What do you think about "e-soaring"?

Discussion in 'Soaring' started by John.Roo, Dec 5, 2013.

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  1. Nov 10, 2019 #361

    henryk

    henryk

    henryk

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    -greate thanks !

    =butyfull aircraft,
    but lower AR=lower L/D=lower fly distance ...

    =how much ?

    BTW=the weight of central wings+extenders =?
     
  2. Nov 14, 2019 #362

    John.Roo

    John.Roo

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    I fully agree Henryk - with lower AR you increase energy necessary for flight.
    But you don´t need always to fly long distance or long time. Sometimes is flight done just for fun :)

    Weight of one complete wing with 15 meters wing extension is approx. 40 kg (no battery of fuel inside).
     
    Last edited: Nov 14, 2019
  3. Nov 14, 2019 #363

    John.Roo

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    Natural hybrid airplane” – what it means?
    People are asking me if I really believe that electric propulsion is ecological. And they always start to speak about "dirty" sources of electric energy like coal power stations. I could start to explain about how to get green energy from renewable energy sources, but I prefer to say:
    “You are forgetting the idea of sport aviation. We are not always flying from point A to point B. We are flying because we love the freedom feeling in the air. And during this type of flying we need only a little bit of energy to get to strongest and cleanest energy source every glider pilots knows – thermals below of cumulus clouds”.

    “Hybrid” typically means that you have two energy sources aboard. U-15E Phoenix has aboard electric propulsion, and second energy source is nature. Of course you can easily fly “cruise flights” with short winglets like with typical sport plane. But when you install the long wing extensions and you reach your first thermal lift you will understand what “natural hybrid airplane” really means :)

    Conclusion - every TMG (even with combustion engine) is "hybrid airplane" helping to make our world cleaner :)
     
  4. Nov 14, 2019 #364

    henryk

    henryk

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    "one complete wing with 15 meters wing extension is approx. 40 kg"= L + R = 80 ?
     
  5. Nov 14, 2019 #365

    henryk

    henryk

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    =QUIKI A-8 ELECTRO ! (Youri Yakovlev...)

    BTW= "kWh" =electric energy, not caopacity or power !
     
  6. Dec 5, 2019 #366

    John.Roo

    John.Roo

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    Electric flying in arctic conditions? No problem :)

     
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  7. Dec 5, 2019 #367

    BJC

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    Nice.

    I'm curious: Is there a minimum battery temperature below which it is not recommended to fly?

    Thanks,


    BJC
     
  8. Dec 7, 2019 #368

    John.Roo

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    Hello BJC!
    This is info I get from battery producer.

    Store and use cells at lower temperatures (5-15°C). As the temperature rises, the service life decreases. Cooling to -35°C does not impair the service life. However, the internal electrolyte freezes around −40°C.

    It means that operation of electric airplanes in winter conditions will request hangar, ideally heated (5-15°C). I can imagine situation when the airplane has to stay outside overnight - than woud be good to keep baterry at 40-80% and before first flight connect charger. During charging will battery temp increase and that will be better for battery capacity and lifetime.

    Best regards!
    Martin
     
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  9. Dec 7, 2019 #369

    BJC

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    John.Roo

    Thanks,


    BJC
     
  10. Dec 8, 2019 #370

    emir_82

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    There is some papers saying that storing the packs at low temperatures extend the battery's calendar life.
    Of course you have to preheat the pack before using it.

    Regards
     
  11. Jan 7, 2020 #371

    opcod

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    Small question Martin.. Can you show the battery system arrangement and was it possible to remove them as well ? Or you all charge onboard .. But in case of a defect cell, how to remove or remove the cell.. ?
     
  12. Jan 10, 2020 #372

    John.Roo

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    Hello!
    They are 3 batteries in U-15E Phoenix.
    2x 40 kg in the wings (replacing fuel tanks) + 1x 70 kg pack in the front. All batteries are removable. Normally we remove only wing batteries for easier transport, but even the front battery can be replaced.
    e-installation.jpg
    However this system is not designed to be charged outside.

    Why?
    Most of safety problems with batteries happened due to a mechanical damage of one cell, too quick discharge or too fast charging. Discharge can be easily controlled - for example if you have 30 kWh battery is OK to use it for 60 kW takepoff power ("2C") and 30 kW power for horizontal flight ("1C").
    Charging is similar - you watch the temperature and system automatically decrease charging current in case temp of cells is too high.
    But mechanical damage is a problem.
    If somebody by mistake drop the battery pack and one cell inside is damaged you can´t see it. Therefore I prefer to keep batteries inside - like in modern electric cars.

    Balancing system is watching each pack in batteries so you run diagnostics and see if there is no problem with cells.

    Best regards!
    Martin
     
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  13. Jan 10, 2020 #373

    opcod

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    About the 30kw and 60kw.. You mean: you have a 60kw batt pack that can deliver up to 2c in discharge, for takeoff, then you lower the rpm, that result in a requirement of only 30kw of power. Right ?
    And indeed, quite right about to drop the batt case by mistake..
     
  14. Jan 10, 2020 #374

    9aplus

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    One question for Martin @John Roo
    How about hot summer use on Adriatic, our island airport can reach easy near 40 C in shade?
    Can that battery pack and E-ngine sustain that extra heat, or flying is possible only in the morning and before the sunset?
    Regards
    Djani
     
  15. Jan 11, 2020 #375

    John.Roo

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    Hello!
    During flying with first prototype we used 5,5 kWh battery and I have been discharging nearly "6C" to get a bit over 30 kW power for takeoff.

    At that time we had Li-Po cells. Li-Po cells are generally allowing higher discharge and re-charge rate. But from my point of view they are also more dangerous.
    I think that "1C" continuous discharge is on very safe side, even "1,5-2C" continuous discharge could be OK, but you have to watch temperature + you decrease battery lifetime. I prefer to stay at max. "1C" or lower and keep temp on max. 40°C or lower. We try to stay at max. 30°C.

    Would be interesting to test U-15E in a very hot conditions. We have been flying in "Czech summer" conditions = 30-35°C in shade without complications. I personally don´t think that you will face problem with battery temp during flight. Of course would be better to keep airplane in hangar (shadow). But I expect that during flight will be thanks to airflow battery temp OK.

    Seems that after "arctic testing"

    is time to make a plan for "tropical testing" in 2020 in Italy or Croatia :)

    Best regards!
    Martin
     
  16. Jan 11, 2020 #376

    9aplus

    9aplus

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  17. Jan 11, 2020 #377

    John.Roo

    John.Roo

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    Hvar and Brač - beautifull places :)
    Probably would be best to keep trailer in Sinj (LDSS) and overfly to Hvar or Brač. Please is there available 400 V/16 (or 32) Amps electricity?
     
  18. Jan 11, 2020 #378

    9aplus

    9aplus

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    3 phases 400 V / 32-50 A =>
    For Sinj - not sure but can ask,
    on Brac available, may be better place for trailer too - 1 h ferry ride Split - Supetar
    on Hvar not on the airport but available near, on the end of the field.
     
  19. Jan 12, 2020 #379

    emir_82

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    Martin

    What kind or brand of BMS are you using? How many temperature sensor it has?

    Regards
     
  20. Jan 13, 2020 #380

    John.Roo

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    Hello!
    We have temp measurement on each battery pack = we measure temp in 96 places.
    Pilot always see the highest temp.
    Sorry, I don´t know exact BMS type, but I will ask.
    Best regards!
    Martin
     
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