On Sunday, April 10, 2022 at 7:07:35 PM UTC-7, Eric Greenwell wrote:
> On 4/10/2022 10:01 AM, Eric Greenwell wrote:
> > On 4/8/2022 7:18 AM, Eric Greenwell wrote:
> >> Trying to get this into it's own thread - 1st try failed.
> >>
> >> On 4/6/2022 6:23 AM, kinsell wrote:
> >> >> The MGM HBC series controllers that were being used(not sure if they still are), can
> >> have a nasty electrical fire if there is a short between board layers. I know this from
> >> first hand experience. The fire stops as soon as power is removed. Very stinky.
> >> >> FWIW
> >> >> UH
> >> >
> >> > That's weird. MGM-Compro is sposed to be a world leader in electrical propulsion
> >> systems. If those guys can screw up, how are we going to get fool-proof zero
> >> maintenance ultra reliable electric motor gliders??
> >>
> >> I have good news for you: we have that glider already! And, it uses an FES propulsion.
> >> Talk to FES owners, monitor their news groups, and you'll discover what I did: the
> >> owners are very happy, and the news groups have very little conversation. Why is that?
> >> One dealer summed it up this way: "What's to talk about? You charge it, you fly it,
> >> repeat as desired."
> >>
> > I'm surprised no one has disputed the claim FES gliders are (relatively) simple to
> > operate, very low maintenance, highly reliable motorgliders. I don't think the claim is
> > exaggerated, but I thought some might think so.
> >
> I haven't heard from anyone disputing my remarks about FES gliders, but I did hear from
> the owner of an FES glider, who also owns a very nice gas glider:
>
> "The FES system is almost as reliable as a bird flapping its wings.
> The need to read the manuals and follow limitations falls on a human.
> So battery care and weather element care might be forgotten maintenance by humans.
> The birds just need to find food and not become food.
> So FES is close to zero but not without fool-proof reliability."
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications
Eric,
FES system incorporates Reed switch(aka contactor, aka proximity sensor) to monitor closed canopy.
Those switches brake. Broken switch prevents activating FES.
I undersood, broken Reed switch prevented use of GP14 electric propulsion in Sebastian Kawa hard landing accident.(not a FES)
The main reason I sell almost 1000/yr of those switches in tiny market of NJ gas stations is: they do brake.
Ryszard Krolikowski

On Wed, 20 Apr 2022 12:15:19 -0700 (PDT), RW wrote:

> FES system incorporates Reed switch(aka contactor, aka proximity sensor)
> to monitor closed canopy.
> Those switches brake. Broken switch prevents activating FES.
> I undersood, broken Reed switch prevented use of GP14 electric
> propulsion in Sebastian Kawa hard landing accident.(not a FES)
> The main reason I sell almost 1000/yr of those switches in tiny market
> of NJ gas stations is: they do brake.
> Ryszard Krolikowski

Simple, CHEAP, obvious solution: add a green LED that is on when sensor
says canopy is closed and locked.

--
--
Martin | martin at
Gregorie | gregorie dot org

On 4/20/2022 12:15 PM, RW wrote:
> On Sunday, April 10, 2022 at 7:07:35 PM UTC-7, Eric Greenwell wrote:

>>>> I have good news for you: we have that glider already! And, it uses an FES propulsion.
>>>> Talk to FES owners, monitor their news groups, and you'll discover what I did: the
>>>> owners are very happy, and the news groups have very little conversation. Why is that?
>>>> One dealer summed it up this way: "What's to talk about? You charge it, you fly it,
>>>> repeat as desired."
>>>>
>>> I'm surprised no one has disputed the claim FES gliders are (relatively) simple to
>>> operate, very low maintenance, highly reliable motorgliders. I don't think the claim is
>>> exaggerated, but I thought some might think so.
>>>
>> I haven't heard from anyone disputing my remarks about FES gliders, but I did hear from
>> the owner of an FES glider, who also owns a very nice gas glider:
>>
>> "The FES system is almost as reliable as a bird flapping its wings.
>> The need to read the manuals and follow limitations falls on a human.
>> So battery care and weather element care might be forgotten maintenance by humans.
>> The birds just need to find food and not become food.
>> So FES is close to zero but not without fool-proof reliability."
>> --
>> Eric Greenwell - USA
>> - "A Guide to Self-launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications
> Eric,
> FES system incorporates Reed switch(aka contactor, aka proximity sensor) to monitor closed canopy.
> Those switches brake. Broken switch prevents activating FES.
> I undersood, broken Reed switch prevented use of GP14 electric propulsion in Sebastian Kawa hard landing accident.(not a FES)
> The main reason I sell almost 1000/yr of those switches in tiny market of NJ gas stations is: they do brake.
> Ryszard Krolikowski

The reed switch itself is extremely reliable, but it is possible to mount it poorly or
connect it to circuity improperly, and those are the major causes of failure. The GP14
accident illustrates that: the mounting exposed the switch assembly to external damage.
After the accident, the design was changed to switches that could be easily protected from
damage.

