On Thursday, August 19, 2021 at 4:58:44 PM UTC-7, Eric Greenwell wrote:
> On 8/19/2021 2:32 PM, 2G wrote:
> > On Thursday, August 19, 2021 at 6:49:25 AM UTC-7, Eric Greenwell wrote:
> >> On 8/18/2021 9:47 PM, 2G wrote:
> >>> On Tuesday, August 17, 2021 at 7:27:10 AM UTC-7, Eric Greenwell wrote:
> >>>> On 8/16/2021 7:09 PM, kinsell wrote:
> >>>>> The ASG32EL was designed as a university project, I.E. one step above a science fair
> >>>>> project. When things go bad, where will all the people be who worked on this? Yes the
> >>>>> cells are in the fuselage instead of the wing, but there's not much you can do to mitigate
> >>>>> a thermal runaway event in the wing.
> >>>> "Science Fair project" brings to mind a few dozen high school students with poster board
> >>>> reports on tables in the gym. Do you really think Schleicher would base the safety of
> >>>> their customers and future on something that trivial? The truth is much more than that:
> >>>> The University of Kassel is a large (25,000 students) institution with research in
> >>>> multiple scientific and engineering fields. The consortium included the University
> >>>> Baden-Württemberg at Mosbach (34,000 students) and companies with expertise in battery
> >>>> technology.
> >>>>
> >>>> And yes, you can mitigate a thermal runaway event. The article in soaring magazine you
> >>>> referenced showed how a failing cell does not trigger thermal runaway in the other cells.
> >>>> Again: do you really think Schleicher would risk their customers and the reputation of
> >>>> their company on a system that depends on every cell being perfect, and where a failing
> >>>> cell would bring disaster?
> >>>> --
> >>>> Eric Greenwell - USA
> >>>> - "A Guide to Self-launching Sailplane Operation"
> >>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >>>
> >>> The article in Soaring DOES NOT show "a failing cell does not trigger thermal runaway in the other cells" - it shows that they could not REPLICATE the event. Obviously, thermal runaway CAN occur because it HAS occurred in multiple electric glider events already mentioned here as well as in cars. You must be completely blind to the evidence.
> >>>
> >>> Tom
> >>>
> >> The article in Soaring tested 18650 cells, as used in Schleicher and JS electric
> >> self-launchers. There have been no thermal runaway events in 18650 cells used in gliders,
> >> and my remarks for this entire thread have applied to 18650 cells, as I have stated
> >> repeatedly. I am not a fan of pouch cells, which have caused problems in gliders, and do
> >> not know much about them.
> >> --
> >> Eric Greenwell - USA
> >> - "A Guide to Self-launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > Of course there have been no thermal runaway of 18650 cells in gliders because there ARE NO gliders currently flying with 18650 cells. Here are 18650 cells in thermal runaway:
> > https://www.youtube.com/watch?v=24fYrV2vCPk
> > This event took only 2.5s:
> > https://www.youtube.com/watch?v=yhwPf7DTZ9o
> > and this describes the experiment:
> > https://onlinelibrary.wiley.com/doi/full/10.1002/advs.201700369
> > Important to realize that 18650 is just a case size - it says nothing about the chemistry or the construction of the cell, so deeming 18650 cells as universally safe is complete folly. The ESS fires all used cylindrical cells. The PNNL study on dendritical formation pertained to the chemistry, not the packaging. There is FAR MORE that we don't know than we do know about lithium battery safety.
> >
> > Tom
> > 18650 cells have been used in the ASG32EL for 5 years, so there is some commercial glider experience with them. The cells used are NMC chemistry, same as the JS3 will use.
>
> The first video uses LiCoO2 cells, which are a poor choice for gliders. NMC is the usual
> choice, because it is much less likely to propagate thermal runway to a neighbor cell, as
> illustrated in tests by NASA and others.
>
> The second video shows tests of individual cell, not in a typical pack. The goal was to
> get a better understanding of the failure mechanisms by purposely placing a heat triggered
> short circuiting device in the cell. It was not a using quantities of specific commercial
> cells, repeatedly tested, that could guide selection by an engineer designing a battery pack.
>
> For whatever it's worth, four of the NMC cells vented but otherwise contained the thermal
> runway in the cell, the fifth one tested burst. The other chemistries did not fare as
> well. No one has suggested 18650 NMC type cells will not suffer runaway or remain intact.
>
> And again I ask: do you really think AS and JS would risk their customers' lives and their
> companies reputation without thoroughly considering all the facts about these batteries?
> AS, JS, and their partners have far more experience and knowledge in this area than either
> of us, so I don't think we can assess the risks nearly as well as they can.
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

I will turn the question onto you: do you really think that LZ Designs would risk their customer's lives and his company's reputation without thoroughly considering all the facts about these batteries?

