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Cierva C.30

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For a description of the format and data included in Production Tables, see here.

Contents

Type Description
Projected Variants

Type Description

  • C.30
  • Two seat direct control autogyro. The aircraft was an all new design, featuring the hanging stick direct control developed with the C.19 Mk.V. The fuselage was of welded steel tube construction, wire bracing being employed in the top and bottom panels aft of the cockpits, with wooden stringers to create a rounded shape. The engine mounting was built up as a complete unit and detachable as such from the fuselage. The mounting ring was a mild steel angle section attached to the fuselage by eight mild steel struts. An aluminium cowling extended from the engine mounting ring to the front bulkhead of the front oookpit. Upper decking of plywood and spruce extended from the cowling to the rear bulkhead of the rear cockpit, finishing flush with the top longerons. The remainder of the body exterior consisted of doped fabric on a framework of plywood and spruoe formersclipped to the top and bottom longerons, and spruce longitudinal stringers.
    A braced tailplane with upturned tips set at 45 degrees was built up from spruce spars and plywood ribs and attached to the upper longerons, the left side of the tailplane having an inverted aerofoil section to counter roll-axis torque produced by the propeller.Both horizontal and tip sections were fitted with trimming tabs. There was a large dorsal and small ventral fin, constructed of small diameter tubes, welded integral with the fuselage. There was no rudder. The wide-track undercarriage had a pair of single legs attached to the upper longerons, wire-braced to the lower, along with a small tail wheel. The three-blade rotor was mounted on an aft-leaning tripod and featured an aerodynamically faired rotor head. The blades consisted of a 1-1/2 in dia nickel chrome steal tube secured to a large fork end, with spruce ribs threaded on to the spar, the whole covered with a plywood skin. The rotor tip consisted of a block of shaped balsa wood.
    The aircraft was erected by National Flying Services Ltd., using a C.19 fuselage converted by Airwork Ltd at Heston, with rotor blades made by Oddie, Bradbury & Cull Ltd at Eastleigh and rotor hub, clutch etc. by the Mollart Engineering Co of Kingston-upon-Thames. One 105 h.p. Armstrong Siddeley Genet Major I powerplant.
  • C.30P Mk.II
  • Pre-production version of the C.30, featuring modified landing gear, with the main leg moved forward and the bracing cables replaced by struts, and a four-legged pyramid rotor mounting. Assembled by Airwork Ltd from similar components to the prototype. One 140 h.p. Armstrong Siddeley Genet Major IA powerplant. (Despite the 'Mk.II' designation, this was the first of the pre-production machines)
  • C.30A
  • (Avro Type 671) As the C.30P but featuring a modified undercarriage. With the original main and bracing leg undercarriage, large vertical movement on landing produced significant lateral motion and resulting large wheel sideloads. The new undercarriage structure featured and outrigger structure that supported the top of the main leg, thus keeping the vertical. One 140 h.p. Armstrong Siddeley Genet Major IA powerplant.

C.30A Specification
Rotor Dia Length Tail Span Disc Area Empty Wt Max AUW Minimum Speed Maximum Speed Range Service Ceiling
37 ft 19 ft 8 in 10 ft 2 in 1075 sq ft 1210 lb 1800 lb 15 mph/ 13 kn 94 mph/ 82 kn 285 mi 6600 ft
11.28 m 5.99 m 3.1 m 99.87 m2 549 kg 816 kg 24 kph 151 kph 459 km 2012 m

  • C.30S
  • As C.30A but fitted with a 203 h.p. Salmson 9Nd powerplant with Ratier propeller.
  • C.30A Rota I
  • (Avro Type 671) As C.30A for Army Cooperation duties, to Air Ministry Specification 16/35. One140 h.p. Armstrong Siddeley Genet Major IA (known in the RAF as the Civet I) powerplant.
  • C.30 Mk.II
  • C.30P G-ACWF used for two-blade and three-blade Autodynamic rotor development and test (see C.40).
  • C.30 Mk.III
  • C.30 Mk.II G-ACWF with experimental two bladed rotor and Autodynamic rotor head features (see C.40), enabling vertical jump starts. New, significantly longer main undercarriage legs with the lower bracing attached near mid leg rather at the wheel hub, and a significant rudder. Experimentation with the C.30 Mk.III led to the abandonment of the two bladed rotor and Autodynamic rotor head.
  • C.30 Mk.IV
  • C.30 Mk.III G-ACWF testing three-blade Autodynamic rotor with central friction damper development and test.
  • C.30 Mk.V
  • C.30 Mk.IV G-ACWF modified to flight test the new three bladed rotor and hub with compound hinging that overcame the problems of the two bladed design. C.30A style undercarrige.
  • C.30J
  • C.30 Mk.V G-ACWF modified as a development prototype for the C.40, fitted with a new rotor head design. One 203 h.p. Salmson 9Ng powerplant.

