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  1. #1

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    3.2 (50cc) to Electric

    What motor/battery combo works best to carry a 15Lb/(50cc) biplane around?

    Hacker Acro15XL or Axi 4130?

    How many NiMHi cells (no lipos)?

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    RE: 3.2 (50cc) to Electric

    AXI 5000 series.....Go to the "electric conversion" section. Greg Covey is doing a H-9 33% Extra or similar..............
    John

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    RE: 3.2 (50cc) to Electric

    You're looking at a MINIMUM of 1500 Watts on a 15lb biplane, more if you're expecting the plane to be aerobatic. If you're looking at 3D, for example, you want to look for closer to 3HP, or ~2000 Watts. Biplanes are extra-draggy and need extra power to make them go.

    At this time, the practical limit of the available ESCs and motors is around 32 3300mAh SubC NiMH cells, or a 10S LiPoly pack. On 32 cells, you're looking at between 45 and 50 Amps to make 1500 Watts, which is a little much for the AXi 4130 series motors. The AXi 5320 and 5330 motors are much better suited to this kind of power. You've got plenty of other choices as well, like the B50L Hackers, Actro 45 and 60 series.

    The important thing is not the motor, but how much power you put through the motor, and how that power is put to the air. All the motor has to do is handle the power; it needs to handle 32 cells at 50 Amps without self destructing. Spin the biggest prop the plane has clearance for, and put at least 1500 Watts into it, and the plane will fly well.

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    RE: 3.2 (50cc) to Electric

    Espirit Model had a decent selection of motors and ESC's so I figuered I'd give them a call. To take a plane like the Sig Sundancer or Aeroworks 27% Ultimate you would need the following. Very nice customer service even though I've not purchased yet.

    Plane Wt. 15Lbs
    Wattage Required 1500Wt
    Prop selection 20X10 - 21X14

    Espirit Models said:

    AXI 5320/28 with Jetti 77 (70a) ESC, giving 30volts and a capacity 0f 6000Mah, 10S-3P would provide ample power for pulling out of a hover, there is also the 8S-3P that would do the job for a pound less I think but less ability to pull out with out speed.. All this would provide about or just more than 3Hp.

    How much flight time would I get from this with throttle management. I dont do heavy 3D, but I can do halfway decent aerobatics.

  5. #5
    Moderator Matt Kirsch's Avatar
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    RE: 3.2 (50cc) to Electric

    Duration is battery capacity divided by average current over the duration of the flight.

    BTW, 1500 Watts is just over 2HP, not 3. 3HP is ~2150 Watts.

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    Maudib's Avatar
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    RE: 3.2 (50cc) to Electric

    Then the second problem rears it's ugly head...

    Getting a 50cc plane that is MORE than 15 lbs with a DA-50 to be 15 lbs with a whole lot of heavy batteries... often an e-converted plane of larger size ends up at least a lb heavier... sometimes more... that big extra (33%) was like 33-34 lbs... with a DA-100 it would have been like 26-27...

    So then wingloading becomes a factor as well as getting the plabe at the projected weight that you selected the powerplant/batteries for...

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    RE: 3.2 (50cc) to Electric

    Matt

    What would I have to do to get 3Hp battery wise. I should at least try to match the out-put of the equivilent gas motor, am I correct? Or should I try to match the static thrust via prop selection/cell count. I suppose lipos are the way to go now.

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    RE: 3.2 (50cc) to Electric

    With the info from above I use this calculation.

    Capacity (Mah) X 60min / continuous amp load =

    6000MahX60min/70=5.14minute of flight time at full throttle.

    I dont think the Axi will need that much draw. I dont fly "balls to the wall" for the entire flight. So I find that this may translate into 10 minutes of decent sky shredding including some Red Barron manuvers. Do I have this correct now? I think I am catching on....

    How should I consider wing loading. I dont now the mathmatical formula, but I do know "sinkrate" which translates to the rest of the world as heavier wing loading. I do believe the airframes are capable of handling the extra pound.

    Aerowork 27% Ultimate 1420sq. in. / (16lbs)256oz.=.18oz./sq.in.
    Sig Sundancer 1702sq. in./256oz.=.15oz./sq.in.

  9. #9
    Maudib's Avatar
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    RE: 3.2 (50cc) to Electric

    You need to convert to sq. ft.... 1420/144=9.86 256oz/9.86 dq. ft = 26 oz per sq. ft. Which is great... only...

    You need to check as to what the planes "really" come in at with a gas engine... often the specs are lighter than real life...

    They might be cming in at 17 and an e-version may come in at 18... Still would be a good flier.


    Then there is flight length... I've been following tat other thread about Greg's Extra conversion and 5-6 minutes does not apeal to me... (you might want to ask how long it takes to charge them batteries at the field for another flight)

    And the talk of the ESC's overheating... and that even the "better ones" would overheat with heavy throttle use...

