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What do you think about "e-soaring"?

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John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
439
Location
Letohrad / Czech Republic
Hello pilots!
Sorry for silence last few weeks.
We were carefully preparing Grenchen, but finally we were stoped by COVID.
It is a pitty because we prepared nice flight from Czech Republic to Switzerland. Well... that is year 2020. Very difficult to make a plans.

First of all - congratulations to winner of e-Trophy. Klaus Ohlmann in Antares 20E is really a hard rival :) and his 357,6 km deserve respect.

2020 results:

1. Klaus Ohlmann, Lange Antares 20E, from Airport Serres, 357.6 km
2. Jürg Weiss, Lange Antares 20E, from Airport Farrenberg, 204.1 km
3. Toni Roth, Birdy, from Airport Mengen-Hohentengen, 185.7 km
4. Eric Raymond, Sunseeker Duo, from Airport Bad Ragaz, 176.1 km
5. Felix Kreier, Lange Antares 20E, from Airport Mollis, 131.7 km
6. Luka Žnidaršič, Ventus 3 FES, from Airport Schänis, 123.6 km
7. Marco Buholzer, Pipistrel Velis E, from Airport Birrfeld, 70.3 km

Looking to 2019 logbook (our flight from Bad Ragaz to Grenchen) and calculating distance we flown last year applying 2020 rules we could achieve distance 178 km. So our electric Phoenix with two pilots aboard could have a nice "fight" for third place with Sunseeker Duo and Birdy :)

1601030701837.pngLSZE Bad Ragaz
Flight2019.09.13 15:33 Z1 hr 37 m (1,6h)2019.09.13 17:10 Z198 km
Blocks2019.09.13 15:27 Z1 hr 50 m (1,8h)2019.09.13 17:17 Z
Maximum Altitude: 3 164 ft, Maximum Speed: 180 kph, Average Speed: 122 kph
1601030701860.pngLSZG Grenchen

I really, REALLY hope that situation with COVID with be better in 2021...

LKCR 2.jpg
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
439
Location
Letohrad / Czech Republic

=some interesting conclusiones... (L/D !)

-AHOI, Martin !
Ahoj Henryk!
Thanks a lot for interesting PDF file about electric GosHawk.

I have to read file carefully, just now I have few comments.
It is interesting to see their approach to electric TMG design.
1) very high aspect ratio wing = small range for CG = crew must be practicaly in CG and not so much luggage.
2) very small area of wing = high load / square meter
3) 30-50 kW motor that is OK unless you would like to try electric glired aerotowing
4) small 12 kWh battery. That is good for price, however to achieve max. power you need 2,5C to achieve 30 kW and over 4C for 50 kW power. I am not fan high "C" rates.... I think that bigger batery would be better (20 kWh at least). Lower "C" = longer lifetime and lower temperatures....
5) 3,3 kW for cruise - that is nice. I beleive that this is calculated power withotu real efficiency of controller, motor and prop, but still nice*. I would like to see really measured results to see efficiency of used propulsion system.

*On last page are technical data claculated with efficiency of 84,5 % = very optimistic for motor and controller :)

Any video or "real" photos?
I found only photos of airframe...
1601032257311.png

Please take my comments like my personal (subjective) comments.
I was comparing written technical data with my "electric" experience with Phoenix D-14 and U-15E :)

Low e-pass 1.jpg
 

henryk

Well-Known Member
Joined
Mar 8, 2010
Messages
5,421
Location
krakow,poland
Phoenix D-14 and U-15E
=retractable undercarrige ? (VERY OK !)

BTW=France constructres was made effective E-propulsion on the base of LEM 200 like
DC motor= (2011)


(MC30E) <113 kg, >6 m/s ! 52 dB , 220 km/h ...
 

henryk

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Joined
Mar 8, 2010
Messages
5,421
Location
krakow,poland
Klaus Ohlmann
=glider with NO motor=3008 km !!!

 

opcod

Well-Known Member
Joined
Aug 28, 2010
Messages
72
Location
Canada
Indeed Martin.. the Windward is quite an airplane style volume with a 1seater wing glider. And on the competition.. the Antares is quite a glider vs the other. Proper comparison is quite the Sunseeker and by being closed by it show the Phoenix is quite good as the wing span is also shorter than the duo.
As on the batt. was it the reason you run higher voltage, as to lower the c rating ?
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
439
Location
Letohrad / Czech Republic
Hello!
My personal opinion is that higher voltage is better.
What is "safe voltage". Lets say 60 V? Than pls. imagine how much Amps you need to get 60 kW power. You would need 1 000 Amps.
With 400 V you need only 150 Amps for takeoff power.
And 30 Amps for cruise.
Using high Amps = necessity to use big electric cables = extra weight.
Our first electra (the prototype with retractible gear) had battery 5,5 kWh on 120 V and for TakeOff I needed 280 Amps (approx. 33 kW). Discharge rate 6C. I did a lot of flights to know that I prefer higher voltage and lower current :)

However even with 60 V you can get lower Amps. You just need to have in motor "more windings". For example propulsion system of Mr. Geiger works perfectly using "4 controllers in one".

So I think that lower voltage systems are OK for trikes, sigle seat UL airplanes and light two seaters. LSA (MTOM 600 kg) and "light" general aviation airplanes will use 400-800 V systems (like actual generation of electric cars).

And big electric airplanes.... who knows? :)

"-higher voltage =higher danger... "
Dangerous can be also highly flamable MOGAS :)
We still need to learn how to work with electric propulsion systems. In past we had to learn how to use fuel and combustion engines.... so we are in +- same situation. And (as in the past) we can also learn from experience from automotive industry. So more electric airplanes and cars = more experience to share :)

Best regards!
Martin
 

opcod

Well-Known Member
Joined
Aug 28, 2010
Messages
72
Location
Canada
hehe Did the same in a Sinus as to land and full taxi up to the spot. Can you also land, very slow in calm day, with the tail wheel touching first ?
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
439
Location
Letohrad / Czech Republic
Hello!
Yes, it is possible to land on three poins.
On asphalt RWY is easy to land on main wheels, on grass RWY is better to touch at slower speed to it is typically three point landing.
 

John.Roo

Well-Known Member
Joined
Oct 8, 2013
Messages
439
Location
Letohrad / Czech Republic
Really? Hard to beleive that ACCEL has only 165 Wh/kg.
In first electra (year 2010) we achieved 154 Wh/kg
In "new" electra (year 2018) we achieved 207 Wh/kg
Incl. cases and wiring between cells.

165 Wh/kg in ACCEL makes sense only if some special temp. management is used (liquid cooling etc.) and is counted in battery weight.
 

henryk

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Joined
Mar 8, 2010
Messages
5,421
Location
krakow,poland
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