Drone Efficiency

[freebeard]

Retractable landing gear upgrade.

[hamsterpower]

I would assume a quad-copter has similar aerodynamic forces to a helicopter. A helicopter can get it's most distance at about 80% max speed. This is where the induced drag is least and the parasitic drag is starting to climb too quickly. You could reduce parasitic drag by shrinking the camera gimble or removing the landing gear. That would both increase the speed and endurance.

[redpoint5]

I had a less than controlled test yesterday comparing 35 MPH (top speed) to 30 MPH, and so far it seems 30 MPH is more efficient. It did seem more efficient than when I flew at 20 MPH, but that is just a gut feeling. My guess is that when I do a more controlled test, that I will find somewhere around 30 to be the most efficient.

Unfortunately 18 MPH is the fastest orbit speed, so I won't be able to count revolutions to judge efficiency.

No good way to do a retractable landing gear without adding servos and other radios to control them.

[jamesqf]

Originally Posted by redpoint5

No good way to do a retractable landing gear without adding servos and other radios to control them.

On spring-loaded pivots, so the force of the air pushes them back while the thing is moving?

[redpoint5]

Originally Posted by jamesqf

On spring-loaded pivots, so the force of the air pushes them back while the thing is moving?

Can't risk it for landing, which can be a bit bumpy. Engineering it to sweep back would be difficult since they are designed to fold out rather than back. It would be easier to take all the hardware out of the shell and build a whole new frame if I wanted to improve aero or weight.

If I ever crash hard enough to break the frame, I'll consider it, but until then I'll just fly. My last crash destroyed every prop even though I had prop guards installed.

[samwichse]

Efficient drones?

Fixed wing.

https://www.amazon.com/Parrot-Disco-.../dp/B01JYRII4Y

[redpoint5]

Yeah, I'm annoyed at how popular quadcopters have become. Helicopters are more efficient since they have a larger disc. Don't know why gyros, GPS, sonar, etc hasn't made their way to helicopters considering the same principles apply. Swash plate is a better control method than variable speed rotors.

[freebeard]

I retract the retractable landing gear suggestion.

Swash plate? You have two controls that fight each other. Tandem rotors after Heinkel or Piasecki.

edit: fact checked myself. Tandem rotors use cyclic and collective pitch. But they are counter-rotating so [shrug].

[hamsterpower]

Originally Posted by redpoint5

Yeah, I'm annoyed at how popular quadcopters have become. Helicopters are more efficient since they have a larger disc. Don't know why gyros, GPS, sonar, etc hasn't made their way to helicopters considering the same principles apply. Swash plate is a better control method than variable speed rotors.

They have but it is still much cheaper and easier to use quad-copters. Conventional helicopters are inherently unstable, quads are stable and all forces are in balance. It makes a much better hover platform at the cost of efficiency.

[samwichse]

Originally Posted by hamsterpower

Helicopters are inherently unstable, quads are stable and all forces are in balance. It makes a much better hover platform at the cost of efficiency.

This isn't true. They are inherently unstable. There is no self correction without constant corrections from the electronic gyro. Try flying one for 10 seconds with the gyro disabled and you'll discover this quickly. There is zero return to self level and it will be like trying to stand on a beach ball.

Adding dihedral between the props helps some at the loss of efficiency.

Quads have become popular recently because of the advent of cheap sold state gyros.