The Chiefs-of-Staff had learnt the value of science in warfare and were receptive to new ideas. Major-General ‘Boom’ Trenchard, commanding the RFC in the Field, welcomed any innovation and promised his pilots an advantage over the Hun. He urged the wireless officers at Biggin Hill to resume the work begun so auspiciously at Brooklands and, specifically, to develop a practical system of air-to air wireless telephony.
His requirements were stringent: a one mile all-round range, no adjustments to the transmitter when in use and only one tuning movement allowed on the receiver. A hundred per cent reliability with perfect speech quality was stipulated, and a maximum aerial length of 150 feet, to be superseded by a fixed aerial if practicable.
Preliminary experiments were commenced in the spring of 1917. One set after another was constructed, tested, and abandoned. Microphones were either too sensitive, or too insensitive, and engine vibration played havoc with the carbon granules. The aerials were long wires of copper, weighted at one end and lowered after take-off. Frequently the operator omitted to reel them in before landing, and the tress around Biggin Hill son became festooned with wires, to the fury of the scientists and the men sent climbing after them.
The difficulties were so great that the project was on the verge of being indefinitely shelved when someone suggested resurrecting the Round-Prince set of 1915 for a final experiment. It was installed in a BE2c, the one remaining Round valve fitted gingerly info place and the operator provided with a microphone of ancient vintage, the ‘Hunningscone’, swathed in cotton wool inside a cardboard box. To everyone’s delight it worked; Prince’s original air-to-ground results were reproduced and the operator’s voice, albeit distorted, was received in a second aeroplane.
This was heartening-, but a long way from Trenchard’s requirements. The wireless technicalities proved fairly simple to solve, but all speech remained obstinately distorted and unintelligible. Every type of microphone was tried, with diaphragms of steel, aluminium, celluloid and mica. Those which gave good results on the ground were inexplicably useless in the air. When, after scores of experiments, some measure of success was achieved, it was discovered that the officer who did all the test-speaking had, with so much practice, trained his voice to get the best out of the microphone – another speaker and the words remained a heart-breaking gibberish. Earphones introduced in to the transmitter circuit helped by allowing the operator to hear the sound of his own voice, but they could not be worn with the regulation flying helmets. The scientists became hatters for a day, designing and sewing new helmets with built-in pockets for microphone and earphones.
One sultry evening in July, as the sun was casting long shadows-over Biggin Hill, two Sopwith 1 ½ Strutters were brought from a hangar and made ready for flight. Shortly after sunset, the calm air of the twilight hour, they took off and followed divergent courses southwards: along the valley to Sevenoaks and across the ridge of the North Downs towards Edenbridge. Once airborne, Lieutenant Andrews, the operator entrusted with the prototype transmitter, unwound the aerial, switched on the set and started to speakinto his microphone.
‘One – Two – Three – Four – Five – Six – Dip – your – wings – if – you – receive – me – Seven – Eight – Nine – Ten – Monday – Tuesday – Wednesday…’
In the second Sopwith Lieutenant Furnival briefly tuned the receiver and waited tensely for it to warm up. Suddenly he heard the words spoken by Andrews, distinct and intelligible above the static and crackling interference from the magneto.
‘ . . Thursday – Friday – Saturday – Sunday – Dip – your – wings – if – you – receive – me – January – February – March….’
Furnival leaned forward to give a triumphant ‘thumbs up’ to his pilot, Captain Peck, who dipped his wings in happy acknowledgement. The distance between the two aircraft increased, but the tinny ghost of Andrews, voice never faltered, never faded. Air-to-air wireless telephony was, at long last, a reality. It was full night when they returned to Biggin Hill, but not too dark for the expectant watchers by the flarepath to see the jubilant waggling of wings against the stars.
Events moved quickly after that; Furnival, Andrews, and Peck repeated and improved their performance until they had sufficient confidence to make a sortie to France with the 1 ½ Strutters and wireless equipment for a command performance before Trenchard and officers of the Air Staff. They crossed the Channel on a clear, sunny day and landed at Boisdingham, near St Omer, where the demonstration was to take place. It was an unqualified success. The two aircraft circuited the field, one transmitting orders which were carried out by the other. A receiver was provided on the ground so that Trenchard could eavesdrop on the aerial conversation and check that there was no dec6ption by flying to a prearranged plan. Afterwards he grumbled that the transmitter operator had given far too many ‘Hullos’. Individual officerswere given the opportunity oi flying as passengers so that they, too, could speak and listen for themselves.
