Weir autogyro and helicopter designations

Cy-27 said that he was working on a Weir designation list which which was the kick in the pants needed to prompt me to finish off my list!
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J&G Weir Company, 1932-1943, and Cierva Autogiro Company (Cierva-Weir), 1943-1951

Weir autogyros and helicopters received simple, sequential 'W' designations. Contemporary sources show 'W.x", 'W-x', and 'W x' styles. For consistancy, I've stuck with hyphens.

For a short history of Weir autogiros/helicopters, see Scottish contributions to rotary wing flight by D. Cameron and DG Thomson, AHS 64th Annual Forum, April 29th-May 1st, 2008. http://eprints.gla.ac.uk/4973/1/4973.pdf
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Weir Aircraft Designations

Weir W-1 - May 1933 autogyro, 1 x 40 hp Douglas Dryad HO-2 engine
- Weir W-1: First successful two-bladed rotor, 8.53 m diameter
-- Weir W-2 aka Cierva C 28 (built under license from Cierva)

Weir W-2 - March 1934 'jump start' autogyro, 1 x 50 hp Weir O-92*
- W-2: 'Cleaned up' W-1, modified 8.53 m diameter W-1 rotor
-- * Some sources apply 'Dryad II' name to the Weir O-92
-- Weir W-2 serial production planned but not realized**
-- ** Some stability problems, fitted with W-3 tail surfaces
-- http://1000aircraftphotos.com/Contributions/9914.htm

Weir W-3 - 1936 experimental single-seat 'direct take-off'* autogyro
- W-3: 1 x 50 hp Weir Pixie I inv'd 4-cyl inline, 5.66 m rotor diameter
-- * clutched 2-bladed 'Auto-dynamic'rotor for VTOL (Cierva concept)
-- http://www.flightglobal.com/pdfarchive/view/1953/1953 - 0098.html
-- http://www.aviastar.org/helicopters_eng/weir_w3.php

Weir W-4 - 1937 Refined W-3, 68 hp Weir Pixie II inverted 4-cyl inline
- W-4: Endplate tail surfaces similar to final W-2 config.
-- W-4 destroyed in early tests (rolled on side during 'jump start')
- W-4: [Project] co-axial rotors helicopter conv., led to W-5

Weir W-5 -- 1938 single-seat helicopter, 4.57m rotor diameter
- W-5: [Project] Coaxial rotors W-4 autogyro conversion
- W-5: 1 x fan-cooled 50 hp Weir Pixie II, side-by-side rotors*
-- * Plywood box beams support the twin lateral 2-bladed rotors
-- W-5 design infl. by Cierva-licensed Focke-Achgelis Fa 61
-- http://www.aviastar.org/helicopters_eng/weir_w5.php

Weir W-6 - 1939, enlarged 2-seat devel. of W-5 helicopter*
- W-6: 1 x fan-cooled 200 hp DH Gipsy Six II, 7.93 m rotor diameter
-- * W-6 used twin 3-bladed rotors, welded steel tube outriggers
-- http://www.aviastar.org/helicopters_eng/weir_w6.php

NB: Weir W-5 and W-6 rotor thrust controlled by rotor speed

W-7 - [Project] 1940 3-seat helicopter, 3-blade main rotor, nose engine
- W-7: Offset torque-countering rotor mounted to starboard u/c struts
-- W-7 aka Weir Gyrodyne (combining features of helicopter and autogyro)
-- W-7 offered to the Royal Navy as a 'Fleet Shadower' ASW a/c

Weir W-8 - [Project] single-seat, single-rotor experimental helicopter
- W-8: Blown rotor through rotor head, see Reply #2

1943 - G & J Weir Ltd. aeronautical department reconstituted as Cierva Autogiro Company (aka Cierva-Weir). These may be described as 'Ciervas' but 'W' designations remain.

