1 hours 43 minutes Flight with 2S NCR18650B Batteries

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A few days ago I made my longest(103 minutes) flight ever with my maiden PolyClub and NCR18650B batteries.

I love PolyClub, it is my favorite RC airplane since 9 years. I was made my first scrap build PolyClub from polystrene foam in 2006 and it was fun. But this time I bought it from the original source (France).
PolyClub is official beginner airplane of France RC hobbyists since years. The airplane made from EPP, works with almost all size motors, almost all batteries and servos. You can fail but it survives. Not fast, not perfect but works.

Thanks to GuixModel from France, They made a favor and shipped this cheap model (€19.90) to UK.
Then I build the model with contact adhesive, cut the battery, servo and receiver compartments and attached the gears.
Unfortunately, I used a lot of old parts on this model. So, I don’t know the brands or specifications of them.
Here is the part list:

  • PolyClub EPP plane from GuixModel link here
  • 2x NCR18650 3400mA Lithium-Ion battery from Ebay
  • 10 Amper ESC (non-branded from 2005)
  • 27mmx8mm Brushless motor (non branded from 2006 or 2007, probably 5A max. at 3S)
  • 2x Henge MD933 metal gear servo from HK
  • 8×4 Propeller
  • 6ch FRSKY receiver

 

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I was expected it will fly around 30-40 minutes with this high power batteries in a windy day.
The wind speed was ~8-12 mph when I was started to flight at 8:30am
I set the timer of the transmitter for throttle-on time to measure real battery powered flight time except thermal flight and ground times.

I’ve landed after 40 minutes maiden flight and measured the batteries as ~7.6 volts.
It was a shock for me because this is higher than nominal voltage of the battery.
So, I returned to flight to finish the battery, but this time I was sitting to ground to rest :)
I took this shot with one hand when flying, it was 51 minutes 52 seconds :)

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This shot from 73 minutes 39 seconds. You can see the plane on the right side of the transmitter as a small white dot.

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After 85 minutes (!!!) I landed again to measure the battery. 85 minutes!!!
The flight time was more than this, because of some thermal flights after wind speed reduced to 5-6 mph.
This is the throttle position statistics(below). As you can see some zero and some very low throttle values there cause of thermals

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My TX battery dropped to 12.2v, I’m really happy to use 2200mA LiPo on my TX :)

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After 103 minutes 24 seconds flight, finally the battery done and plane landed safely.
Unfortunately, I faced with limits of my transmitter. It has 2 digit for minutes and rolling to zero after 99 minutes :/

But no problem, this is my personal record with 2 cell battery, and I was expected only 40 minutes 😀

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You can see the last throttle statistics in this photo.
As you can see, The throttle was >%50 for almost all time because of low battery voltage at the final minutes.
I measured 6.2 volts after landing.

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Here is the winners. Batteries, Motor and ESC.
ESC was important, because most of them cannot regulate the servo voltage at 6.2 volts.

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This is me. Happy but burned badly cause of UV radiation :/
Next time I will bring a tent and chair to rest. :)

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What is next?

I have ordered a cheap action cam from Banggood to record this flights.
And I’m thinking to cover the PolyClub with thin plastic film to reduce the drag.

Last,
These batteries are awesome. Peak currents are limited but perfect for slow flyers and breaking records.

See you next time…
Melih

 

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