Saunders ST-27

infobox Aircraft
name=Saunders ST-27
type=Airliner
manufacturer= Saunders Aircraft Company


caption=Saunders ST-27 flying for Air Atonabee c.1984 postcard
designer= David Saunders
first flight=28 May 1969
introduced=
retired=1980s
status=
primary user=Air Atonobee
more users=Aerolineas Centrales de Columbia
produced=1969–1976
number built=12
unit cost=
developed from=de Havilland Heron
variants with their own articles=The Saunders ST-27 regional airliner was build in the 1970s by the Canadian Saunders Aircraft Company in Gimli, Manitoba, Designed as a conversion of the earlier de Havilland Heron, the ST-27 was the most radical DH Heron conversion program, featuring two Pratt & Whitney Canada PT6 turboprops and a stretched fuselage. Despite its promise as a regional airliner, the project collapsed when Manitoba government funding was withdrawn.

Design and development

Using 13 surplus de Havilland Herons, the David Saunders created a conversion with some engineering input from Aviation Traders (Engineering). The remanufactured design was based on a stretched fuselage to accommodate 23 passengers, a lengthened nose to fit a radar, reshaped vertical tail (also increased in size) and two Pratt and Whitney PT6A turboprops replacing the original four Gipsy Queen piston engines along with other minor changes.

Operational history

Originally based in Quebec, the Saunders operation moved to Manitoba in 1971 when substantial government start-up funding was obtained. The Manitoba government eventually invested $52 millions (Canadian) until 1976. Only 12 ST-27s were built. Although the improved performance of the turboprops was appreciated by prospective customers, the lack of a US certification limited potential sales. Two Saunders ST-27s were dry-leased to "Sky-West" in order to provide scheduled air service to Yorkton, Dauphin and Brandon (from Saskatoon and Winnipeg) as an economic development project. Other ST-27s served as regional airliners in Ontario and elsewhere but few air carriers were exploiting this route system at the time. The notable exception was Air Atonabee operating scheduled passenger service from the Island Airport (Toronto), using ST-27 aircraft beginning in 1974; by 1984, it was carrying 25,000 passengers annually.

aunders ST-28

With only meagre sales success and with old Herons becoming more expensive, the company decided to manufacture a new version based on the original ST-27. The first ST-28 was manufactured at the Gimli, Manitoba factory using new jigs and tooling supplied by Hawker Siddeley Aviation. Although superficially similar to the earlier ST-27, the new aircraft benefited from the experiences flying the earlier airliner in regular service. Larger cabin windows, an increased rudder size, four-bladed propellers and a host of other enhancements were incorporated in the ST-28. The first flight of the prototype, "C-FYBM-X" took place on 18 July 1974.

While testing was taking place towards an American certification, the Saunders company had plans for series production but no firm orders and a tremendous drain on available funding. The precarious financial situation eventually led to a review by the Manitoba government and the withdrawal of funding in 1976. The company was forced to windup operations and sold all assets and rights to Air Otonobee, one of the primary operators of the earlier ST-27. By the early 1980s, the sturdy airliners began to fade from service with the last ST-27 being retired during this period.

Aftermath

"C-GCML" (cn 009) was converted from DH Heron 14095 in 1974 and is now on display at the Canadian Bushplane Heritage Centre, Sault Ste Marie, Ontario, Canada. The ST-28 prototype is still found at Gimli in a derelict and abandoned condition in a reclamation yard owned by the Western Canada Aviation Museum.

Operators

;BAR
* Tropical Air Services ;CAN
* Air Atonabee (Otonabee Airways) - City Express
* Atlantic Central Airlines
* Bayview Air Service
* Bearskin Lake Air Service
* Labrador Airways
* Northward Aviation
* On Air
* Patricia Air Transport
* St. Andrews Airways
* Voyageur Airways ;COL
* Aerolinas Centrales de Colombia - ACES Colombia

pecifications for Saunders ST-27

aircraft specifications

plane or copter?=plane
jet or prop?=jet
ref=

crew=2
capacity=23
payload main=
payload alt=
length main=55 ft 10 in
length alt=17.03 m
span main=71 ft 6 in
span alt=21.79 m
height main=15 ft 7 in
height alt=4.75 m
area main= 499 sq. ft
area alt= 46.36 m²
airfoil=
empty weight main= 8,824 lb
empty weight alt= 4,002 kg
loaded weight main=
loaded weight alt=
useful load main=
useful load alt=
max takeoff weight main= 14,500 lb
max takeoff weight alt= 6,577 kg
more general=

engine (jet)=Pratt & Whitney PT-6A
type of jet=turboprop
number of jets=2
thrust main=
thrust alt=
thrust original=
afterburning thrust main=
afterburning thrust alt=
engine (prop)=
type of prop=three-blades
number of props=2
power main= 750 hp
power alt= 559 kW
power original=

max speed main=
max speed alt=
cruise speed main= 211 mph
cruise speed alt= 370 km/h
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main= 860 nmi
range alt=1,594 km
ceiling main= ft
ceiling alt= m
climb rate main=
climb rate alt=
loading main=
loading alt=
thrust/weight=
power/mass main=
power/mass alt=
more performance=

armament=

avionics=

References

*Gerritsma, Joop. "The Saunders ST-27: A Prop-Jet Commuter Liner by Conversion." "Canadian Aviation Historical Society – Journal, Vol. 35, No. 4, Winter 1997".
*Molson, Ken M. and Taylor, Harold A. "Canadian Aircraft Since 1909". Stittsville, Ontario: Canada's Wings, Inc., 1982. ISBN 0-920002-11-0