Hello everyone

[G+_ConstructorsCorner]

Hello everyone. My question on the quad copter lifting 5kg. Is a helicopter stronger than a quad copter? I don’t know the aerodynamics behind it, but I would think one or two large blades would be more thrust. They are larger in size. But the steering advantage is with the quad copter. You don’t see the military flying quad copters.

 

I know the challenge was for the quad copter. But why doesn’t a quad copter have a simple transmission. You could have gears that convert between quad blades or one blade for lifting.  The gearing would be light. You could have 4 blades and use the same motors with a cam to lock the motors into one large blade. I need to draw a picture, but I hope this makes some sense. Basically it would be converting a quad copter into a single blade helicopter for lifting and then switch back.

 

Also it would be good to know if 4 small blades are more powerful then one.

[G+_Taylor Graham]

Quadcopters don't scale. A full scale heli is going to be using a gas turbine or something, but you cant put four huge turbines on something and expect it to fly. No electric motor is going to match the weight/power of a turbine at full scale, and no battery could sustain it without weighing a ton or relying on chemical fuel. The turbine wins because of it's efficiency at scale and the energy density of its fuel.

 

I'm guessing 4 propellers are going to match the trust of a single propeller if the blade area and pitch are the same. How much air you move is directly proportional to the blade area and pitch. Adding a single rotor and all of that equipment to your quad is just going to add weight. Even if the single rotor was slightly more efficient, the weight would most certainly cancel it out.

 

If you want to build a crazy lifting quad, find a way to retrofit a gas heli's motor into a belt-driven quad design (like the stingray 500). With that design, you have the benefit of being able to use a single motor/engine.