Projected Variants

  • Rota Mk.2
  • A cleaned-up C.30 with a new rotor head and tail arrangement. This may have been solely an Avro project.

Production Details - All UK Built Aircraft

C/n (1) Initial
Registration		 Type Notes
1 aircraft built by National Flying Services, Hanworth, for the Cierva Autogiro Co. Ltd., Hanworth. First flew April 1933.
1 G-ACFI C.30 Retained by Cierva.
1 aircraft built by Airwork Ltd., Heston for the Cierva Autogiro Co. Ltd., Hanworth. First flew October 1933.
AH1 G-ACKA C.30P Mk.II Retained by Cierva.
80 aircraft built by A.V. Roe & Co. Ltd., Manchester. Delivered between December 1933 and 1937. A further 4 aircraft were cancelled.
658 G-ACIM C.30P Initially retained by Cierva.To Lioré-et-Olivier, Paris in March 1934.
659 G-ACIN C.30P Retained by Cierva.
660 G-ACIO C.30P Retained by Cierva.
705 G-ACUI C.30A Unknown, but possibly retained by Cierva. Later to the Hon. A.E. Guiness. Impressed as HM581 in September 1942. To Essex Aero Ltd. in 1945 as G-AHTZ.
706 G-ACVC C.30A Initially retained by Cierva. Sold abroad in August 1934.
707 G-ACVX C.30A Unknown, but possibly retained by Cierva. Later to the Hon. Mrs Victor Bruce. To NV Autogiro Import, Hillegersberg in October 1937 as PH-ASA.
708 G-ACWF C.30A Retained by Cierva and progressively modified as the Mk.II, Mk.III, Mk.IV, Mk.V and C.30J. Impressed as DR624 under contract H.546635/41. Restored as G-AHMI to Fairey Aviation Ltd on 23 April 1946.
709 G-ACWG C.30A Initially retained by Cierva. To Etablissements Lioré-et-Olivier, Paris in July 1936 as F-AOHY.
710 G-ACWH C.30A Retained by Cierva. Impressed as DR623 under contract H.546635/41. Restored as G-AHLE to Cierva Autogiro Ltd on 23 April 1946.
711 G-ACWI C.30A Initially retained by Cierva. To Club de l'Autogire de France, Neuilly-sur-Seine in October 1935 as F-AOIO.
712 G-ACWJ C.30A Initially retained by Cierva. To NV Autogiro Import, Rotterdam in January 1935 as PH-HHH. Cancelled from Dutch register in January 1938 and stored by Cierva. Impressed as AP508 under contract B.50801/40 in June 1940.
713 G-ACWK C.30A Initially retained by Cierva. To Germany in November 1934 as D-3164; later D-EKOM
714 G-ACWL C.30A Initially retained by Cierva. To Germany in November 1934 as D-EKOP.
715 G-ACWM C.30A To Albert Batchelor, Broadstairs. Impressed as AP506 under contract B.50801/40 in June 1940. Restored as G-ACWM to Horace Reginald Philip, Herne Bay, on 24 May 1946.
716 G-ACWN C.30A To Austin Dobson, Haselmere. Sold abroad February 1937.
717 G-ACWO C.30A Initially retained by Cierva. To the Autogiro Flying Club Ltd in February 1939. Impressed as V1187 under contract B.53192/39 in December 1939. To Southern Aircraft (Gatwick) Ltd in May 1946, sold to Belgium for spares.
723 K4230 C.30A Rota I To RAF (See Military Table).
724 K4231 C.30A Rota I To RAF (See Military Table).
725 G-ACUT C.30A Unknown, but possibly retained by Cierva. To Airwork Ltd in June 1934.
726 G-ACUU C.30A To Air Service Training, Hamble. Impressed as HM580 in September 1942. Restored as G-AIXE to Cierva Autogiro Co Ltd on 23 May 1946, but later restored to G-ACUU (G-AIXE reissued to an Avro 19).
728 G-ACWP C.30A Initially retained by Cierva. To Ernest Joseph Jobling-Purser. Impressed as AP507 under contract B.50801/40 in June 1940.
731 G-ACWR C.30A To J.G. Weir. Impressed as V1186 under contract B.53192/39 in December 1939.
732 G-ACWS C.30A To J.H. Moller. Impressed as AP509 under contract B.50801/40 in June 1940. Restored as G-AHUC to Cierva Autogiro Co Ltd on 11 June 1946; to A.B. Helikopterflyg, Bromma in July 1946 as SE-AZA.
