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Hello guys! Motor sizing?

#1
Hello all,
I've been trying to get into this hobby for about a year now, and slowly but surely, I'll m getting there. I got all the expensive parts.... just waiting for some hobby funding to finally dive in. Questions, first of all, when designing your own plane (foam board) what factors determine what size motor and prop you need? I'm assuming weight isn't the only factor, but if not... How do you go about calculating this? Next question: I will be using a Spektrum DX6 for my first transmitter. Are there basics I should know about first? What's a good way to go about learning my transmitter? Thanks in advance guys. Really excited to get in this. PS: my first plane will be an ft simple scout that I already got the speed kit and b pack for. But I'd like to do custom stuff in the future.
 

Merv

Well-known member
#2
what factors determine what size motor and prop you need? I'm assuming weight isn't the only factor, but if not... How do you go about calculating this?
Weight is a major factor, also how you want to fly. Here are some general guidelines. Most motor manufactures give some advice on prop size. If you want to fly fast, get a high Kv (2,200+) motor. For a beginner, I'd recommend a lower Kv motor, something 1,000-1,400 Kv. It will give you more time to react.
  • 50 to 70 watts per pound is the minimum level of power, good for park flyers and lightly loaded slow flyers.
  • 70 to 90 watts per pound is perfect for trainers and slow-flying aircraft.
  • 90 to 110 watts per pound is good for fast-flying scale models and some sport aerobatic aircraft.
  • 110 to 130 watts per pound is what you want for advanced aerobatics and high-speed aircraft.
  • 130 to 150 watts per pound is needed for lightly loaded 3D models and ducted fans.
  • 150 to 210+ watts per pound gives unlimited performance for any 3D model.
For more information check out; https://www.modelairplanenews.com/electric-back-to-basics/#outer-popup
 
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