2
PRELIMINARY NOTES
This model came about in early 2020 during a period of Corona Virus restrictions,
and was designed to use items at hand at the time. Specifically, it was designed to be
a small balsa build to use the diminutive 5.1 x 3.1 inch folding props I had on hand.
These suit a 2mm to 2.3mm shaft, so originally an old Hacker B20 motor was fitted.
This has been recently replaced with an inexpensive contemporary Surpass Hobby
20mm R/C car motor with a 2.3mm shaft, which works really well in this application.
Although designed for a 20mm in-runner, the nose is wide enough to fit up to a
28mm outrunner if desired, but some modifications will be required. The
construction notes assume previous experience building similar models.
Despite its small size, this model is very efficient with its Selig 3021 airfoil and keeps
up very well with the larger gliders at our field. Penetration is especially good.
Whilst clearly only “semi-scale”, this model was designed to keep the character of
the original Dart with its small tail volume compared to the wing. This necessitates a
Centre of Gravity further forward than you would normally expect. A small amount
of lead ballast will likely be necessary to achieve the CG on the plans. The first flight
of the prototype was with a much too rearward CG, which, combined with large
control throws made for a very unstable model! The CG on the plans should
definitely be adhered to!
This Dart could easily be built as a slope-soarer by using a solid balsa nose instead of
the motor. This construction manual assumes that the builder is familiar with
“traditional balsa construction methods”. The construction notes and plans have
some small changes from the original prototype which reflect improvements, and
should take precedence over any differences noted compared to the photographs.
The manual will assume that a kit of all parts has been cut before assembly
commences. Metric and imperial sizes are used interchangeably. The parts layout
files are recommended only. These, and the plans may be used as desired for private
purposes. For commercial use, please contact the designer.
Graham Reddin
Sydney, Australia
May 2021
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Summary of Contents for SLINGSBY DART 17
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