View source for Engineering:Scottish Aviation Twin Pioneer

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{|{{Infobox aircraft begin
 |name = Twin Pioneer
 |image = Twin Pioneer Prototype at Farnborough 1954.jpg
 |caption = Twin Pioneer prototype bearing Scottish Airlines markings at the 1955 Farnborough SBAC Show 
}}{{Infobox aircraft type
 |type = Transport
 |manufacturer = [[Company:Scottish Aviation|Scottish Aviation]]
 |designer = 
 |first flight = 25 June 1955
 |introduced = 1956
 |retired = 1972<ref name=h75>Hagby: 75</ref>
 |produced = 
 |number built = 87 
 |status = 
 |unit cost =
 |primary user = {{wipe|Royal Air Force}}
 |more users = Malaysia <br /> Nepal
 |developed from = [[Engineering:Scottish Aviation Pioneer|Scottish Aviation Pioneer]]
 |variants with their own articles = 
}}
|}
The '''Scottish Aviation Twin Pioneer''' was a British [[Engineering:STOL|STOL]] transport aircraft built by [[Company:Scottish Aviation|Scottish Aviation Limited]] at Prestwick Airport, Scotland, during the 1950s. It was designed for both civil and military operators. It was conceived as a twin-engined version of the [[Engineering:Scottish Aviation Pioneer|Pioneer]] light transport. Both aircraft required "an area only 30m (99ft) by 275m (902ft) in which to operate."<ref>[http://www.rafmuseum.org.uk/cosford/collections/aircraft/scottish-aviation-twin-pioneer-ccii.cfm Royal Air Force Museum – Scottish Aviation Twin Pioneer] {{webarchive|url=https://web.archive.org/web/20080220220446/http://www.rafmuseum.org.uk/cosford/collections/aircraft/scottish-aviation-twin-pioneer-ccii.cfm |date=20 February 2008 }} rafmuseum.org.uk Retrieved: 11 May 2010</ref>

==Design and development==

Powered by two Alvis Leonides radial engines, the Twin Pioneer was a high-wing cabin monoplane with a triple fin and rudder assembly and fixed tailwheel undercarriage.<ref name="jawa61 p181">Taylor 1961, p. 181.</ref> The prototype Twin Pioneer, registered ''G-ANTP'', first flew at Prestwick Airport on 25 June 1955.<ref name="Jackson p127">Jackson 1988, p. 127.</ref> Flight trials demonstrated that the aircraft had a very short landing run and the aircraft was displayed at the September 1955 Society of British Aircraft Constructors Show at Farnborough.<ref name="ae51 p26">Hemming ''Air Enthusiast'' August to October 1993, p. 26.</ref><ref>{{cite news |url=https://news.google.com/newspapers?id=6GpAAAAAIBAJ&sjid=rpsMAAAAIBAJ&pg=2750%2C6101075 |title=Development of Twin Pioneer |work=The Glasgow Herald |date=22 October 1956 |access-date=24 November 2016}}</ref>

Three pre-production aircraft were built for trials, and sales and demonstrations.<ref name="Jackson p127"/>

In 1958, the 33rd aircraft was used as a prototype for the '''Series 2''' with Pratt & Whitney Wasp R-1340 radial engines of which 5 had been ordered by Philippine Air Lines. In 1959, a '''Series 3''' version was developed to use the improved Alvis Leonides 531 radial engine.<ref name="Jackson p128">Jackson 1988, pp. 128-9.</ref>

Early in its operational life in 1957 the Twin Pioneer suffered two fatal accidents due to fatigue failure which caused the outer panel of the wing to detach from the aircraft in flight.<ref name="ASN1">[http://aviation-safety.net/database/record.php?id=19570830-0 ASN Aircraft accident Scottish Aviation Twin Pioneer 1 JZ-PPX 30 Aug 1957 off Japen Island, Papua New Guinea] aviation-safety.net Retrieved: 28 January 2020</ref><ref name="ASN2">[http://aviation-safety.net/database/record.php?id=19571207-0 ASN Aircraft accident Scottish Aviation Twin Pioneer 1 G-AOEO 7 Dec 1957 Fezzan, Libya] aviation-safety.net Retrieved: 28 January 2020</ref> This issue required significant re-design of the structure and adversely impacted sales.<ref name="BAe1">{{cite web| url = https://www.baesystems.com/en/heritage/scottish-aviation-twin-pioneer| title = Scottish Aviation Twin Pioneer {{!}} BAE Systems {{!}} International}} </ref>