Despite the ‘HuIIo’s’, Trenchard was delighted and asked for two squadrons to be equipped at once. Air-to-air wireless telephony presaged a revolution in aerial tactics; for the very first time a flight commander could speak to his pilots throughout an action, giving orders that would be instantaneously heard.
‘With regard to the wireless telephone apparatus recently sent here for test’, reported Trenchard to the Directorate of Military Aeronautics, trials have been made with highly satisfactory results. I am very pleased that this problem appears to have been solved and I consider that it reflects much credit on those who have been engaged in the experimental work and the design of the apparatus.
Somehow the Germans had got wind of this most secret equipment. Prisoners were captured carrying documents offering a large reward for the salvage of any parts of the set.
‘As far as we know,’ warned Trenchard, ‘the enemy has not yet evolved any practical form of wireless telephony, and it is therefore most important to prevent our instruments falling into his hands intact.’
The initial batch of twenty sets was produced by Woolwich in record time and received a thorough testing at Biggin Hill. Furnival returned to France to equip and train No 11 Squadron, flying Bristol Fighters from Bellevue, on the Arras front. The instructional flights had to be sandwiched in between operations and, with the enemy’s eagerness to obtain a set in mind, great care was taken to remove them before the aircraft flew over the trenches. As 11 Squadron was often ordered up three or four times daily, little progress was made until permission was granted for ‘A’ Flight to be out of the line for a week. The pilots and observers were disgusted. They regarded the wireless telephone as a diabolical box of tricks that kept them from the important business of chasing, and killing, the Hun/ Captain Hooper, however, the Australian commander of ‘A’ Flight, had great faith in the new equipment. He and Furnival persevered with the recalcitrant aircrews until ‘Hooper’s Circus’, flying as one in obedience to his orders by wireless telephone, could perform an immaculate aerobatic drill which became the envy of every squadron in France.
After 11 Squadron had been equipped, Trenchard considered the risk too great to continue to work so close to the Front and sent Furnival home to organise a school of wireless telephony at Biggin Hill.
AII of a sudden it seemed to the cynically-minded veterans of wireless research that the whole outcome of the war in the air had come to depend on wireless telephony. Recalling their struggle for apparatus at Brooklands, they marvelled at the flood of new equipment, the nine brand-new B.E. 2es, the hangars that were erected overnight and the way in which experienced wireless officers were snatched from other units to become instructors. A former professional singer Lieutenant Gooch, was seconded as O.C. voice tuition, while a team of Leatherworkers set up a workshop to provide each pupil with a tailored helmet.
By November, 1917, some thirty-six officers a week were passing through the school. The word soon spread to France that a course at ‘Biggin on the Bump’ meant a cushy billet in the Bell Hotel, Bromley, a chance to visit the girl friend and see the latest West End shows. As Christmas drew near, squadron commanders were overwhelmed with applications for instruction in wireless telephony. Most regrettably, the school closed for the duration of the Christmas holidays !
On one memorable occasion the instructors and pupils were commanded to display their skill before King George V and an assembly of generals on the Horse Guards Parade. At the appointed hour the flight from Biggin Hill swept low over the Horse Guards and dipped wings in a Royal Salute.
For the next thirty minutes they banked, climbed and dived in one of the most amazing exhibitions of aerobatics Londoners had ever witnessed. Through a receiving set His Majesty heard the Flight Commander give order for the ‘bombing’ of St Pauls and the interception of an enemy ‘raider’, over the Crystal Palace. Two aircraft peeled off, proceeded to these objectives and returned to report by wireless: ‘Missions completed’. His Majesty and the generals were fascinated by the precision of the display, but the Flight Commander was not so easily satisfied. He had detected one pilot lose formation for a few fleeting seconds. While the others were contentedly downing tankards of beer in the Mess at Biggin Hill, this miscreant was kept flying an ‘aerial pack-drill’ round and round the airfield until his petrol ran out – the order for this penance being given, of course, by air-to-air wireless telephony.
Sooner or later the Germans would lay hands on an intact set and then nothing could stop them listening to our airmen speaking en clair as they flew over the Front. The wireless officers at Biggin Hill began to consider the possibilities of a code. Something simple was needed, easy to speak, and comprehend, yet. meaningless to the enemy. Elaborate tests were made to determine with precision the best words to employ.
Pilots were given long lists of words which they repeated ad nauseam in flight, while patient listeners on the ground noted the degrees of clarity and intelligibility.
‘Hullo, Dollars (Biggin Hill Call-sign). Hullo, Dollars. Pole… Pole… Pole… Pole… Bole… Bole… Bole…Toll…Toll…Toll… Pale…Pale… Pale..’
