dangerous type. As for
the yuuuge batteries needed for electrically propelled gliders, I think
I'd wait for safer battery chemistry. LiFePO4 batteries are a lot
safer, and their energy density - and price - are being improved so that
they can compete with other types of lithium batteries. They are
already used in some electric cars.

[Eric Greenwell]

You should look at the Jonkers JS3 RES electric self-launcher using LiFePo batteries. It's the
only one I know of using that kind of battery.

[emirs...@gmail.com]

Eric,

I think that is probably a typo mistake, the voltage range and capacity is typical for 3000-3500 mAh li-ion cell.

[Eric Greenwell]

emirs...@gmail.com wrote on 2/27/2021 1:19 PM:
> Eric,
>
> I think that is probably a typo mistake, the voltage range and capacity is typical for 3000-3500 mAh li-ion cell.

> It's a bit awkward to drill down to it, so here's a short cut. Go to this page:
https://jonkersailplanes.co.za/res-system/

Then scroll to the section with this:


Battery specification

Battery type EMECTRIC 96-4 400V
Battery configuration 96S4P LiFePo
Battery Voltage 270V-400V
Capacity per battery 4.7kWh
Battery Weight: 22kg (48.5 lbs)
Maximum number of batteries 2

[emirs...@gmail.com]

O



Yes, I saw the same.
But when you do the maths the values correspond to li-ion chemistry.

[Eric Greenwell]

Ah, now I see what you mean, and since I can't find any mention of LifePo on the Emectric
website, I suspect you are right, and it is in error.

[Scott Manley]

One of the Alisport Silent 2 gliders being offered on Wings & Wheels is mine. It was the perfect glider for me. I literally loved everything about it. Easy to rig, easy to fly, all the glide performance I needed, simple operation of the power system. It is for sale because I decided to stop flying real aircraft, not because I am in any way disappointed with the aircraft. It is low time because I didn't fly it as much as I thought I would.

[ProfJ]

On Wednesday, 24 February 2021 at 14:42:01 UTC-7, d...@nadler.com wrote:
> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> Discus amongst yourselves...

Some comments:

- High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.

- Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.

[Andrzej Kobus]

So how big is the electric glider market vs. electric car market? Things get done with proper research and funding. I don't see that happen for the glider market. I suggest you review David's presentation. He discussed this point.

[2G]

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.

Tom

[Eric Greenwell]

> 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.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"

lyhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1

[2G]

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.

[John Cochrane]

For the moment the big limitation seems to me to be weight. I looked hard at the AS33 electric. You get one launch to 2000' and then 9000' of climb to get home. For that, it's really hard to get off the ground at less than 10 lbs/ft2 empty, and 10.5 in 15 m mode. Gas has a wonderful energy density. I'm surprised some sort of hybrid doesn't make sense, gas to recharge a smaller battery, then eliminate the drive elements with an electric motor. But I presume they worked the numbers on this.

John Cochrane BB

[Eric Greenwell]

John Cochrane wrote on 3/3/2021 8:53 PM:
> For the moment the big limitation seems to me to be weight. I looked hard at the AS33 electric. You get one launch to 2000' and then 9000' of climb to get home. For that, it's really hard to get off the ground at less than 10 lbs/ft2 empty, and 10.5 in 15 m mode. Gas has a wonderful energy density. I'm surprised some sort of hybrid doesn't make sense, gas to recharge a smaller battery, then eliminate the drive elements with an electric motor. But I presume they worked the numbers on this.
>

A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
your potential retrieve distance is shorter, instead of an imminent landing.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"

https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Eric Greenwell]

2G wrote on 3/3/2021 6:11 PM:
> On Tuesday, March 2, 2021 at 8:27:55 PM UTC-8, Eric Greenwell wrote:
>> 2G wrote on 3/2/2021 7:25 PM:
>>> On Tuesday, March 2, 2021 at 6:28:27 PM UTC-8, Andrzej Kobus wrote:
>>>> On Tuesday, March 2, 2021 at 4:10:48 PM UTC-5, ProfJ wrote:
>>>>> On Wednesday, 24 February 2021 at 14:42:01 UTC-7, d...@nadler.com wrote:
>>>>>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
>>>>>> Discus amongst yourselves...
>>>>> Some comments:
>>>>>
>>>>> - High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.
>>>>>
>>>>> - Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.
>>>> So how big is the electric glider market vs. electric car market? Things get done with proper research and funding. I don't see that happen for the glider market. I suggest you review David's presentation. He discussed this point.
>>>
>>> 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/motorgliders/publications/download-the-guide-1