We know the answer: he did.

This is a stupid question because it is totally faith based, and I don't deal in faith - only facts. I have enumerated the facts, but you won't listen..

Tom

On 8/19/2021 8:33 PM, 2G wrote:

>>
>> And again I ask: do you really think AS and JS would risk their customers' lives and their
>> companies reputation without thoroughly considering all the facts about these batteries?
>> AS, JS, and their partners have far more experience and knowledge in this area than either
>> of us, so I don't think we can assess the risks nearly as well as they can.
>> --
>> Eric Greenwell - USA
>> - "A Guide to Self-launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> I will turn the question onto you: do you really think that LZ Designs would risk their customer's lives and his company's reputation without thoroughly considering all the facts about these batteries?
>
> We know the answer: he did.
>
> This is a stupid question because it is totally faith based, and I don't deal in faith - only facts. I have enumerated the facts, but you won't listen.
>
> Tom
>
My question was *specifically* about AS and JS - nobody else. You obviously have some
faith in Schleicher's abilities, as you have owned three Schleicher gliders, and did not
proof test the wings with tons of sandbags on your 31Mi glider when you received it, brand
new, from Schleicher. Seems like a faith-based decision, with no verification of the
wing's strength, etc, by you.

My question was never about the outcome of Schleicher's process, but only about the scope
and quality of it. So, for the last event in our "Wander in the Weeds" tour, how about
answering the question (remember: it's about the quality of the process they went through
to arrive at their solution, and not the solution itself; also, only about AS and JS):

Do you really think AS and JS, with their university and commercial partners, would risk
their customers' lives and their companies reputation without thoroughly considering all
the facts about these batteries?

(other pilots are welcome to answer the question, too)

--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

On Friday, August 20, 2021 at 8:09:50 AM UTC-7, Eric Greenwell wrote:
> On 8/19/2021 8:33 PM, 2G wrote:
>
> >>
> >> And again I ask: do you really think AS and JS would risk their customers' lives and their
> >> companies reputation without thoroughly considering all the facts about these batteries?
> >> AS, JS, and their partners have far more experience and knowledge in this area than either
> >> of us, so I don't think we can assess the risks nearly as well as they can.
> >> --
> >> Eric Greenwell - USA
> >> - "A Guide to Self-launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > I will turn the question onto you: do you really think that LZ Designs would risk their customer's lives and his company's reputation without thoroughly considering all the facts about these batteries?
> >
> > We know the answer: he did.
> >
> > This is a stupid question because it is totally faith based, and I don't deal in faith - only facts. I have enumerated the facts, but you won't listen.
> >
> > Tom
> >
> My question was *specifically* about AS and JS - nobody else. You obviously have some
> faith in Schleicher's abilities, as you have owned three Schleicher gliders, and did not
> proof test the wings with tons of sandbags on your 31Mi glider when you received it, brand
> new, from Schleicher. Seems like a faith-based decision, with no verification of the
> wing's strength, etc, by you.
>
> My question was never about the outcome of Schleicher's process, but only about the scope
> and quality of it. So, for the last event in our "Wander in the Weeds" tour, how about
> answering the question (remember: it's about the quality of the process they went through
> to arrive at their solution, and not the solution itself; also, only about AS and JS):
>
> Do you really think AS and JS, with their university and commercial partners, would risk
> their customers' lives and their companies reputation without thoroughly considering all
> the facts about these batteries?
> (other pilots are welcome to answer the question, too)
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

What I have faith in are scientific studies, expert failure analysis and accident reports. I can't comment on designs of which I have exactly ZERO details - and neither can you (at least an informed comment). Your unending faith in Schleicher and (GULP!) Jonkers is touching, but that is not what you ordered, which is a glider currently being totally redesigned by a company that hasn't lived up to a single promise (I wonder why?).

Dendritic growth has been traced to a solvent used in ALL of the lithium chemistries (ethylene carbonate), and has appeared in both pouch and cylindrical cells. Are you aware that the electrolytes used in lithium batteries is flammable? Apparently not. Are you aware that temperatures in cells undergoing thermal runaway can reach 1,400C? Apparently not. Are you aware that the smoke and fumes emitted by cells undergoing thermal runaway is toxic? Apparently not. Are you aware that the accident statistics of electric gliders are MANY ORDERS OF MAGNITUDE higher that electric cars? Apparently not.

Tom

"Are you aware that the accident statistics of electric gliders are MANY ORDERS OF MAGNITUDE higher that electric cars? Apparently not."

