Thread: New Product Model Aero Polaris Ultra ARF
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Old Jan 08, 2013, 04:24 PM
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Canada, ON, Ottawa
Joined Feb 2006
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Ultra on 4s

The wind dropped and I was able to get in a flight before dark to try out 4s. Earlier in the day I had got some readings on 3s, so I had a baseline to compare with.

Using a 4s 2200 30C battery and 8x4 APC prop, the model accelerated faster than it did on 3s and was able to climb vertically from takeoff. It was obviously faster in level flight. So the simple answer to the basic question is: Yes, 4s does give it quite a performance boost.

Does it do this at the expense of excessive current draw? No, the momentary peak current on opening the throttle was 26A (380 watts) and the average power at WOT, including during vertical climbs was about 20-22A (300-320 watts). These are quite conservative figures and in line with Scott's comment that an 8x4 would work nicely on 4s.

When I slowed down to what I considered a comfortable cruise, as I did several times during the flight, the power required turned out to be 10-12A (140-170 watts). Minimum cruise power just staying in the air was about 8A (120 watts).

My earlier brief test flight on 3s with 8x6x3 prop also gave a peak static reading on opening the throttle of 26A (260 watts), while average power at WOT was around 18-20A (200-220 watts).

I didn't get a very precise reading of cruise power on 3s but would estimate it to be around 12-14A (130-155 watts) from previous information. (You would expect the power required to be similar, regardless of 3s or 4s, and that's roughly what we see.)

Bottom line? Polaris Ultra flies very nicely on either 3s or 4s. If you feel the need for vertical climb and extra top speed, go for 4s. If you're satisfied with 45-60 degree climbs and a little less top speed, 3s is ample for normal flying, including aerobatics. I will use both 3s and 4s at different times, but mostly, I think, 3s.

Don't forget, you need to change the prop for the different voltages. Running on 4s with the 8x6x3 would draw a lot of current!
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