[Hank Nixon]

On Wednesday, March 3, 2021 at 11:53:15 PM UTC-5, cochra...@gmail.com wrote:
> For the moment the big limitation seems to me to be weight. I looked hard at the AS33 electric. You get one launch to 2000' and then 9000' of climb to get home. For that, it's really hard to get off the ground at less than 10 lbs/ft2 empty, and 10.5 in 15 m mode. Gas has a wonderful energy density. I'm surprised some sort of hybrid doesn't make sense, gas to recharge a smaller battery, then eliminate the drive elements with an electric motor. But I presume they worked the numbers on this.
>
> John Cochrane BB

Hybrid, at best, would provide no benefit in weight and the complexity of both solutions added together.
The problem the manufacturer's have is that they know the users expect to launch at max weight and have acceptable safety margins at launch.
This requires powerful motors having high consumption. Oh- and we want long range for retrieves.
All this adds up to big batteries.
Now insert this into an airframe designed for high wing loading and IGC specified maximum mass.
You end up with a glider not suitable for eastern US, nor most of Europe.
Waiting for new batteries that will solve this problem is a fools errand.
Maybe manufacturers should consider 2 options on batteries. 1/2 the battery in the '33 would save somewhere around 65 lb by my estimate. On a 107 sq ft glider, that is a big deal.
I'm looking now at electric 29E possibility. With the system I have in the '24E(L) I would expect a launch and around 3000 feet of additional retrieve climb from a system that would add about 40 lb to the weight of the 29E. With 25kw available at launch I see as a dry self launch only ship.
FWIW
UH

[Eric Greenwell]

Hank Nixon wrote on 3/4/2021 8:56 AM:
> On Wednesday, March 3, 2021 at 11:53:15 PM UTC-5, cochra...@gmail.com wrote:

>> For the moment the big limitation seems to me to be weight. I looked hard at the AS33 electric. You get one launch to 2000' and then 9000' of climb to get home. For that, it's really hard to get off the ground at less than 10 lbs/ft2 empty, and 10.5 in 15 m mode. Gas has a wonderful energy density.. I'm surprised some sort of hybrid doesn't make sense, gas to recharge a smaller battery, then eliminate the drive elements with an electric motor. But I presume they worked the numbers on this.

>>
>> John Cochrane BB
> Hybrid, at best, would provide no benefit in weight and the complexity of both solutions added together.
> The problem the manufacturer's have is that they know the users expect to launch at max weight and have acceptable safety margins at launch.
> This requires powerful motors having high consumption. Oh- and we want long range for retrieves.
> All this adds up to big batteries.
> Now insert this into an airframe designed for high wing loading and IGC specified maximum mass.
> You end up with a glider not suitable for eastern US, nor most of Europe.
> Waiting for new batteries that will solve this problem is a fools errand.
> Maybe manufacturers should consider 2 options on batteries. 1/2 the battery in the '33 would save somewhere around 65 lb by my estimate. On a 107 sq ft glider, that is a big deal.
> I'm looking now at electric 29E possibility. With the system I have in the '24E(L) I would expect a launch and around 3000 feet of additional retrieve climb from a system that would add about 40 lb to the weight of the 29E. With 25kw available at launch I see as a dry self launch only ship.
> FWIW
> UH
>

The JS3 RES batteries are set up like an FES glider, even though it's a mast mounted motor
system: two batteries can be carried in the motor bay, but only one is required for operation.
They are about 50 lbs each. Being able to remove and charge them elsewhere should be a great
convenience.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"

https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Mark Mocho]

Energy density is the "elephant in the room" that determines a lot about electric vs. internal combustion. The Tesla S uses a 100 kWh battery that weighs 1,375 lbs. 100 kWh is approximately the same energy contained in 2.1 gallons of AvGas. So, you have a 2 gallon capacity (about 13 lbs.) in a 1,375 lb. container. Makes perfect sense to me. NOT!

And we aren't even bringing up the environmental impact of producing the battery and then disposing of it when its life is used up.

