The design report

Landing gear fabrication 5.5
The design layout of the landing gears was very basic in detail and the manufacture of
them was taken into little consideration during the design stages. The fuselage was
designed in order to hold the 4 basic gears in place with the front gears being able to fit
into the same compartment as their corresponding servo. The landing gears by
themselves had not been thought out so during fabrication, many decisions had to be
made. The gears had to be strong in tension and compression yet light enough to stick to
weight estimations. Thus, steel rods which were easily available were opted for.
Figure 5.5.01
The bending of landing gears in order to hold the wheels were more complicated than
expected. Since no special machinery was available and due to time constraints, it was
decided that they would just be done by hand at the laboratory instead of seeking
assistance at any local metal working store. This meant that the landing gears were not
bent to an exact right angle. They also did not have a clear and defined bend, but rather
curved upwards to meet the required angle. This proved fatal later during ground tests
and the fact the metal itself was not stable on tarred road but performed better on
flatter concrete proved that the coefficient of friction between the two different surfaces
made a significant difference on the forces experienced by the gears.
The major improvement that was implemented into the design was a suspension
system for the rear gears that was holding approximately 75% of the total load. This
system is shown in figure 5.5.01 and 5.5.02. The suspension had to be limited to a 1cm
spring due to its lack of earlier addition to the design. The fuselages were not designed
to allow for such a system and the bottom plate of the fuselages restricted the allowance
for the suspension spring. The spring was placed between the gear holder placed in the
fuselage above and a stopper below. Finding screws and stoppers also seemed a
challenge at the time as hex key that was required to use some of the stoppers were not
available. We overcame this by using a Philips screw driver to force out the hex screw
on the stoppers.