I don't know how many gas pumps NJ has, or how many switches are in each pump, but it
sounds like there was a problem in design, manufacturing, or maintenance.
--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications

> > FES system incorporates Reed switch(aka contactor, aka proximity sensor)
> > to monitor closed canopy.
> > Those switches brake. Broken switch prevents activating FES.

I don't know where you got this idea about the FES.
As you can see documented in the manuals after three increasingly aggressive warnings, it lets you start the FES, even with a broken switch.
https://www.front-electric-sustainer.com/Manuals/FES%20FCU%20INSTRUMENT%20manual%20v1.93.pdf

On 4/20/2022 1:22 PM, Martin Gregorie wrote:
> On Wed, 20 Apr 2022 12:15:19 -0700 (PDT), RW wrote:
>
>> FES system incorporates Reed switch(aka contactor, aka proximity sensor)
>> to monitor closed canopy.
>> Those switches brake. Broken switch prevents activating FES.
>> I undersood, broken Reed switch prevented use of GP14 electric
>> propulsion in Sebastian Kawa hard landing accident.(not a FES)
>> The main reason I sell almost 1000/yr of those switches in tiny market
>> of NJ gas stations is: they do brake.
>> Ryszard Krolikowski
>
> Simple, CHEAP, obvious solution: add a green LED that is on when sensor
> says canopy is closed and locked.
>
When the canopy is open, running the FES might cause the blades to strike the canopy
before they open completely. The sensor is there to protect the blades and the canopy
during the ground run of the motor that is part of the preflight.

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

On 4/10/22 10:29, Eric Greenwell wrote:
> On 4/10/2022 8:37 AM, Mark Mocho wrote:
>>
>>> The pilot's fresh air vents still work normally, and if the battery
>>> box design meets the
>>> certification requirements, he will not need to bail out, but simply
>>> land at an airport.
>>
>> Or you can simply land directly below the place your wings or fuselage
>> melted. Venting fumes probably won't compensate for the heat of the
>> battery fire.
>>
> "Fumes" may not be a good choice of words for what is very hot gases. My
> understanding is "venting fumes" is not the certification requirement;
> instead, the battery box must protect the glider from the catastrophic
> failure of one cell, and the cell fire must not spread to other cells.
> Venting the gases overboard is part of the solution; a fire resistant
> box is another part. There may be additional measures used to meet the
> certification requirements, of course.
>

So really it just boils down to a placard issue: "Spontaneous Rapid
Disassembly of the battery box prohibited".

RW schrieb am Mittwoch, 20. April 2022 um 21:15:23 UTC+2:
> On Sunday, April 10, 2022 at 7:07:35 PM UTC-7, Eric Greenwell wrote:
> > On 4/10/2022 10:01 AM, Eric Greenwell wrote:
> > > On 4/8/2022 7:18 AM, Eric Greenwell wrote:
> > >> Trying to get this into it's own thread - 1st try failed.
> > >>
> > >> On 4/6/2022 6:23 AM, kinsell wrote:
> > >> >> The MGM HBC series controllers that were being used(not sure if they still are), can
> > >> have a nasty electrical fire if there is a short between board layers. I know this from
> > >> first hand experience. The fire stops as soon as power is removed. Very stinky.
> > >> >> FWIW
> > >> >> UH
> > >> >
> > >> > That's weird. MGM-Compro is sposed to be a world leader in electrical propulsion
> > >> systems. If those guys can screw up, how are we going to get fool-proof zero
> > >> maintenance ultra reliable electric motor gliders??
> > >>
> > >> I have good news for you: we have that glider already! And, it uses an FES propulsion.
> > >> Talk to FES owners, monitor their news groups, and you'll discover what I did: the
> > >> owners are very happy, and the news groups have very little conversation. Why is that?
> > >> One dealer summed it up this way: "What's to talk about? You charge it, you fly it,
> > >> repeat as desired."
> > >>
> > > I'm surprised no one has disputed the claim FES gliders are (relatively) simple to
> > > operate, very low maintenance, highly reliable motorgliders. I don't think the claim is
> > > exaggerated, but I thought some might think so.
> > >
> > I haven't heard from anyone disputing my remarks about FES gliders, but I did hear from
> > the owner of an FES glider, who also owns a very nice gas glider:
> >
> > "The FES system is almost as reliable as a bird flapping its wings.
> > The need to read the manuals and follow limitations falls on a human.
> > So battery care and weather element care might be forgotten maintenance by humans.
> > The birds just need to find food and not become food.
> > So FES is close to zero but not without fool-proof reliability."
> > --
> > Eric Greenwell - USA
> > - "A Guide to Self-launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications
> Eric,
> FES system incorporates Reed switch(aka contactor, aka proximity sensor) to monitor closed canopy.
> Those switches brake. Broken switch prevents activating FES.
> I undersood, broken Reed switch prevented use of GP14 electric propulsion in Sebastian Kawa hard landing accident.(not a FES)
> The main reason I sell almost 1000/yr of those switches in tiny market of NJ gas stations is: they do brake.
> Ryszard Krolikowski