==Operational history==
[[File:Labuan-Twin-Pin.JPG|right|thumb|Scottish Aviation Twin Pioneer at Labuan]]
[[File:SAL Twin Pioneer XL993 ABIN 15.06.68 edited-2.jpg|thumb|right|RAF Twin Pioneer CC.1 wearing sand camouflage in service in 1968.]]
The military version could carry external stores such as bombs under the stub wings. One aircraft became the first aircraft for the newly formed [[Organization:Royal Malaysian Air Force|Royal Malaysian Air Force]] when it was delivered on 16 January 1962; the type served with the air force for 12 years.

The {{wipe|Royal Air Force}} ordered 39 aircraft, which were built between 1958 and 1959, deployed in [[Place:Aden|Aden]] and the Far East.<ref name="BAe1"/> It was used extensively by British forces in the Malayan Emergency and the later confrontation in Borneo. In August 1959, No. 78 Squadron RAF at Khormaksar received some Twin Pioneers to supplement its single engine Pioneers.<ref name="Thetford p470">Thetford 1988, p. 470.</ref>  The Twin Pioneers were employed in moving troops and supplies around the wilderness and on occasions lending support to the Sultan of Oman.  A series of double engine failures caused problems with the squadron losing two aircraft on the same day. Unsuitable soft and hard landing strips were also causes of failures during landings.

Other squadrons that operated the Twin Pioneers were No. 152 Squadron RAF based at Muharraq in Bahrain and No. 21 Squadron RAF,<ref name="Thetford p470"/> which reformed with the type at Benson in May 1959. The squadron then moved to Kenya and in June 1965 to Aden. No. 152 operated around the Persian Gulf and in 1959, No. 209 Squadron RAF based at Seletar began to receive Twin Pioneers. These operated in Borneo and Malaya.  The SRCU (Short Range Conversion Unit) at RAF Odiham also flew three Twin Pioneers for aircrew training. RAF No. 230 Squadron in the UK was the last military operator of the Twin Pioneer. The squadron operated the type in an interesting sand-colour camouflage scheme.

Although mainly used in military operations, the Twin Pioneer was also successful as a commercial transport for operation in areas without proper airfields, where unprepared surfaces were often the norm. Twin Pioneers were sold  as survey aircraft to oil exploration companies with some of the first sales to Rio Tinto Finance and Exploration Limited, and the Austrian and {{wipe|Switzerland}} government survey departments. Three were used by the 'Kroonduif' in Dutch New Guinea.

One Twin Pioneer served as a [[Engineering:STOL|STOL]] training aircraft with the Empire Test Pilot School (ETPS) at RAE Farnborough for many years.

==Variants==

*'''Twin Pioneer''' : Prototype aircraft with {{convert|540|hp|kW|abbr=on}} Alvis Leonides 503 radial engines, one built.<ref name="Jackson p128"/>
*'''Twin Pioneer Series 1''' : Production aircraft with {{convert|560|hp|kW|abbr=on}}Alvis Leonides 514 radial engines, 23 built.<ref name="Jackson p128"/><ref name="BAe1"/>
**'''Twin Pioneer CC.Mk 1''' : Military version of the Series 1 for the Royal Air Force, 32 built.<ref name="BAe1"/>
*'''Twin Pioneer Series 2''' : Production aircraft with {{convert|600|hp|kW|abbr=on}} Pratt & Whitney R-1340 radial engines, 6 built.<ref name="Jackson p128"/>
*'''Twin Pioneer Series 3''' : Production aircraft with {{convert|640|hp|kW|abbr=on}} Alvis Leonides 531 radial engines, 18 built.<ref name="Jackson p128"/><ref name="BAe1"/>
**'''Twin Pioneer CC.Mk 2''' : Military version of the Series 3 for the Royal Air Force, 7 built.<ref name="BAe1"/>

