It seems that most e-twins are designed around using large capacity, centrally located main battery/timer instead of two individual batteries/timers/esc's. Paul Walker posted recently about his search for smaller esc's. Paul's comments piqued my interest and raised a few questions in my mind regarding a shared big battery/timer vs two totally separate smaller esc/battery/timer systems.
https://stunthanger.com/smf/gettin-all-amp'ed-up!/esc-for-smaller-motor/ https://stunthanger.com/smf/open-forum/ringmaster-p-pdf-files/msg501750/#msg501750From Paul's thread, he demonstrated that his Park 480 equipped Flite Streak can fly a full pattern using around 800mah. Paul didn't list the line length or weight of the test plane, but one could assume that it was at least 25-30oz ready to fly. Pat Johnston has reported flying his similarly sized 28oz rtf Shark 402 on a Park 480 sized motor(Arrowind 2810) using about 900-1100 mah from a 1550 battery. This is a pretty light combo, motor/esc/battery/prop at around 10oz or slighly less, complete.
These questions come as I have been curious about the power arrangement for an electric twin. 650"+sq. or so. A minimalist, carbon tube fuselage design, probably in the mid-high 50 oz range, based around an Impact wing/tail and numbers. I wonder if a twin equipped with two 1130kv Cobra 2808's
(2.85oz each), two Talon 25 esc's and two 4s/1350-1550mah 4s batteries would have enough oomph and mAh capacity to cleanly fly a 55-60oz, 650-680" flapped twin stunter on 65-68ft+ .018" lines? This is allowing for 20oz +/- for 2 complete, but separate power packages.
For comparison, I do know Gordan Delaney's Pathfinder Two
(now owned by Howard Rush) runs two OS FP15's
(phasers set on kill) to very good affect. On his huge Gemini twin, two 2 OS-35-s engines, 10" props, powered that plane with much authority and contest cred. And his previous classic, Too Much twin used two fox 35's. Those planes are huge! 900-1000sq.in or something. A 650" plane is small in comparison...
Given the 400"/28oz Streak/Shark model, would the efficiency of 650sq.in twin at double that 28oz weight (56+oz) and two power packages be enough for serious stunt? Bob Hunt has commented that his next twin effort will likely be employing motors smaller than the 1100kv Power 10's he previously used, hence my question about the 1130kv 2808 Cobra. Any thoughts or observations would be interesting.
So to summarize my questions:
- Pros/Cons of two independent power systems vs central battery/timer.
- 2808 Cobra / Park 480 sized motors on an Impact sized twin.