[Nicholas Kennedy]

A Electrical engineer once said to me:
If you got a battery you got battery problems.
I own 3 vehicles and 3 motorcycle's, it seems like I'm always buying batteries.
When the tug rolls up to me and the line boy runs up with the rope I smile and say to my self
" this is cheap"
I generally release right into a big fat thermal.
Fly safe in 2021
Nick
T

[john firth]

On Thursday, March 4, 2021 at 2:55:20 PM UTC-5, Mark Mocho wrote:
> Energy density is the "elephant in the room" that determines a lot about electric vs. internal combustion. The Tesla S uses a 100 kWh battery that weighs 1,375 lbs. 100 kWh is approximately the same energy contained in 2.1 gallons of AvGas. So, you have a 2 gallon capacity (about 13 lbs.) in a 1,375 lb. container. Makes perfect sense to me. NOT!
>
> And we aren't even bringing up the environmental impact of producing the battery and then disposing of it when its life is used up.

Has anyone in the SLS group been considering some FLYING?
the wave systems in the East have been awesome in the last few days (Mar02-04)
Not too cold at 10K (-10C) ; an eyeball dream suggested that Lk Placid to Bangor Me
and return (650KM) or much further south would have been possible.
Besides Lk Pl., there must be numerous airports with plowed runways and aprons.

enviously

John Firth (Ottawa)

PS cannot find how to start a new subject!

[Martin Gregorie]

Here are some free-wheeling thoughts inspired by what I've read about the
Aptera hybrid road vehicles: the prototype used an all-electric drive
chain connected to a battery with a 40 mile range when fully charged. It
also carried a small ICE generator pack - on ling trips the rig was said
to average 120 mpg.

So, how would a similar set-up work for us?

Say, use a pylon-mounted electric motor coupled to a battery capable of
take-off olus a 2000 ft climb (i.e. a somewhat higher than normal winch
launch) and carry a small ICE generator pack to be run during and after
launch to recharge the battery.

A modern 20cc 2-stroke can knock out 2.5 hp at 9000rpm (around 1.8 kWh,
so with a 40% efficient generator you can recharge the battery at a 0.7
kWh rate from a unit with a guestimated weight of 1.5 Kg (750 g motor
plus the same weight for the generator) plus fuel at around 9,7 kWh/litre
(thats 12 kWh/kg) so something like 1.2 kWh/liter of fuel can be put back
into the battery after launch (assuming motor efficiency 25% and
generator efficiency 40%). Now, scale the system up a bit and use a 200cc
generator set and you've got an equipment weight of 15 kg plus fuel and a
recharge rate of around 12 kWh. Time to recharge a 20 Kwh launch battery
is around 1.7 hours, so a fair time to be listening to the (muffled)
engine behind you, but a much lighter system than a pure electric system
(launch battery + 15kg generator set) would be.

What did I miss?

[Eric Greenwell]

Mark Mocho wrote on 3/4/2021 11:55 AM:
> Energy density is the "elephant in the room" that determines a lot about electric vs. internal combustion. The Tesla S uses a 100 kWh battery that weighs 1,375 lbs. 100 kWh is approximately the same energy contained in 2.1 gallons of AvGas. So, you have a 2 gallon capacity (about 13 lbs.) in a 1,375 lb. container. Makes perfect sense to me. NOT!
>
> And we aren't even bringing up the environmental impact of producing the battery and then disposing of it when its life is used up.
>

There seems to be an anomaly with your numbers: The 100 kWh battery delivers about 400 miles of
range. How is it possible to go that far on the equivalent of 2.1 gallons of Av Gas?

And yet, wouldn't you love to have access to a Tesla S? I know I would! I was an engineer
during my working years, and even I don't buy energy density when I choose a car (or glider),
and neither do pilots looking for a self-launching glider. And obviously, they are finding what
they like, despite the energy density disparity.

[Dan Marotta]

9,000 RPM makes quite a racket, no matter the muffler. Have a good
noise canceling headset...

Dan
5J

[Kenn Sebesta]

> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> your potential retrieve distance is shorter, instead of an imminent landing.

I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.

I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.

Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

[Martin Gregorie]

On Thu, 04 Mar 2021 14:27:53 -0700, Dan Marotta wrote:

> 9,000 RPM makes quite a racket, no matter the muffler. Have a good
> noise canceling headset...
>

Yeah, I know - the engine I took weight and power numbers was a 20cc RC
aircraft engine, while I was iriginally thinking of thre 20cc petrol
engines you used to see on small chainsaws and big drills.

But, add a bit of weight and bulk for water cooling and put it in a sound-
absorbing box with the motor/generator combo sat on rubber mounts and I
think you cound reduce the sound level quite a lot.

But, the main poing of my piece was to show just how light and relatively
fuel efficient such a small generator set would be compared with an
battery of equivalent capacity.

A litre of gas or diesel fuel weighs 800g and has an energy capacity of
9.7 kWh.

Totally OTT: As an ex-free flight model flyer, I think the finest engine
sound I've ever heard was a 1cc Cyclon-06 glow motor with an open exhaust
spinning a 7" x 4" prop at 30,500 rpm on 25% nitro fuel mix.

[Moshe Braner]

I'd prefer a quiet engine, like the ones on small Honda generators.
Presumably 4-stroke, so a bit heavier, but very efficient (for a small ICE).

I'll leave it to the IGC folks to tear their hair out on how to deal
with the engine noise no longer being an indicator of (simultaneous)
propulsion.

Perhaps for a "sustainer" model you could run the engine only when you
decide you need propulsion, and have an engine large enough to supply as
much power to the batteries as the electric motor is using, or a bit more.

[Mark Mocho]

"There seems to be an anomaly with your numbers: The 100 kWh battery delivers about 400 miles of
range. How is it possible to go that far on the equivalent of 2.1 gallons of Av Gas?"

Eric- the main reason that the numbers seem skewed is the relative efficiency difference between modern brushless electric motors (often over 90%) and typical Internal combustion engines, which barely reach 30% efficiency.

For a reasonable overview of the gas vs. electric debate, I highly recommend an article in the January 2021 issue of "AOPA PIlot" magazine entitled "hp versus kW" by Peter Rez, "an Arizona State University physics professor from Scottsdale who flies a Mooney."

[Matthew Scutter]

I think what he was trying to get at, is that comparing on the basis of energy density isn't very meaningful. We should be comparing distance-retrievable/kg and height-climbable/kg across different ICE and electric solutions.

[Eric Greenwell]

Hi Kenn,

I'd like to be on that list.

Eric

Kenn Sebesta wrote on 3/4/2021 1:55 PM:
> There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me).

[Hank Nixon]

What is contact info for the list mentioned?
Thx
UH

[Kenn Sebesta]

On Friday, March 5, 2021 at 8:00:05 AM UTC-5, Hank Nixon wrote:
> On Thursday, March 4, 2021 at 4:55:30 PM UTC-5, Kenn Sebesta wrote:

> > ... There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me)...

> What is contact info for the list mentioned?
> Thx
> UH

While Google Groups no longer displays email addresses, they can be pulled from RSS readers. I sent you an invite.

(Sometime in the near future I'll set up a better way to join the group.)

[2G]

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.

[BobW]

> 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.

Yogi Berra - many laughed at him - was right. (Look up his body of work
involving malapropic wisdoms...you'll know when you've found the appropriate
one for this particular bit of thread drift!) Perhaps tellingly, he never
became a billionaire.

Who knows - he mighta been a decent soaring pilot!

[Hank Nixon]

You can't buy experience, but you do pay for it!
UH

[Eric Greenwell]

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:

...

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.

[emirs...@gmail.com]

Kenn,

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

Regards

[Mark Mocho]

"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)

[Bob Kuykendall]

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.

[kinsell]

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.

[jfitch]

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.

[Eric Greenwell]

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!

[Herbert Kilian]

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

[Eric Greenwell]

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.

[Kenn Sebesta]

> 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.

[Eric Greenwell]

Kenn Sebesta wrote on 3/6/2021 10:31 AM:
> 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.

I know people want much more than a launch! Note that sustainers are sold by all the major
manufacturers; actually, pretty much all the manufacturers. A company (LZ Design/FES) arose to
service that market electrically. A corollary to your density remarks is doubling the battery
capacity of that "launch only" glider won't add significant weight or cost, and would enable a
couple of saves or a self retrieve. A launch-only glider with easily swapped batteries might
make sense as a busy club glider where pilots are flying for an hour near the airport, but no
one else will buy one.

