3 Alisport Silent 2 Electros for sale in Wings and Wheels.

On 12/12/2020 11:53 PM, Matthew Scutter wrote:
On Sunday, December 13, 2020 at 2:31:33 PM UTC+10, Eric Greenwell wrote:

Once I get to about 40% remaining, I can only get ~15kW instead of 22kW. Around 30% it warns me to reduce power below 8kW to prevent battery damage, but doesn't prevent me from continuing. I need about 3.5kW for level flight and 8kW is a ~200ft/min climb. Haven't discharged past 20% yet but it was still able to achieve 8kW at that level.
The default charger is 1200W, so even at 110v 10A should be fine, I also purchased a small 600W 'travel' charger that fits more comfortably in the cockpit with me if I outland at a remote airfield and wanted to recharge overnight, or to tour with.


So since the power (and voltage?) decreases as the batteries are
partially discharged, when it says XX% remaining, what is it a
percentage of? Amp-hours? Energy? Altitude it can climb? And how
accurate is that prediction? (As we know it was disastrously wrong in a
rooftop in CT.)

On Monday, December 14, 2020 at 12:02:14 AM UTC+10, Moshe Braner wrote:
On 12/12/2020 11:53 PM, Matthew Scutter wrote:
On Sunday, December 13, 2020 at 2:31:33 PM UTC+10, Eric Greenwell wrote:

Once I get to about 40% remaining, I can only get ~15kW instead of 22kW.. Around 30% it warns me to reduce power below 8kW to prevent battery damage, but doesn't prevent me from continuing. I need about 3.5kW for level flight and 8kW is a ~200ft/min climb. Haven't discharged past 20% yet but it was still able to achieve 8kW at that level.
The default charger is 1200W, so even at 110v 10A should be fine, I also purchased a small 600W 'travel' charger that fits more comfortably in the cockpit with me if I outland at a remote airfield and wanted to recharge overnight, or to tour with.

So since the power (and voltage?) decreases as the batteries are
partially discharged, when it says XX% remaining, what is it a
percentage of? Amp-hours? Energy? Altitude it can climb? And how
accurate is that prediction? (As we know it was disastrously wrong in a
rooftop in CT.)

That glider looked (relatively) intact so I hope the logs from the aircraft will provide some insight when the accident report comes out.

7.2.3 Battery packs available energy and consumption
Each of the 10 battery icons on the screen represents 10 % of the total available
energy. The number of displayed battery icons represents the remaining energy in the
battery. It is calculated by comparing the total theoretical available energy of the battery
packs (3,8kWh) with the consumed energy per unit of time. The actual consumed energy
depends on power setting and the duration of powered flight.
Calculation is quite accurate at lower power settings. At high power settings,
voltage drop in the battery packs is larger, and thus usable battery capacity reduced.
Because of this reason, a yellow warning message: “Low Voltage! Reduce power!� might
appear, even if a few battery icons are still displayed.

On Sunday, December 13, 2020 at 2:49:43 PM UTC-8, Matthew Scutter wrote:
On Monday, December 14, 2020 at 12:02:14 AM UTC+10, Moshe Braner wrote:
On 12/12/2020 11:53 PM, Matthew Scutter wrote:
On Sunday, December 13, 2020 at 2:31:33 PM UTC+10, Eric Greenwell wrote:

Once I get to about 40% remaining, I can only get ~15kW instead of 22kW. Around 30% it warns me to reduce power below 8kW to prevent battery damage, but doesn't prevent me from continuing. I need about 3.5kW for level flight and 8kW is a ~200ft/min climb. Haven't discharged past 20% yet but it was still able to achieve 8kW at that level.
The default charger is 1200W, so even at 110v 10A should be fine, I also purchased a small 600W 'travel' charger that fits more comfortably in the cockpit with me if I outland at a remote airfield and wanted to recharge overnight, or to tour with.

So since the power (and voltage?) decreases as the batteries are
partially discharged, when it says XX% remaining, what is it a
percentage of? Amp-hours? Energy? Altitude it can climb? And how
accurate is that prediction? (As we know it was disastrously wrong in a
rooftop in CT.)
That glider looked (relatively) intact so I hope the logs from the aircraft will provide some insight when the accident report comes out.

