What do you thing about "e-soaring"?

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

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  1. Feb 11, 2014 #61

    JenDAG

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  2. Feb 11, 2014 #62

    autoreply

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    I completely disagree.

    In existing systems (Antares), the batteries are very heavy, increasing wing loading, cost, etc. Almost 150 kg total system mass...

    What I need as a glider pilot is a system that gives me >4 m/s climb for 300 meters and then at least 0.5-1 m/s to at least 2.5-3 km. When I self-launch, I still need a quick, 300 meter climb to dig me out. Compared to the Antares (or FES) system, I think you can loose a lot of weight by going for a small/light motor and prop, sufficient batteries for only that quick climb and a 5 hp gas motor/generator set that sustains the further climb out and can recharge the "boost" batteries in flight.

    The only fundamental problem with that is that batteries that have the right power density for this only just start to emerge, but they do exist.

    A jet does all that and is a much better choice for in flight (far lighter total weight, even for 200 km sawtooth flights). Unfortunately, take-off is unlikely to be practical in the real world, both due to noise and the very high thrust requires for ballasted (or even empty) take-off. Personally, I'd opt for a jet that's just enough thrust to launch safely unballasted. In those rare cases there's no tug, you can still ditch the ballast and go flying yourself.
     
  3. Feb 11, 2014 #63

    JenDAG

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    At my employment we did some hybrids, full hybrids, range extenders for car manufacturers, some of them you can buy, and it does not convienced me as long term solution or good for airplane use.
    For me it is sophisticated hot fix of low energy density of available accus.

    I'm just not a fan of this systems, but I understand that someone could be keen on it.
     
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  4. Feb 13, 2014 #64

    Aircar

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    Mitja -no response.... "did I...?" I blew your diagram up and I think I see your problem ; I work everything on wind axis and would have drawn it with the crankshaft level (as it really is ) and the direction of rotation rather than apparent wind --the first follows the latter and is the convention in windmill design.

    The hitch MIGHT be that you haven't realized that to act as a windmill the flow direction has to reverse --the 'old' leading edge becomes the trailing --it is best to have an airfoil with blunt (rounded 'trailing' -when a prop -'leading' when a mill (or turbine to be correct)--the ARA D sections fulfil this requirement but in practice metal props have sharp edges at both ends and the airfoil matters far less than the 'sense' of the camber . (also 'undercambering the root end helps but the outer part of the blade can easily overpower it if not --just as autogyros (or windmills do)

    As I said you can prove it to yourself by experiment that this works ( I never argue with an experiment even if 'really,really,REALLY' sure that the 'theory' says something else ;) -- the test I suggested to you (grab a desk fan and take it out in a wind ) can also show that it works --most desk fans don't have an airfoil, just a curved plate which has the "right" camber and twist and doesn't know it is running 'backwards' (and a generator won't mind either for regen. I tested my 'pseudo feathering' propeller by the 'roof rack method' many years ago and wanted it to be roughly neutral as regards windmilling and it was close --also when control line flying and breaking a prop (wooden in those days) a replacement prop brought back to the flying field by bicycle made a nice 'spinner' when facing backwards (ie camber aft ) held on a pencil.

    BTW I am exitting HBA (might take a look every so often but quitting the losing game of trying to give advice or trying to stop outright stupidity and even maybe loss of life --eg by NOT speaking up someone here might precipitate the death of a member who has access to a light aircraft and is convinced he is quite safe landing into traffic --other mistakes are just wrong headed or wasteful but some are for keeps)
     
  5. Feb 13, 2014 #65

    ultralajt

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    I think it is better for me to care of my own bussines rather than arguing here about donkey shadow....

    don-kihot.gif
     
  6. Feb 14, 2014 #66

    Aircar

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    Because of the nature of this 'reply' and the insinuation inherent in it, I decided, after some thought, to make one last response and 'wrap up' the subject from my point of view anyway --any insults or innuendo that someone wants to post after this will go unanswered.

