Construction details. This is a POV-Ray rendering of the .dat file
of the Mk.II pilot, minus the rubber bands, tiller line, and external battery.
As you can see, it is nothing fancy. There was a Mk.I version which used fewer
Lego elements, but pieces kept getting detached and lost under the leaves in
my garden during the 'landing' phase. (The external battery is the major weight
factor, and I figured that a couple more Lego bricks weren't going to have a
lot of impact on performance.)
Top view. Note the large rubber bands wrapped around the RCX fore-and-aft
to stop the battery cover being torn off during landing. You can see the tiller
line which is attached to the cam on the micromotor and runs through the holes
in the 1x8 Technic beams. The line is wrapped a couple of times around the ball
peg on the cam and held secure by the white rubber band (easier to reposition
than using knots). Similarly, there are small black elastic bands wrapped figure-eight
fashion around the triple-length Technic pegs at the ends of the 1x16 beams; these
are used to secure the RCX to the bridle loops of the kite. Not shown in this
picture is the bead of hot-melt adhesive that I later ran around the base of the
micromotor to tack it in place -- the micromotor detached *every single time* (during
the landings) until I used the hot-melt.
Bottom view. A single 9V battery provided power and reduced weight
(the six internal AAs are removed after connecting the 9V battery). The
battery was stuck to the battery cover of the RCX using Sticky Back Velcro.
Industrial Strength. White.
The power was transferred to the RCX's AC/DC port using a 9V battery connector
(RS # 910-0344) connected with mini butt-splices (RS# 910-1332) to a dark-blue-tipped
Radio Shack AdaptaPlug (cut from RS# 273-1614). One of the butt-splices failed after
the landing of flight # 8, otherwise this proved a very satisfactory and
sturdy arrangement. In particular, the battery never detached from the RCX
battery cover during flight or landing; rather, until I fitted the large rubber
bands to hold it in place, the RCX battery cover was occasionally torn off during
I thought that using Velcro would let me reposition the battery pack to fine-tune
the weight distribution. What I found was that the performance of the kite was
not particularly sensitive to the fore-and-aft positioning of the battery
(presumably because of the way in which the RCX was slung under the kite), but
was somewhat sensitive to lateral positioning; i.e., the battery needs to be
attached under the center line of the long dimension of the RCX.
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