[Kenn Sebesta]

On Saturday, March 6, 2021 at 2:03:25 PM UTC-5, Eric Greenwell wrote:
> Kenn Sebesta wrote on 3/6/2021 10:31 AM:
> > 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.
> I know people want much more than a launch! Note that sustainers are sold by all the major
> manufacturers; actually, pretty much all the manufacturers.

You might be right! I think we're looking at this same coin from two different sides. I'm at the stage of my gliding career where just getting up and staying up is the goal, whereas you are quite a lot more accomplished and value the ability to get home after a long flight. It's tough for me to guess which direction the larger market needs, we'll see what it ultimately decides. As you point out, it's very easy to adjust the amount of available battery energy.

> A corollary to your density remarks is doubling the battery capacity of that "launch only" glider won't add significant weight or cost, and would enable a couple of saves or a self retrieve.

For sure! Although keep in mind that the battery is the single highest $ component of the propulsion system. Moreover, batteries have a fixed lifespan with or without use, so some people might prefer a lower TCO and a lighter plane. I think the beauty of electric is the ability to tailor this to specific needs. We can even imagine the same plane with a lightweight pattern launch battery, and a heftier XC battery.

The genius of all this is that as battery tech improves the existing plane just gets better and better. When you're looking at your replacement pack 5-10 years down the road you'll automatically benefit from all the improvements and your new pack will either be cheaper, or it'll fly longer, or it'll be lighter. Maybe all three. Certainly never saw 100LL get cheaper, better, and lighter!

[Martin Gregorie]

On Fri, 05 Mar 2021 20:56:50 -0800, jfitch wrote:

> 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.
>

Has anybody else on here read David Brin's 'Existence'?

It suggests one way to make mass electric-powered air transport work: Put
the pax and cargo in nice accommodation on a large airship and tow it
cross country behind an electric locomotive running on repurposed AmTrak
tracks.

What he describes is an interesting case of "look ma! No batteries!".

[Martin Gregorie]

On Sat, 06 Mar 2021 12:13:38 -0800, Kenn Sebesta wrote:

> For sure! Although keep in mind that the battery is the single highest $
> component of the propulsion system. Moreover, batteries have a fixed
> lifespan with or without use, so some people might prefer a lower TCO
> and a lighter plane. I think the beauty of electric is the ability to
> tailor this to specific needs. We can even imagine the same plane with a
> lightweight pattern launch battery, and a heftier XC battery.
>

Speaking as a pilot whose launch method of choice is the winch, I think
the way to go could well be an electric sustainer launched with an
electric winch: potentially 100% green and no need for big, heavy
batteries.

However, launching an electric sustainer with a Polish gravity launch
would be super-cool.

> The genius of all this is that as battery tech improves the existing
> plane just gets better and better.
>

All the practical battery chemistries have been tried by now and their
specific energy capacities are well-known, so I suspect that future
improvement will be along the lines of incremental weight reduction,
better durability and, possibly, price reduction as recycling techniques
are improved. OTOH if battery recycling doesn't become very close to zero
loss for the active material in a battery, prices will rise as mines get
worked out, and IIRC the reserves of these sources are fairly well-
known.

Questions we need to know the answers for very soon are:

- How widespread is battery material recycling at present?

- Can you yet buy a battery containing recycled Lithium?

- If not, why not?

[Mark Mocho]

It suggests one way to make mass electric-powered air transport work: Put
the pax and cargo in nice accommodation on a large airship and tow it
cross country behind an electric locomotive running on repurposed AmTrak
tracks.

And just what happens when the train goes under a bridge?

Another unicorn inspired idea. Keep 'em coming. I need the laughs.

[Martin Gregorie]

The author is a bit more than a unicorn, methinks. He's well-regarded in
technical circles.

Anyhow, if such a system was set up it could obviously only work on lines
that have no tunnels and that don't run in deep valleys (so not on the
Glendale-Denver line obviously), and that have been 'adjusted' so that
the line is always at the top of the crossing stack.

It would also be faster than the old Goon Show concept of horse-drawn
zeppelins.

[Mark Mocho]

> It would also be faster than the old Goon Show concept of horse-drawn
> zeppelins.