Many Series 1 aircraft were subsequently converted to Series 3 standard, including the prototype and all the remaining RAF CC.Mk 1 aircraft.<ref name="Thetford p470"/>

==Operators==

=== Civil Operators ===
[[File:Scottish Aviation Twin Pioneer Srs3, VH-AIS.JPG|thumb|right|Scottish Aviation Twin Pioneer Srs3, VH-AIS]][[File:Twin Pioneer of Air Atlantique.jpg|thumb|right|Twin Pioneer of Air Atlantique at Exeter in 1998]]'''{{flag|Australia}}'''

* Twin Pioneer Air
* Capricorn Air

'''{{flag|Austria}}'''

* Austrian Airlines

'''{{flag|Canada}}'''

* Eastern Provincial Airways

[[File:Scottish Aviation Twin Pioneer Srs3, Atlantic Air Transport AN0242347.jpg|thumb|An Atlantic Air Transport Scottish Aviation Twin Pioneer Srs3]]
[[File:Scottish Aviation Twin Pioneer.jpg|thumb|A Scottish Aviation Twin Pioneer of JF Airlines]]
'''{{flag|Ecuador}}'''

* TAME

'''{{flag|Iceland}}'''

* Flugfélag Íslands

'''{{flag|Indonesia}}'''

* Garuda Indonesia
* Merpati Nusantara Airlines<ref>{{Cite web|date=15 November 2017|title=Twin Pioneer : Sang Pionir Bermesin Ganda Andalan di Papua|url=https://aviahistoria.com/2017/11/15/twin-pioneer-sang-pionir-penerbangan-di-papua/|access-date=10 February 2021|website=aviahistoria.com|language=id}}</ref>

'''{{flag|Iran}}'''

* Civil Aviation Club of Iran

'''{{flag|Kuwait}}'''

* Kuwait Airways

'''{{flag|Laos}}'''

* Royal Air Lao

'''{{flag|Malaysia}}'''

* Malaysia–Singapore Airlines

'''{{flag|Nepal}}'''

* Royal Nepal Airlines

'''{{flag|Netherlands New Guinea}}'''

* De Kroonduif

'''{{flag|Nigeria}}'''

* Nigeria Airways

'''{{flagicon|North Borneo}} Crown Colony of North Borneo'''

* Borneo Airways

'''{{flag|Norway}}'''

* Fjellfly

'''{{flag|Philippines}}'''

* Philippines Airlines

'''{{flag|Sierra Leone}}'''

* Sierra Leone Airways

'''{{flag|Switzerland}}'''

* Swissair

'''{{UK}}'''

* Air Atlantique ({{wipe|Classic Air Force}})
* JF Airlines 
* Flight One Ltd.

===Military operators===
;{{flag|Indonesia}}
* {{wipe|Indonesian Air Force}}<ref>{{cite web|url=http://armstrade.sipri.org/armstrade/page/trade_register.php|title=Peace Research Institute|publisher=Stockholm International Peace Research Institute|year=1971|access-date= 10 February 2021}}</ref>
;{{flag|Malaysia}} 
* [[Organization:Royal Malaysian Air Force|Royal Malaysian Air Force]] received 15 aircraft.<ref name="Jackson p130">Jackson 1988, p. 130.</ref>
;{{flag|Nepal}}
;{{flag|Oman}}
* {{wipe|Sultan of Oman's Air Force}}
;{{UK}}
* {{wipe|Royal Air Force}}
** No. 21 Squadron RAF (RAF Eastleigh then RAF Khormaksar – May 1959 to September 1967)
** No. 78 Squadron RAF (RAF Khormaksar – October 1958 to June 1965)
** No. 152 Squadron RAF (RAF Muharraq – December 1958 to June 1965)
** No. 209 Squadron RAF  (RAF Seletar – March 1959 to December 1968)
** No. 225 Squadron RAF
** No. 230 Squadron RAF (RAF Odiham – January 1960 to December 1961)
** No. 224 Group Support Flight
** No. 1310 Flight RAF
** RAF Katuanayake Station Flight operated one aircraft.
** RAF Odiham Station Flight
* Empire Test Pilots' School operated one aircraft from 1965 to 1974.<ref name="Jackson p554">Jackson 1988, p. 554.</ref>
* Short Range Conversion Unit (RAF Odiham)

