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ProModeler Scorpion Power
Dr.Ben

rrMaster

Richmond, VA, USA

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In our models, the higher the voltage of the set up, the lower the average current seen during the flight. My 6s model has noticeably higher current spikes than my 7S model on the same motor and shorter blades and lower model weight. I asked my EE friend how Ohms law applies in these situations, and he told me it could not be neatly applied in this kind of a system.

When the rules changed in AMA and F3C to allow 12s versus 10s models, we went from needing 6000mah packs to get through a flight with little reserve to being able to easily get through a flight with 5000's.

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

08-13-2016 09:41 PM
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AirWolfRC

rrProfessor

42½ N, 83½ W

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When the rules changed in AMA and F3C to allow 12s versus 10s models, we went from needing 6000mah packs to get through a flight with little reserve to being able to easily get through a flight with 5000's.
And there's your answer.
The amount of power to fly an aircraft will not change with a change in battery voltage. It will still require the same WATTS and a given routine will still require the same WATT HOURS.

As I said in my first post on this thread,
Look at the over all package as a finite power source. You have so many watt-hours of energy and can deliver that power just so fast (the "X" rating of the pack).
10S x 6.000 x 3.8V = 228 Watt Hours
12S x 5.000 x 3.8V = 228 Watt Hours

08-13-2016 09:46 PM
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Richardmid1

rrProfessor

Leeds, England

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Leave him alone he's half got it!

You don't get more wattage by increasing the voltage and reducing the current, you get the same wattage.

10v * 10A = 100w

20v * 5A = 100w

60% of the time, it works every time!

08-13-2016 09:47 PM
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Richardmid1

rrProfessor

Leeds, England

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I don't want Dan's head to explode but I've got more watt hours in my 10s 800 than a 14s 800!

60% of the time, it works every time!

08-13-2016 09:53 PM
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AirWolfRC

rrProfessor

42½ N, 83½ W

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I don't want Dan's head to explode but I've got more watt hours in my 10s 800 than a 14s 800!
? ? ? . . . No you don't . . .

10S times 0.8 will always be less than 14S times 0.8

08-13-2016 09:54 PM
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Richardmid1

rrProfessor

Leeds, England

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10s 8000 vs. 14s 5000.

The point here is that there is NOT a huge and noticeably difference between a 12 and 14s setup.

60% of the time, it works every time!

08-13-2016 09:58 PM
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AirWolfRC

rrProfessor

42½ N, 83½ W

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Just do the math,

10 x 0.8 x 3.8V = 30.4 Watt Hours
14 x 0.8 x 3.8V = 42.6 Watt Hours

10 x 8.000 x 3.8V = 304 Watt Hours
14 x 5.000 x 3.8V = 266 Watt Hours

08-13-2016 10:02 PM
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Richardmid1

rrProfessor

Leeds, England

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Ah no sorry you miss read my reply, I meant my 10s 800 as in Trex 800 and 14s 800 as in a typical 800 size heli 14s setup which is 14s 5000mah.

60% of the time, it works every time!

08-13-2016 10:06 PM
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AirWolfRC

rrProfessor

42½ N, 83½ W

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I just read what you wrote

08-13-2016 10:09 PM
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Richardmid1

rrProfessor

Leeds, England

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So can we conclude that if you increase the pack watt hours you can increase power but you will also add extra weight?

60% of the time, it works every time!

08-13-2016 10:15 PM
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AirWolfRC

rrProfessor

42½ N, 83½ W

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If you increase pack watt hours . . .

. . . you fly longer . . . or you fly faster . . . or both . . .

The percent watt hour increase will be more than the percent weight increase.

08-13-2016 10:26 PM
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Richardmid1

rrProfessor

Leeds, England

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The percent watt hour increase will be more than the percent weight increase.
There is a point of deminishing returns where the head speed needs to increase to get the same performance in which case the heli no longer flys for longer. The whole crazy power, 3 minute flight time thing gives E helis a bad name!

60% of the time, it works every time!

08-14-2016 07:53 AM
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AirWolfRC

rrProfessor

42½ N, 83½ W

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Most all helis operate at a much higher head speed than best performance head speed.

A typical heli can carry twice the load with lower head speed.

The only reason for high head speed is for "snap" in performance.

If you're no good at energy conservation, then higher head speed (and shorter battery life) lets you still look good.

08-15-2016 01:51 AM
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