Aerial Attack –the Zeppelin

It is well documented that the political, technical, and to a lesser extent social, changes in the late 19th century converged to create a climate of fear and suspicion that led inexorably to the outbreak of the First World War. By the dawn of the new century it was broadly accepted that war was all but inevitable – it was just a matter of time. The advent of balloons and dirigibles, with the prospect of heavier-then-air aircraft soon to follow, gave future warfare a new dimension and foremost among those warning of the consequences was H. G. Wells. In 1901 he wrote ‘An Experiment in Prophesy’ for the North American Review, wherein he concluded: “Everybody everywhere will be perpetually and constantly looking up, with a sense of loss and insecurity, with a vague distress of painful anticipations. By day, the victor’s aeroplanes will sweep down upon apparatus of all sorts in the adversaries’ rear and will drop explosive and incendiary matters upon them, so that no apparatus or camp or shelter will any longer be safe.”

Then, for the broader readership he wrote ‘The War in the Air’, a story of a catastrophic war that was serialised in the popular Pall Mall magazine in 1908. In the aftermath of a global war and the collapse of society a character says, in the epilogue: “There was a great fight all hereabouts one day, Teddy – up in the air. Great things bigger than fifty ’ouses, bigger than the Crystal Palace – bigger, bigger than anything, flying about up in the air and whacking at each other….”

These and other writings cemented in people’s minds the notion that any future war would draw civilians into the conflict as well as the military, with mass destruction of property and high casualties. Governments were mindful of the threat, many believing the dire predictions to be broadly correct and that the country’s ability to sustain a war would be dealt a lethal blow. There was real fear that under attack the civilian population would be driven to panic, society would collapse and the war would be lost. Equally there were those who feared that the population could rise up and overthrow the government that had failed to protect them, and again the war would be lost. It did not matter much whether the authorities wished to protect the public or to protect the status quo, and hence themselves, a means to defend against attack would be essential. Billing probably had a foot in both of these camps.

Immediately prior to the outbreak of war it was well known that Germany was engaged in building large dirigibles, mostly of the Zeppelin type, and that the small scout-type single and two seat aircraft in service with the RFC and RNAS would be incapable of engaging them once they were in the air. On the other side, towards the end of 1914 the German high command debated on the merits of launching bombing raids on Britain, and both the Army and Navy were supportive of the idea.

Admiral Alfred von Tirpitz wrote that, “the measure of the success will lie not only in the injury which will be caused to the enemy, but also in the significant effect it will have in diminishing the enemy’s determination to prosecute the war”.

It was the lack of an effective aerial defence against raids by airships that led, in the very first weeks of the war, to the formulation of plans to hit the Zeppelin production facility and sheds at Düsseldorf, Cologne, Cuxhaven and Friedrichshafen, the disappointingly unsuccessful mission in which Billing himself had participated.

The first Zeppelin attacks against the British Isles took place on 19th January 1915. After a few aborted sorties, the first bombing of London occurred on 31st May. These raids would not prove particularly effective but exposed for all to see the country’s inability to defend itself against them.

Government policy for the defence of Britain at the outbreak of war was that it fell largely within the domain of the Admiralty, while the Army fielded the British Expeditionary Force and the RFC to fight on the continent, and overseas forces defended the Empire. The Navy patrolled the coast, Marines were available to be deployed onshore, as they had been in Belgium during the German’s advance, and they soon had an aerial force almost as effective as that of the Army. Hence it was the Admiralty that took the lead in formulating a defence against the

Zeppelins along the coast and around the cities. Later this was bolstered by the RFC who took over the role inland, manning searchlights, anti-aircraft guns and airfields.

P.B.23E and P.B.25

The first element of Billing’s vision for the defence of Britain to see the light of day was not one of the four types described in his original masterplan but the high-speed ‘destroyer’ single-seat type that was intended to accompany the large patrol machine.

The P.B.23E, the ‘E’ denoting experimental, was, as Billing’s book had described, a single-seat pusher scout. The nacelle was skinned in aluminium, possibly a tentative attempt to provide a small degree of armour protection for the pilot, and set mid-gap between the biplane wings and held by fore and aft strut pairs to the centre section of the upper wing and by a single strut pair at the rear to the centre section of the lower wing. A forward pair of lower struts ran directly to the axle of the undercarriage. The four upper and two lower nacelle struts were also the only support for the wing centre section panels.