==Aircraft on display==
===Australia===
*Twin Pioneer Mk 3 ''VH-SYS'' is airworthy in the collection of the Historical Aircraft Restoration Society at Shellharbour Airport near Wollongong, New South Wales
*Twin Pioneer Mk 3 ''VH-EVC'' at Walker's Aviation Museum, Barellan, New South Wales

A Mk 1 aircraft is privately owned and is in open storage on a private airfield in Queensland

===Indonesia===
*Twin Pioneer Mk 1 ''PK-GTB'' (ex ''JZ-PPZ'') at Manuhua Air Force Base, Biak Numfor Regency, Papua<ref>{{Cite web|date=21 November 2016|title=Lanud Manuhua Laksanakan Re-colour Monumen Pesawat — TNI Angkatan Udara on Twitter|url=https://twitter.com/_TNIAU/status/800651025665298433|access-date=10 February 2021|website=twitter.com/_TNIAU|language=id}}</ref>

===Malaysia===
[[File:Malacca-Twin-Pioneer-Malaysian-airforce-FM1064-Mar-2001-00.JPG|thumb|right|Scottish Aviation Twin Pioneer of the Royal Malaysian Air Force]]
;On display
*Twin Pioneer Mk 3 ''FM1064'' at the Melaka Transport Museum

Twin Pioneer Mk 3 ''FM1001'' is in the collection of the Royal Malaysian Air Force Museum, located since 2021 at RMAF Sendayan, but the museum is closed

===United Kingdom===
;On display
*Twin Pioneer CC.1 ''XL993'' at the {{wipe|Royal Air Force Museum Cosford}}, Shropshire, England.<ref name="WR195">Ellis 2016, p. 195</ref>
*Twin Pioneer Mk 2 ''G-BBVF'' at the National Museum of Flight, East Fortune, Scotland.<ref name="WR310">Ellis 2016, p. 310</ref>

;Stored or under restoration
*Twin Pioneer Mk 3 ''G-AZHJ'' has been acquired by the South Wales Aviation Museum at St Athan for restoration as a museum exhibit.<ref name="WR275">Ellis 2016, p. 275</ref>

Twin Pioneer Mk 2 ''G-APRS'' (G-BCWF) was airworthy in the collection of the Classic Air Force, Coventry, England.<ref name="WR274">Ellis 2016, p. 274</ref> It was transported to Stirling, Scotland in July 2018 to be converted to a 'glamping' home.<ref>[https://www.scotsman.com/news/vintage-plane-s-new-lease-of-life-as-holiday-home-for-high-flyers-1-4769140 Twin Pioneer to be converted to Holiday Home] Retrieved: 29 January 2020</ref>

