Introduction: Desktop Ornithopter

By
About: I work in IT as a manager of a team responsible for server based applications. I am also a lecturer in Database Design, XHTML and CSS at the University of London, England

To create a flying machine that simulated bird wing movement ( an ornithopter) but was able to have smooth movement.

The difficulty in creating an ornithopter is the issue of having smooth and consistant wing movement. Many people have tried building these and never quite get the movement right with the wings flapping unevenly.

This little project started about 18 months ago whilst pondering how to do it... this little instructable hopefully explains how I got around the problem.

Step 1: Items Used

1. Coffee Stirrers
2. 4mm MDF
3. Motor from redundant 1990's video camera
4. Various cogs and clips from video camera
5. 2mm thick dowels from PC cleaning equipment
6. SupaGlue
7. Twine

Build Time

6 hours

Step 2: The Upper Mechanism

The main difficulty that presented itself from the beginning was the issue of the smooth motion required to get the wing blades to move smoothly. This diagram shows a schematic overlay of the wing coupling on the ornithopter. The upper wing joints forming a triangle are fixed and the lower (in the current shot) is fixed to the cam. You will note that the distance between the couplings at the low stroke and high stroke is 36mm but at mid point the distance between the central coupling and each out joint is 30mm.

Due to this issue I saw fit to cut a slit in the wing blade (circled in blue on the left) with a length of 6mm, the difference between the maximum coupling distance and the the shortset coupling distance. The couplings were made by drilling a 2mm dowel into MDF and then feeding the blades onto them. The blades were kept in place my minute aluminium washers found in the video camera.

Step 3: Lower Mechanism

This is where a simple cam mechanism worked an absolute treat. This part required a bit of trial and error but it was finally worked our using some graph paper, a compass and my trusty metal ruler. The trick is to ensure that the three arms creating the cam are cut to specific lengths so that the upthrust and down thrust do not create a jam at the lowest and highest points. The measurements I used are:

  • Arm A - 20mm
  • Arm B - 52mm
  • Arm C - 73mm

Note that there is no real need for the white polythene cog behind arm A but it was a good support. Behind the system shown is a small cog which inturn is attached to a small 6 Volt motor. This motor was absolutely fantastic, it was taken from an old video camera in the lens housing. It appears the motor was used focus the lens. Not a fast motor but had a very, very strong torque.

Step 4: End Notes

You will note that ornithopter appears to be held together with twine. The reason for this was that the motor that was used was so powerful and with such a high torque that it had a habit of grinding over the gears. The twine was introduced to increase the tension on the cogs connecting the motor to armature A's axle.

Before I get some silly comment from someone, I do have this published on my website (non-commercial) and I have a few photographs and a few concept designs and mpg of the ornithopter. Please enjoy it for what it is, thank you.

Ornithopter library

The whole idea was just a method to see the best way to get linear motion from circular