Does the amount of safety data on electric gliders provide statistically significant info, and is that data valid for gliders we might consider in future?

I expect we would all like a well informed comparison of the many safety aspects of the different ancillary power options for gliders, including fire safety, crash safety, mechanical reliability, ease of use, time from activation to provide climb power, drag if activation fails, rate of failure to deliver climb power and rate of climb achievable. probably among others. At the moment I don't even have any idea how the fire safety of electric compares to ICE. My guess is that a front electric motor is currently the safest form of ancillary power for a glider. What do others guess?

If I was considering investing in a new glider, I would worry that progress in ancillary power units over the next few years might cause powered gliders currently available to depreciate much more than we have been used to.

On 8/21/2021 9:50 AM, waremark wrote:
> If I was considering investing in a new glider, I would worry that progress in ancillary power units over the next few years might cause powered gliders currently available to depreciate much more than we have been used to.

Interesting point. I'm sure the newly available retractable motor electric gliders, with
their higher power, will take sales away from the gasoline self-launchers sales, and
probably from some of the FES sales, too. I suspect the FES gliders increased the total
number of gliders sold (of all kinds), due to sales to pilots already owning a towed
glider, but who would never buy a gasoline glider because of perceived complications in
operation and maintenance.

--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

On Saturday, August 21, 2021 at 9:50:31 AM UTC-7, waremark wrote:
> "Are you aware that the accident statistics of electric gliders are MANY ORDERS OF MAGNITUDE higher that electric cars? Apparently not."
> Does the amount of safety data on electric gliders provide statistically significant info, and is that data valid for gliders we might consider in future?
>
> I expect we would all like a well informed comparison of the many safety aspects of the different ancillary power options for gliders, including fire safety, crash safety, mechanical reliability, ease of use, time from activation to provide climb power, drag if activation fails, rate of failure to deliver climb power and rate of climb achievable. probably among others. At the moment I don't even have any idea how the fire safety of electric compares to ICE. My guess is that a front electric motor is currently the safest form of ancillary power for a glider. What do others guess?
>
> If I was considering investing in a new glider, I would worry that progress in ancillary power units over the next few years might cause powered gliders currently available to depreciate much more than we have been used to.
Since flying a glider is already about two orders of magnitude more dangerous than driving a car, and in either case you are about two orders magnitude more likely to die in a crash unrelated to an electrical fire, I'd say the contribution of electric power to safety or the lack thereof is in the round off error for both cars and gliders.

The resale value raises some interesting questions. In automobiles the battery packs have around a 10 year stated life, and you can already see the trend in used electrics, declining value as they approach 10 years but recovering if the battery pack has been recently replaced. This is far less true of ICEs in cars and negligible in ICE gliders as far as I can tell. Kinda like refinishes. You can spend $35K on a refinish and recover $15 in resale because of it.

On Saturday, August 21, 2021 at 9:50:31 AM UTC-7, waremark wrote:
> "Are you aware that the accident statistics of electric gliders are MANY ORDERS OF MAGNITUDE higher that electric cars? Apparently not."
> Does the amount of safety data on electric gliders provide statistically significant info, and is that data valid for gliders we might consider in future?

Yes, it does. According to LZ Designs there are 270 FES gliders flying right now. The number of know fires is, at least, 3, and probably double that number. This puts the odds of having a "fire" (really a thermal runaway) at 1 in 100 (minimum), or more likely 1 in 50. This is about the same as the Space Shuttle.

>
> I expect we would all like a well informed comparison of the many safety aspects of the different ancillary power options for gliders, including fire safety, crash safety, mechanical reliability, ease of use, time from activation to provide climb power, drag if activation fails, rate of failure to deliver climb power and rate of climb achievable. probably among others. At the moment I don't even have any idea how the fire safety of electric compares to ICE. My guess is that a front electric motor is currently the safest form of ancillary power for a glider. What do others guess?

We have heard of other types of electric failures other than fires. More than one had the controller shut down during launch because of a faulty temperature reading. At least one wouldn't shut down the motor on command. I would guess that electric propulsion is no better, statistically, the ICE, and may be worse. No doubt that the least reliable means are jets.

>
> If I was considering investing in a new glider, I would worry that progress in ancillary power units over the next few years might cause powered gliders currently available to depreciate much more than we have been used to.

What will cause them to depreciate more will be the number of "fires" and other untoward events. I wonder what the resale value of the Chevy Bolt is right now.

