P.Grosz, G.Haddow, P.Shiemer Austro-Hungarian Army Aircraft of World War One (Flying Machines)

Aviatik 30.07

  Work on the experimental 30.07 bomber, the largest aircraft built in Austria-Hungary, began on 5 November 1915 when Flars established a design team of Flars engineers jointly directed by Oberleutnant Professor Richard von Mises and Ingenieurleutnant Karl Saliger. By January 1916 the airframe configuration had been agreed upon. The wing profile was tested in Knoller's wind tunnel at the Polytechnic Institute, where Professor Richard Katzmayr analyzed propeller and propulsion design. In his writings, Mises conveys the excitement and manifold difficulties encountered in bringing such a complex project to completion.
  On 24 November 1915, Aviatik received a Regiebau contract (a government-managed, cost-plus-fixed-fee agreement) for which the company provided space and labor but assumed no engineering responsibility. Component manufacture began at Esslingen in December 1915, causing the Flars resident inspector to complain that regular production work was being neglected. Airframe assembly of the Mises bomber, now numbered 30.07 (project designation Gr.I), was under way in January 1916.
  The 30.07 bomber was constructed around two internal transmission units, powered by the experimental 300 hp Daimler V-12 engine. Each was fitted with a double-ended crankshaft that drove, via two gearboxes and outrigger shafts, a pair of counter-rotating, tractor airscrews mounted athwart the fuselage. The power units, installed sideways in the fuselage, were separated by the pilot's cockpit. The outriggers were mounted independently of the wing structure, a desirable feature in case of transmission shaft failure. The power units were manufactured by Daimler and serviced by MAG engineers.
  The transmission was bench-tested in mid-March 1916, followed by full airframe thrust measurements on 19 May. When the bomber appeared for taxi trials on 1 June, the undercarriage collapsed, requiring a stronger shock cord assembly. One totally unexpected problem was the "hours of frustrating toil" required to start the engines. The new engines were prone to sparkplug oiling, and worse, since an auxiliary starting mechanism was not provided, it was physically awkward and exhausting to swing the propellers. An extended taxi run was performed on 27 June. Finally, after careful engine servicing on July 1, test pilot Ingenieur Franz Sattler performed taxi runs and several short hops to satisfy himself that the aircraft was controllable in flight. On 2 July 1916, with Mises in the co-pilot's seat, 30.07 made its maiden flight around the Aspern airdrome lasting ten minutes. Two days later on its second flight, 30.07 reached 350 meters (1148 ft) but during landing, the bomber lost speed and stalled-in from four meters (13 ft). The damage was expected to be repaired by 20 July, allowing time for minor structural changes and engine removal for overhaul.
  The 30.07 was destroyed on 28 July 1916. In an official report, Mises stated that the 30.07 hung sharply to the right at takeoff. Sattler reacted by pulling up too quickly and crashed from 20 meters (66 ft) onto the right wing. "Kindling wood", remarked Mises who, like Sattler, was spared injury thanks to the strongly-built pilot's enclosure. In spite of the short time aloft, flight evaluation was generally positive; the prototype flew smoothly with great stability and, except for the sluggish aileron response, was relatively easy to control. Most of the improvements concerned the engines. Mises recommended better cooling, new carburetors, and auxiliary engine starters. The bomber was grossly overweight owing to the unexpectedly high drive-system weight, which in turn reduced the useful load by 1000 kg (2205 lb). Some 300 kg (662 lb) would have to be removed to make the design viable. The Mises bomber remained a priority program and construction of the improved 30.17 and 30.18 bombers was already under way.