    I hope that Mitja's cryptic but clearly insulting 'riposte' ( a 'smart arsed' post ?) will not deter anyone with an idea to pursue the regenerative soaring idea since it HAS I think a lot to offer ( I thought so 43 years ago when I wrote about the idea (1971) [Topaz I will soon send you the article and other stuff I promised -maybe you could repost it on HBA for 'historical purposes'] . I gained a lot from reading technical articles that used to appear in aviation magazines like Air Progress and the soaring magazines (the like of which do not do so today -having been dumbed down for general consumption) --and the OSTIV notes that I bought as a kid . From these sort of things a general idea of how technical arguments should be presented and used to explain technical subjects can be gleaned --later on the treasure chest of Aeronautical Journal and other technical aero magazines became available from university libraries -all free except for the time needed to find and study them (their was of course no internet and technical information was much harder to come by -or create, in the world of slide rules and log tables ...maybe the fingertip availability of information by the web now devalues information itself (and Disinformation is just as easily found) As the old saying goes 'Data is not information, information is not knowledge , knowledge is not wisdom' (sic) It is unfortunate that so much posting on HBA does not conform to the old standards of veracity and the rules of academic conduct..

    Anyone is free to carry out the experiments I detailed in attempting to inform Mitja (and I should say that I have or had a high regard for his work )
    and to simply follow the technical reasoning and check it against reality . (the implication is that I am lieing or stupid --cartoon or not )

    After just finding this cartoonesque response I decided to check if anything was already on HBA -turns out there was -- April 4 2012 "Propeller as Turbine" -- Orion 'dispatched' the questioner in pretty harsh terms but himself failed to clearly elucidate the error in the idea that they are the same --he appears to have misunderstood the question as well and, in my opinion, went off on a tangent mistaking the OP as trying to get 'free energy' somehow by operating his notional windmill/propeller in a wind tunnel and thereby 'making a profit' after using the energy to run the wind tunnel .

    The questioner said nothing of this kind and I believe that Orion was out of line in being so 'devastating' (I forget the exact word used but something like that) -only one member addressed the salient point of the camber and twist disequalities between a wind turbine and a propeller . Orion is not here to defend himself and I think he would have been big enough to admit he got it wrong in any case but the HBA members who came to the 'defence' of the questioner were also a bit surprised by the harshness shown.

    Anyway-so much for 'tone' --in terms of fact I stand by my post.

    There are numerous NACA and other reports on circular arc airfoils (those that work in either flow direction) and they are common in gas turbines and sail theory -- double circular arc (having different upper and lower surface curvatures and radii at each end) having thickness are also well researched (this allows a propeller to reverse flow direction to act as a turbine --thereby permitting the concept of regenerative soaring) And also featuring in Jay Carter's High speed gyroplane and the aborted Sikorsky X wing among others .

    Many times on HBA threads some incorrect assertion is made and soon gathers yet more 'supporters' who bolster it and reinforce each other so that ,left unchecked, the false statement will go down as gospel --this is a sort of mob behaviour or psychology . The 'wisdom of crowds' effect that was hoped to arise from the net often turns out to be --descent to the lowest common denominator and, in this field, can have real consequences (and that is to say not just being irritating or frustrating but to hurt or even kill people from bad advice )

    NACA TR 319. TR 365 are two typical papers -Whitcomb published on 'reversible' airfoils also and there is a fascinating sequence of letters from Wilbur Wright about Otto Lilienthal's tests on circular arc airfoils for anyone interested to see how significant this obscure little topic actually was in the history of aeronautics (History of Aeronautics _Anderson) Luckily the Wrights actually tested things.
     
  7. Feb 14, 2014 #67

    WonderousMountain

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    Those giants are not to be trifled with. I admire your courage. May all the lions cower before you Mijta!
     
  8. Feb 16, 2014 #68

    JenDAG

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  9. Feb 17, 2014 #69

    kennyrayandersen

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    In my opinion this will eventually be cool and common; however, right now it's just really expensive. If the cost could come down, then I think it could be widely used.
     
  10. Feb 17, 2014 #70

    John.Roo

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    Hello dear friends!
    Thank you JenDag for article about Silent 2.I will read it today evening – seems to be interesting review.