Tom

Interesting accident report on a Pipestrel Alpha Electro crash. They
didn't establish that the batteries caused the crash, but a boatload of
problems prior to the crash were observed, see section 1.15:

https://www.onderzoeksraad.nl/nl/media/attachment/2020/7/10/fatal_loss_of_control_accident_with_with_a_pipistrel_alpha_electro_near_stadskan.pdf

Unexplained whistling sounds coming from a battery pack are never a good
sign.

On Saturday, August 21, 2021 at 7:01:23 PM UTC-7, 2G wrote:
> Yes, it does. According to LZ Designs there are 270 FES gliders flying right now. The number of know fires is, at least, 3, and probably double that number. This puts the odds of having a "fire" (really a thermal runaway) at 1 in 100 (minimum), or more likely 1 in 50. This is about the same as the Space Shuttle.
> Tom

I know of 3 fires in the AS Wankel powerplant in US gliders alone, with fewer numbers in the fleet. Since you are flying that powerplant you are risking your life every flight.

In the Netherlands crash of the Pipistrel they in fact established that the batteries "played no roll in the cause of the accident."

On Sunday, August 22, 2021 at 8:41:43 AM UTC-7, jfitch wrote:
> On Saturday, August 21, 2021 at 7:01:23 PM UTC-7, 2G wrote:
> > Yes, it does. According to LZ Designs there are 270 FES gliders flying right now. The number of know fires is, at least, 3, and probably double that number. This puts the odds of having a "fire" (really a thermal runaway) at 1 in 100 (minimum), or more likely 1 in 50. This is about the same as the Space Shuttle.
> > Tom
>
> I know of 3 fires in the AS Wankel powerplant in US gliders alone, with fewer numbers in the fleet. Since you are flying that powerplant you are risking your life every flight.

We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.

>
> In the Netherlands crash of the Pipistrel they in fact established that the batteries "played no roll in the cause of the accident."

That is hard to reconcile with the numerous technical problems with the plane prior to the accident flight. The plane slowed significantly below target airspeeds until it entered a stall/spin. The rear battery charge indicator showed ZERO at the time of the crash (section 2.2.3), which must have been disconcerting to the pilot, especially in light of the problems he experienced earlier.

The numerous technical problems also show that electric planes ARE NOT "maintenance free."

Tom

On Sunday, August 22, 2021 at 1:43:21 PM UTC-7, 2G wrote:

> We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.
> Tom
You seem to want to compare electric glider safety with electric automobiles, battery factories, municipal energy storage facilities, and lately even the Space Shuttle - and yet object to a comparison with other gliders. Surely a comparison with other glider powerplants is more relevant? Electric powerplants in gliders do not have belts, so aren't susceptible to the failure you mention. Safety is a relative term, and only meaningful in comparison with alternatives.

The fact is, you are comparatively likely to die in a glider, but it is highly unlikely to be due to a fire from any cause. So far there has been exactly one death cited in this thread with an electrical fire as a contributing cause (though not the proximate cause). Scores die every year due to a myriad of other causes, this is where concern is warranted.

On Sunday, August 22, 2021 at 5:07:28 PM UTC-7, jfitch wrote:
> On Sunday, August 22, 2021 at 1:43:21 PM UTC-7, 2G wrote:
>
> > We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.
> > Tom
> You seem to want to compare electric glider safety with electric automobiles, battery factories, municipal energy storage facilities, and lately even the Space Shuttle - and yet object to a comparison with other gliders. Surely a comparison with other glider powerplants is more relevant? Electric powerplants in gliders do not have belts, so aren't susceptible to the failure you mention. Safety is a relative term, and only meaningful in comparison with alternatives.
>
> The fact is, you are comparatively likely to die in a glider, but it is highly unlikely to be due to a fire from any cause. So far there has been exactly one death cited in this thread with an electrical fire as a contributing cause (though not the proximate cause). Scores die every year due to a myriad of other causes, this is where concern is warranted.

So, how many glider pilots have died from gasoline fires? Be specific.

On Sunday, August 22, 2021 at 6:08:28 PM UTC-7, 2G wrote:
> On Sunday, August 22, 2021 at 5:07:28 PM UTC-7, jfitch wrote:
> > On Sunday, August 22, 2021 at 1:43:21 PM UTC-7, 2G wrote:
> >
> > > We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.
> > > Tom
> > You seem to want to compare electric glider safety with electric automobiles, battery factories, municipal energy storage facilities, and lately even the Space Shuttle - and yet object to a comparison with other gliders. Surely a comparison with other glider powerplants is more relevant? Electric powerplants in gliders do not have belts, so aren't susceptible to the failure you mention. Safety is a relative term, and only meaningful in comparison with alternatives.
> >
> > The fact is, you are comparatively likely to die in a glider, but it is highly unlikely to be due to a fire from any cause. So far there has been exactly one death cited in this thread with an electrical fire as a contributing cause (though not the proximate cause). Scores die every year due to a myriad of other causes, this is where concern is warranted.
> So, how many glider pilots have died from gasoline fires? Be specific.
As far as I know, the same number that have died in electrical fires: none. If we include contributing causes, maybe the score is 0 to 1. Which of course abjectly ignores the main point: These causes are statistical noise, beneath intelligent consideration, compared to thousands of glider deaths from other causes. You will improve your chances far more by keeping your speed up and not skidding the turn to final, than choosing ICE over electric power.