An 80hp Le Rhône rotary engine was installed at the rear of the nacelle and drove a two-blade propeller. The outer wings, straight with no sweep- back, were set in a single bay with a large gap and no stagger. Only the lower wing had dihedral on the outer panels. The monoplane tail held twin fins and rudders and was supported by four struts running from the outer extremities of the centre sections of the top and bottom wings back to the rear spar of the tailplane at the point where the twin fins were attached. These struts were braced laterally by two wires each side that ran from the top and bottom of the rearmost wing struts down to the attachment point on the tailplane. The control surfaces are said to have been actuated via Bowden cables rather than a more conventional cable and pulley system. The aircraft was armed with a single Lewis gun firing through the nose of the nacelle, which placed the breaches low down by the pilot’s feet.

The P.B.23E was sent to Hendon for trials in September 1915 where is was given the nickname ‘Sparklet’ on account of the nacelle resembling the small metal bulbs that held the gas charge for soda syphons. The results of the flight trials do not appear to have been retained but the aircraft is believed to have been sent to the Isle of Grain, the test facility of the RNAS, before returning to Hendon, where it was still present in July 1916. At some point it had been modified with enlarged fins. Billing later claimed that it had a top speed of 120mph, which is highly improbable, while a contemporary estimate was 90mph. It may have been Billing who later referred to the aircraft as ‘Push-proj’, a contraction of pusher projectile, a nickname to match his exaggerated claim for speed.

The pusher concept must have been viewed by the RNAS as having merit because they contracted the company to build 20 examples of an improved aircraft with the same layout. The P.B.25 was much more than a modified version of the P.B.23E as the entire structure had been redesigned.

The metal-clad nacelle was dropped in favour of one with fabric cover and it was both longer and deeper. The lower support struts now comprised a pair of inverted V struts to the front spar of the wing and single struts to the rear. There was no direct connection between the nacelle and the undercarriage, which was now attached to the lower wing centre section only. The greater depth of the nacelle created space for the Lewis gun in a more convenient position ahead of the windscreen lying within a trough while the increase in length placed the engine to the rear of the wings so that cut-outs for the propeller were no longer required.

The engine in the first example of the aircraft was a 110hp Clerget while the others in the production batch had a 100hp Gnome Monosoupape. The Clerget drove a two-bladed propeller while for the Gnome this was replaced by a four blade type.

To improve balance, the outer wing panels were set with 11 degrees of sweep. The top wing was of slightly greater chord than the lower and the top ailerons were increased in size by adopting reverse taper. The enlarged tailplane and fins, the tailplane attachment struts and light wire bracing were all carried forward from the modified P.B.23E.

The first P.B.25s were completed and sent for flight testing in September 1916 and the entire batch of 20 had been delivered by February 1917. The pilots found that there was much to criticise. The high centre of gravity and position of the undercarriage presented a high risk of the aircraft tipping onto its nose when landing or traversing rough ground, and the pilot was in a very exposed and poorly protected position should this occur. The aircraft was distinctly unstable in flight too.

The use of Bowden cables for the tail controls may have simplified the difficult problem of running cables between the mid-set nacelle, down to the lower wing and across to the tail, while avoiding the arc of the propeller, but it gave a very imprecise movement of the surfaces, initial movement of the stick often resulted in no effect while moving just a tad more would cause a sudden coarse jerk of the elevators. The rudder was similarly less precise but not to the same extent. The airframe was judged as rather flimsy, the tailplane bracing in particular lacking rigidity.

Performance was not acceptable and way below the basic specification that Billing had outlined. Top speed was 89mph at ground level, 83.5mph at 10,000ft. It took 11 minutes to climb to 6,000ft and 21 minutes to reach 10,000ft, the height at which it was intended to operate. By the time it had been constructed conventional aircraft types such as the Sopwith Pup had proven superior. The P.B.25 does not appear to have entered service.

Zeppelin destroyer – the P.B.29E

While the P.B.25 was part of Billing’s defence masterplan it was intended to play second fiddle to the larger aircraft designed specifically to intercept and destroy marauding dirigibles. Billing claimed that he had been summoned by Commodore Murray Sueter at the Admiralty, given indefinite leave from his duties and instructed to design and build such an aircraft. This is almost certainly an exaggeration or even untrue as other aircraft designed for much the same purpose were already being built by Vickers and Armstrong-Whitworth, among others. Regardless of Billing’s narrative no order for the aircraft was ever issued by the Admiralty and it was never allocated an official serial number.