Weir W-9 - 1944 2-seat single-rotor helo, fan thrust countered rotor torque
- W-9: 1 x 200 hp DH Gipsy Six II,* 10.97 m main rotor diameter
-- * Some sources say powered by 1 x 205 hp DH Gipsy Queen 31
-- W-9: Prompted by Sikorsky R-4/R-5, first flown 1946

Weir W-10 (I) - (Project) See reply #11, tri-rotor helicopter
- W-10: 2 x Armstrong-Siddeley Cheetah radials, 3 x rotors
- W-10: Abandoned in favour of W-11, desig. re-allocated

Weir W-10 (II) - (Project) 1946 single-rotor helicopter
- W-10: 4-to-6-seat helicopter, similar in layout to W-9
- W-10: 1 x 510 hp Armstrong-Siddeley Cheetah, 14 m rotor diameter

Weir W-11 - Air-Horse, 3-rotor helicopter designed for crop dusting
- W-11 : To AM Spec. E19/46, Air-Horse aka 'Spraying Mantis'
- W-11 : As conceived (mock-up), 2 x rotors forward + 1 x aft
- W-11 : Post wind tunnel tests, 1 x rotor forward + 2 x aft
-- W-11: 1 x 1,620 hp Rolls-Royce Merlin 24,* 14.32 m rotor diameter
-- * Orig. intention to power with Merlin 32?, see reply #11
- W-11 : As flown, 1950, crashed on flight tests, development terminated
- W-11T: (Project) 1949 twin-engined W.11 deriv., 2 x RR Merlin 502**
-- ** Merlin 502s mounted on stub wings to facilitate re-engining
-- ** Alt. turboshafts envisioned or auxiliary propellers on stub wings
-- https://www.flightglobal.com/pdfarchive/view/1946/1946 - 1288.html

Weir W-12 (I) - (Project) See reply #11, tri-rotor helicopter
- W-12 (I): Revamped version of the first Weir W-10 project

Weir W-12 (II) - (Project) Reduced-scale W.11 devel., 2 variants
- W-12 (II) : 2 x (??) shp Rolls-Royce Dart turbines
- W-12 (II) : Passenger vers., 12 pax (half that of W-11 Air-Horse)
- W-12A (II): Freighter vers., clamshell rear doors, 1.5 ton payload

Weir W-13 - [not assigned]

Weir W-14 - Skeeter 1948 2-seat experimental helicopter, x 1
- W-14: Prototype for Saro Skeeter military training helicopter
-- Deve. taken over by reformed Cierva company, 2 x prototypes
-- W-14 Skeeter I : 1 x 110 hp Jameson FF-1 HO-4, x 1 (G-AJCJ)
-- W-14 Skeeter II: 1 x 145 hp DH Gipsy Major X, x 1 (G-ALUF)
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Excellent list, Apophenia !

Here are some addidional notes on some of the offerings listed above:

W.2 Autogyro

Fuselage and engine design by G.Walker and the rotor head and twin wooden rotor blades looked after by J. Bennett. Similar to W.1 and utilised a Weir 50 hp flat twin-cylinder engine. Like the W.1, considered a development autogyro for Cierva and both were flown by Cierva himself as well as Alan Marsh and Reggie Brie. First flew from Abbotsinch with the first auto-dynamic rotor head for the jump start of autogyros.

W.3 Autogyro

A single-seater was powered by an inverted Weir Pixie rated 50hp 4-cylinder in-line engine and fitted with a two-bladed 'auto-dynamic' rotor. Rotor diameter: 5.66 m, length: 4.37 m, height: 2.16 m, gross weight: 295 kg. Rolled out and first flew July 1936 with markings of W-3.

W.4 Autogyro

This was a more elegantly finished version of the earlier W 3 design. Weir W 4 included the auto dynamic jump-off feature where the rotor was engaged through a direct drive shaft to start lifting. The drive then switched to the tractor airscrew to move forward having already lifted off.he twin rotor Weir W 4 single seat autogyro was powered by a Weir Pixie engine uprated from the W 3 model. The design was the last autogyro made by Weir who by 1938 turned attention to helicopter design.

W.5 Helicopter

The W.5 was a single-seater powered by an air-cooled engine; each of the two two-bladed rotors had cyclic and collective pitch control. C.G.Pullin, Weir's chief designer, first thought of converting the W.4 autogyro into a helicopter by using two co-axial rotors. He finally decided upon using a system of rotors carried by outriggers on either side of the fuselage, like the Fa.61. First flight at Dalrymple, Ayrshire, on 7 June 1938, piloted by R.A.Pullin, son of the designer. By the outbreak of World War II it had logged eighty hours' flying time.

