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| Electric Flight Discuss Electric Flight in Canada |
Topic Review (Newest First)
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| 07-31-2012 07:35 AM | ||
| philipa_240sx |
Re: Help choosing the motor Quote:
I recently built up a Dumas Tiger Moth kit. It's a beautiful plane. The first motor was a Motrolfly DM2203-1600 outrunner spinning an 8" prop. Way too much speed and the plane didn't respond well. I swapped in a 1350 kv version of the same motor spinning a larger 9" prop at a much slower speed and it transformed the plane. |
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| 07-31-2012 06:44 AM | ||
| Xanadu |
Re: Help choosing the motor Ihave successfully used the following on the Electri-cub. Turnigy 35-30 1100 kv motor, with 18amp esc, 11x7 prop, 3S 2200 ma lipo. Has gobs of power if you want, but will cruise the skys for 15 minutes easy. |
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| 07-27-2012 01:29 PM | ||
| fixer |
Re: Help choosing the motor Hey Florin; I have built this plane (balsa kit, not arf) and I have the specs for you as it was when completed. It was built from the instructions with no changes to make it lighter or stronger. (stock so to speak) SS45 electrifly esc, AR600 rx 2oz 3s 2200 batt (I checked 4 of them) 7oz fuze with servos 17oz (all servos are Hi tech 225 BB) wing with servo 12oz Rim fire 35-36-1200kv with adjustable motor mount 7oz This comes out at 3.5 lb all up. I wanted sport performance, (I may put a light camera on board in future) so a guide that I consulted came up with this. I hope it gives you some more help. Motor Recommendations: Best Speed Setup / Best Thrust Setup / Best Combination Motor 35-48-850 / GPMG4640 35-36-1200 / GPMG4620 35-48-850 / GPMG4640 Gear Ratio N/A N/A N/A Gear Drive Not Required Not Required Not Required Propeller 12x10 in., Electric 11x5.5 in., Electric 12x10 in., Electric Battery 3200 mAh, 11.1v 3200 mAh, 11.1v 3200 mAh, 11.1v ESC SS-60 / GPMM1850 SS-60 / GPMM1850 SS-60 / GPMM1850 ESC Motor Adapter GPMM3123 GPMM3123 GPMM3123 Motor Mount Medium / GPMP1255 Medium / GPMP1255 Medium / GPMP1255 Current Draw 46 amps 45 amps 46 amps Approximate Speed 64 mph 51 mph 64 mph Approximate Thrust 52 oz. 53 oz. 52 oz. Weight of Power System 16.3 oz. 13.9 oz. 16.3 oz. Approximate Flight Time at Full Throttle 4 minutes 4 minutes 4 minutes Watts per Pound 127.75 125 127.75 Flight times can be increased by reducing the throttle or by using two battery packs connected in parallel. Please note that the weight of the motor mount is not included in the system weight. The weight of the different mounts can be found on the ElectriFly web site. |
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| 07-27-2012 09:42 AM | ||
| Florin |
Re: Help choosing the motor Thank you guys for your inputs. I researched myself a lot, until I got tired as the research yielded old motors that are not available anymore, or motors that are currently available but ranging in weight from 80 grams to 160 grams...and ranging in power between park450 to .25 glow equivalent. In the past I used to overpower, but this is a very light cub that I really want to power "just enough" and fly slow and nice. The way Philip explained it makes sense, starting from the "scale flight ~60w/lb" rule of thumb. Thanks again guys, I'll get back to you with pics and movies from the maiden flight 
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| 07-26-2012 08:02 PM | ||
| uberjay |
Re: Help choosing the motor Quote:
No worries.... 'sall good  J |
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| 07-26-2012 07:10 PM | ||
| Guest |
Re: Help choosing the motor Florin, did you try Googling? I did a search on "Electrifly electricub brushless" and got piles of possibilities. Here's one that looks interesting -- a number of suggestions in a couple posts alone. http://www.wattflyer.com/forums/arch...p/t-45426.html |
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| 07-26-2012 05:45 PM | ||
| philipa_240sx |
Re: Help choosing the motor Jason, My post is a little confusing... I did the calculations for a 3lb plane and recommended a 180W motor. But when I added up the weights I realized the model would come in much lighter than that.  For a bit less power, the following work: Turnigy Park 450 http://www.hobbyking.com/hobbyking/s...ner_890kv.html Motrolfly DM2210-1080 http://www.subsonicplanes.com/Motrolfly_Motors.html |
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| 07-26-2012 03:11 PM | ||
| uberjay |
Re: Help choosing the motor Quote:
. One thought though, looking at the original brushed motor I pasted info on from the specs it was claiming 165 W which is darn near your 180 (or 150) W recommendation Phil. I kinda knew that the weight would generally go down and so was, I suppose, leaving out a few details. I figured if the original plane could fly with the 580 grams of thrust at least that as a minimum would do given the implicit weight savings.Either way.... all good. Next time I'll be more verbose  .J |
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| 07-26-2012 02:14 PM | ||
| philipa_240sx |
Re: Help choosing the motor Quote:
I usually go by the watts/lb rule. For scale flight that's ~60w/lb. Brushed & ni-cad power systems are heavy, so you can lighten the plane a fair bit going brushless and lipo. So lets say you get the plane down to 3lb using a lighter power system: 3lb * 60W/lb = 180W I would also stay with the 10" prop recommended for the brushed power system. There are a number of motors that would meet these requirements. Here are a few examples: Turnigy 2836-1000 HeadsUpRC PowerUp 450 Slofly Motrolfly DM2215-950 For an ESC, I would err on the side of caution and get a 40A Hobbywing Flyfun (also sold as the Turnigy Plush 40A), This ESC has a 3A switchmode BEC which is plenty to drive 4 decent sized servos. Add in your 3S 2200mAh lipo and your power system will be ~300g in terms of weight. Your looking at an AUW of 1000g or about 2.2 lb. Hmm, that would be quite the rocket ship with ~180W of power on tap! You could probably get away with a smaller/lighter motor in the 150W range! |
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| 07-26-2012 11:04 AM | ||
| uberjay |
Re: Help choosing the motor Hey there, the product page you linked to at the bottom has this stated in the motor section: "GPMG0710 (S-600) (for direct drive)" And the motor page for the S-600 () shows: Performance specs while turning an 8x4 propeller load w/8.4V input: RPM: 11,820-12,300 Current: 26-28A Power: 165 watts Thrust: 19-21 oz. That 21 oz is about 590 grams of thrust. So if you can aim for that amount of thrust from the brushless you're looking at you should be good. Also, the S-600 shows a can diameter of 36.5 mm. So you will probalby need to consider that when selecting a brushless - depending on what the motor / firewall bay has for room. I suspect others with more experience can weigh in here, but I hope this at least helps you get moving forward. Thanks, J |
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