By ANN Correspondent John Ballantyne
Think back to ultra-yesteryear... You might remember this one.
The basic design began life as the Cloud Dancer. It offered the
hope of achieving the dream for those of us who began powering our
hang gliders. Our goal was to power up to the lift, then shut down,
and SOAR. However, adding an engine is complicated and affects
the machines flying characteristics more than you might think at
first.
At first, the Cloud Dancer appeared to be a very good compromise
between sailplane and ultralight. However, actual use revealed some
problems and some crashes.
The design was bought by a second company who significantly
redesigned the Cloud Dancer (i.e. changed the V tail to cruciform)
and renamed it the Cumulus. Still, flying it proved to be less than
the original dream promised.
Dave Ekstrom, President of Ultralight Soaring
Aviation, hopes to fulfill the original dream of a powered craft
that is reasonably capable of soaring. He has gained the production
rights for the Cumulus and has already done some thoughtful
work.
"The basic design of the Cumulus is excellent," he said. It is a
conventional design with ailerons, flaps that can also go up for
reflex, and cruciform tail. I have made changes such as offering a
full-span aluminum wing covering in addition to the original
aluminum-then-fabric wing. Buck-riveted aluminum wing skins will
also be much less sensitive to ultraviolet ray degradation (read
"sunshine").
He has placed welded tabs at strategic locations around the
pilot's seat to facilitate assembly, and for convenience in
mounting instruments and accessories. The wing tips will be
redesigned, a larger tail is now framed with welded chrome-moly
tubing, and a redesigned throttle/spoiler control allows
simultaneous or separate changes in throttle and spoiler settings.
Additionally, the new seat allows for more fuel capacity behind the
pilot and optional wing tanks will increase options for buyers.
Another choice will be shorter wings for a "sport plane with
soaring capability."
The new Cumulus has not flown yet. Dave reports
that some 6 individuals are pressing him very hard to get it
flying, and into production. The manual is "80% done." He is
exhibiting a partially completed first unit at EAA Sun 'n Fun
and will now accept deposits from customers. But... Dave does
not expect to begin kit deliveries until September, at best.
This reporter hopes that the long-awaited dream of powering up
to the thermals for an afternoon of soaring is about to come true.
ANN will carefully watch development and report along the way.
Factory Expectations:
Wing span 43 feet, empty weight 360 lbs, gross weight 640 lbs,
max speed (Vmax) 90 mph, cruise range 35-75 mph, stall (best flaps)
32 mph, Engine ROTAX 447, best Sink 190 fpm at 34 mph, glide angle
20:1 at 43 mph, rate of climb 1000fpm, limit load +4.4/-2.0G, wing
loading 4.56 lbs/sq ft.
NTSB Final Report: Aviat A1
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