W.6 Helicopter

The W.6 design was much larger than its predecessors. A two-seater helicopter powered by a more powerful fan-cooled engine located in the nose. Each of the side-by-side rotors had three blades made of compressed wood with leading edges in metal. They rotated at 275 r.p.m. and had both cyclic and collective control all enclosed within the hub. A ratchet-type freewheeling device was used for flying in auto-rotation. The maiden flight took place in Scotland on 27 October 1939, but World War II, then in its early stages, caused all work to be stopped on the W.6 in the middle of 1940. The machine was still in existence, minus its engine, as late as 1950. Engine: 1 x Gipsy (205 hp), rotor diameter: 7.62 m, length: 8.53 m, height: 3.2 m, gross weight: 1070 kg, cruising speed: 128 km/h, rate of climb: 198 m/min, absolute ceiling: 3,810 m.

W.7 Helicopter

Yawing control was by brakes or clutches on the differential shafts.

W.8 Helicopter

Design used a blown single-rotor system which Weir called "The Reaction System". This was a compressor fitted to a de Havilland Gipsy Six or Rolls-Royce Kestrel. Not successful.

W.9

Helicopter Used the Gipsy (205 hp) engine from the Weir W.6.

Weir Jaberwock (1937) Helicopter

A project derived from the remains of the W.4 by C.G.Pullin which got no further than the mock-up stage.

Sources:

Janes All The Worlds Aircraft - Various Editions (Sampson Low)
The Sycamore Seeds: Early British Helicopter Development by Charles Mackay (2014) Published by MacKay (ISBN 0957344333)
Cuttings from Air Pictorial (?)

Weir W.7 and W.8

And W.11

Great list once again, thanks a lot Apophenia!

Please note the spelling for alternate crop-spraying version of Air Horse ought to be Spraying Mantis.

Thanks folks! I've added a few details I'd left out on the W-10 project.

Cy-27 - Great stuff ... I knew you'd come up with some good details!

"A project derived from the remains of the W.4 by C.G.Pullin which got no further than the mock-up stage." I wonder if that might be the W-4 helicopter conversion concept that, eventually, led to the W-5?

Maveric: Thanks especially for the W-8! I'd seen that drawing as accompanying the blown rotor patent but never identified as the W-8.

Skyblazer: Thanks for proofing :-[ Of course, if they knew then what we know about some agricultural sprays, 'Spaying Mantis' wouldn't be far off

There's some confusion over which piston engine was to be fitted to the 'Spraying Mantis' - both the Merlin 24 and Merlin 32 (as 'Merlin XXXII') are listed. I went with Merlin 24 because, although the power output is the same, it seemed more reasonable use an engine tailored for bomber use rather than for fighters.

Speaking of Weir and engines, here's a few powerplant details ...

The Douglas Dryad was a 1932 horizontally-opposed 2-cyl of 75 cid/1,229 cc putting out 36 hp @ 3000 rpm, 40 hp @ 4000 rpm, and 52 hp @ 4500 rom (for take off). The Dryad was designed by Cyril G. Pullin and George E. Walker.

Some sources shown William Douglas Ltd. of Bristol closing down in 1932, prompting Pullin and Walker to move to Weir in 1933. Not so -- Douglas continued production of motorcycles until 1957. Obviously, Pullin and Walker just found Weir's rotory-wing projects more interesting

At Weir, Pullin and Walker evolved the 92 cid/1,507 cc O-92 from their Dryad. The O-92 put out 45 hp. By then, Pullin* was the chief designer for G & J Weir Ltd's aircraft department. Some sources refer to the O-92 as the 'Dryad II' but I'm not sure if that name was officially adopted.

The next Pullin/Walker engine design for Weir was an inverted 4-cylinder of 45-67 hp. This engine is invariably referred to as the 'Pixie'. I'm not sure that is accurate. In some sources, the W-3 and W-4 powerplants are dubbed Weir MkI and MkII. The name Pixie seems to have been applied when the rights to the engine was bought in 1938 by Aero Engines, Ltd. of Bristol (that firm being regarded by some as a successor to Douglas).

