trebor Posted March 19, 2015 Share Posted March 19, 2015 Nearly ready to test my Fun cub and ran a few props. I could do with some advise here as to which one would be best or could I use them all ? The motor is marked up 1100 kv . 525w 45 Esc Tested on my watt meter at maximum throttle Wood prop 11x5 draws 29.67 amp h Apc prop 11x5.5 draws 29.98 amp h Apc prop 12x6 draws 35.90 amp h Quote Link to comment Share on other sites More sharing options...
Tim C Posted March 19, 2015 Share Posted March 19, 2015 Trebor, they will all fly it fine, I would probably plump for the APC 5.5< I had one on mine for a while (but with a 910kv motor) so you will potentially have a bit more speed, but my estimated 330w ish will be fine and longer flight times over the 12x6 Quote Link to comment Share on other sites More sharing options...
trebor Posted March 19, 2015 Author Share Posted March 19, 2015 Cheers Tim, I just charged my batteries so hopefully a test this weekend. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted March 19, 2015 Share Posted March 19, 2015 Wooden props are usually more effeciant than nylon (they dont flex under load) but they are comparatively fragile so can be an expensive option unless every landing is a good one - in many cases a nylon prop will survive a nose over when a wooden one will shatter So go with the 11x5.5 APC one - at least for now Quote Link to comment Share on other sites More sharing options...
andyh Posted March 21, 2015 Share Posted March 21, 2015 why limit yourself to 330w on an 11x5/5.5? prop it up to 12x6 & give yourself 400w to play with. you have a throttle stick, you don't have to use it all the time Quote Link to comment Share on other sites More sharing options...
trebor Posted March 21, 2015 Author Share Posted March 21, 2015 This is my first electric plane so I'm a bit worried it might look like my avatar... I've checked the amps, I suppose I should have checked the wattage through the motor. Is there anything else I've missed ? Quote Link to comment Share on other sites More sharing options...
John Privett Posted March 21, 2015 Share Posted March 21, 2015 It's the current (Amps) that is the main limiting factor for a motor. If a motor is quoted as having a limit of (say) 30A then propping it so it draws (say) 40A is asking for trouble whether you use 1 cell, 2 cells, 3 cells or whatever... With the higher cell counts you'll get a higher Wattage - and also more rpm. But you won't be able to achieve the (supposed) maximum wattage on a lower number of cells. So, when you initially said, "The motor is marked up 1100 kv . 525w" the '525W' marking on the motor is somewhat meaningless without also stating the voltage. If the motor is safe for 50A then yes, 525W is achievable on 3 cells, but not on 2. Or maybe it's only rated at 30A in which case 525W could be achieved on 5 cells, but not 4 or less. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted March 21, 2015 Share Posted March 21, 2015 Terbor if you know the amps you were drawing (on full volume) then multiply that by the voltage of the lipo connected at the time - the result is the wattage generated (do you "generate" Watts????) With thanks to Messers Ohm and Law Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted March 22, 2015 Share Posted March 22, 2015 In the original post trebor said he used a watt meter so surely I hope he knows exactly how many watts each prop took from the battery. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted March 22, 2015 Share Posted March 22, 2015 At 08:11 he said "I suppose I should have used the watt meter"........ Having and Using not always the same thing! Quote Link to comment Share on other sites More sharing options...
trebor Posted March 22, 2015 Author Share Posted March 22, 2015 I can see now why some stick to liquid power... First time I've really used a watt meter, this one seems to save the highest readings to flash them on and off quickly at the end which I find a bit confusing especially when it's too quick to read. Quote Link to comment Share on other sites More sharing options...
andyh Posted March 22, 2015 Share Posted March 22, 2015 I think this is the motor you have: **LINK** which is rated at 37A, so you should be safe with the 12x6 Quote Link to comment Share on other sites More sharing options...
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