7.2.3 Battery packs available energy and consumption
Each of the 10 battery icons on the screen represents 10 % of the total available
energy. The number of displayed battery icons represents the remaining energy in the
battery. It is calculated by comparing the total theoretical available energy of the battery
packs (3,8kWh) with the consumed energy per unit of time. The actual consumed energy
depends on power setting and the duration of powered flight.
Calculation is quite accurate at lower power settings. At high power settings,
voltage drop in the battery packs is larger, and thus usable battery capacity reduced.
Because of this reason, a yellow warning message: “Low Voltage! Reduce power!� might
appear, even if a few battery icons are still displayed.

How far you will need to self-retrieve depends upon the flight, not the glider. A Mini-Lak was the glider involved in the case I cited, and the pilot was attempting a 750k record flight. And the oft-quoted self-retrieve distance is way too optimistic - I would cut it in half, and that might be too generous (having to clear a mountain range, for example).

Arguing about the circuit amperage is nit-picking (20A is pretty much standard, but 15A may do as well): you have to have a dedicated circuit is the point.

These electric gliders will perform, just realize that the manufacturer's are not giving you the entire picture on their limitations, particularly regarding safety.

Tom

Eric Greenwell wrote on 12/11/2020 2:05 PM:
Charles Zabinski wrote on 12/11/2020 1:48 PM:
There are 16 Silent 2 Electros in the FAA Registration Data Base.* 3 are for sale and are all
low time.* Any thoughts?* Are they uncomfortable, poor penetration, what?

Call the owners and talk to them. The Electro owner I know likes to talk about his, but he also
flies it a lot. Here is his OLC logbook for the 2020 season:

https://www.onlinecontest.org/olc-3....t=olc&pi=10497

Here's the OLC logbook of another 13.5M/FES glider pilot I know: Phil Rose. He flew seven
flights in Ely this year in his miniLak, garnering several state, national, and World records
in the process. He might be a good source of information for choosing the miniLak over an Electro.

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

Eric Greenwell wrote on 12/13/2020 8:25 PM:
Eric Greenwell wrote on 12/11/2020 2:05 PM:
Charles Zabinski wrote on 12/11/2020 1:48 PM:
There are 16 Silent 2 Electros in the FAA Registration Data Base.� 3 are for sale and are
all low time.� Any thoughts?� Are they uncomfortable, poor penetration, what?

Call the owners and talk to them. The Electro owner I know likes to talk about his, but he
also flies it a lot. Here is his OLC logbook for the 2020 season:

https://www.onlinecontest.org/olc-3....t=olc&pi=10497

Here's the OLC logbook of another 13.5M/FES glider pilot I know: Phil Rose. He flew seven
flights in Ely this year in his miniLak, garnering several state, national, and World records
in the process. He might be a good source of information for choosing the miniLak over an Electro.

And the missing link!

https://www.onlinecontest.org/olc-3....t=olc&pi=51117

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

2G wrote on 12/13/2020 4:47 PM:
On Sunday, December 13, 2020 at 2:49:43 PM UTC-8, Matthew Scutter wrote:

Once I get to about 40% remaining, I can only get ~15kW instead of 22kW. Around 30% it warns me to reduce power below 8kW to prevent battery damage, but doesn't prevent me from continuing. I need about 3.5kW for level flight and 8kW is a ~200ft/min climb. Haven't discharged past 20% yet but it was still able to achieve 8kW at that level.
The default charger is 1200W, so even at 110v 10A should be fine, I also purchased a small 600W 'travel' charger that fits more comfortably in the cockpit with me if I outland at a remote airfield and wanted to recharge overnight, or to tour with.

So since the power (and voltage?) decreases as the batteries are
partially discharged, when it says XX% remaining, what is it a
percentage of? Amp-hours? Energy? Altitude it can climb? And how
accurate is that prediction? (As we know it was disastrously wrong in a
rooftop in CT.)
That glider looked (relatively) intact so I hope the logs from the aircraft will provide some insight when the accident report comes out.
.....

