Maj H.Q.A. Reeves
Bell device for location of containers
Messrs L.G. Wilson,
P.T. Trent,
B.H. Chibnall
Welcase
Messrs L.G. Wilson,
P.T. Trent,
B.H. Chibnall
Welman
Lt Col J.R.V. Dolphin
Time Pencil
Cdr A.G. Langley RN
AC delay
Maj C.R. Bailey, Capt
M.B. Donald,
Mr R.S. Potter
Anti-removal switch (air armed)
Mr E. Cotterill
Anti-removal switch (water armed)
Mr E. Cotterill
Limpet speed switch
Maj C.V. Clarke, Mr E.
Cotterill
Pigeon delay switch
Mr E. Cotterill
Overhead wire cutters
Messrs S.F. Beech, C.J. Sutton
Trim valve
Maj J.I. Meldrum, Mr E.
Porteous
Lt Col J.R.V. Dolphin
Folding seat for Welfreighter
Lt Col J.R.V. Dolphin, Mr G.H. Clarke
Collapsible dinghy
Mr H. Harradine,
Lt Col J.R.V. Dolphin
Nail firing device
Mr E. Norman,
Maj Critchfield,
Maj H.Q.A. Reeves
Sucker device
Mr F.A.O. Waren,
Maj C.E.M. Critchfield,
Maj H.Q.A. Reeves
Altimeter fuse
Mr G.J. Sutton
Oil nitrate incendiary
Dr C.H. Bamford,
Mr D.L. Levi
Directional incendiary
Dr C.H. Bamford
Phosphorous iodine gel
Dr C.H. Bamford,
Mr D.L. Levi
Magnesium flash incendiary
Dr C.H. Bamford,
Mr D.H. Malan
Small pocket delay incendiary
Messrs D.W. King,
A.R.D. Wilde,
Maj O.J. Walker
Flash grenade
Mr D.W. King,
Maj O.J. Walker
Jet Thermite bomb
Dr F. Panzner
Paper tube delay
Maj C.R. Bailey
Pocket smoke generator
Maj O.J. Walker
Tyesule
Col L.J.C. Wood,
Dr F.A. Freeth
Welmine
Lt Col J.R.V. Dolphin,
Mr E. Norman,
Mr L. Berg
Remote control firing mechanism for pistol
Lt Col J.R.V. Dolphin,
Mr E. Norman
Buoyant limpet
Maj H.Q.A. Reeves,
Maj C.E.M. Critchfield
Tree spigot gun
Maj C.V. Clarke,
Mr G.J. Sutton,
Maj E. Ramsay Green
Tree spigot bomb
Mr G.J. Sutton,
Maj C.V. Clarke,
Capt J.P.B. Flowerdew,
Col G.O.C. Probert
Tree spigot fuse
Mr G.J. Sutton
Tree spigot sight
Mr G.J. Sutton,
Capt J.P.B. Flowerdew,
Mr E.G.R. Welch
Plate spigot sight
Mr G.J. Sutton,
Capt J.P.B. Flowerdew
Plate spigot gun
Mr G.J. Sutton,
Mr E. Norman,
Capt J.P.B. Flowerdew,
Maj C.V. Clarke
ISRB Allways fuse
Lt Col H.H. King
APPENDIX C
ABBREVIATIONS
ACOS
Admiral Commanding Orkneys and Shetlands.
AFDC
Airborne Forces Development Centre.
AFEE
Airborne Forces Experimental Establishment.
C
The symbol of the head of MI6.
CCO
Chief of Combined Operations.
CD
Symbol of the executive director of SOE.
CIGS
Chief of the Imperial General Staff.
COHQ
Combined Operations Headquarters (London).
COS
Chief of Staff.
DMI
Director of Military Intelligence.
DMWD
Department of Miscellaneous Weapons and Devices.
DNC
Director of Navy Contracts.
DNE
Director of Navy Engineering.
DNI
Director of Naval Intelligence.
DNOR
Department of Naval Operational Research.
DSR
Director of Scientific Research.
EH
Electra House.
EM
Electrician’s Mate.
ERM
Engine Room Mechanic.
FANY
First Aid Nursing Yeomanry.
FO(S)
Flag Officer (Submarines).
GS(R)
General Staff (Research) – later MI(R).
HADDA
High Altitude Delayed Dropping Apparatus.
IPF
Inshore Patrol Flotilla.
ISRB
Inter-Services Research Bureau (Cover name for SOE).
ISSU
Inter-Services Signals Unit (Cover name for SOE).
MGB
Motor Gun Boat.
MGOF
Master General of Ordnance Finance.
MI(R)
Military Intelligence (Research).
MO1(SP)
Military Operations 1 (Special Projects) (Cover name for SOE).
MTB
Motor Torpedo Boat.
NID
Naval Intelligence Department.