Aviatik 30.07 Specifications
Engine: 2 x 300 hp Daimler
Wing: Span Upper 22.60 m (74.15 ft)
Chord Upper 3.00 m (9.84 ft)
Chord Lower 3.00 m (9.84 ft)
Sweepback Upper 4 deg
Gap 3.06 m (10.04 ft)
Total Wing Area 118 sq m (1270 sq ft)
General: Length 15.37 m (50.43 ft)
Height 4.45 m (14.60 ft)
Track 3.60 m (11.81 ft)
Empty Weight 2800 kg (6174 lb)
Loaded Weight 4500 kg (9926 lb)
Maximum Speed: 135 km/hr (84 mph)


Aviatik 30.17 and 30.18

  Concurrent with the assembly of the Aviatik 30.07 (Gr.I) prototype, preliminary design work continued on two prototypes, 30.17 (designation Gr.II) and 30.18 (Gr.III), that would incorporate improvements based on the limited experience gained with the 30.07. The guidelines, laid down on 3 August 1916, recommended raising the engines to place the exhaust system in the slipstream and installing a modified transmission system. The fuselage was shortened and fitted with a ventral gun position. The undercarriage was redesigned with lighter wheels and steel springs replaced the rubber shock cords. Components salvaged from the 30.07 crash were used in the 30.17 airframe. As projected, the 30.17 and 30.18 bombers were powered by two 345 hp Daimler V-12 engines, manned by a crew of four and capable of carrying a 350-500 kg (772-1102 lb) bomb load.
  At the time the contract for two bombers was signed on 5 October 1916, the assembly of the 30.17 was nearing completion at Esslingen. It arrived at Aspern in late October 1916. By then the bomber program had lost much of its impetus. Mises was unable to devote full time to his project for he had been promoted to supervise the Flars engineering department. Mises hinted at personality clashes within Flars but did not elaborate. As Flars' "technical fireman", he travelled extensively to correct problems and in October 1916, Mises was ordered to Flek 11 in Mostar to gain flying experience with operational aircraft. In his absence, the Mises bomber program came to a halt. Faced by the escalating air war on the Italian Front, the LFT could hardly justify diverting manpower and scarce materials for a project that promised no immediate benefit. In fact, little flying was undertaken with the 30.17 during the winter months. To make production space available at Esslingen, on 10 May 1917 the 30.17 was transferred to Flek 6 in Wiener-Neustadt where sufficient tests were performed to enable Oberleutnant Antal Lanyi-Lanczendorfer to submit a fairly comprehensive flight report (23 November 1917):
  1) the aircraft begins to roll with engines turning at 900 rpm.
  2) suspension and tail skid are very good; tires are unsatisfactory.
  3) the aircraft can take off and fly on one engine.
  4) the aircraft maneuvers freely. When a gust caused the left wing to drop, it was righted easily using the ailerons.
  5) rudders are well balanced and elevator controls are more sensitive than those of the Brandenburg G.I.
  6) all controls can be manipulated without using excessive force.
  7) aircraft lands easily, undercarriage strength appears adequate.
  8) faults: the engines oil-up rapidly and are difficult to stop.
  After the engines had been removed and modified by Daimler, the 30.17 was ordered to Strasshof on 28 January 1918 to install service equipment in preparation for frontline evaluation with Flik 102/G. But at Wiener-Neustadt on 19 March, the 30.17 was damaged beyond repair during a landing approach. It appears that a low-altitude stall, such as destroyed the 30.07, was the cause. Fortunately, the robust cockpit structure prevented injury to the flight crew.
  The last Mises bomber, 30.18, completed in December 1916, was given a lighter airframe and ailerons were fitted to the lower wings. Flight trials began at Aspern in January 1917. The 30.18 was slightly damaged on 25 May 1917 because the new 345 hp Daimler engines failed to produce full power. From June to September 1917, cursory flight tests were performed at Flek 6 using the more reliable 300 hp Daimler engines. The 30.18, again fitted with 345 hp engines, was damaged on 1 April 1918 during the course of flight and speed trials. The bomber was reported in good condition at Aspern on 25 October 1918.

Aviatik 30.17 Specifications
Engine: 2 x 345 hp Daimler V-12
Wing: Span Upper ca 22.60 m (74.15 ft)
Chord Upper 3.00 m (9.84 ft)
Chord Lower 3.00 m (9.84 ft)
Gap 3.06 m (10.04 ft)
Total Wing Area 118 sq m ( sq ft)
General: Length 14.45 m (47.41 ft)
Height 4.25 m (13.94 ft)
Track 3.60 m (11.81 ft)
Empty Weight 3078 kg (6787 lb)
Loaded Weight 4720 kg (10,408 lb)