    I too have a project I'd consider converting... a Chip Hyde Vision... Shoul dbe about 15 lbs with a DA-50... at 1450 sq. in. A pretty decent candidate for e-conversion...

    But I dunno.

    I'd want about 15 minutes of flight time... (2 7.5 minute flights) and have the plane no more than 16 lbs. Otherwise I can't see a benefit over a DA50 that will be a lb lighter, run 20 minutes on a tank that I can "recharge" in 60 seconds, have full power over that 20 minutes and will cost $1200 less to get in the air.

    Why do I even want to do it? It would be neat... but only if it would perform.

  10. #10
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    RE: 3.2 (50cc) to Electric

    With the practical limit of 32 cells, you're talking close to 70 Amps because NiCd and NiMH cells are lucky to hold 1 Volt per cell under load. With a 10S LiPoly pack, it would probably be closer to 60 Amps. But, do you really need 3HP? A "3HP" gasoline engine is rated for 3HP at maximum possible load. That's not how the engine runs in the real world.

    I think once they get the kinks worked out, Greg's 33% Edge conversion will perform every bit as well as its gasser counterpart. He's sailing into fairly uncharted waters, so a setback or two is to be expected.

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    RE: 3.2 (50cc) to Electric

    Wing loading calculator here
    E-flight duration calculator here

    I prefer the Hacker C50's on bigger planes. I have a C50 on a 11+ pound Exclusiv Modelbau Funtana. I flew it with 9 lipolys last year, and I'm going to 10 this year.

    Watts per pound is the key, IMHO. If you haven't checked it out, there's MUCH more information about electric power here.

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    RE: 3.2 (50cc) to Electric

    I saw KatManDew's Funtana fly... though it's not a 50cc size bird, it was VERY impressive. Plenty well powered...

    At just under 80" it's impressive in size though... they rcommend a 24cc gas engine for it or a 1.40-1.60 glow engine.

    In this case the gas powered models are supposed to come in 1 lb lighter, but you put half of that back in a full fuel tank...

    I actually considered a Hacker C-50XL and sent Hacker Brushless USA an e-mail with interest and a couple questions... no response.

    I was probably leaning toward the AXI 5320, but only saw getting maybe one 7-8 minute "balls to the wall" flight with 2 TP-8000 5s4p packs.

    The good news was that it might be possible to get ti about the same weight as a DA50 powered one... but the single flight per day thing is what has slowed me down.

    What's the best way to charge a 10s4p pack? Who makes the highest amp charger? Anything in the 8 amp range for 1C on them TP packs... if so I could charge in about an hour...

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    RE: 3.2 (50cc) to Electric

    but the single flight per day thing is what has slowed me down.
    ??????? I've flown my Funtana 6 or 7 times in as many hours. 8 to 14 minute flights which never came close to running the batteries "dry", and I could have flown more flights during that period, but I always have one or more other planes with me at the field to fly, and when I'm at the field that means I'm not at work, which means I'm not on a schedule, so I like to sit and rest like everyone else does, and free up the sky for other pilots. And all I have is an old 6 amp Orbit charger and a Triton.

    but only saw getting maybe one 7-8 minute "balls to the wall" flight with 2 TP-8000 5s4p packs
    To drain 8000 mah packs in 7-8 minutes means you would have pull 60 to 70 amps, at full throittle, the entire time you were in the air. That's not a realistic scenario.

    Flight duration and frequency are just simply not a problem.

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    Moderator Matt Kirsch's Avatar
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    RE: 3.2 (50cc) to Electric

    I've always questioned the "refuel and be back in the air in 60 seconds" mantra some wet flyers use to put down electric. Yeah maybe it's true, but how many REALLY fly like that? Not too many. Most take a flight, then take a break, "kibbitz" with the guys, watch others fly, or just enjoy the outdoors. If they average a flight an hour, they're doing well.

    The AstroFlight 109 is the best deal in high-capacity lithium chargers. It'll do up to 9 cells at up to 8 Amps. You'd need two of 'em and a couple of good golf cart batteries, but you could feasibly fly the big 'un several times a day.

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    RE: 3.2 (50cc) to Electric

    A thought about the AXI 5320 for a large aerobatic plane.... (actually the 5330 is the biggext AXI on Hobby-Lobby). Hobby Lobby lists the 5330 for "planes up to 20 pounds". But they list the 4130 for "planes up to 16 pounds", and the 4130 is the motor they recommend for the 4.5 pound Switch Blade........

  16. #16
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    RE: 3.2 (50cc) to Electric

    That's true...I've seen you fly it a couple times in one day... without charging I think. And again your plane is 11 lbs not 16lbs and your motor is probably drawing 40-50 amps at full throttle not 80-90... You also mentioned increasing the cells to 10 from 9 so I assume you wanted a little more power?

