David Davis Posted April 30, 2014 Share Posted April 30, 2014 The last thing I need is another model especially as I'm selling up and emigrating but there was this Albatros DVa ARTF kit on eBay and I'd had a few so I bid on it and won it, kidding myself that I needed biplane flying experience prior to committing aviation with my BE2e, a long-term build project. The Albatros is mostly fretted plywood and air, it has a wingspan of 1325mm or 52 inches, a length of 1045mm or 41 inches and it weighs 1.3kg or just under 3 pounds. It requires a 3S Lipo and a 40 Amp speed controller. I have ascertained that the 2200 Lipos I use in my Foamy WOT 4 will fit and I have a new 50 Amp ESC doing nothing so those ends are covered. The recommended propeller is a 12x6. I have a problem with motor selection. According to the notes which come with the kit, the recommended motor is a "2815/09." I know that motor size is described by the length of the motor followed by the diameter of the motor in millimetres , or is it the other way round, but what does the "09" mean? I have two motors in stock which might suit. The first one is a KEDA TR2830/22 which has a KV rating of 1050. This motor will fit the structure of the fuselage if mounted on a ply plate to bring it forward a bit. The second one is an Axi 2820/10 which is physically much larger and heavier than the KEDA and which will not fit into the structure unless I cut out a slot for it. The third alternative would be for me to buy a 2815 motor. I see that Giant Cod has several in stock with KV ratings from 1100-1500KV. So what should I do? Any advice from those with greater knowledge of, and enthusiasm for, electric flight would be appreciated. Quote Link to comment Share on other sites More sharing options...
Pete B Posted April 30, 2014 Share Posted April 30, 2014 An Emax 2815/09 has a KV of 950, which will allow you turn a larger prop at lower rpm than those with a higher KV. That would be much more suitable for the Albatros than the higher KV motors. See threads here and here for more info. Pete Quote Link to comment Share on other sites More sharing options...
malcolm woodcock 1 Posted April 30, 2014 Share Posted April 30, 2014 I like the Turnigy L2215J 200 watts of genuine power and very efficient, light to. Quote Link to comment Share on other sites More sharing options...
PatMc Posted April 30, 2014 Share Posted April 30, 2014 There are 3 versions the E-max 2815/09 with different KVs. IMO the 920KV version Pete links to above is the most suitable. I have one in an OD glider using 9x5 folding blades with a spinner that extends them to 9.75" (effectively a 9.75x5.4 prop). My setup draws 21A using 3s so I'd expect a 12x6 with 3s to draw under the 30A max for this motor. Quote Link to comment Share on other sites More sharing options...
Caveman Posted April 30, 2014 Share Posted April 30, 2014 I have two Emax 2815/09 920kV motors. One in in a Multiplex Funcub and the other in a biplane which is yet to fly, althought the motor have been used in other models. I run them on 2200 3S 20C batteries using 11x7 propellers. With this setup they peak at a tad under 400 watts. I would have thought that a 12x6 prop would give similar results - I used the 11x7 to give better ground clearance. The motors are good and sturdy with a 5mm shaft. However, I have replaced the bearing in both motors as over a couple of years the old ones became really noisy. With new bearings (about £5 a pair) they are now like new. Cheers GDB Quote Link to comment Share on other sites More sharing options...
David Davis Posted May 1, 2014 Author Share Posted May 1, 2014 Thanks for the advice gentlemen, I'll go with the Emax 2815/09. Quote Link to comment Share on other sites More sharing options...
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