Yes, it would effectively take the speed and omnidirectional attribute of air travel and relegate it to the pathways and speed range of a railroad. And only if you can find a rail line that has no tunnels, bridges or power transmission lines crossing it. And you now eliminate travel to destinations that have no existing rail lines.

It's like taking a wireless voice communication system and turning it into a teletype. Oh, wait- That's the iPhone.

Being well-regarded in technical circles does not necessarily mean you won't come up with a bad idea once in a while.

Next up: How to make an ASG-29 perform like a paraglider.

[Martin Gregorie]

On Sun, 07 Mar 2021 06:38:22 -0800, Mark Mocho wrote:

> Being well-regarded in technical circles does not necessarily mean you
> won't come up with a bad idea once in a while.
>

Indeed, IME his SF varies in quality and ingenuity: some (Earth, Sundiver
plus the next two followups, Kil'n People, The Practise Effect) were
excellent, the others including Existence, not so much.

> Next up: How to make an ASG-29 perform like a paraglider.
>

Good luck with that: I'd settle for a new build carbon Libelle.

[Eric Greenwell]

Mark Mocho wrote on 3/7/2021 6:38 AM:
>
> Next up: How to make an ASG-29 perform like a paraglider.
>

I have dreams like that. It makes the off-field landings so much easier, way better than the
already very good high-deflection landing flaps. I envy birds for their STOL skills, and wish
our gliders could emulate them. The closest we've come might be the 90 degree flaps like Dick
Schreder used, or the BRS parachutes.

[Moshe Braner]

Or you can use the newfangled idea of making that airship very narrow
and fly it very low to the ground so it can go under the bridges and
through tunnels. Oh wait...

While the rest of the world has double-tracked and electrified their
long-range railroads (e.g., the trans-Siberia), here in the US we sit on
our heels while a few loonies play with "pods" and other nonsense.

But I'm getting further off topic. Gliders are nice. They don't need
no steenkin' engines.

[Eric Greenwell]

Moshe Braner wrote on 3/7/2021 2:07 PM:
> But I'm getting further off topic.  Gliders are nice.  They don't need no steenkin' engines.

Alright! Back to Basics: bungey launch! Or is it still OK to use electric motors? No steenk there.

[John Galloway]

I have yet to see a glider take off (bungee launches excepted) or return from a field without an engine.

[Mark Mocho]

> I have yet to see a glider take off (bungee launches excepted) or return from a field without an engine.

Does the one in the tow vehicle count?

[Tom BravoMike]

> > I have yet to see a glider take off (bungee launches excepted) or return from a field without an engine.

See and believe:
https://youtu.be/_JNg9zwvDkI?list=PLC40EB4949AD5395B

Been there, done that. With a favorable wind one circle was enough to get high over the heads of the observers at the gravity launch site, and hours long ridge/wave soaring was possible.

BTW, Bezmiechowa is the place where Wanda Modlibowska set a new women's duration record of 24 hours 14 minutes in May 1937. When I was there for the first time, other pilots from our group did night ridge soaring in a 'Bocian' glider (by design equipped with position lights). The ridge line was marked with a series of campfires.

In 1993-95 night flights were still part of the training for licensed glider pilots in some places in Poland. Happy to have that exotic (and extinct?) endorsement in my logbook.

Just keen memories in a thread about dreams about self-launching gliders (in expectation of a new soaring season).

[Moshe Braner]

On 3/7/2021 6:08 PM, Eric Greenwell wrote:
> Moshe Braner wrote on 3/7/2021 2:07 PM:
>> But I'm getting further off topic.  Gliders are nice.  They don't need
>> no steenkin' engines.
>
> Alright! Back to Basics: bungey launch! Or is it still OK to use
> electric motors? No steenk there.

Lighten up, Eric and others. I was just saying that in gliders we don't
need to be dragged cross-country by a locomotive. I have nothing
against launching by some motorized thing or another.

And back to the topic, we have some people who believe all the hype from
Saint Elon about new batteries etc, and others who are more skeptical.
But we all revel in what has been achieved in electric glider launching
and sustaining, and hope for more. It's a lot more feasible than
electric air transport.

Personally I think that dragging an expensive battery pack along in
every glider is inefficient use of resources. But then you may say the
same about dragging equally, if not more, expensive composite structures
around the sky. We do what we have to do to achieve our aerial dance
performances. Then we land, and like any performance art, it's all gone
poof, into the past. We only do it because we love it.