NNIU
Norwegian Navy Independent Unit.
PID
Political Intelligence Department.
PPS
Parliamentary Private Secretary.
PWE
Political Warfare Executive.
RAE
Royal Aircraft Establishment.
RAOC
Royal Army Ordnance Corps.
RE
Royal Engineers.
REME
Royal Electrical and Mechanical Engineers.
R/T
Radio Telephony.
SFDC
Special Forces Development Centre.
SHAEF
Supreme Headquarters Allied Expeditionary Force.
SIS
Secret Intelligence Service.
SO
Special Operations.
SRD
Services Reconnaissance Department. (Cover name for SOE’s Australian counterpart.)
STS
Special Training School.
W/T
Wireless Telegraphy.
APPENDIX D
SUMMARY OF THE WORK OF THE ENGINEERING SECTION
The inventiveness and skill of the Engineering Section may be appreciated from this summary of its achievements. Up to the end of 1942 the following equipment had been invented and developed to a degree, though some items never went into production:
A silent .22 pistol, possibly a silenced version of the U.S. Hi-Standard pistol.
A .22 machine gun.
The Welgun.
The Welhit silent short-range projector.
Various underwater containers.
A collapsible ski-sledge for dropping by parachute.
Special marlin spikes for containing explosives.
Camouflaged oil drums containing depth charges.
Numerous camouflaged containers.
Collapsible ladders and steps. Two types of scaling ladders were designed at Station XII for use by the Commandos.
A rope climbing device for use on ½-in rope was tested in April 1943 and after one or two adjustments was sent for user trials. A collapsible bridge. A grapnel dev
ice.
A short time delay for a parachute canopy. A release switch for a parachute canopy.
A smoke boat, a smoke screen to operate from a robot motorboat.
In October 1942 a metal case was designed to accept an ampoule of liquid
which was to be broken and used to put searching dogs off the scent.
Research into a suitable liquid had not at that time come up with an answer.
By the end of the war many more devices had been invented, which are listed below.
DEVICES WHICH WENT INTO PRODUCTION
Underwater and Marine
The Welman one-man submarine.
The Welfreighter stores-carrying submarine.
The motorised submersible canoe ‘Sleeping Beauty’.
Silencer for outboard motor.
Silent power unit canoe with flexible drive.
Containers, deep water, quick opening, Mks I and II.
Suction-adhesion device for limpets.
Nail firing device for charge adhesion to steel ships.
Nail firing device for charge adhesion to wooden ships.
Small arms and other weapons.
Silenced Sten gun Mk II
Silenced Welrod Mk IIa .32 in.
Silenced sleeve gun.
Silenced Welrod 9 mm.
Silenced M1 carbine (in conjunction with CSAR).
Miscellaneous
Welbike folding motorcycle.
Overhead wire cutter Type 6.
Skeleton keys.
Grease gun for use with abrasive grease for axle boxes.
Drive attachment for Welbike for battery charging generator.
Collapsible ladder.
Tyre cutter.
DEVICES WHICH WERE ISSUED FOR AD HOC OPERATIONS
Welsilencer, a silent .22 pistol.
Blowpipe.
Collapsible bridge.
Silent prison bar cutter.
Collapsible ski sledge for dropping by parachute.
Marlin spikes containing explosive.
DEVICES WHICH ENGINEERING SECTION DEVELOPED BUT WHICH NEVER WENT INTOPRODUCTION FOR VARIOUS REASONS
Welmine (magnetic).
Welmine (percussion).
Welmine (jettison-head).
Towing container (water).
Welbum (motor attachment for swimmers).
Limpet (stream lined, scraper).
Small-calibre machine carbine.
Special .22 magazine (2/1).
Machine pistol Type I Mark II.
Silent 9 mm machine gun.
Silent 9 mm Luger pistol.
Gas gun.
Welpen (.22 fountain pen pistol).
Verey light fired from Spigot Pistol.
Silent killer (spring gun).
Device for crossing Dannert wire fence.
2-in mortar grapnel device for minefields.
Welbike trailer.
Smokescreen to operate from Welbike.
Underwater glider.
NOTE
This information was drawn from the appendices to the History of the R&D Section provided by kind permission of the SOE Adviser to the FCO.
APPENDIX E
EXAMPLES OF CAMOUFLAGED DEVICES
Camouflage Section could disguise almost any piece of military equipment as an innocuous everyday item. Furthermore, many of their products were actually booby-trap devices. The following are examples of the skills of this talented team.
Clever containers were made in the form of:
A metal drum inside a fish barrel.
Metal flagons.
Plaster logs.
Wooden logs hollowed out.
Packing cases for everyday items.
Plaster vegetables and fruit.
Driftwood and spars.
Cement bags.
Fish boxes.
Wireless sets were camouflaged as:
Bundles of faggots.