733 G-ACWT C.30S To Cierva Autogiro Co Ltd. To Etablissements Lioré-et-Olivier, Paris in July 1936 as F-AOLK. See note 3.
734 VR-HCT C.30A To Far East Aviation Co Ltd. To the Chinese Central Government, Nanking in 1936.
735 LN-BAD C.30A To J.L. Tiedemanns Tobaksfabrik, Oslo. To Norwegian Army Air Service in 1934 as 99 (See Military Table). To Rolf von Bahr, Stockholm in Sep 1936 as SE-AFI.
736 G-ACWU C.30A To Cierva Autogiro Co Ltd. To Alpar, Berne in December 1934 as HB-MAB.
737 G-ACXW C.30A To Light Planes (Lancashire) Ltd. Impressed as BV999 under contract B.50801/39 in January 1941. Restored as G-ACXW to Fairey Aviation Ltd on 23 April 1946.
738 PP-TAF C.30A Exported to Brazil.
739 OK-ATS C.30A To Bata Ltd, Zlin.
740 SE-AEA C.30A To AB Autogiro Agenturen.
741 VT-AFF C.30A To Prince Ghanshyam Singhji of Limbdi, Kathiawar, via Tata Sons Ltd, Bombay.
742 VT-AFS C.30A To Tata Sons Ltd, Bombay.
743 G-ACXG C.30A Unknown, but possibly retained by Cierva. To A.A. Noer & Co. Ltd. To NV Autogiro Import, Hillegersberg in June 1937 as PH-ARA.
744 G-ACXV C.30A To A.V. Roe & Co. Ltd. To Ministerstvo obrany České republiky in December 1935 as OK-IEA.
745 G-ACYP C.30A To Ministerstwo Komunikacji, Poland in October 1934 as SP-ANN.
746 K4232 C.30A Rota I To RAF (See Military Table). To Rolf von Bahrs Company, Helicopter-Flyg, Sweden, as SE-AZB.
747 K4233 C.30A Rota I To RAF (See Military Table). To Southern Aircraft (Gatwick) Ltd on 22 June 1946 as G-AHXI. To Heraldis, Grimbergen in July 1948 as OO-ADK.
748 VT-AFQ C.30A To Tata Sons Ltd, Bombay.
749 G-ADKY C.30A To Cierva Autogiro Co Ltd. To Italy, August 1935.
750 M-1 C.30A To Danish Army (See Military Table). To Rolf von Bahr, Stockholm in October 1940 as SE-AKW.
751 K4234 C.30A Rota I To RAF (See Military Table).
752 G-ACWZ C.30A To Redhill Flying Club.
753 G-ACXA C.30A To Cierva Autogiro Co Ltd. To Regia Aeronautica as MM30030. (See Military Table). To Vittorio Bonomi, Milan in 1935 as I-CIER
754 OK-IEA C.30A Registration G-ACXB reserved but ntu. To Czechoslovakia.
755 G-ACXC C.30A Registration reserved but ntu.
756 ES-SCA C.30A To the Spanish Aeronautica Naval (See Military Table).
757 ES-SCB C.30A To the Spanish Aeronautica Naval (See Military Table).
760 G-ACXR C.30A To Lawrence Eustace Venn, London.
771 G-ACYH C.30A Retained by Cierva. Impressed as DR622 under contract H.546635/41. Restored as G-AHRP to Jack Gillam, London in April 1946.
772 G-ACXP C.30A To the Bristol and Wessex Aeroplane Club Ltd. To W.C. Gatenby & H.A. de Kantzow, Essendon in January 1935 as VH-USQ.
774 K4235 C.30A Rota I To RAF (See Military Table). To Fairey Aviation Ltd on 8 May 1946 as G-AHMJ.
775 G-ACYE C.30A To the Earl of Essex. Impressed as AP510 under contract B.50801/40 in June 1940. Restored as G-ACYE to Jack Gillam, London on 6 June 1946.
776 G-ACYC C.30A To Henlys Ltd, London. To Etablissements Lioré-et-Olivier, Paris in November 1935 as F-AOHZ.
777 LY-LAS C.30A To Lietuvos Aero Klubas (Lithuanian Aero Club).
779 C.30A To the Soviet Union.
780 G-ADCK C.30A To the Commonwealth Mining and Finance Co. To the Commonwealth Prospecting Co., Perth in July 1935 as VH-UUQ.
781 41-2 C.30A To the Spanish Air Force (See Military Table).
782 41-3 C.30A To the Spanish Air Force (See Military Table).
791 G-ACZV C.30A To A.A. Nathan. To France in April 1937 as F-BDAA.
792 VH-USR C.30A To A.T. Reid, Mascot.
793 K4236 C.30A Rota I To RAF (See Military Table).
796 K4237 C.30A Rota I To RAF (See Military Table).
798 G-ADBJ C.30A To Arthur Quilton Cooper, Ingatestone.
800 C.30A To French Air Ministry.
801 C.30A To French Air Ministry.
