Building a J-3 Piper Cub with an Electric Motor

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SUMMARY

The forum discussion centers on the conversion of a J-3 Piper Cub, typically powered by a .46 glow fuel motor, to an electric motor setup. The user has invested approximately $700 in components, including a $200 4200mAh Lithium-Polymer battery pack rated at 14.8V-DC. The electric motor is capable of delivering 500-900 Watts of power, with a peak output of 1100 Watts for short bursts, allowing for an estimated flight time of 15-20 minutes at moderate throttle settings. The conversation highlights the efficiency of electric motors compared to traditional glow engines, emphasizing the need for careful testing and setup to ensure safe operation.

PREREQUISITES
  • Understanding of electric motor specifications, including KV ratings and power outputs.
  • Knowledge of Lithium-Polymer battery characteristics and safety precautions.
  • Familiarity with RC aircraft assembly and control surface setup.
  • Experience with bench testing for electric motors and propeller configurations.
NEXT STEPS
  • Research electric motor efficiency and performance metrics for RC aircraft.
  • Learn about Lithium-Polymer battery charging techniques and safety measures.
  • Explore RC aircraft control surface calibration and servo installation best practices.
  • Investigate the impact of weight reduction techniques on RC aircraft performance.
USEFUL FOR

This discussion is beneficial for hobbyists and enthusiasts involved in building and converting RC aircraft, particularly those interested in electric propulsion systems and battery management. It is also relevant for individuals looking to enhance their knowledge of RC aircraft assembly and performance optimization.

  • #31
Pengwuino said:
Speaking of which, i want to blow up GWS's factories. Those a-holes sell their A-10's with absolutely no way of flying on stock/recommended electronics.

I wouldn't exactly call those GWS's "model airplanes," they are more like novelty items to display in your trash can.
 
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  • #32
Penguino, an electric motor can out perform a Glow engine if set up properly
The motors have gotten more efficient, but the big breakthrough is the li-poly batteries, which provide a lot of energy for a relatively low weight. This makes the models significantly lighter, requiring less power for flight.
 
  • #33
When it's ready, maybe you can have a buddy take some videos of the model in action and post them here. Waiting to see that cool looking model in action.
 
  • #34
cyrusabdollahi said:
I wouldn't exactly call those GWS's "model airplanes," they are more like novelty items to display in your trash can.

THREAD CLOSED!
 
  • #35
Pengwuino said:
THREAD CLOSED!
Nah, just the trashcans with the GWS models in them.
 
  • #36
Wow, this is a nice cub. Maybe some day...too expensive, $599.99 for just the airframe.

http://www.davepatrickmodels.com/dpm/piper-clipped/pictures/Rear-view-Clipped-jpg.jpg

http://www.davepatrickmodels.com/dpm/piper-clipped/pictures/Front-view-Clipped-C.jpg
 
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  • #37
Santa has come early!

Here is the motor, Damn its big!

http://www.uploadfile.info/uploads/d3ac803568.jpg

http://www.uploadfile.info/uploads/cba1930f4f.jpg
Motor, Motor Mount, Prop shaft, 80A electronic speed controller, and ESC RS232 programming cable.
 
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  • #38
probbaly just a small hand...
 
  • #39
I used to build and fly model airplanes. I built a tiger 60 (not the arf model, made for a .60 two-stroke engine or a .80 four-stroke)...
http://www.carlgoldbergproducts.com/tiger60D.htm
I put a .91 four-stroke on it. On its first flight, it lifted off and went perfectly straight! (usually you have to make some adjustments). The bad thing is that the thing took off just a little above idle. I don't think I reinforced the wings and how they attatck to the fuselage enough to handle that engine. I haven't flown it since in fear of a lack of ability to fly it, and it sits in my basement.

I haven't flown a model in over 6 years now, but when I do again, I'm going to start with my trusty strudy birdy (http://www.hobbico.com/airplanes/hcaa1010.html , it's a really underpowered plane, but oh well, good to learn with). When I was learning to fly, the crystal went out on the radio when the thing was at full therottle and about 500 ft in the air. I watched it turn over and dive down straight into the ground. I found the engine nearby, replaced the carberator, bent the tail back into shape, put some epoxy on the cracks in the fuselage, and it was flying the next day. That plane is freakin durable, i mean the fuselage is made from a drainage spout, I had to replace it once, so I went to the hardware store and cut a new one out one afternoon.oh yeah, and for a real cub, pick up a trade-a-plane. You can find cubs for like 20 grand in that thing! Of course, you're going to need a pilot's license for that number.
 
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  • #40
Cyrus, forget the camera and fit bombs, we can find out where the P lives.
just think, no more P guano.
 
  • #41
The plane I flew on this weekend looks almost like Cyrus's model plane. I know nothing about planes though, but they do look similar.

Pretty sweet. I went 3000 feet in the air. I got to see everything!
 

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