    My concern is that a 16-17lb 50cc plane will take a good deal more throttle to maintain average flight... and you've seen me fly KatManDew... I like to keep the 3D going... SO I guess I'd average 50-60 amps with bursts to 100... Even at 50 amp that's 9.6 minutes... less because I will be flying hard at least 1/3 of the time I'm in the air... so I don't see getting a second flight without charging at the field or having another battery pack...

    In doing some thrust calcs... it doesn't look like the AXI wuld put out enough thrust to 3D on a 16 lb ship... this is based on HL's info:

    10S LiPo
    20x13 prop
    5780rpm
    91.0A
    2088 watts

    My thrust calc says 16.03 lbs thrust... compared to a DA50 spinning a 22x8 prop at 7,000 rpm or 34.43 lbs of thrust...

    Yet they say the rule of thumb is for 3D you want 100 watts per lb and more if you can get it... so the AXI LOOKS like it would be great at 2088 or 130.5 watts per lb... but the thrust numbers don't add up... and the amp draw is pretty high...

    So how does one figure out "watt" to do?

    I don;t want to invest $800 ina battery pack and another $400-600 in a motor & ESC setup only to find out it's marginally powered.

    I haven't seen any videos of powerful, wrung out 50cc conversions and that's why I'm cautious about taking the steps...

    If I do the conversion, I'll strip the plane of covering and lighten the fuse as much as possible... then cover with some transparent covering (because the plane is built beautifully and the Balsa is nice grade too... (at least on my gas powered one)



    Matt:

    You are right... I average 6 or so flights on a good day... shooting the bull and enjoying company. I usually take 2 planes to the field... and most definitely the other would be a gasser. But I would like to fly it more than once a day... so charging at the field (unless my calcs are off) is a necessity...

    I have an Orbit... it can do 5S lipoly right? And I'd need 2 chargers I guess one for each 5S4P pack? It wouldn't be a big deal to pick up another one...


    ORIGINAL: KatManDEW

    but the single flight per day thing is what has slowed me down.
    ??????? I've flown my Funtana 6 or 7 times in as many hours. 8 to 14 minute flights which never came close to running the batteries "dry", and I could have flown more flights during that period, but I always have one or more other planes with me at the field to fly, and when I'm at the field that means I'm not at work, which means I'm not on a schedule, so I like to sit and rest like everyone else does, and free up the sky for other pilots. And all I have is an old 6 amp Orbit charger and a Triton.

    but only saw getting maybe one 7-8 minute "balls to the wall" flight with 2 TP-8000 5s4p packs
    To drain 8000 mah packs in 7-8 minutes means you would have pull 60 to 70 amps, at full throittle, the entire time you were in the air. That's not a realistic scenario.

    Flight duration and frequency are just simply not a problem.

  17. #17
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    RE: 3.2 (50cc) to Electric

    Maudib: You weren't around much last year after I started flying my Funtana. Almost never as a matter of fact. But you were present the day I maidened it, at which time I flew it three times after 4 PM, recharging between flights. But I guess you didn't catch that. Point being that I can and do, and others can and do, recharge and fly multiple times a day, and your "One flight per day" statement is derogatory misinformation.
    I have an Orbit... it can do 5S lipoly right?
    You don't even know how many cells your own charger can handle, so how can you make judgmental statements about recharging capabilities?

    I personally don't think a 33% conversion makes sense at this point in time. And for my personal requirements I don't think a 50cc conversion makes sense at this point. But the topic of this thread was not my personal requirements, OR YOUR personal requirements. It was BiplaneCrasher's 50cc-to-electric, fitness for use.

    My thrust calc says 16.03 lbs thrust... compared to a DA50 spinning a 22x8 prop at 7,000 rpm or 34.43 lbs of thrust...
    Just one of the reasons that I wouldn't use an AXI, as I stated in the first place. But to be fair and open minded, Motocalc is supposedly not good at predicting outrunner performance. There's a pretty good chance I will have a a AXI 4130 in the air this year, so I will get some first hand experience with it to see how it performs versus reports and calcualted results. And that should give a realistic indication of how the other big AXI's perform compared to reports and calculated results. First hand experience. Not assumptions and guesses.

    If you don't think electric power makes sense, then why not stick to what you know, and forget the uninformed derogatory misinformation?

  18. #18
    Maudib's Avatar
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    RE: 3.2 (50cc) to Electric

    EXCUSE ME?

    I'm asking for assistance here! I'm getting some conflicting information and this thread was exactly what I'm interested in, so that's why I participated. I don't think I've taken a derrogatory attitude about anything... I'm looking for people with experience to help me understand this all this information that seems confusing.

    If I seem overly cautious, then I apologize... I just think it's a lot of money to invest without gaining some level of confidence as to it's performance.