    About prices….
    I am in a little bit different position.
    Why?
    Simple explanation…
    Silent, Apis. Song… mentioned airplanes are one-seaters = you can use small and cheap combustible engine. Probably two stroke.
    In this category is also big price pressure, because for 10T EUR you can have nice second hand composite glider.
    Yes – it will be a pure glider, but for remaining 30-40T EUR (price difference between used glider and new “electric” UL glider) you can have a lot of aerotows
    J

    In “normal” Phoenix we use Rotax 912.
    It is also not 100% fair, because electric solution will not offer 80hp J
    Anyway lets count….
    Rotax 912 – 12T EUR (all prices without VAT)

    Radiators, exhaust… cosmetic things – cca. 2 000 EUR

    Compare to
    ...

    Electric motor – 2.5 T EUR (in case you will buy one, real costs to build one are lower)

    Electric controller – 1 600 EUR / 3 500 EUR (“small” one up to 30kW / “big” one up to 60kW)

    Battery 8kWh (1 hour flight) – 6 000 EUR
    Chargers cca. 2 000 EUR

    Propeller, rescue system, instruments… practically same prices.


    So you have Rotax 912 engine version against electric motor version and prices are +- the same.
    I don´t expect to have soon batteries with more density… but I expect soon prices of batteries droping down.
    It means situation different from automotive industry – hobby electric self-launch motorgliders cheaper than combustible versions.
    Due to low prices of combustible cars you have electric car normally much more expensive.

    Of course you pay less for get less.
    1 hour of flight (8kWh) instead of 10 hours (110 lit fuel tanks).

    Recharge 2,5 hours instead of 5 min refueling etc…

    Therefore I see near future in aeroclubs and glider pilots.
    Reason why I write “aeroclubs” is simple – aeroklub pilots are always trying to get back home = no problem if heavy “superchargers” are based on one place
    J


    Well, anyway we try to get in touch with producers of chargers for electric cars to use same standards and make real dream of pilot driving electric car (scooter) to the airfield to make soaring flight with his electric motorglider using the same re-charge plug.


    Best regards!

    Martin
     
  11. Feb 17, 2014 #71

    henryk

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  12. Feb 27, 2014 #72

    JenDAG

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  13. Feb 28, 2014 #73

    Growlzler

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    Successful development and deployment depends on a lightweight; high power density; dependable and fail safe battery source - Lithium Ion technology is currently the choice for all electric aviation efforts. Of course it follows that market penetration will not be high until high availability and low cost can be achieved. Remember that economies of scale affect not only cost but also reliability.

    Tesla's Elon Musk has announced a $2 Billion investment to establish a battery manufacturing plant to realize these goals by 2020 [Forbes story here]. Hopefully the batteries produced will overcome the "zero charge bricking" the current packs suffer from.

    There's some scuttlebutt about Lithium being paired with Sulfur (Lithium-Sulfur). This reportedly would increase the power density by a factor of 2-4X that of the current technology and extend the number of charge/discharge cycles.

    Of course this is "popular science" stuff right now but it is the grail researchers are working on. Could be Musk has a leg up from his pals at Stanford who've been working on Lithium-Sulfur battery technology.

    There's no guarantee that automotive batteries will serve the needs of e-soaring self launch systems but I think it's a good place to begin a "basis of estimate" from. The technology developed will no doubt have trickle down effects.


    A lot can happen in five years though...,

    Growlzler
     
  14. Feb 28, 2014 #74

    autoreply

    autoreply

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    Hybrids IMHO are the holy grail:
    http://www.houseofbatteries.com/documents/VL6A.pdf

    With about 7 hp/kg (realistically) you'll empty those batteries in just over a minute. Combine that with a small 4-stroke/generator and we're done. No more massive weight added (even FES is 35 kg)
     
  15. Feb 28, 2014 #75

    JenDAG

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    If you can survive suffering complexity of two systems, then go for it.


    Troubles with piston engines especially for genset applications are torsional vibrations. Higher for 4 stroke engines, less cylinders worse.
    Better would be micro turbine with high speed generator, which is directly connected to main shaft at compressor side. Very light machine, but efficiency lower than IC piston engine, cca 10% less, 25%.
     
  16. Feb 28, 2014 #76

    JenDAG

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    Autoreply,
    what sailplane are you flying?
    How much water balast you usualy take, if any?
    What is total surface area of air brakes?

