opinions for equipment on 88-90" imac plane

[tobytorkn]

hey guys, for imac this year i am scratch building a 88-90" yak 55. i currently fly the advanced sequence and often practice the unlimited sequence. i would like some opinions as to a reliable motor,esc, etc? i'm building this plane to be light and build for e-power so weight will be kept to a minimum (hollowed foam cores/lighter balsa/etc). i would like to use a123 batteries if at all possible, but will listen on other battery options as well. this plane will be used and abused over an imac season (500 flights/summer) and will generally need to fly 10minutes of high power maneuvers (vertical snaps, rollers, etc.) i really need power, ease of use, and reliability. any and all advice is VERY appreciated. toby silhavy www.silhavyaerosports.net

[appleflyer]

do you know how much it will way? the hacker A60 would work if it will be under 18lbs.

[MarkF]

The most power for the least amount of amps and the lightest weight would be the Neu 1521 1.5y 6.7 gearbox. 12s 5000 to 6000 mah cells. Dont bother with a123 if you want to go light and powerfull. There's video to prove this setup if you look.

Mark

[tobytorkn]

thanks for the info guys. the reason for using the a123 is ease of use and longevity of the packs (number of charge cycles). i really put a lot of practice in and i don't want to go through 4 sets of batteries in a summer. as far as build weight i want it to come in the 16-18 lb range. again, the weight is going to be determined by the batteries i use. how many charge cycles are guys getting with the newer lipo batteries now? as far as i've read its about 125-150 cycles done properly. this just won't be cost effective really. keep it coming guys. all input is APPRECIATED!!!! toby.... www.silhavyaerosports.net

[Jeffery]

Most of the 50cc planes are coming in at 16~18 lbs with 12S1P 5000mah lipos and 10 minute flights are major exercises in throttle control, I don't think you'll get 10 minutes of "high power manuevers". You'd be really lucky to get 10 minutes of Basic. A123 cells are 2300mah and you need about 14S to equal 12S lipo, and you'd need 14S2P to get 4600mah capacity. An A123 cell weighs 72g, or a little over 2kg of batteries. The 12S 5000mah lipos will weigh about 1450~1500g, so about 1 1/4 lbs more battery for equivalent power/duration (you can run A123 down to nothing without hurting, so 4600mah isn't really less usable capacity). Might not hurt too bad in IMAC if you try to select light stuff for the rest of your components.

The baddest stuff is never "cost effective", gasoline is cost effective.

Wanted to add a link to a thread about A123 in 3D. The general consensus is, a small (say up to 6S) A123 powered 3D plane is possible, after you get larger like 50cc-sized plane, they are too heavy for 3D. IMAC might be a different story.

http://www.rcgroups.com/forums/showthread.php?t=722914