Building a J-3 Piper Cub with an Electric Motor

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Discussion Overview

The discussion revolves around the construction of a J-3 Piper Cub model airplane powered by an electric motor instead of the traditional glow fuel engine. Participants explore various aspects of the conversion process, including battery specifications, motor capabilities, and expected flight performance. The conversation touches on technical details, personal experiences, and the challenges associated with building and flying electric model aircraft.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Personal experience

Main Points Raised

  • One participant mentions using a $200 4200mAh Lithium-Polymer battery pack with specific voltage and current ratings, expressing concerns about battery safety during charging.
  • Another participant questions the expected flight duration, suggesting that the battery might only last 4 minutes at maximum power output.
  • Some participants discuss the power output of the electric motor compared to a glow fuel engine, noting the efficiency of electric motors.
  • There are conflicting views on whether the model will be able to take off successfully, with some asserting that the electric motor is powerful enough, while others express skepticism about weight considerations.
  • A participant shares their past experience with building a similar model, recounting challenges faced during initial flights and offering encouragement to the builder.
  • Technical details about the motor's specifications, including its RPM rating and direct drive configuration, are provided, along with a discussion about the implications of gearing versus direct drive.

Areas of Agreement / Disagreement

The discussion contains multiple competing views regarding the feasibility of the electric conversion and the expected performance of the model. There is no consensus on whether the model will successfully take off or how long it will fly on the electric setup.

Contextual Notes

Participants express uncertainty about the model's weight and its impact on flight capability. There are also unresolved questions regarding the efficiency of the motor and battery setup, as well as the implications of using a direct drive system versus a geared motor.

Who May Find This Useful

Individuals interested in model aircraft construction, electric propulsion systems, and those considering similar conversions from glow fuel to electric motors may find this discussion relevant.

  • #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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