Greg Covey

I decided to use a second 4-cell Kokam pack to balance my Extra 300S instead of re-working the control rods. I wanted to keep my glow-conversion review on track and test fly it with NiCd packs as well since others will likely choose that option. I'll look for another model to test out a single pack on.

Hannu Vuorinen

Hi,

No, 10s3p and 10s6p SHD2000´s, 10s3p for my Agwagon tug, and 10s6p for my 14ft Super Cub

Greg Covey

Hannu,

You're either a crazy man or just too wealthy! Is that a half-scale plane?

A 10s6p pack of Kokam 2AH cells has a capacity of 12AH that can deliver 400 amps! Awesome setup...

Here is a shot of my rudder servo to finish up the assembly on my Extra 300S.

Hannu Vuorinen

Hi,

Well, wealthy no, just becouse earlier mentioned packs..
Super Cub is wingspan of 14ft and it is scale 1:2,7
In Super Cub I need "only" 90 amps, as that is limit of new 42V Hacker Acro 90 amp ESC.
Honestly, by a lot of experience with earlier 1/4 Cub, this Super Cub will cruise little over 25A current,
my "small" one was using 9 amps average through flight when doing "sunday-flying cruising"

Regards,
Hannu

Greg Covey

Hannu,

Why the 12AH capacity? My assumption is that because you can then have several flights throughout the day without needing to recharge. Is this correct?

Regards.

Greg Covey

My Extra 300S is ready to test fly using the following setup below. This is basically the same setup used in my Skylark except that the 14x7 prop is replaced with a 15x10 because I have more ground clearance.
[ul][*] AXI 4120/14[*] Jeti Advance 70amp Opto ESC[*] APC 15x10 e-prop[*] Kokam 4s2p 2AH (20C) pack[*] 50amps measured (640w) static full throttle
[/ul]

Hannu Vuorinen

Hi,

yep, by using 12Ah capasity I can get approx 25-30 minutes operating time, or some 5-7 aerotows made for 5 meter gliders
Also some weight is needed for balancing, so I thougt it is more sense to put higher capacity flight pack
than adding lead in nose..

Sprink

What sort of RPM are you getting with that set up?

Hannu Vuorinen

Torcman tested motor with 2x30 cells (parallel pack) at 32 volts approx 5100 rpm, 26x10" prop

FAA

Great article Greg !

I am busy doing mine also, but am putting in a 4130-16 in it.

I plan to start on 20 cells (3300 GP's) on a 16x10 for 878 Watts.

Nick

Greg Covey

Thanks, Nick.

You may want to look at your 16" prop clearance since I feel like mine is max'ed out with a 15" prop.

Good luck!

Greg Covey

We test flew the Graupner Extra 300S this weekend and the performance was excellent! The power system didn't provide unlimited vertical climb but it was strong enough for most maneuvers except sustained knife edge.

I found no glitches with the plane or power system. Take-offs and landing were smooth. The power system can handle sustained full-throttle when needed.

Charging was made easy by first unplugging the battery cable using my opening cut into the bottom of the cowl.

One of my favorite parts about glow to electric conversions is that the plane looks just as good at the end of the flight as it did when I first finished it. No wipe-down needed!

Greg Covey

I flew the AXI-powered Extra 300S a few more times yesterday. The 4120 motor does provide a decent power level for all maneuvers except for sustained knife edge and long vertical runs.

To obtain extreme power with the Extra 300S, I would recommend an AXI 4130 motor. I should be able to take some video today and post it next week.

Greg Covey

Here are some photos of the Extra 300S maiden voyage. It took off with authority and needed no trimming once airborn.

Greg Covey

I didn't take many in-flight shots so you'll have to watch the video for a better perspective on how it flies. We were both impressed at just how light it felt in the air! My CG setting was about 1/4" forward from the stock recommendation.

Greg Covey

Landings were smooth and controlled without any bad tendancies. Sometimes the elevator can get too sensitive on Extras when the CG is too far aft.

This conversion is now one of my favorites. The AXI motor makes it simple and maintenance-free. The two packs of 4s Kokam 2.1AH (20C) are wired in parallel and mounted on either side of the firewall. Recall that I just couldn't get a good balance using only one pack. Lastly, the Graupner Extra 300S is a great .40-size plane that simply flies fantastic!

Greg Covey

Here are two videos of the AXI-powered, Graupner Extra 300S.

[link=http://www.gregcovey.com/RCU/Extra300S.wmv]Video 1[/link] (6meg)

[link=http://www.gregcovey.com/RCU/Extra300S2.wmv]Video 2[/link] (6meg)