Wingtip Propeller Theory

 

There have been a number of studies of how efficient putting propellers on the wing tips would be.   We will try to collect some good ones here.

 

Below is a video of a simulation:

Below is a list of papers:

  1.  Analysis and Design of a Small-Scale Wingtip-Mounted Pusher Propeller 
  2. Aerodynamic Analysis and Optimisation of Wingtip-Mounted Pusher Propellers 
  3. Experimental and numerical study onwingtip mounted propellers for lowaspect ratio UAV design



If you want to place solar panels on a wing, it is easier to have a rectangular wing.  I think for this shape wing the wing tip losses as a glider would be more severe and so having wing tip propellers makes for a bigger win than normal shape wings.



Comments

Post a Comment

Popular posts from this blog

Switching from iNav to Ardupilot for Flight Controller

   We had been using iNav software for the flight controller but have decided to switch to Ardupilot the following reasons:    1) Ardupilot can have a "companion processor" like the Jetson Nano that does vision/AI and decides things like which way to go.   We really want to explore what can be done with AI on a solar powered airplane.   Like can it avoid clouds and stay in the sun more, can it scan the horizon with a telephoto camera looking for boats, can it head for a boat automatically, etc.   This seems fun.    2) Ardupilot can use a companion processor to communicate over cell data network (4G) to a ground station.  With this we could fly all around Anguilla and still have communication between the ground station and the airplane.  So from the ground we can change the mission plan during the flight.    We could decide to go to a particular boat, or decide to come home because the change of rai...
Read more

MPPT in iNav software

Image
  Solar panels produce the most watts when operated at some ideal voltage called Vmppt. Normally people use special hardware called an MPPT controller to draw power from the solar at that voltage and then convert it to the right voltage for a battery. We have worked out a program for iNav so that this extra hardware and weight won't be needed.   The idea is to adjust the throttle higher if the voltage is higher than ideal and to lower it if the voltage is lower than idea.   Since we already have a computer onboard that knows the battery voltage and controls the motors, we can get things operating at the ideal voltage just using some software.  This will help keep weight down on solar airplanes we make.   We also save any conversion losses or power limitations of the MPPT hardware.   You can see this in the video and the picture after that.     Here is a shot of the program: A shot of the supercapacitor, flight controller, volt meter: ...
Read more

Copper Clad Aluminum Wire

Image
  Aluminum wire is 61% as conductive a copper and only 30% of the weight .   So for the same amount of conductance it is half the weight.   Since weight is an important thing on a solar airplane, this is interesting.  The first problem is that the layer of oxide on aluminum makes it very hard to solder to.   We need to connect wires together, so this is a problem. There are copper clad aluminum wires .   The core is aluminum but the outside is copper.   This way you get most of the light weight of aluminum but you can still solder to it like copper.   Below is a picture: A bundle of thin strands seem to have a bad reputation for corroding if outdoors.  I am hopeful that a single solid core, about 1.5 mm diameter, would last well enough for me.  However, I am can't find this on Amazon so far. There is a place in China that might work .   There is a useful website for calculating power loss in a wire depending on ...
Read more