FES (Front Electric Sustainer)

On Nov 5, 5:10*am, LimaZulu wrote:
On 4 nov., 18:10, Herbert kilian wrote:

Here is a video of a composite launch of a LAK 17 by means of auto-tow
followed by using the electric sustainer that is installed in front of
the pilot. *Looks like a promising new launch method provided the car
gets the glider high enough for a dealing with any launch
interruptions.http://blog.cafefoundation.org/?p=4759
It says nothing about the time it takes to get to around 1,500' AGL,
the altitude I usually release from tow. *The remaining charge in the
Li-Po batteries may not be sufficient for a normal stustainer
operation (20-30 min) at the end of the day but you can always throw
in more batteries, I suppose.
Herb, J7

You can download igc file of this flight, where you can see climb rate
data.
At end of flight was another climb for about 1000m (17-20kW of power)

http://www.onlinecontest.org/olc-2.0....html?dsId=213....

As there is adjustable throttle, pilot can fly horizontaly on low
power (4kW only due to very clean aerodinamic) for more than one hour
with fully charged batteries (4,2kWh of energy in 30kg of batteries).
Total climb available with 4,2kWh is about 1500m, at 400kg take-off
weight.
So with initial 450m (1,500' AGL) of climb to catch thermal, there is
still about 2/3 energy left. This is enough for another 65 km of
horizontal flight to get home!

Regards,

Luka

Thank you Luka, very interesting.
Since you seem to a member of the development team, there are other
questions I have. Of utmost interest is of course the amount of drag
that the folded propeller creates and how it typically affects the
glider's polar. As time goes on, you will most likely offer
conversion kits for a number of gliders and I hope, my LS8-18 might be
one of them.
Also, what is the min height you must have for the shaft center of the
prop from the ground, is that a restriction?(nobody should be tempted
to ground launch or land with the prop running) Are gliders with 4
inch wheels OK?
This would be a great kit to put on our experimental certified gliders
here in the US!
You probably heard this before but I had this idea about 5 years ago
and made some sketches but never took the steps to verify the
concept. Congratulations on making it work! You should try to get an
article into 'Segelfliegen'.

Herb