The listeners made a careful note. A code containing ‘Pole’ could use ‘Pale’ but not ‘Bole’, o’ ‘Toll’. Through the earphones the voice of the pilot sounded faintly irritable.
‘Tale… Tale… Tale… I’m thirsty! … Beer… Beer… Beer… Sorry, as you were… Moll … Moll… Moll… Male… Male… Male…’
Although in English words the meaning is generally conveyed by the consonants, telephonically speaking these were less dependable than the vowels whose sounds had a greater amplitude. Long vowels and diphthongs proved the best, and words-of two syllables lessened the chances of mishearing.
‘Hullo, Dollars . . Bolo . . Bolo . . Bolo . . Koodoo .. .Koodoo . . Koodoo . . Daily . . Daily . . Daily. . Baby. .
Baby. . Baby. .’
There were puzzled faces in the wireless hut. The last two words were indistinguishable.
‘Delete “Baby”, try “Booty”.’
After further exhaustive trials it was agreed that short double-words like ‘Dog-rose’, and ‘Shot-gun’ would provide the most effective code. They transmitted clearly and, taken together in a short context, often had a comic meaning of their own guaranteed to flummox the unimaginative Hun.
By the end of 1917 the Wireless Testing Park had grown to such an extent that it was accorded a more distinguished title, becoming the Wireless Experimental Establishment – W.E.E. in short. Major H. T. B. Childs replaced Major Orme as C.O. when the latter obtained a much desired transfer to an operational station. The sight of fourteen German Gothas flying serenely over Biggin Hill one July morning had been too much for him. ‘God damn it,’ he yelled in broad Devon accents, ‘only one Sopwith Pup and not even a round of live ammo on the ‘drome. I’m finished playing with wireless!’
Every way that wireless could potentially help in the air was under study. Old equipment was improved, new sets designed and tried out, including spark, continuous-wave and W/T transmitters, crystal and valve receivers, valve amplifiers and tonic-train transmitters. Wireless telephony sets were greatly improved by the substitution of the new ‘hard’ French valves for the imperfectly evacuated Round valves, and the first Home Defence squadron was equipped. Aperfield Court, a spacious mansion with large grounds some two miles from Biggin Hill, was requisitioned and a powerful transmitter installed for the ground-to -air control of fighters defending London against German raiders.
In March, 1918, further important changes took place. Anticipating the fusion of the RFC and the RNAS in the RAF, the decision was taken to concentrate all wireless research at Biggin Hill. The RNAS establishment at Cranwell was closed down; the work being done by the Royal Engineers at Woolwich for the Royal Flying Corps was transferred, and Lieutenant-Colonel LF Blandy, DSO, former O.C. Wireless for the Army in France, assumed overall command of the greatly expanded Wireless Experimental Establishment.
Simultaneously, work was started on the permanent buildings of the South Camp, as the site of the Wireless Experimental Establishment was known. Plans were drawn up for a new Officers’ Mess, together with barrack-blocks, laboratories, workshops, and steel and concrete hangars. It was an ambitious project that was to cost £220,000, and take as long as two years to complete. AlI building materials were in short supply and a mere wireless research establishment stood low in the scale of priorities. There was friction between the contractors and the newly created Air Ministry. Labourers downed tools on being given orders by uniformed officers, while the airmen resented the British workman’s habit of taking Saturday afternoons off with, or without, permission.
Over 600 men were employed on the construction work and Biggin Hill became an El Dorado to the neighbouring villages. As an agricultural labourer a man earned a bear 39s. 6d a week; for unskilled work on the South Camp he received over £4 in weekly wages. The hours were shorter and the contractors considerately provided a fleet of buses to pick up the men each morning and return them to their cottages at night. Local squires and farmers denounced this mollycoddling and gloomily discussed their labour shortage in the saloon bars; on the other side of the partition their former employees drank their beer contentedly, happy in the security of work at Biggin Hill for many months to come.
When the Wireless Testing Park had first moved in, only fighters were flown; now twin-engined bombers, Handley Page 0/400s and D.H. 10s, were being used and more fields had to be requisitioned for the lengthening runways. It was hard on the farmers but at least it provided some memorable occasions for the other ranks ordered out on the ‘gardening racket’. W. Wallis recalled:
Immediately at the rear of the aerodrome was a fruit farm, with a large acreage devoted to strawberries, bush fruit of every description and numerous well established apple and other fruit trees.
The owner of this farm was called to the South Camp and informed that the R.A.F. were immediately extending the ‘drome to include most of his farm.
