The goal is to make a simple mostly 3D print a drone that can take off and land vertically but fly much longer than normal quadcopters.   To do this we will use a design with minimal motors and electronics.   We have a design where the only electrical stuff is an android watch, a bluetooth motor controller, a batter, and a single motor and propeller.   The basic type is a "Monocopter".   Two examples are below:

First one is gas powered and no controls at all.

Second one has remote throttle.

Third one has a funny but real control.

Next one has seemingly good control and can do about 15 mins on 450 mAh battery

Samarai UAV

Last one was CAD designed and 3D printed.

There is s small sort of tail wing that keeps the main wing at the right angle.   This also works after the power goes out, so the device lands with a sort of maple leaf seed autogyro.

 Probably the wing will be a number of 3D printed pieces connected together making a frame.   Since it is rotating the shape of the 3D pieces should make a twist like a propeller.  This way the inside helps thrust even though it is moving slower.  Then over this frame we can put a  Monokote shrink wrap skin  (or Ultrakote) which  works well for model airplanes.  It seems Monokote does stick to plastic.   Someone has 3D printed the frame of a wing and then covered it with Monokote like I plan to do.   There is also a flying wing with 3D printed frame and Ultrakote cover.    And another plane with 3D printed frame.

One guy imported NACA airfoil dat files to FreeCAD and then lofted them.  He made a python macro for FreeCAD.  We can get the NACA files for a propeller and loft those.

There is also airfoiltools.com which has lots of tools for getting sections of wings and such.

The phone/watch will talk over bluetooth to the motor controller.   The phone has a compass, GPS, camera, rotation sensors, acceleration sensors, etc.    If the phone wants to tilt the plane of rotation it can make the wing go faster on the side it wants to go up.  We are probably doing on the order of 5 rotations per second, which is plenty of time for a computer to do things.    To go higher it makes the average power on the rotation higher.

If we are 0.55 lbs or less we don't need a license in USA.   So 250 grams (8.8 ounces) or less we don't need FAA license.   My Samsung duos is about half that.  Phantom 3 max takeoff is 1.3 Kg.   Flight battery alone is more than this.  DGI Mavic is 1.6 lbs.

There are waterproof  Android Wear watches that are under 60 grams.   Like Sony SmartWatch 3 for under $100 with bluetooth, GPS, compass, gyro.  It is 2 years old and Sony SmartWatch 4 should be out any time.   So probably a smartwatch is the way to go.  Not sure if they have cameras yet.  Some smartwatches are less than $40.

There are several drones that are less than 250 grams so one idea it to take parts from one of these.  Some of these, like the parrot,  can be controlled from a smarphone.  The mini drones seem to have flight times more like 10 minutes.  The Heli-max 230si can do 15 minutes.  One place says Heli-max is only 127-132 grams.  It has ability to carry camera and still be under 250 grams I think.  So it seems it could carry lots of battery and stay up longer.  Hum.

So we may be able to use Android watch to talk to minidrone but really only using 1 of the propellers to run our monocopter.   So should fly longer.   Danger is that minidrone controller knows which way is up and is trying to turn propeller off and on all the time.

Looks like a 3 foot long and 3 inch wide by 1/4 inch thick piece of balsa weighs 1.5 to 4 ounces.  It seems plausible we can make a wing for around that weight.

It seems App-Inventor also works for Android Watches

We can take picture at near the same spot in the rotation 5 times a second or whatever and then use anti-shake algorithm on video.

Seems like there is a good chance of getting like 1 hour hover time if quad can get 15 minutes.

Going into the wind with a mono-copter means more lift as wing goes into the wind and less as it moves away.   This could be big trouble as we may not be able to adjust the speed enough to compensate.   Hum.  Problem to think about here.   Big trouble.  Really needs to twist every rotation like a helicopter blade.  Some chance we can get some twist by having propeller above or below.   Might have a  rotation between payload/batteries and wing with spring.   Fear we need a servo controlling tail section.  Also seems much more stress than had been thinking.   Would be find inside a big building but out in the real world this design has problems.

Could have screen aimed down and do different colors for different points on the compass so when viewed from below you can see that it knows which way it is pointed.  And it would be fun.  Maybe flasshing differnt colors to show battery level or other things.  Could show which direction it thinks the wind is coming from.

Still wondering if we could get by with only controlling the motor.   Might have motor twist the wing.  Might have different speeds make the tail behave different.  Like the centripital force might rotate it to make it work differently.   Like full power on motor overpowers the tail and rotates the wing a bit.   If we can normally operate on half power on the motor, this might work.  Motor can be above wing so less danger of getting hit on landing and so can torque the wing.

Ultrakote is 3.4 grams per square foot, much lighter than monokote.

Ordered a Sony Smartwatch 3 and a Heli-max  on Nov 14th.

Weight budget 250 grams:
     Watch:   50 grams - without band
     Cover:   7 grams
    Battery 1200 mah:  23 grams      - if we have extra use bigger battery
   Bluetooth:  17 grams   = guess so far - TinySine duel motor controller- could also do a light
   3D frame: ?




Questions:
  1)  Can compass handle 5 rps or 10 rps?  - Test spinning phone seems to say yes.
  2) Can bluetooth control work at 1/10th second?  I think so.

One idea is to take a tiny drone and put it on the wing instead of just one engine.   The above drone is 1.6 ounces.   Then we could have 2 props above the wing and 2 below.  Then we could twist the wing as needed.  If we could control the drone engines directly via bluetooth then it would be really nice.  A bit of googling and it seems the normal bluetooth commands are high level things like forward, stop, flip and not telling one motor what to do.  Maybe there is a test mode or something.   Would want to hook in a larger battery.    The Metakoo flies for 5 or 6 mins on 3.7 volt 150 mAh battery.   There are 3.7 volt 1500 mAh batteries that are 40 grams.   So flight time of around an hour might be possible.

The camera could just take a picture once every rotation when it was pointing North (or something). So the video could not be rotated without having to spin the camera. It might be 5 frames per second or whatever the rotation speed is, so not perfect high quality video. But I am thinking more of delivering packages.

If you were trying to build a drone big enough to deliver a package some distance this could be a lower cost design that the normal quadcopter. It really only has one moving part, the motor/prop. You could use a cell phone or some other electronics to control it. It it wanted to tilt to go in one direction it could make the blade rotate slower on that side and faster on the other side. This would tip the plane of rotation in the direction you wanted to go. This should be easy enough to do in software. A phone also has a compass and GPS (along with tilt and rotation sensors). So a simple phone can have all the needed sensors. There are lighter weight electronics used in drones.

The lift a wing gets is proportional to the mass of air it pushes down and the velocity it pushes it at. The energy to do this is proportional to the mass of air and the velocity squared. So the trick to long term efficient flight it to push a lot of air down but at a slow velocity. One way that we might be able to do this with a low cost vertical take off drone is a "monocopter" or "charybdis". Here are some links:

If you were trying to build a drone big enough to deliver a package some distance this could be a lower cost design that the normal quadcopter. It really only has one moving part, the motor/prop. You could use a cell phone or some other electronics to control it. It it wanted to tilt to go in one direction it could make the blade rotate slower on that side and faster on the other side. This would tip the plane of rotation in the direction you wanted to go. This should be easy enough to do in software. A phone also has a compass and GPS (along with tilt and rotation sensors). So a simple phone can have all the needed sensors. There are lighter weight electronics used in drones.