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* Pullin had also designed engines for his own firm, Ascot-Pullin Motorcycles of Letchworth.
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Apophenia said:

I went with Merlin 24 because, although the power output is the same, it seemed more reasonable use an engine tailored for bomber use rather than for fighters.

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Care to develop on that? ???

Greatwork my dear Apophenia.

Skyblazer said:

Apophenia said:

I went with Merlin 24 because, although the power output is the same, it seemed more reasonable use an engine tailored for bomber use rather than for fighters.

Click to expand...

Care to develop on that? ???

Click to expand...

Sure, the simplest reason to assume Merlin 24 over Merlin 32 is availability. The Merlin 24 powered all late production Lancaster B.Mk.Is, Mk.I Specials, and B.Mk.VII (FE)s. The Merlin 32 powered a comparatively small number of aircraft -- Barracuda Mk.II (x 1,688), Seafire L Mk.IIc (~ 25), Seafire FR Mk.IIc (~ 30), and Spitfire PR XIII (x 36).

Apophenia said:

Skyblazer said:

Apophenia said:

I went with Merlin 24 because, although the power output is the same, it seemed more reasonable use an engine tailored for bomber use rather than for fighters.

Click to expand...

Care to develop on that? ???

Click to expand...

Sure, the simplest reason to assume Merlin 24 over Merlin 32 is availability. The Merlin 24 powered all late production Lancaster B.Mk.Is, Mk.I Specials, and B.Mk.VII (FE)s. The Merlin 32 powered a comparatively small number of aircraft -- Barracuda Mk.II (x 1,688), Seafire L Mk.IIc (~ 25), Seafire FR Mk.IIc (~ 30), and Spitfire PR XIII (x 36).

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Thanks! ;-)

I might muddy the waters here with the Air Horse as it seems that Weir re-allocated designations. In Aeroplane Monthly, January 1978 there is a comprehensive article on the Air Horse by Elfan Ap Rees. From that article:

W.10 was a tri-rotor with two Armstrong Siddeley Cheetah engines.
W.10 was scaled up to the W.11 as flown. The earlier smaller design was put aside and the designation W.10 was re-allocated to the five seat single rotor helicopter.
W.11T was the growth version of the W.11 with the two Merlin 502 engines mounted on stub wings (offering the possibility of the alternative engines and even auxiliary propellers).
Later versions of the W.11T were given the designation W.12 and W.12A. The W.12 designation earlier having been used for a re-vamped W.10 tri-rotor.

This corroborates an article for The Royal Aeronautical Society in the 1960s by K Watson (Weir Chief Mechanical Engineer). Watson has the W.11 as the flown Air Horse, the W.10 as the smaller version (10,000 lb a.u.w.) with two Armstrong Siddeley Cheetahs and the W.12 with two Merlins. Watson makes no mention of the allocation of these designations to any other machines.

In respect of the engine used, an article in American Helicopter Magazine March 1949 by H A Marsh (Chief Test Pilot) says the first Air Horse mock-up had two rotors forward and one aft. (Extensive wind tunnel tests by R.A.E. Farnborough proved stability would be much improved with the two rotors aft and one forward so it went ahead in that configuration). The article in Flight, 4 July, 1946 that mentions the Merlin 32 looks like that first mock-up. At the same period, an article in The Aeroplane refers to the tri-rotor to be called Air Horse ‘to be’ powered by Merlin 32. It looks like it was originally the intention to use the Merlin 32 but all articles on the Air Horse that actually flew seem to say it was powered by the Merlin 24.

Apophenia said:

Weir W-2 - March 1934 'jump start' autogyro, 1 x 50 hp Weir O-92*
- W-2: 'Cleaned up' W-1, modified 8.53 m diameter W-1 rotor
-- * Some sources apply 'Dryad II' name to the Weir O-92
-- Weir W-2 serial production planned but not realized**
-- ** Some stability problems, fitted with W-3 tail surfaces

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The Weir W-2 survives at Scotland's National Museum of Flight at East Fortune. I believe it's the only Weir design to survive.