[2G]

On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > your potential retrieve distance is shorter, instead of an imminent landing.
> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.
>
> I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
>
> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

Why don't you start by naming JUST ONE that replaced an ICE with an electric.

Tom

[Eric Greenwell]

Bungee AND gravity launch! Yahoo!

[Eric Greenwell]

2G wrote on 3/7/2021 8:30 PM:
> On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
>>> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
>>> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
>>> your potential retrieve distance is shorter, instead of an imminent landing.

>> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..

>>
>> I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
>>
>> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
>
> Why don't you start by naming JUST ONE that replaced an ICE with an electric.
>
> Tom
>

Hank Nixon.

[2G]

And what was the glider?

[Charlie M. (UH & 002 owner/pilot)]

ASW-24e

[Eric Greenwell]

2G wrote on 3/7/2021 9:06 PM:
> On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
>> 2G wrote on 3/7/2021 8:30 PM:
>>> On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
>>>>> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
>>>>> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
>>>>> your potential retrieve distance is shorter, instead of an imminent landing.
>>>> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
>>>>

>>>> I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
>>>>
>>>> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

>>>
>>> Why don't you start by naming JUST ONE that replaced an ICE with an electric.
>>>
>>> Tom
>>>
>> Hank Nixon.
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> And what was the glider?
>

Hank has posted about the glider a number of times on RAS. Search for "Nixon", or look in the
thread "What is involved regulation wise adding an electric motor to a glider?" Here is are
some details from Hank:

Some data from first hand experience:
ASW-24E converted to electric from 2 cycle Rotax gas.
Power system including all items is right at 100 lb added to pure sailplane airframe weight.
This is a pylon mounted retractable system.
Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
Your cost estimate is a bit less than1/2 what it would require for parts, not including items
required to do the airframe conversion and assuming the person doing this can fabricate
required items, engineer and wire the system, design and construct the prop, etc.
This assumes perfect efficiency and nothing destroyed or scrapped going through the learning
process. Of those I am aware of that have done ,or are doing this, nobody has had that good
fortune.
FWIW
UH

[Eric Greenwell]

Moshe Braner wrote on 3/7/2021 6:04 PM:
> Personally I think that dragging an expensive battery pack along in every glider is inefficient
> use of resources.  But then you may say the same about dragging equally, if not more, expensive
> composite structures around the sky.  We do what we have to do to achieve our aerial dance
> performances.  Then we land, and like any performance art, it's all gone poof, into the past.
> We only do it because we love it.

I think having towplanes sit idle on the ground Monday through Friday is an inefficient use of
resources; ditto for tow planes sitting idle in poor weather, while I'm 100 miles away, looking
at growing cumulus.

But, I agree with the basic point that sharing the launch system is a more efficient use of
resources, and a way to do that with a self-launcher is a partnership, especially with partners
that have different or flexible schedules. Electric self-launchers seem particularly
well-suited to partnerships, with their easier use of the motor.

[Moshe Braner]

On 3/8/2021 8:41 AM, Eric Greenwell wrote:
> Moshe Braner wrote on 3/7/2021 6:04 PM:
>> Personally I think that dragging an expensive battery pack along in
>> every glider is inefficient use of resources.  But then you may say
>> the same about dragging equally, if not more, expensive composite
>> structures around the sky.  We do what we have to do to achieve our
>> aerial dance performances.  Then we land, and like any performance
>> art, it's all gone poof, into the past. We only do it because we love it.
>
> I think having towplanes sit idle on the ground Monday through Friday is
> an inefficient use of resources; ditto for tow planes sitting idle in
> poor weather, while I'm 100 miles away, looking at growing cumulus.
>
> But, I agree with the basic point that sharing the launch system is a
> more efficient use of resources, and a way to do that with a
> self-launcher is a partnership, especially with partners that have
> different or flexible schedules. Electric self-launchers seem
> particularly well-suited to partnerships, with their easier use of the
> motor.

If battery packs were standardized and removable (better for charging
anyway), then could also share them between gliders. Of course on the
day when the weather is really good everybody will be competing for the
use of the shared battery. Plug several shared standard batteries into
the electric winch on that day? ("Blue Sky" thinking here...)