How far you will need to self-retrieve depends upon the flight, not the glider. A Mini-Lak was the glider involved in the case I cited, and the pilot was attempting a 750k record flight. And the oft-quoted self-retrieve distance is way too optimistic - I would cut it in half, and that might be too generous (having to clear a mountain range, for example).

Arguing about the circuit amperage is nit-picking (20A is pretty much standard, but 15A may do as well): you have to have a dedicated circuit is the point.

These electric gliders will perform, just realize that the manufacturer's are not giving you the entire picture on their limitations, particularly regarding safety.

Why does it have to be a dedicated circuit for a 1200W charger? Especially if it's a 20 amp
circuit?

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

How far you will need to self-retrieve depends upon the flight, not the glider. A Mini-Lak was the glider involved in the case I cited, and the pilot was attempting a 750k record flight. And the oft-quoted self-retrieve distance is way too optimistic - I would cut it in half, and that might be too generous (having to clear a mountain range, for example).


Tom

Why would you need to clear a mountain range on a self retrieve? Motor
to the nearest airport and land. It's stupid to kill yourself trying to
get home when a safe landing can be made elsewhere, but then who ever
said that glider pilots are "smart", especially those of us with motors
or engines?

--
Dan
5J

On Sunday, December 13, 2020 at 8:25:36 PM UTC-8, Eric Greenwell wrote:
Eric Greenwell wrote on 12/11/2020 2:05 PM:
Charles Zabinski wrote on 12/11/2020 1:48 PM:
There are 16 Silent 2 Electros in the FAA Registration Data Base. 3 are for sale and are all
low time. Any thoughts? Are they uncomfortable, poor penetration, what?

Call the owners and talk to them. The Electro owner I know likes to talk about his, but he also
flies it a lot. Here is his OLC logbook for the 2020 season:

https://www.onlinecontest.org/olc-3....t=olc&pi=10497

Here's the OLC logbook of another 13.5M/FES glider pilot I know: Phil Rose. He flew seven
flights in Ely this year in his miniLak, garnering several state, national, and World records
in the process. He might be a good source of information for choosing the miniLak over an Electro.
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

And he is also the pilot I cited who landed his miniLak out, stating to me that he didn't think he had the battery capacity to do a self-retrieve even though he was quite a bit less than 100k out of Ely.

Tom

On Monday, December 14, 2020 at 8:20:42 AM UTC-8, Dan Marotta wrote:
How far you will need to self-retrieve depends upon the flight, not the glider. A Mini-Lak was the glider involved in the case I cited, and the pilot was attempting a 750k record flight. And the oft-quoted self-retrieve distance is way too optimistic - I would cut it in half, and that might be too generous (having to clear a mountain range, for example).

Tom

Why would you need to clear a mountain range on a self retrieve? Motor
to the nearest airport and land. It's stupid to kill yourself trying to
get home when a safe landing can be made elsewhere, but then who ever
said that glider pilots are "smart", especially those of us with motors
or engines?

--
Dan
5J

Because the nearest airport IS on the other side of a mountain range! That is exactly what happened at Ely last summer.

Tom

How far you will need to self-retrieve depends upon the flight, not the
glider. A Mini-Lak was the glider involved in the case I cited, and the
pilot was attempting a 750k record flight. And the oft-quoted
self-retrieve distance is way too optimistic - I would cut it in half,
and that might be too generous (having to clear a mountain range, for
example).

Why would you need to clear a mountain range on a self retrieve? Motor to
the nearest airport and land. It's stupid to kill yourself trying to get
home when a safe landing can be made elsewhere, but then who ever said
that glider pilots are "smart", especially those of us with motors or
engines?

Because the nearest airport IS on the other side of a mountain range! That
is exactly what happened at Ely last summer.

O-o-o-o-kay...to my way of thinking, this is less a " battery/self-retrieving
thing" than it is a "Kids, *never* get beyond gliding distance/'known-lift'
from a safely-landable option" thing. I knowingly/stupidly did - once - and
that was more than enough to cure me forever (even though: 1) I already knew I
was being stupid/foolish, and 2) no landout was necessary). And, yes, I'm
"thoroughly familiar" with unlandable/western-mountain-y territory.

Take foolish risks, expect foolish results...

Bob W.

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