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Old Nov 03, 2012, 03:58 AM
gibbo9000 is offline
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Got a good clear run with the Mythos today - using A60 - 6XS V2. Had read a lot about props and batteries - so here is my subjective view based on pushing them through the front end of P13.

For 6s I used 2 x 6s 3,000mah 40c in parallel.
  • 18 x 12e - a good airspeed for the airframe, with buffer for windier conditions; but not enough vertical grunt for half clover, stall turn, half sqaure loop etc . . .
  • 19 x 10e - a bit slower with penetration (a bit like a 4 stroke), and will climb through tall manouevres, but it has no margin for buffety/windy conditions and I struggled to keep it on line at times (so just not quite fast enough)
  • 20 x 10e - similar to 19 x 10 for speed, but struggled on long uplines more.
All of these were pulling in the 80-90 amp region (using Eagle Tree logger). It may be that with higher spec batteries (65c) the 20 x 10 comes on song around 100+ amps, but that is another league in battery investment I haven't made.

Then I tried 8s using 2 x 4s 4,000 mah 40c in series.
  • 19 x 8e - almost too much for the airframe, happily accelerates up uplines, groovy through rolls / 45 up lines etc. Would fly P13 without going above 2/3 throttle - at peak pulled 100amps.
  • 18 x 8e - felt best of the bunch today. Good speed - and will be better once I have worked on throttle curve. Smoother than 19 x 8 to fly as only peaking at 80 ish amps. But prop was cavitating a bit on uplines (may need to try a gas one!)

I stress this is subjective and F3A oriented. It is great fun to fly on 6s 19 x 10e and its knife edge loop is just amazing, rolls awesome -- and I would happily fly it like that as a big sport model. But for F3A I am thinking 8s for climb into clover leaf, stall, and square loop with half rolls (which showed up 20 x 10) etc. where you need some grunt and airpseed to keep it straight and locked on line. Also happy on 40s packs on 8s, whereas I think it struggled on 6s 40s.

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