A Mumo adding machine.
Domestic wireless sets.
Portable gramophones.
A vacuum cleaner.
Rocks, for depositing wireless sets on a beach or in open countryside. A rubber armchair which was inflated with a pump and the wireless set placed under the seat.
Concealment of various miniature communications receivers (MCRs) was achieved by disguising them as:
Antique German clocks.
A paper punch.
A German water bottle.
A Belgian tea can.
A German manual.
A German bible.
A brandy flask.
On the offensive front, explosives were incorporated into all kinds of articles to transform them into incendiaries or lethal bombs:
Hollow wooden nuts or bolts containing explosive would replace rusty old genuine ones.
Wooden logs could conceal an explosive charge which would detonate when thrown on a fire or into a furnace. Chianti bottles.
Bicycle tyre pumps which would inflate a tyre when used with short strokes but explode when used normally.
Food tins could conceal a bomb. Research into explosive food tins revealed that the pneumatic type were considered too dangerous as an unintentional air leak would cause it to detonate.
Incendiary soap contained a cavity with metallic sodium in it. This ignited on contact with water.
A shaving brush could contain an incendiary device.
Cigarettes could be made to start a real fire.
An innocent-looking book could conceal a bomb.
Wooden road blocks could hide explosive devices.
Ships’ fenders could be made to explode.
An anti-personnel grenade could be made to look like a normal torch.
Chinese stone lanterns could conceal either explosive or incendiary devices.
Copies of Balinese carvings were cast in solid high explosive.
Japanese sauce tins could be made to explode.
An incendiary briefcase (single lock) had wiring concealed in the lining of the case and a quilt of potassium nitrate to assist the combustion.
The incendiary attaché case and the incendiary suitcase were variations on the above theme.
The Thatched Barn produced 43,700 cigarettes made of incendiary or explosive material for use by SOE agents.
APPENDIX F
OPTIMISATION OF AIR SUPPLY EQUIPMENT
To apply the criteria discussed on page 17¾ quantitatively it is necessary to know how the speed of descent (v) depends on the load (M) and on the parachute size expressed either in terms of its diameter (D) or area (A). Because of the complex airflow round a parachute and the porosity of the fabric from which the canopy is made, any detailed theory would be very complicated. Nevertheless, valuable information can be obtained using simple theoretical arguments. First, using the mathematical technique of ‘dimensional analysis’, it turns out that, independent of the details of any theory, the rate of descent is proportional to the square root of the load divided by the diameter of the chute: v is proportional to √M/D. It follows that doubling the load increases the rate of descent by √2 = 1.41; while doubling the diameter of the chute halves the rate of fall.
The important operational result is that, if for a mixed load of packages the load and chute sizes are chosen so the √M/D (or √(M/A) is the same for all loads, then they will fall at the same speed.
The ASR files contain the following table of recommended parachute sizes to be used for panniers of various weights. The origin of these figures is uncertain, but they were probably arrived at empirically. Maximum and minimum weights are given for each parachute size: attention here is directed to the upper weight limit for each parachute size.
Recommended Values of M and D for use with Panniers
If the above quantities are converted to metric (SI) units then the mean values of √M/D and √ (M/A) are 1.15 kg½m-1 and 1.30 kg½m-1 respectively.
The values of √M/D and √(M/A) for the various load/chute combinations are seen to be constant to within a few percent. So by
accident or design loads conforming to the specifications in the table should fall at roughly the same rate. To obtain a value of the actual rate of descent a more detailed but still very crude theory is needed. This links the rate of descent to the density of air, and leads to the two equivalent equations.
v = 4.60 √M/D = 4.05 √(M/A)
Thus, using the mean values of √M/D and √(M/A) gives
v = 5.29 m per sec or 17.2 ft per sec
This is equal to the impact speed of a load dropped from a height of 1.42 m or 4.64 ft.
Similar calculations for filled C or H containers weighing 330 lb (150 kg) with a 28 ft chute give an impact speed of 6.3 m per sec, or 21.2 ft per sec: this is equivalent to the terminal speed of a drop from 7 ft. The same containers on a 22 ft chute would fall at 8.3 m per sec or 27 ft per sec. equivalent to a free drop from 11 ft.
It is not known whether in the parachute dropping trials at Henlow or Cardington any attempt was made to measure accurately the speed of descent of parachuted loads but by the end of 1943 work, mostly at Henlow, had established the optimum size of parachute in relation to load. As a reasonable compromise a parachute with a 22 ft canopy, carrying a net load of 220 lb (100 kg) (the C-type container weighed 96 lb (43.5 kg), the H-type 86 lb (39 kg)) and giving an impact velocity of 27 ft per sec was accepted. That this is in close agreement with the calculated value suggests that the simple theory is adequate for the purposes of calculating impact speeds.
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