[2G]

This glider was converted from a sustainer to a self-launcher, apparently to provide a capability it did not have before and not because the engine did not perform as intended.

Tom

[2G]

Also, Hank concluded with this piece of advice:

"To my knowledge this has been done once so far in the US .
If you want an electric sailplane- buy one."

Sounds prudent to me.

Tom

[Eric Greenwell]

Some people like the challenge, much as glider pilots do in their flying (or they'd get an
airplane): Ken Sebesta, a participant here, has removed the self-launching gas motor from his
AC-5 Russia and is replacing it with an electric motor. I believe he's bench-tested the motor,
ESC, and batteries, and is now working out the motor mounting details.

[Dan Marotta]

I just gotta ask, "Why"?

What is the cost of the conversion? Is the engine failed and not
repairable? Are there a lot of brownie points for "saving the planet"?

If I wanted to, my gas powered Stemme could reach just about anywhere in
the western states on a single tank of gas. The electric offerings from
Stemme have great range at the expense of carrying a gas-powered
generator along to make the electric power to run the motor. Where's
the advantage?

Dan
5J

[John Johnson]

Enjoying this thread. I'm a newbie - flying XC for about a year now. I definitely would like self-launch capability and just some 'modest' sustaining capacity left over. My land outs and close calls to-date could have all been mitigated by 10min (or less) of sustaining assist. If I fly so deep into marginal conditions that I need an hour of power to get home, I must have really made some bad decisions. Soaring conditions here in southern AZ are pretty great but land out options can be challenging. I see sustaining needs as more about dealing with localized exceptions and improving your land out choices. If I needed >1 launch or >10-15min flight time, I don't think the conditions were aligned for the XC flight I was looking for anyway.

Example: I was recently surprised by continuous 7-9kt sink over a 15mi final glide. I started out with a 3200' agl arrival altitude cushion and watched it drop to <200ft as I soldiered home and left my last favorable LO options behind. I was stuck looking at an emergency bailout on a mine tailing that has generated a number of scary tales in my club. I was lucky to find some lift off a local feature just 2mi out and got enough altitude to make the field in good shape. 2-3min of powered sustaining flight would have made that a non-event.

One launch and some modest assist capacity would be awesome and fit my primary goals:
- independent launch capability
- backup for the times I need a short boost to avoid a land out or help get me to a safer land out option
- I'm ok with landing out on occasion if its safe and retrievable
- Really prefer electric over ICE

Seems like the current mast-mounted electric technology is just about there for my goals. It's now more about solution maturity, track record, and $$ as I watch how things shake out. I do, however, want hear about alternate use models and scenarios that could affect my decisions.

JJ

[Eric Greenwell]

Dan Marotta wrote on 3/9/2021 7:42 AM:
> I just gotta ask, "Why"?
>
> What is the cost of the conversion?  Is the engine failed and not repairable? Are there a lot
> of brownie points for "saving the planet"?
>
> If I wanted to, my gas powered Stemme could reach just about anywhere in the western states on
> a single tank of gas.  The electric offerings from Stemme have great range at the expense of
> carrying a gas-powered generator along to make the electric power to run the motor.  Where's
> the advantage?
>
> Dan

Don't take it personally :^) Kenn is converting an AC-5 Russia, a WAY DIFFERENT glider than the
Stemme! It has a rattlely, unreliable motor of modest power, but I'll let Kenn fill in the details
of his decision.

>
> On 3/8/21 8:51 PM, Eric Greenwell wrote:
>> 2G wrote on 3/8/2021 5:19 PM:
>>> On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
>>>> On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
>>>>> 2G wrote on 3/7/2021 9:06 PM:
>>>>>> On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:

...

>>>
>>> Also, Hank concluded with this piece of advice:
>>>
>>> "To my knowledge this has been done once so far in the US .
>>> If you want an electric sailplane- buy one."
>>>
>>> Sounds prudent to me.
>>
>> Some people like the challenge, much as glider pilots do in their flying (or they'd get an
>> airplane): Ken Sebesta, a participant here, has removed the self-launching gas motor from his
>> AC-5 Russia and is replacing it with an electric motor. I believe he's bench-tested the
>> motor, ESC, and batteries, and is now working out the motor mounting details.
>>
>>