I'm having a hard time understanding the ready set power systems for a .15 sized airplane. It seems the 3s 2200 is a common battery size for a .15? That sounds pretty big to me. An average 3s 2200 is around 6.5 oz, whereas a fox 15x is 3.5oz. Then you have a motor, esc and timer? Even a fox 35 is only 7oz. Am i missing something? Please help.
I want to make an akromaster with lights in the wings. It's getting dark early! Thanks guys
You are right, weight is everything in this size range!
I fly a 1/2A Pathfinder & a Wee Duper Zilch with 3Sx1300 packs, using about 1000mah. These airplanes are the same size as the Akro, and both are outstanding flyers. The PF finished off at 15 oz, the WDZ at 13 oz which is also a good target weight for the Akro. Both of these are excellent stunt models. I demo'd then passed around the PF at the Brodak Fly-In a few years ago and people really enjoyed it. It is amazing how deep you can go into a corner with a 15oz airplane! The WDZ is OTS legal but I only fly modern patterns with it - seems a shame to hold it back to the Old Time Pattern. Using .012 x 50' lines (eye to eye), but will soon be flying on Spiderwire which should be just a smidgen better:
Prop: APC 7x5EP
Motor: Arrowind 2210 kv=1560
ESC : Arrowind 18A
Pack: 3Sx1300
Timer: Hubin FM-0c
BTW, the Arrowind motor sizes are based on internal dimensions (like AXI Cobra or Scorpion) If you use a Turnigy (outside dimensions) then the equivalent size would be about a 28-28 or so. Also key is that the kv be at least 1500 - need to spin it up.
On birds this size the enemy is WEIGHT! Andy Borgogna built a PF using this power system (I think he changed the motor out later on) and reported here on SH that he was able to save around 1 oz by eliminating the bullet connectors, shortening the wires and soldering the motor wires directly to the ESC. I did not do this but if I ever got around to a re-build I probably would. BTW Andy also use the KR timer system.
There is probably a lighter battery connection than the Deans Ultra plugs too but these are handy (to me) for other reasons. Should also mention that these are a few years old & Lipo technology has progress. I'd bet you could find either lighter 1300's or the similar size/weight packs at 1500 mah or so.
For a hotter set-up, I also have a Jr Flite Streak that I "motored up" to use an 8x6EP prop and 3Sx1800. It really scoots on .012 x 50' lines - like a Flite Streak should! This one is 15.8oz. Several folks flew this at the 2014 Brodak Fly-in and it produced instant smiles...
Prop: APC 8x6EP
Motor: Arrowind 2215 kv=1180
ESC : Arrowind 18A
Pack: 3Sx1800
Timer: Hubin FM-0c