Power System

Some of this information is on other pages of the journal but I wanted to consolidate all the power systems information on one page.

3/4/06 - I bought four Castle Creations Phoenix 45 amp Electronic Speed Controller's. Forty-five amp ESC's may be a bit over kill but they don't weigh or cost much more and I won't have to worry about over-amping them. A very nice thing about Castle Creations Phoenix ESC's is that they have upgradeable software using their Castle link software and USB link. Which helps to keep all four ESC's in balance to each other and very easy to set up too.

The motors, props, prop adapters and battery packs were bought from Hobby-Lobby. I went with the AXI 2820/12, Poly Quest 4000 mAh 3s (11.1v) packs and Graupner 10-7 three bladed props. Four of each! The Polyquest packs will just fit through the hole in the bottoms of the nacelles where the superchargers are and fit nicely inside the nacelles.

I wanted to and it was recommended to me that I should use one or two big packs and run all the motors/ESC's off it so that when the battery dumps all the motors would shut off. Having the battery in the nose of the aircraft would help with balancing but there is no way to cool the packs and the ESC's ( the speed control HAS to be near the battery) and I would get hit by voltage losses on the long wires. Having the motor/ESC/battery in each nacelle simplifies things a bit, keeps the wires short and provides good cooling air. I don't plan on running the batteries down to cut off voltage so I should have no problems with motors cutting off.

Charging is done using two Astroflight 109 Lithium chargers. I made "Y" connectors to to connect two batteries to each charger. In between the charger and each battery is a PolyQuest PCM guard that chargers each individual cell to 4.2 volts. I can recharge all four batteries in about 45 minutes.

All four ESC's throttle leads connect together with "Y" connectors then go through a switch and then to the receiver. When I'm ready to fly I connect the batteries to the ESC's but leave the switch off until I have all four batteries connected up. I also have a "Y" from the receiver throttle connection so I can connect a 4.8v nicad pack and test servos without connecting the motor power. I once connected just one motor battery and turned on the receiver but for some reason it didn't like that at all . So it's either all four or none.

The motors go on. I made motor extensions from some hickory but they shrunk when the humidity dropped so I made new ones from birch plywood.

The battery slides in through the supercharger opening. I started with small, scale openings but enlarged them so I could remove the batteries easier. The superchargers are held in with rare earth magnets and the rear and a screw at the front.

 

AXI 2820/12
CC-45 ESC
PolyQuest 4000mAh 11.1v

Full throttle test

Prop Static
voltage
Run
voltage after 10 sec
amps watts prop RPM

Graupner 10-7 3 Blade -resin fiber

12.4 10.5 36 390 8400

Zinger 10-8
2 Blade -wood

11.6 10.6 32 345 9100

The Graupner prop is within the limit for the system but I like the Zinger numbers better and they proved to be the best. The 10-8 fly it a little faster and I can cut back on the throttle after takeoff. Cruise speed throttle setting is around 1/2 with the 10/8 Zinger. I also want to try a 10-8 APC to see what it will give. I have been flying with the 10-7 3 bladed props for the scale look and they work good. Cruise speed throttle setting is around 3/4 with them but it flies just fine and I still have a good climb rate.

 

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Updated July 14, 2009