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1/10th
scale MODEL DEVELOPMENT
THE
DAM BUSTER: Does size matter? It certainly does,
when testing out a theory on a budget. We were not
about to commit ourselves to building a solar powered
boat without some persuasive evidence that the theory
would work. Remember the Dam Busters? Barnes
Wallace developed his early theory for the
"bouncing bomb" using ping pong balls and a
catapult. Later, after convincing the Ministry of
Defence that he had a good idea, Mr Wallace was allowed
to use a proper test tank for some months.
A
model is an ideal way of obtaining first hand practical
experience of the problems ahead. In fact, most of
the design challenges can be put to the test in this way
then multiplied up. Any problems encountered on
the model should be the same as the full size vessel.
ISSUES:
There are three main areas of concern:
1)
will the proposed design prove stable ?
2)
will the model hull move efficiently in water ?
3)
will solar generation provide enough power to move the
model ?
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WHAT
SIZE: In order for results to be as accurate as
possible, we needed to make our model as large
as could be practically manhandled. 1/10th
scale meant that the completed model would weigh
in at about 55lbs and measure 6 feet. That is
about as bulky as one would like, when it comes
to launching onto any pond, or the sea.
Inevitably most testing would be conducted by
the one person working alone.
Click
on this picture to see Catamaran construction
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CONSTRUCTION:
UPVC piping of the rainwater variety served as
the submerged tubes. The first model was formed
mostly of aluminium sheet on box section steel
frames. For the superstructure, a male mould or
plug, was made of 1/2" chipboard coated
with resin. The submerged cone sections were
turned in pine ( thanks Bill) and coated with
resin. Dateline Marine Services (specialist
model mouldings) produced the female moulds and
the first impressions at a substantial discount
(thanks Lloyd). The next model used ordinary
3/16" and 1/2" ply and a shaped foam
core to replace the formed ally sheeting low
down.
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SWATH
MODEL ELECTRICS CATAMARAN
MODEL CRIVETRAIN
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AMATEUR
YACHT RESEARCH SOCIETY
MODEL
POWER BOAT ASSOCIATION