802 C.30A To French Air Ministry.
803 C.30A To French Air Ministry.
804 C.30A To French Air Ministry.
805 K4238 C.30A Rota I To RAF (See Military Table).
806 K4239 C.30A Rota I To RAF (See Military Table). To Basil Henry Arkell in October 1946 as G-AIOC.
808 C.30A To Far East Aviation Co Ltd. To the Chinese Central Government, Nanking in 1936
815 OE-TAX C.30A To Austria.
818 (none) C.30A To the Belgian Air Force (See Military Table)
unknown K4296 C.30A Rota I To RAF floatplane (See Military Table).
unknown K4775 C.30A Rota I To RAF (See Military Table).
985 M-2 C.30A To Danish Army (See Military Table). To Rolf von Bahr, Stockholm in October1940 as SE-AFZ, but ntu; used as spares for SE-AKW.
1029 1 C.30A To the Yugoslav Air Force (See Military Table).
1030 2 C.30A To the Yugoslav Air Force (See Military Table).
1031 R-340 C.30A To Juan Reges Aymá, Argentina. To LV-CEA; LV-FBI. See Note 2.
1032 C.30A To Argentina.
unknown K6553 C.30A Rota I Intended for RAF (See Military Table), but cancelled.
unknown K6554 C.30A Rota I Intended for RAF (See Military Table), but cancelled.
unknown K7286 C.30A Rota I Intended for RAF (See Military Table), but cancelled.
Total Production  82
Total Production (Not Completed)  4
C.30 in Military Service (In Alphabetic Order By Country)
Serial Range C/n Type Batch
Qty		 Conv. Canc'd Notes
Belgium 1 aircraft built by (See Military Table)., Manchester and supplied to the Belgian Military Aviation (Belgische Militaire Vilegwezen) for evaluation. Delivered in May 1935.
(none) 818 C.30A 1
Denmark 2 aircraft built by (See Military Table)., Manchester and supplied to the Danish Army Air Corps (Hærens Flyvertropper). Delivered in February 1936 and July 1937 respectively.
M-1, M-2 750, 985 C.30A 2
Italy 1 aircraft supplied to the Regia Aeronautica for evaluation in August 1935.
MM30030 753 C.30A (1) Ex G-ACXA.
Norway 1 aircraft supplied to the Norwegian Army Air Service in 1935.
99 735 C.30A (1) Ex LN-BAD.
Spain 2 aircraft built by (See Military Table)., Manchester and supplied to the Spanish Navy (Aeronáutica Naval). Delivered in September 1934.
ES-SCA, ES-SCB 756, 757 C.30A 2
2 aircraft built by (See Military Table)., Manchester and supplied to the Spanish Air Force (Ejército de la República Española). Delivered in December 1934.
40-1, 40-2 781, 782 C.30A 2 Later reserialed 21-2, 21-3 then YI-2, YI-3 respectively.
United Kingdom 10 aircraft ordered from A.V. Roe and Co. Ltd., Newton Heath, Manchester, to Contract 294074/33, Requisition 99/33. Delivered between February and May 1935.
K4230 - K4239 (see main table) C.30A Rota I 10 For evaluation by the RAF in Army Co-operation units.
1 aircraft ordered from A.V. Roe and Co. Ltd., Newton Heath, Manchester, to Contract 321859/34. Delivered in May 1935.
K4296 (unknown) C.30A Rota I 1 Fitted with Short Bros type F61 floats and tested at the Maritime Aircraft Experimental Establishment, Felixstowe.
1 aircraft ordered from A.V. Roe and Co. Ltd., Newton Heath, Manchester, to Contract 354064/34. Delivered in January 1935.
K4775 (unknown) C.30A Rota I 1 To RAE as trial for larger engine. Fitted with 160-180 h.p. Armstrong-Siddeley Genet (Civet) Major.
2 aircraft ordered from A.V. Roe and Co. Ltd., Newton Heath, Manchester, to Contract 404387/34, but cancelled.
K6553 - K6554 C.30A Rota I 2
1 aircraft ordered from A.V. Roe and Co. Ltd., Newton Heath, Manchester, to Contract 439134/35, but cancelled.
K7286 Rota Mk.2 1 See Note 5
Yugoslavia 2 aircraft supplied to the Yugoslav Air Force. Delivered between November 1946 and April 1948.
1, 2 1029, 1030 C.30A 2
Total 21 -2 3