On Sunday, August 22, 2021 at 7:10:22 PM UTC-7, jfitch wrote:
> On Sunday, August 22, 2021 at 6:08:28 PM UTC-7, 2G wrote:
> > On Sunday, August 22, 2021 at 5:07:28 PM UTC-7, jfitch wrote:
> > > On Sunday, August 22, 2021 at 1:43:21 PM UTC-7, 2G wrote:
> > >
> > > > We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.
> > > > Tom
> > > You seem to want to compare electric glider safety with electric automobiles, battery factories, municipal energy storage facilities, and lately even the Space Shuttle - and yet object to a comparison with other gliders.. Surely a comparison with other glider powerplants is more relevant? Electric powerplants in gliders do not have belts, so aren't susceptible to the failure you mention. Safety is a relative term, and only meaningful in comparison with alternatives.
> > >
> > > The fact is, you are comparatively likely to die in a glider, but it is highly unlikely to be due to a fire from any cause. So far there has been exactly one death cited in this thread with an electrical fire as a contributing cause (though not the proximate cause). Scores die every year due to a myriad of other causes, this is where concern is warranted.
> > So, how many glider pilots have died from gasoline fires? Be specific.
> As far as I know, the same number that have died in electrical fires: none. If we include contributing causes, maybe the score is 0 to 1. Which of course abjectly ignores the main point: These causes are statistical noise, beneath intelligent consideration, compared to thousands of glider deaths from other causes. You will improve your chances far more by keeping your speed up and not skidding the turn to final, than choosing ICE over electric power.

Next question: how many airborne gasoline fires have there been in motorgliders?

On 8/22/2021 6:08 PM, 2G wrote:
> On Sunday, August 22, 2021 at 5:07:28 PM UTC-7, jfitch wrote:
>> On Sunday, August 22, 2021 at 1:43:21 PM UTC-7, 2G wrote:
>>
>>> We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.
>>> Tom
>> You seem to want to compare electric glider safety with electric automobiles, battery factories, municipal energy storage facilities, and lately even the Space Shuttle - and yet object to a comparison with other gliders. Surely a comparison with other glider powerplants is more relevant? Electric powerplants in gliders do not have belts, so aren't susceptible to the failure you mention. Safety is a relative term, and only meaningful in comparison with alternatives.
>>
>> The fact is, you are comparatively likely to die in a glider, but it is highly unlikely to be due to a fire from any cause. So far there has been exactly one death cited in this thread with an electrical fire as a contributing cause (though not the proximate cause). Scores die every year due to a myriad of other causes, this is where concern is warranted.
>
> So, how many glider pilots have died from gasoline fires? Be specific.
>
So far, I've found one: https://www.atsb.gov.au/media/5777185/ao-2018-009_final.pdf

I found several cases of in-flight fires in Stemmes, but none of them involved fatalities
caused by the fires. It was only a 20 minute search, primarily for Stemmes, since I
thought there was a fire related fatality in one.

--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

On 8/22/2021 1:43 PM, 2G wrote:
> On Sunday, August 22, 2021 at 8:41:43 AM UTC-7, jfitch wrote:
>> On Saturday, August 21, 2021 at 7:01:23 PM UTC-7, 2G wrote:
>>> Yes, it does. According to LZ Designs there are 270 FES gliders flying right now. The number of know fires is, at least, 3, and probably double that number. This puts the odds of having a "fire" (really a thermal runaway) at 1 in 100 (minimum), or more likely 1 in 50. This is about the same as the Space Shuttle.
>>> Tom
>>
>> I know of 3 fires in the AS Wankel powerplant in US gliders alone, with fewer numbers in the fleet. Since you are flying that powerplant you are risking your life every flight.
>
> We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.

There was an in-flight fire in England, which some suspected was from a muffler beyond
it's required replacement date.

There were two in-flight bearing related fires I know of: Dr. Jack and Ed Salkeld.

There was a fourth in-flight fire in an ASW 22BLE 50R from an over-charged starter battery.

There was fifth fire on the ground in Australia, resulted from a fuel hose being pulled
loose. I don't remember the AS model on that one.

