Oops

On Thursday, June 6, 2019 at 6:15:41 PM UTC-5, Soartech wrote:
On Wednesday, June 5, 2019 at 10:40:09 AM UTC-4, ripacheco1967 wrote:
On Wednesday, June 5, 2019 at 7:58:22 AM UTC-5, son_of_flubber wrote:
The fireman seemed unaware of the battery fire hazard.

That is scary ... Lithium batteries are extraordinarily dangerous when punctured... If they were properly trained they would treat it as a gasoline leak.

https://www.youtube.com/watch?v=zmCXz3cJ2dY

I know the pilot. We took off at separate airports but decided to meet in Vermont. We had just completed the flight to VT but a massive, dark, high cloud deck moved in rapidly making it nearly impossible to get back without him using lots of battery. This is a rare situation so he had no experience on the low end of the charge curve. He said the battery gauge had 18 minutes left. In the pattern he hit sink behind a ridge and needed more altitude. Attempted to power up but he said the motor made a strange sound as if the prop brake was ON. By then too low to use the ballistic chute. He attempted to put it into some trees but it fell out into the roof. The trees probably soaked up enough energy to save him from injury. No stall or spin. Not funny.

I am new to gliders but I know some about these batteries ... These batteries are tricky... voltage drops suddenly at one point... must know and understand how they perform... how they degrade over time... how temperature affects them...

https://i.stack.imgur.com/LV91V.gif

It's a little advertised feature of the FES: at lower battery levels
you can't get full power from the motor (i.e. sufficient to climb). I
know of another FES owner who has ended in a field due to this.




At 06:34 07 June 2019, ripacheco1967 wrote:
On Thursday, June 6, 2019 at 6:15:41 PM UTC-5, Soartech wrote:
On Wednesday, June 5, 2019 at 10:40:09 AM UTC-4,
ripacheco1967 wrote:
On Wednesday, June 5, 2019 at 7:58:22 AM UTC-5,
son_of_flubber wrote:
The fireman seemed unaware of the battery fire hazard.
=20
That is scary ... Lithium batteries are extraordinarily
dangerous when
=
punctured... If they were properly trained they would treat it as a
gasolin=
e leak.
=20
https://www.youtube.com/watch?v=3DzmCXz3cJ2dY
=20
I know the pilot. We took off at separate airports but decided
to meet
in=
Vermont. We had just completed the flight to VT but a massive,
dark, high
=
cloud deck moved in rapidly making it nearly impossible to get
back
without=
him using lots of battery. This is a rare situation so he had no
experienc=
e on the low end of the charge curve. He said the battery gauge
had 18
minu=
tes left. In the pattern he hit sink behind a ridge and needed
more
altitud=
e. Attempted to power up but he said the motor made a strange
sound as if
t=
he prop brake was ON. By then too low to use the ballistic chute.
He
attemp=
ted to put it into some trees but it fell out into the roof. The trees
prob=
ably soaked up enough energy to save him from injury. No stall
or spin.
Not=
funny.

I am new to gliders but I know some about these batteries ...
These
batteri=
es are tricky... voltage drops suddenly at one point... must know
and
under=
stand how they perform... how they degrade over time... how
temperature
aff=
ects them...

https://i.stack.imgur.com/LV91V.gif