Foreign Derivatives

Loiré-et-Olivier (Société de Constructions Aéronautiques d'hydravions Lioré-et-Olivier) - See Note 4
C.30
As A.V. Roe built C.30S except for the addition of small finlets below the tailplane, at the junction with the upswept tips. One 156 h.p. Salmson 9Nc, 175 h.p. Salmson 9Ne or 140 h.p. Armstrong Siddeley Genet Major IA powerplant.
C.30S
(S = Special) As C.30 but fitted with a long travel undercarriage. One 175 h.p. Salmson 9Ne powerplant.
C.301
As C.30 with uprated Messier oleo-pneumatic shock absorbers, flotation devices to facilitate ditching at sea, a modified tail unit, tabs on the rotor blades and tripod main rotor support. One 175 h.p. Salmson 9Ne powerplant with Chauvière propeller.
C.302
As C.301 with new vertical fin, a stabiliser with marked dihedral and an automatic pitch change mechanism. One 175 h.p. Salmson 9Ne powerplant (initial use on first aicraft only) or 203 h.p. Salmson 9Ng powerplant with Chauvière Type 308M propeller.
French Production Details
Serial Range C/n Type Batch
Qty		 Conv. Canc'd Notes
4 aircraft built by A.V. Roe & Co. Ltd., Manchester, and imported by Loiré-et-Olivier. Following some minor modifications, they were given LeO c/ns and purchaced by the French Government under Contract No. 994/4 in Aircraft Plan I in December 1934.
F-AOHY C.30-01 C.30A (1) Ex c/n 709, G-ACWG.
F-AOHZ C.30-02 (1) Ex c/n 776, G-ACYC.
F-AOIO C.30-03 (1) Ex c/n 711, G-ACWI.
F-AOLK C.30-04 (1) Ex c/n 733, G-ACWT.
25 aircraft ordered from Loiré-et-Olivier, Paris, for l'Armée de l'Air, to Contract 277/5. Delivered between October 1935 and July 1936.
F-402 - F-406 C.30-2 - C.30-6 C.30A (5) Manufactured by A.V. Roe & Co. Ltd, Manchester as c/ns 800 - 804. Probably delivered as kits for assembly by LeO. Four of this batch, beginning with C.30-2, were transferred to l'Aéronavale before delivery.
F-406 - F-425 C.30-7 - C.30-25 C.30 20 Some aircraft fitted with Genet Major powerplants, some with Salmson, the latter requiring enlarged tailplanes.
4 aircraft ordered from SNCASE, Paris, for l'Aéronavale, to Contract 390/7. Delivered in 1937 ?
HY-61 - HY-64 C.30-26 - C.30-29 C.30 4 C/n 26 converted to to C.30S F-AOLL. See note 3.
30 aircraft ordered from SNCASE, Paris, for l'Armée de l'Air, to Contract 377/7. Delivered between January and September 1938.
F-426 - F-455 C.30-30 - C.30-59 C.30 30
2 prototype aircraft built by SNCASE, Paris.
F-BDAA, F-BDAB 01, 02 C.301 2 Registrations unconfirmed. C/n 01 first flew in April 1938.
100 aircraft ordered from SNCASE, Paris, for l'Aéronavale, to Contract 767/8, in August 1938. 5 delivered, the remainder cancelled.
HY-65 C.301-1 C.301 1
HY-81 - HY84 C.301-2 - C.301-5 4
C.301-6 - C.301-100 95
100 aircraft ordered from SNCASE, Paris, for l'Aéronavale, to Contract 767/8, in September 1939. Cancelled.
C.301-101 - C.301-200 C.301 100
3 aircraft built SNCASE, Paris.
F-AOLL C.302-1 C.302 (1) Converted from C.30S, c/n 26.
C.302-2 1 Not completed.
F-BDAD C.302-3 (1) Converted from C.30, c/n C.30-15.
Total Production 61 (11) 196
Focke-Wulf Flugzeugbau AG, Bremen, Germany
C.30 Heuschrecke
As A.V. Roe built C.30A, except fitted with 160 h.p. Siemens Sh 14a powerplant.
German Production Details
C/n Initial
Registration		 Type Notes
Approximately 30 aircraft built by Focke-Wulf Flugzeugbau AG, Bremen, Germany, under licence from the Cierva Autogiro Co. Ltd., out of planned production of 40. Known registrations are:
D-EEJE C.30
D-EELA C.30
D-EHHY C.30
D-EIPO C.30 To D-ICCH
D-EIRO C.30
D-ENMO C.30
D-EYNA C.30
D-IBWS C.30
D-INCR C.30
Total Production  30
Total Production (Not Completed)  10