    You obviously are very knowledgable about this stuff an had hoped you would look at the questions I raised and shed some light on the confusion...

    Anyone else care to help with my question pertaining to this threads topic... converting a 50cc ARRF to e power?

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    RE: 3.2 (50cc) to Electric

    Hey no kung-foo fighting...

    I read this thread like a Hawk and love all the input. Converting a large gas plane may be unreasonable, but there may be newer, more efficient motors but the summer, or newer batteries to make it feasable. I am also not jumping into it. The only thing I do not agree with in the strick mathmatics involved. It looks bad on paper, but it may turn out to fly well after all with choice of prop/cells.

    Thanks everyone.

  20. #20
    Maudib's Avatar
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    RE: 3.2 (50cc) to Electric

    I'm still researching my 50cc project...

    It looks like there are some decent options now, with some brand new motors being tested for performance...

    It still is looking like only 1 flight per charge, but if I can charge it at the field with a single charger in an hour, it might still be a viable option.

    Here's a pic of the Vision with the covering stripped off... it's well built and pretty light... but I think I can get 6-8 oz off it with a dremel.

    Note from moderator: Link to competing site removed. It was not a link given in response to a question.
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  21. #21
    Moderator Matt Kirsch's Avatar
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    RE: 3.2 (50cc) to Electric

    Boy, did I miss some stuff...

    A word on HL's claims of "planes up to XXX pounds." That's to simply FLY the plane, that is, pull it fast enough that lift exceeds weight such that the plane is simply flying. It won't necessarily climb or do aerobatics. If you're expecting a 4130 to pull a 16lb plane fully 3D, or a 5320 to haul a 20lb plane straight up, you need to adjust your thinking quite a bit.

    The main limitation of the AXi outrunners in a 3D application is lack of torque. Sure they have more torque than a conventional motor, direct drive, but a gear a conventional motor down, and you can easily exceed the torque of a direct drive outrunner. You can drive a far larger prop on the same Watts, converting more of the Watts into thrust instead of speed. That is what you need for good 3D.

    That's why you see people using a 4130 on a small plane. They take advantage of the torque from the larger motor to drive a larger prop than the "right" motor is capable of driving.

    Outrunners are like glow engines in a sense; they have a limited range of propellers that they can drive with reasonable efficiency, and without causing a meltdown. The advantage they have is that they're simpler to deal with because you don't have the infinte options that a conventional motor and gearbox present, with roughly the same efficiency.

    Edited for atrocious grammar.

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    RE: 3.2 (50cc) to Electric

    definately, A DA is known over 5hp. why play around with 2 or 3hp for more money

  23. #23
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    RE: 3.2 (50cc) to Electric

    Because I'll already have one with a DA-50 on it... This is more or less to explore something new...

    I've not turned up a "perfect" solution yet, but there might just be one out there... or at least one just on the horizon...

    I realize a geared motor is swing the bigger prop, but some of the smaller ones I've heard are kind of noise and in some cases downright irritating...

    The sweet whirrrr of a direct drive would be preferable, but again I realize that may not be possible just yet.

    For me, it's not a comparison of gas vs. electroc... at this point there is no comparison, $$ to power...

    But if it can be feasibly done, and I'm able to recharge and fly it 3 times a day, it would just be plain neat.

  24. #24
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    RE: 3.2 (50cc) to Electric

    Welp, the technology IS out there...

    One of the reasons to "play around with 2 or 3 hp" is because a good portion of the 5HP that a DA50 is "rated" to produce is DA blowing sunshine up your butt.

    2250 Watts is 3HP. If you're drawing 70 Amps on 32 cells, you're making 3HP, and there's no arguing it. That 5HP rating from DA is just like any other airplane engine's HP rating, either fabricated through "extrapolation" or by using in impractically small prop and running the engine at an impractically high RPM.

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    RE: 3.2 (50cc) to Electric

    A Hacker C50 15XL on 10S3P Thunder Power lipos will power a 15 lb airplane and have plenty of authority on pull out. If you go above 15 you'll start to run out of power. The Hacker Team has been flying a 16.5 lb Dave Patrick Edge and it has plenty of power for pull out but the system is working hard. You'll need to make sure the motor, speed control and batteries get plenty of air. For true 3d performance you'll need at least 150 watts per pound. So 2250 watts for 15 lbs airplane is easy to acheive with the single Hacker setup. You can push them pretty reliably to 2750 watts if you provide good cooling. Up to 3000 watts is possible but everything needs to be perfect! I'm currently using a twin Hacker setup in a HAnger 9 Edge 33%. Over 5000 watts APC 27x13 electric and it has plenty of power. It only ways 23lbs with the new Thunder Power Gen 2 lite 10S3P packs.

    Steve Rojecki
    Team JR
    Team Hacker


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