If you put a power plant in a glider, you risk fires, whether it's gasoline or batteries
used to power it.

And a sixth fire from a canopy reflection initiated fire (I'm almost certain that was also
an AS glider), so you don't even need a power plant!

--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

On 8/22/2021 8:25 PM, 2G wrote:
> On Sunday, August 22, 2021 at 7:10:22 PM UTC-7, jfitch wrote:
>> On Sunday, August 22, 2021 at 6:08:28 PM UTC-7, 2G wrote:
>>> On Sunday, August 22, 2021 at 5:07:28 PM UTC-7, jfitch wrote:
>>>> On Sunday, August 22, 2021 at 1:43:21 PM UTC-7, 2G wrote:
>>>>
>>>>> We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.
>>>>> Tom
>>>> You seem to want to compare electric glider safety with electric automobiles, battery factories, municipal energy storage facilities, and lately even the Space Shuttle - and yet object to a comparison with other gliders. Surely a comparison with other glider powerplants is more relevant? Electric powerplants in gliders do not have belts, so aren't susceptible to the failure you mention. Safety is a relative term, and only meaningful in comparison with alternatives.
>>>>
>>>> The fact is, you are comparatively likely to die in a glider, but it is highly unlikely to be due to a fire from any cause. So far there has been exactly one death cited in this thread with an electrical fire as a contributing cause (though not the proximate cause). Scores die every year due to a myriad of other causes, this is where concern is warranted.
>>> So, how many glider pilots have died from gasoline fires? Be specific.
>> As far as I know, the same number that have died in electrical fires: none. If we include contributing causes, maybe the score is 0 to 1. Which of course abjectly ignores the main point: These causes are statistical noise, beneath intelligent consideration, compared to thousands of glider deaths from other causes. You will improve your chances far more by keeping your speed up and not skidding the turn to final, than choosing ICE over electric power.
>
> Next question: how many airborne gasoline fires have there been in motorgliders?
>
Stemmes have had several, so many that there have been ADs issued for significant changes
in the engine compartment.

--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

On Sunday, August 22, 2021 at 8:53:08 PM UTC-7, Eric Greenwell wrote:
> On 8/22/2021 6:08 PM, 2G wrote:
> > On Sunday, August 22, 2021 at 5:07:28 PM UTC-7, jfitch wrote:
> >> On Sunday, August 22, 2021 at 1:43:21 PM UTC-7, 2G wrote:
> >>
> >>> We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.
> >>> Tom
> >> You seem to want to compare electric glider safety with electric automobiles, battery factories, municipal energy storage facilities, and lately even the Space Shuttle - and yet object to a comparison with other gliders. Surely a comparison with other glider powerplants is more relevant? Electric powerplants in gliders do not have belts, so aren't susceptible to the failure you mention. Safety is a relative term, and only meaningful in comparison with alternatives.
> >>
> >> The fact is, you are comparatively likely to die in a glider, but it is highly unlikely to be due to a fire from any cause. So far there has been exactly one death cited in this thread with an electrical fire as a contributing cause (though not the proximate cause). Scores die every year due to a myriad of other causes, this is where concern is warranted.
> >
> > So, how many glider pilots have died from gasoline fires? Be specific.
> >
> So far, I've found one: https://www.atsb.gov.au/media/5777185/ao-2018-009_final.pdf
>
> I found several cases of in-flight fires in Stemmes, but none of them involved fatalities
> caused by the fires. It was only a 20 minute search, primarily for Stemmes, since I
> thought there was a fire related fatality in one.
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

This glider was a home-brew conversion of an ICE sustainer to AMT jet engines. On the day prior to the accident a test engine video showed raw fuel being expelled from one of the engines and excessive flames coming out of the engine. There was also no firewall between the engine compartment and the cockpit. This glider should not have been run under power with these deficiencies.

Tom

On 8/23/2021 8:35 PM, 2G wrote:

>>> So, how many glider pilots have died from gasoline fires? Be specific.
>>>
>> So far, I've found one: https://www.atsb.gov.au/media/5777185/ao-2018-009_final.pdf
>>
>> I found several cases of in-flight fires in Stemmes, but none of them involved fatalities
>> caused by the fires. It was only a 20 minute search, primarily for Stemmes, since I
>> thought there was a fire related fatality in one.
>> --
>> Eric Greenwell - USA
>> - "A Guide to Self-launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> This glider was a home-brew conversion of an ICE sustainer to AMT jet engines. On the day prior to the accident a test engine video showed raw fuel being expelled from one of the engines and excessive flames coming out of the engine. There was also no firewall between the engine compartment and the cockpit. This glider should not have been run under power with these deficiencies.
>
I didn't realize it had been modified, but if we are to exclude glider fires due to pilot
errors, I think we should also exclude the Taurus fire, since the pilot chronically stored
the glider batteries improperly.

