Otter 40 was
delivered to the RCAF on 27th May 1954 with serial 3682. It was originally
posted to Air Material Command at Rockcliffe, but almost immediately continued
on across the country to the Sea Island base at Vancouver, where it joined 121
Communications & Rescue Flight, with whom it was to serve for three years. It
adopted the unit's QT code and during this period flew alongside the Flight's
other Otter 3680. During August 1955, it was engaged in the search for Pacific
Western Airlines Grumman Mallard CF-IOA, already referred to in relation to
3680. It joined the search on 12th August, flying to Price Island via the
Douglas Channel. It also searched along the Kittimat-Terrace-Lakelse route, and
the Skeena River en route to Smithers. Whilst based at Sea Island with the
Flight, it was also involved in many marine rescues and medevacs.
3682 suffered a “C” category accident on 10th May 1957 in the course of a
cross-country training flight from its base at Sea Island. To quote from the
report: “A glassy water approach was begun from about 150 feet above the water,
at 55 knots, and with between 18 and 20 inches of manifold pressure. This was
maintained until nearing the water. The starboard wing dropped and the aircraft
settled rapidly. Power and left rudder partially corrected the attitude but the
aircraft stalled heavily onto the starboard float. Rippling of the skin of the
tail section resulted. The pilot initiated his approach from an altitude which
did not give him sufficient opportunity to have settled into the proper landing
attitude before the aircraft touched down”.
In June 1957 the Otter went to DHC at Downsview for repairs as a result of this
incident and for incorporation of the All Up Weight modification and in January
1958 it went to No.6 Repair Depot at Trenton for storage. In March 1958 however
it went back to Downsview, having been loaned to DHC for experimental purposes.
It was to become an experimental STOL Otter. The first modifications made to the
aircraft were to install oversize flaps and drooped outer-wing leading edges.
Known as the “Batwing Otter”, 3682 was flown in this configuration during summer
1959. “In order to study the flap's behaviour in the regime known as 'ground
effect', 3682 was mounted on a twenty foot high steel tube frame, and rigged at
an in-flight attitude, with calibrated balance pick-ups at each of the three
landing gear axle sockets. This contraption, mounted on wheels, was towed at up
to 40 mph up and down the runways at Downsview, behind a one-ton truck, to
quantify the lift and drag induced by the huge flaps”. The test data was used,
amongst other purposes, to design a new vertical tail, which was installed on
3682. It was flown in an all-silver scheme, with 'DRB-DHC Stol Research
Aircraft' titles on the rear fuselage, the 'DRB' being the Defence Research
Board. These tests with the “Batwing Otter” concluded in 1960.
The next modification to 3682 was to install a General Electric J-85 jet engine
in the cabin, with a nozzle protruding out through the fuselage sides. The
nozzle could be varied, to provide thrust on take-off and drag to slow the speed
for landing. Testing in this configuration continued during 1961/62, with 3682
making its last flight with its P&W R-1340 piston engine installed on 10th
October 1962. The Otter's next modification was to have two P&W Canada PT-6
turbine engines installed, still retaining the J-85 jet engine in the cabin,
this conversion taking place during the winter of 1962/63. It made its first
flight as such on 7th March 1963 and flight testing continued until 15th July
1965. It had to be grounded at that stage, as it was found that the very
extensive modifications made to the aircraft over the years and the rigorous
flight testing which the Otter had undergone, had caused serious structural
cracking. The Otter was pushed off to the airfield perimeter at Downsview and
the
engines, instruments and all useful parts removed. It languished there until
“reduced to spares and scrap in March 1967”. The full story of 3682's
modifications and test flying and the personnel involved is very well told in
Sean Rossiter's book “Otter and Twin Otter”, to which the reader is recommended.
History courtesy of Karl E Hayes from DHC-3
Otter: A History (2005) |