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The
Evolution of a Rubber Model |
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Some 14-15 years ago when I was starting to play
with rubber models, I was attracted to a tiny
design called Baby Toots (designed
by a Karl Dieckman and published in Model
Airplane News, April 1950). This diminutive
airplane was but 13” span, with a near-elliptical
Ritz wing of 29 sq.
ins. area. It was claimed to be not only spin-proof
but also capable of almost 1 ½ minutes
duration.
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Baby Toots |
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This model is probably the foundation of
my current preference for models with twin
fins and single-blade folders!
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Baby Toots stabilizer was
a bit overbuilt and heavy for its size, resulting
in the addition of a quantity of nose ballast
to compensate. Though I never achieved the
claimed duration, Baby Toots
proved an interesting little model to fly
- with an initial skyrocket climb, settling
into many flights around the 60-70 second
mark. This model eventually thermaled out
of the park and onto the rooftops of an industrial
area. |
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Baby Toots |
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Its performance encouraged me to draw up a
50% enlargement of the plan. Outlines were
retained but I substituted a thin undercambered
airfoil for the original Ritz wing, and modified
the structure to suit. |
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The new model was Christened Mini
Toots. Once again nose ballast was
required even though the stab had been built
proportionately lighter. I also found that
I'd been over-generous with the general structure,
because the model was heavier than expected.
Still, it was more consistent than its predecessor,
flew very well, and gave me a great deal of
pleasure. |
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Mini-Toots
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Mini-Toots was then enlarged
a further 50% and Toots 150
took to the air. The fuselage nose had been
lengthened by one bay, but the model still
required a small amount of ballast. |
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structure was lightened substantially –
especially the wing. This version, with 30g
of TAN2 rubber, proved to be a very good performer.
It achieved some good local contest scores
before it vanished into the woods, when it
was caught in a thermal that was stronger
than the "dethermalized" rate of
descent. |
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Toots 150 |
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I was very encouraged, so I drew up and built
a larger airplane of 210 sq. in. wing area.
The wing outline was blunted slightly and
some further attention given to weight reduction
using laminated parts, tapered spars, etc.
The original fuselage design was replaced
by a longer, somewhat uglier one, and the
model was powered with 50 grams of TAN2. I
named this new version Ellipsis. |
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Flight tests were very impressive, with the
model trimming out easily up to about 85%
power. I decided to enter this model in a
dawn Unlimited one-flight event,
mainly to assist in making up the numbers
on the entry list. At contest time I wound
the motor until it was virtually creaking,
and launched with some hope that it would
survive the initial burst. Later, when the
other models were landing, Ellipsis
was still circling on high. |
Ellipsis |
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It finally hit the roof of a distant
farmhouse after a flight of around 5
½ minutes! Nobody was more surprised
than I. The model hasn’t been
flown in competition very often, as
Unlimited Rubber contests are few and
far between in this area. But it has
always performed well when opportunity
has permitted.
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