--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

On Sunday, August 22, 2021 at 9:14:43 PM UTC-7, Eric Greenwell wrote:
> On 8/22/2021 1:43 PM, 2G wrote:
> > On Sunday, August 22, 2021 at 8:41:43 AM UTC-7, jfitch wrote:
> >> On Saturday, August 21, 2021 at 7:01:23 PM UTC-7, 2G wrote:
> >>> Yes, it does. According to LZ Designs there are 270 FES gliders flying right now. The number of know fires is, at least, 3, and probably double that number. This puts the odds of having a "fire" (really a thermal runaway) at 1 in 100 (minimum), or more likely 1 in 50. This is about the same as the Space Shuttle.
> >>> Tom
> >>
> >> I know of 3 fires in the AS Wankel powerplant in US gliders alone, with fewer numbers in the fleet. Since you are flying that powerplant you are risking your life every flight.
> >
> > We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.
> There was an in-flight fire in England, which some suspected was from a muffler beyond
> it's required replacement date.
>
> There were two in-flight bearing related fires I know of: Dr. Jack and Ed Salkeld.
>
> There was a fourth in-flight fire in an ASW 22BLE 50R from an over-charged starter battery.
>
> There was fifth fire on the ground in Australia, resulted from a fuel hose being pulled
> loose. I don't remember the AS model on that one.
>
> If you put a power plant in a glider, you risk fires, whether it's gasoline or batteries
> used to power it.
>
> And a sixth fire from a canopy reflection initiated fire (I'm almost certain that was also
> an AS glider), so you don't even need a power plant!
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

A fire involving a drive belt has a very limited fuel source, quite unlike a propulsion battery. And if an engine fire does start we can cut off the fuel supply with the fuel shutoff valve - a lithium battery thermal runaway (fire) will not stop and burn until completely consumed (refer to Tesla's advice on how to deal with an electric car fire that I posted earlier). Gasoline engine fires occur almost entirely while the engine is running, which is just for a few minutes. Electric glider fires can, and virtually all have, occur at any time. Gasoline engines have been in use for over 60 years in gliders and are quite robust. Electric gliders have been in use for a relatively few years and are demonstrably fragile, with minor events like a gear-up landing leading to battery fires. There is no known shock level that is safe for these batteries, so if you have a hard landing, or hit a pothole while trailering, how do you know if the batteries have been damaged? Charging of batteries to 100% is linked to both electric glider and car (Chevy Bolt) battery fires. And the solution of limiting charging to 80% didn't work (at least for the Bolt).

The more I look into this the more questions I have.

Tom

On Monday, August 23, 2021 at 8:48:32 PM UTC-7, Eric Greenwell wrote:
> On 8/23/2021 8:35 PM, 2G wrote:
>
> >>> So, how many glider pilots have died from gasoline fires? Be specific..
> >>>
> >> So far, I've found one: https://www.atsb.gov.au/media/5777185/ao-2018-009_final.pdf
> >>
> >> I found several cases of in-flight fires in Stemmes, but none of them involved fatalities
> >> caused by the fires. It was only a 20 minute search, primarily for Stemmes, since I
> >> thought there was a fire related fatality in one.
> >> --
> >> Eric Greenwell - USA
> >> - "A Guide to Self-launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > This glider was a home-brew conversion of an ICE sustainer to AMT jet engines. On the day prior to the accident a test engine video showed raw fuel being expelled from one of the engines and excessive flames coming out of the engine. There was also no firewall between the engine compartment and the cockpit. This glider should not have been run under power with these deficiencies.
> >
> I didn't realize it had been modified, but if we are to exclude glider fires due to pilot
> errors, I think we should also exclude the Taurus fire, since the pilot chronically stored
> the glider batteries improperly.
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

It was fully explained in the accident report. The Taurus was a factory built and EASA certified, and the ASH25E was not, so they are in completely different categories. The ASH25E owner also flew it with a know fuel leak, which is completely inadvisable. The Taurus owner's improper battery charging underscores the electric glider's fragility to misuse and it is unclear what role this played in the accident. I would expect that such misuse might result in faster battery degradation, but not in a catastrophic fire. If that were known it should have been clearly stated in the POH, but I don't think it was.