==Incidents and accidents==
*Structural failure caused the first Twin Pioneer crash, of JZ-PPX operated by Kroonduif of Indonesia on 30 Aug 1957 about 8 miles off Japen Island, Papua New Guinea, both occupants died.<ref name="ASN1"/>
*The same structural failure also caused the second Twin Pioneer crash, of G-AOEO operated by Scottish Airlines on 7 Dec 1957 near Fezzan, Libya, all 6 on board died, including David McKintyre, the co-founder of Scottish Aviation Limited and a driving force behind the company.<ref name="ASN2"/><ref name="BAe1"/>
*On 10 March 1960, G-ANTP, operated by Scottish Airlines, crashed on take-off at Jorhat-Rowriah Airport, India, killing all 3 persons on board.<ref>[http://aviation-safety.net/database/record.php?id=19600310-0 ASN Aircraft accident Scottish Aviation Twin Pioneer 1 G-ANTP 10 March 1960, Jorhat-Rowriah Airport, India] aviation-safety.net Retrieved: 28 January 2020</ref>
*A recorded loss of a Twin Pioneer occurred on takeoff from Limbang Airport on 17 May 1967. The aircraft, operated by Malaysia-Singapore Airlines, carried the registration ''9M-ANC''. The cause was given as ''unknown''.<ref>[http://aviation-safety.net/database/record.php?id=19670517-0 ASN Aircraft accident Scottish Aviation Twin Pioneer 1 9M-ANC Limbang Airport (LMN)] aviation-safety.net Retrieved: 16 September 2010</ref>
*In Royal Air Force service three aircraft had fatal accidents:
**2 March 1961 – XL966 of 21 Squadron flew into rising ground at Mount Meru, Tanganyika, Tanzania, one killed.
**14 February 1963 – XN318 of 209 Squadron flew into a wooded cliff in Borneo, all five onboard killed.
**18 April 1963 – XL994 of 152 Squadron dived into the ground near Bu Hafafa in Oman, all eight onboard killed.
*Two aircraft had accidents while being operated by Garuda Indonesian Airways:
**On 14 May 1963, the Scottish Aviation Twin Pioneer '''3''', ''PK-GTC'' Garuda Indonesian Airways, damaged beyond repair. No one injuries.<ref>[https://aviation-safety.net/database/record.php?id=19630514-0 ASN Aircraft accident Scottish Aviation Twin Pioneer PK-GTC 14 May 1963]</ref>
**On 20 September 1963, a Scottish Aviation Twin Pioneer 1, registration ''PK-GTB'' Garuda Indonesian Airways, crashed into terrain. Other reports say this Twin Pioneer was damaged on landing. Killed all 7 people on board.<ref>[https://aviation-safety.net/database/record.php?id=19630920-0 ASN Aircraft accident Scottish Aviation Twin Pioneer PK-GTB 20 September 1963]</ref>

==Specifications (Twin Pioneer CC Mk.1)==
[[File:Twin Pioneer CC.Mk 1 Undercarriage.jpg|thumb|right|Fixed undercarriage of Twin Pioneer CC.Mk 1]]
{{Aircraft specs
|ref=Jane's All the World's Aircraft 1958-59<ref name=JAWA1958-59>{{cite book |title=Jane's All the World's Aircraft 1958-59 |editor1-last=Bridgman |editor1-first=Leonard |year=1958 |publisher=Jane's All the World's Aircraft Publishing Co. Ltd. |location=London |pages=98–100}}</ref>
|prime units?=imp
<!--
        General characteristics
-->
|crew=2 (pilot and co-pilot)
|capacity=16 passengers / 12 fully equipped  troops / 10 paratroopers / 12 patient litters / {{cvt|3400|lb|0}} of air-droppable cargo
|length ft=45
|length in=3
|length note=
|span ft=76
|span in=6
|span note=
|height ft=12
|height in=3
|height note=
|wing area sqft=
|wing area note=670
|aspect ratio=8.74
|airfoil=[[Physics:NACA airfoil|NACA 4415]]<ref name="Selig">{{cite web |last1=Lednicer |first1=David |title=The Incomplete Guide to Airfoil Usage |url=https://m-selig.ae.illinois.edu/ads/aircraft.html |website=m-selig.ae.illinois.edu |access-date=16 April 2019}}</ref>
|empty weight lb=9600
|empty weight note=
|gross weight lb=14000
|gross weight note=
|max takeoff weight lb=14600
|max takeoff weight note=
|fuel capacity={{cvt|371|impgal|USgal l|0}} in military versions + 1 or 2 {{cvt|100|impgal|USgal l|0}} cabin auxiliary tanks; ({{cvt|247|impgal|USgal l|0}} in civil versions); {{cvt|9|impgal|USgal l|0}} oil tank in each engine nacelle
|more general=
<!--
        Powerplant
-->
|eng1 number=
|eng1 name=Alvis Leonides 514/8
|eng1 type=9-cylinder air-cooled radial piston engine
|eng1 hp=540
|eng1 note=for take-off
::::{{cvt|520|hp|0}} maximum continuous