Production Summary

All U.K. Production By Type
Type Built New Conv Canc'd Total
C.30 1 1
C.30P Mk.II 1 1
C.30P 3 3
C.30A 64 1 65
C.30S 1 1
C.30A Rota I 12 3 15
82 (0) 4 3
All French Production By Type
Type Built New Conv Canc'd Total
C.30 54 54
C.301 7 195 202
C.302 (2) 1 3
61 (2) 196
All German Production By Type
Type Built New Conv Canc'd Total
C.30 Heuschrecke 30 10 40
30 (0) 10

Notes

  1. All Avro produced aircraft c/ns are almost certainly prefixed R3/CN/.
  2. Spanish Civil Engineer Juan Reges Aymá had settled in Argentina and in 1935 bought a C-30A, c/n 1031, and returned to Buenos Aires. La Cierva and Reges Aymá had arranged a partnership, whereby Reges Aymá would represent La Cierva, in Buenos Aires, in order to manufacture, under license, the C-30A at the Military Aircraft Factory in Córdoba. This, however, never came to pass.
  3. Both A.V. Roe and Loiré-et-Olivier produced a variant called C.30S. They were not the same (See Produced Types List)
  4. Loiré-et-Olivier was nationalized in 1936, following which it was merged with Chantiers aéronavals Étienne Romano, Potez, CAMS and SPCA in order to form the Société nationale des constructions aéronautiques du Sud-Est (SNCASE) on 1 February 1937.
  5. Given as 'Rota II' in [4], but this designation should only be applied to the C.40.

Production References

  1. Cierva Autogiros - The Development of Rotary-Wing Flight, Peter W. Brooks (Airlife, 1988)
  2. Autigiro - Rotary Wings Before the Helicopter, Arthur W.J.G. Ord-Hume (Mushroom Model Publications, 2009)
  3. Impressments Log Vol 1, Peter W. Moss (Air-Britain, 1963)
  4. The K File, The Royal Air Force of the 1930s, J.J. Halley (Air-Britain Publications, 1995)
  5. The History Of Danish Military Aircraft Volume 1, Ole Nikolajsen
  6. https://www.ab-ix.co.uk/pdfs/f-aaaa.pdf
  7. https://www.ab-ix.co.uk/pdfs/vt-aaa.pdf
  8. Golden Years of Aviation
  9. https://www.belgian-wings.be/cierva-c30a-autogiro
  10. https://arqueologiaaeronautica.blogspot.com/2014/06/avro-671-la-cierva-c30a-matr-lv-fbl.html
  11. RAF Air Historical Branch: Contract Delivery Cards (Dept of Archive and Aviation Records, RAF Museum, Hendon, Records MFC-78-8-1)
  12. Introduction to Autogyros, Helicopters, and Other VSTOL Aircraft Volume I - Overview and Autogyros, Franklin D. Harris (NASA Center for AeroSpace Information, May 2011)
  13. BARG Roundel Aug 1996
  14. BARG Roundel Oct 1996