Tom

On Sunday, August 22, 2021 at 9:20:30 PM UTC-7, Eric Greenwell wrote:
> On 8/22/2021 8:25 PM, 2G wrote:
> > On Sunday, August 22, 2021 at 7:10:22 PM UTC-7, jfitch wrote:
> >> On Sunday, August 22, 2021 at 6:08:28 PM UTC-7, 2G wrote:
> >>> On Sunday, August 22, 2021 at 5:07:28 PM UTC-7, jfitch wrote:
> >>>> On Sunday, August 22, 2021 at 1:43:21 PM UTC-7, 2G wrote:
> >>>>
> >>>>> We are taking risks every time we fly. I only know of one of the fires you are talking about, and it wasn't a fuel fire (the main bearings seized and the heat started the belt on fire). You should start a separate discussion that deals with those fires in a rational manor, not to deflect the safety issues concerning electric power.
> >>>>> Tom
> >>>> You seem to want to compare electric glider safety with electric automobiles, battery factories, municipal energy storage facilities, and lately even the Space Shuttle - and yet object to a comparison with other gliders. Surely a comparison with other glider powerplants is more relevant? Electric powerplants in gliders do not have belts, so aren't susceptible to the failure you mention. Safety is a relative term, and only meaningful in comparison with alternatives.
> >>>>
> >>>> The fact is, you are comparatively likely to die in a glider, but it is highly unlikely to be due to a fire from any cause. So far there has been exactly one death cited in this thread with an electrical fire as a contributing cause (though not the proximate cause). Scores die every year due to a myriad of other causes, this is where concern is warranted.
> >>> So, how many glider pilots have died from gasoline fires? Be specific..
> >> As far as I know, the same number that have died in electrical fires: none. If we include contributing causes, maybe the score is 0 to 1. Which of course abjectly ignores the main point: These causes are statistical noise, beneath intelligent consideration, compared to thousands of glider deaths from other causes. You will improve your chances far more by keeping your speed up and not skidding the turn to final, than choosing ICE over electric power.
> >
> > Next question: how many airborne gasoline fires have there been in motorgliders?
> >
> Stemmes have had several, so many that there have been ADs issued for significant changes
> in the engine compartment.
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

The Stemmes were particularly prone to fire as found in this 2001 incident:
https://aviation-safety.net/wikibase/65918
I believe that ADs have been issued that addresses these problems. Certification doesn't mean that an aircraft doesn't have unsafe design issues.

Tom

On Monday, August 23, 2021 at 8:58:14 PM UTC-7, 2G wrote:
> A fire involving a drive belt has a very limited fuel source, quite unlike a propulsion battery. And if an engine fire does start we can cut off the fuel supply with the fuel shutoff valve - a lithium battery thermal runaway (fire) will not stop and burn until completely consumed (refer to Tesla's advice on how to deal with an electric car fire that I posted earlier).
>
> Tom
Nonsense. The ASH bearing/belt fires did not put themselves out once the belt was consumed, in those cases the glider landed and the fire had to be extinguished with external resources and only after extensive structural damage to the glider. Epoxy burns quite well once lit, the glider itself is the fuel supply. Even in canopy caused fires the gilder will burn to the ground unless extinguished. In the case of two of the FES fires, both were extinguished with fire retardant sustaining damage similar to the ASH fires.

On Tuesday, August 24, 2021 at 9:11:46 AM UTC-7, jfitch wrote:
> On Monday, August 23, 2021 at 8:58:14 PM UTC-7, 2G wrote:
> > A fire involving a drive belt has a very limited fuel source, quite unlike a propulsion battery. And if an engine fire does start we can cut off the fuel supply with the fuel shutoff valve - a lithium battery thermal runaway (fire) will not stop and burn until completely consumed (refer to Tesla's advice on how to deal with an electric car fire that I posted earlier).
> >
> > Tom
> Nonsense. The ASH bearing/belt fires did not put themselves out once the belt was consumed, in those cases the glider landed and the fire had to be extinguished with external resources and only after extensive structural damage to the glider. Epoxy burns quite well once lit, the glider itself is the fuel supply. Even in canopy caused fires the gilder will burn to the ground unless extinguished. In the case of two of the FES fires, both were extinguished with fire retardant sustaining damage similar to the ASH fires.

That's very interesting because neither of these incidents are in the NTSB aviation database that I could find. Perhaps you can inform us of the dates and/or N numbers of the gliders involved so I can look up the NTSB accident reports (which should have been submitted due to the "extensive structural damage").

Tom

While you are comparing different types of fires caused by engines/fuel/batteries etc., don't forget you can also have a fire caused by your wheelbrake:
https://www.bea.aero/en/investigation-reports/notified-events/detail/accident-to-the-schempp-hirth-arcus-m-registered-d-kkoy-on-30-07-2019-at-sisteron-theze-aerodrome/
;-)