    Would you mind to investigate dependency of air brakes deployment on upcurrent strength to keep 0-0,5m/s climb?
     
  17. Mar 1, 2014 #77

    henryk

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  18. Mar 1, 2014 #78

    autoreply

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    Suffering? It's actually simpler as every other system (save full electric). Pilots don't suffer from the complexity. They suffer from the inreliability (and the extra drag when failed) and the weight.
    Pure electric is still far too heavy for many pilots and even more sailplanes. Most airframes can't accomodate another 40-50 kg of non-lifting mass.
    Now hybrids. 8 kg of those batteries gives about 55 SHP. With 350 kg flying mass, you're looking at a climb speed of 7-8 m/s, so after half a minute you've gained 200 meters and still about 60% of your battery-capacity. Now, if your tiny gaspowered engine/generator decided to fail upon prop start, you still have plenty of reserve battery and height. That gas engines/genset can be very light. Now total systems weight is less than half that of the FES-battery pack.
    Compare that to the FES system. Pathetic climb speed. Conventional turbo's are worse. Both are a total no-go in the mountains. (and work great over the flatlands)
    Nobody cares about efficiency for these kind of things. Simply take the lightest 2-stroke with reasonable reliability and connect it to a genset.

    I don't own one, so that varies. Most of my time on Discus, LS4, Pegase, Janus (A,B,C), Duo (and XLT), N3 and Ka6/13.
    Usually fly empty unless competition.
    I don't follow?
     
  19. Mar 1, 2014 #79

    JenDAG

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    OK, pilots may not, but operetors/owners have to take care about two systems, complete gasoline engine systems and complete electgric motor and generators systems which doubles aircraft maintenance requirements.

    Could you post some links?
    Often fuel system and fuel itself weight is not included in IC engine system tolat weight.

    How much drag you can add to glider in for example 3m/s climb in upcurrent (updraft, thermals) to decrease it to 0-0.5m/s climb.
     
  20. Mar 28, 2014 #80

    John.Roo

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    Hello dear friends!
    AERO 2014 is approaching and our work on 18m wing extensions is speeding up.

    When we will install them I will make some photos for you
    J


    Two new interesting things…


    FAA don´t want passengers in electric airplanes.

    “c. Prohibit the carriage of passengers, flight over densely populated areas, and night or instrument flight rules (IFR) operations in the following:

    “(1) Experimental LSA aircraft that formerly held a special LSA airworthiness certificate;
    “(6) Electric-powered aircraft.”
    Honestly – I can understand.
    I only hope that “passenger” doesn´t mean co-pilot with valid pilot license :)


    And SolarStratos project (
    http://www.solarstratos.com)

    Well this is very special project.
    I am only missing some detailed info…
    350kg is EW or MTOW?
    Is in this weight already calculated “up to 80kg Li-ion battery”?
    I would say that 350 kg EW for 20m wing span two seat airplane incl. 80kg of batteries inside is very good result.
    But then is coming small problem… 2 persons + oxygen + 2x “solar” heated astronaut suit (non-pressurized cockpit), parachutes (or ballistic rescue system)… and all this climbing to 80 000 feet with 13,5 kW electric motor?

    When I read about similar projects I also carefully read offer for sponsors – I really recommend J
    Be with us
    http://www.perlanproject.org/donate/


    My comment?
    “For 360 000 USD you can sponsor one wing of Perlan II, for 50 000 EUR you pre-pay one seat for one flight in Solar Stratos…. or you can take 100 000 EUR and start your own life challenge!”

    Why 100 000 EUR?

    In this price you can buy for example:
    - brand new Duo Discus (OK, no engine, but perfect performance and two seats)
    - new Silent Targa electric with trailer and new car (one seater, but electric self-launch)
    - for a bit more you have two seat Taurus from Pipistrel (two seat, retractible engine)

    - even our PhoEnix with 18m wing span (two seat, retractible gear….) will be far below this price….


    Please note!
    Many other projects/airplanes are existing, please take my short list like a sample and check actual pricelist of products you like J

    You may never climb to 80 000 ft… but you will make YOUR dream to discover freedom of flying come true!

    Best regards!
    Martin
     
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