Day 3 - Saturday 15th February 2003
After the completion of the basic frame last weekend, this weekend's job was to get the undercarriage sorted out. Most of the week was spent working out how this could be achieved.
Ideas
I had three ways of making the undercarriage move:
- Springs
- Gravity
- Electric motor
The first two would require latches to keep them in the unsprung or up position. The electric motor would require a battery and some switches (not really a problem).
Gravity, although a nice option (it's free), I decided against, because it lacks 'professionalism' - ie. it'll look a bit amateur.
Since I wanted three legs, and I had two gas springs, I had to either come up with a way to either use one spring on one leg and the other on the other two, or buy some more.
Appearing undercarriage
The first idea I had was to have the legs extend downwards:
The second idea I had was to have the legs unfold from underneath the body:
The third idea I had was an extension to this - reducing the angle at which the legs rotated:
The problem with gas springs
All the gas springs that were easily accessible to me were too large to fit in the model, so gas springs could not be used. That left the electric motor.
Undercarriage arrangements
My original paper model had three legs - one at the nose, and two on each wing. However, there are a number of options available:
The two front legs was an interesting idea, but I decided against it - it does not seem to be very stable. Having the rear legs parallel makes it easier to move, as only one connection is required. However, the design chosen was the last one - it has a compactness to it.
Now the materials and arrangement was chosen, it was time to do some work...