The poor bloke was in a highly indignant state as acres and acres of luscious strawberries were to be destroyed, and was given a few days to pick what he could. He asked permission to enrol Service personnel as pickers!
I have never seen such a rush of volunteers for a fatigue party!
Pending developments, the little work required to be done on the ‘drome was done in record time on the first day of ‘Operation Strawberry’ and one then adjourned to the farm where the picking was done on the basis of: ‘The best for myself and what I can’t eat I’ll put in the basket for the farmer’.
By the end of the day the fatigue party had eaten so many strawberries that they were ashamed to look at one another!
The Station’s nominal roll now mustered 593 persons all told: 68 officers, 297 men and 228 women – W.R.A.F.s who had volunteered for cooking, clerical and M.T. duties. There was even an ‘Ancient Mariner’, a retired Captain, R,N., who had attached himself to the Mess. Whenever anything had to be moved, a hut, wrecked aircraft or hangar, the cry was raised for ‘Barnacle Bill’. With rope, pulleys and rollers he performed, prodigious feats of haulage, disdaining a land-lubberly crane or tractor.
In August was given the first demonstration of controlling the movements of a tank from the air by wireless telephone, and two months later the first long-distance flight entirely by wireless navigation. Air-to-tank telephony came too late to be of practical use in the war effort, but the wireless navigational work was of fundamental importance. It had been known for a long time that a bearing could be taken on a wireless transmitter station by a receiver fitted with a loop aerial tuned to the signal of maximum, or minimum, strength. By plotting the bearings taken in two stations, the position of the-receiver could be determined with a fair degree of accuracy, but it was considered impossible to design an airborne D/F set which could pinpoint the position of an aircraft in flight. Encouraged by Blandy, one of his wireless officers, P. P. Eckersley, tackled the problem with such success that, in October, 1918, a Handley Page O/400, equipped with D/F set and loop aerial, was flown from Biggin Hill to Paris and back again entirely on wireless bearings.
There was a Iow mist scudding in from the sea on the morning chosen for the flight with ten-tenths cloud overhead. Blandy and the crew of the 0/400 were gleeful when they saw the weather; all landmarks would be hidden and there could be no talk afterwards of cheating with visual sights. Their two passengers, Maj-Gen. Sefton Brancker and an aide, arrived at Biggin Hill in equally high spirits; they regrettably had little faith in wireless as an aid to navigation and confidently expected the flight to be called off: To their surprise the O/400 taxied out on schedule and within three minutes was flying through the overcast, out of sight of land.
Near the coast the navigator took bearings on the Marconi stations at Chelmsford and Poldhu, and gave the pilot his course for Boulogae. At the predicted time the O/400 dipped down through the clouds and there below lay the harbour; Brancker was impressed but not convinced. For the next ninety minutes the flight continued-on over unbroken cloud, flying a course set with bearings taken on transmitters in France. The two passengers were starting to joke pessimistically about being lost and the possibility of landing on the wrong side of the Front when the navigator then passed a confident message: ‘Within five minutes we shall be over Paris.’ The pilot brought the O/400 down in a shallow dive through the clouds and there was Le Bourget, with the Eiffel Tower unmistakable in the distance They landed at the aerodrome, the crew looking forward to a night’s roistering in Paris, but Brancker was in a hurry to return to London. Blandy left them at Le Bourget and drove off in a car, customarily reserved for Winston Churchill, to report to Trenchard on the new D/F equipment. The flight back to Biggin Hilt was equally sensational.
An accurate course was flown to Boulogne, the Channel crossed in clouds and landfall made at Dungeness at the predicted time. Brancker, by now an enthusiastic convert to the possibilities of wireless D/F, asked if he could satisfy a lifelong ambition and see Brighton from the air. Fresh bearings were taken on the two Marconi stations, a new course worked out and flown until the navigator, stop-watch in hand, signalled the pilot to descend – ahead lay the Brighton pier and inland the domes of the Royal Pavilion.
By the end of the war Britain led the world in the many uses of wireless in the air. The Germans had been unable to develop anything comparable to our systems of wireless telephony and direction-finding, nor, for that matter, had our Allies. The Americans were intensely interested in the work being done at Biggin Hill and requested permission for a party of officers from the U.S. Signals and Aviation Wireless Unit to visit the Station. This was granted as a courtesy between allies, and the visitors spent several instructive days at the Wireless Experimental Establishment.
RAF Biggin Hill, Graham Wallace, Putnam & Co Ltd, London, 1957