|prop blade number=3
|prop name=de Havilland Propellers DH PD 205/323/1 constant-speed feathering propellers
|prop dia ft=<!-- propeller aircraft -->
|prop dia in=<!-- propeller aircraft -->
|prop dia note=
<!--
        Performance
-->
|max speed mph=165
|max speed note=at {{cvt|1450|ft|0}} (Civil)
*'''Maximum continuous cruise:''' {{cvt|163|mph|kn km/h|0}} at {{cvt|3400|ft|0}} (Civil)
|cruise speed mph=119
|cruise speed note=at {{cvt|5000|ft|0}} (Civil)
|stall speed mph=60
|stall speed note=
|never exceed speed mph=
|never exceed speed note=
|minimum control speed mph=
|minimum control speed note=
|range miles=791
|range note=
|ferry range miles=
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling ft=17000
|ceiling note= (Civil)
|climb rate ftmin=1250
|climb rate note= (Civil)
|time to altitude=
|lift to drag=
|wing loading lb/sqft=20
|wing loading note= (Civil)
|fuel consumption lb/mi=
|power/mass=
|more performance=<br />
*'''Take-off distance to {{cvt|50|ft|0}}:''' {{cvt|1120|ft|0}} (Civil)
*'''Landing distance from {{cvt|50|ft|0}}:''' {{cvt|1170|ft|0}} (Civil)
<!--
        Armament
-->
|bombs= up to {{cvt|2000|lb|0}} of bombs, under undercarriage sponsons

|avionics=
}}

==See also==
{{aircontent|
|related=
*[[Engineering:Scottish Aviation Pioneer|Scottish Aviation Pioneer]]
|similar aircraft=
*[[Engineering:Percival Pembroke|Percival Pembroke]]
|lists=
*List of aircraft of the Royal Air Force
|see also=
}}

==References==

{{reflist}}

===Bibliography===
{{refbegin}}
*Ellis, Ken, ''Wrecks and Relics 25th Edition''. Manchester, England. Crecy Publishing, 2016. {{ISBN|978 191080 9037}}
*Green, William. ''Macdonald Aircraft Handbook''. London. Macdonald & Co. (Publishers) Ltd., 1964.
*Donald, David, ed. ''The Encyclopedia of World Aircraft''. London: Aerospace Publishing, 1997. {{ISBN|1-85605-375-X}}.
*Hemming, Nick. "'Primrose' & Friends: The Scottish Aviation Twin Pioneer". ''Air Enthusiast'', Fifty-one, August to October 1983. pp.&nbsp;21–31.
*Jackson, A. J. ''British Civil Aircraft 1919-1972 Vol 3'', 2nd Edition (reprint) 1988. London: Putnam {{ISBN|0-85177-818-6}}
*Taylor, John W. R. ''Jane's All The World's Aircraft 1961–62''. London: Sampson Low, Marston & Co. Ltd, 1961.
*Thetford, Owen. ''Aircraft of the Royal Air Force 1918–57'', 8th edition. London: Putnam, 1988.
{{refend}}

==External links==
*[https://www.rafmuseum.org.uk/research/collections/scottish-aviation-twin-pioneer-ccii/ RAF Museum entry]
*[http://www.flightglobal.com/pdfarchive/view/1955/1955%20-%200357.html "Twin Pioneer – Large Loads from Small Fields"] a 1955 ''Flight'' article


[[Category:STOL aircraft]]
[[Category:High-wing aircraft]]
[[Category:Twin piston-engined tractor aircraft]]

{{Sourceattribution|Scottish Aviation Twin Pioneer}}