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

Lohner 10.17

  Before embarking on the production of 24 Lohner B.VII (Type J) Pfeilfliegers, the LA ordered one prototype, designated J-01 (AE 201) and powered by a 150 hp Daimler engine, for test and evaluation. When the contract was signed on 17 January 1915, the J-01, later designated 10.17, was nearing completion. It was delivered on 5 March 1915 and performed its maiden flight on 18 March with Fahnrich Edmund Sparmann at the controls. Some minor control problems resulting from the airfoil-shaped tailplane were reported, but these would be corrected on the production machines. In comparison trials supervised by Flars engineer Richard von Mises, the 10.17 prototype, powered by the improved 160 hp Daimler engine, reached 2000 meters (6562 ft) in 17 minutes as compared to 26 minutes with the original 150 hp engine. Because of protracted engine problems, the 10.17 was not accepted until 14 August 1915. It was assigned to Flik 17, one of the first squadrons to receive the Lohner B.VII series 17 production aircraft. During frontline trials the 10.17 reached an altitude of 3500 meters (11,482 ft) in September 1915, and flew several operational missions. The 10.17 was sent to the factory in March 1916 for repairs which were completed in May. It is on record that 10.17 served with Flik 16 through October 1916.


Lohner 10.28

  To evaluate the experimental 150 hp Praga V-12 engine the LA ordered one Lohner Type Js prototype, 10.28 (AE 310), on 29 October 1915, from a projected batch of three aircraft (AE 310-312). The air-cooled Praga V-8 and V-12 engines proved extremely unreliable and only sporadic flight tests were performed. Karl Kriger's flight log recorded one (maiden?) flight of the 10.28 at Aspern in March 1916. After Flars prepared the installation drawings in January 1917, Lohner fitted a 150 hp (or 120 hp) Daimler engine and the re-engined 10.28 was accepted by Flars on 1 March 1917. The 10.28 was under repair in September 1917, written-off in October and stored at the Aspern depot in March 1918.


Lohner B.V Series 16

  Since the Rapp Motoren Werke of Munich were represented in Austria-Hungary by the Motor-Luftfahrzeug-Gesellschaft (in which Lohner had an interest), it was to be expected that an aircraft powered by a Rapp engine would be proposed to the LA. The result was that Lohner received a contract on 17 January 1915 for 24 Type H Pfeilfliegers powered by the 140 hp Rapp V-8 engine. Recurring engine problems - primarily carburetor fires, excessive oil consumption and endless mechanical modifications - delayed the first Type H acceptance until April 1916, a year later than scheduled. In the event, the LFT cancelled the order after accepting only six machines because the Type H was too heavy to meet the performance specifications. These were designated Lohner B.V series 16.01 to 16.06 (AE101-106). Plagued by recurrent carburetor fires in training service with Fleks 3, 4, 8, 9, and 14, the dangerous B.V aircraft were grounded and placed in storage to await further developments, (see Lohner B.VI series 16.1)

Lohner B.IV Series 16 Specifications
Engine: 140 hp Rapp
Wing: Span Upper 14.40 m (47.24 ft)
Span Lower 10.00 m (32.81 ft)
Chord Upper 1.85 m (6.07 ft)
Chord Lower 1.70 m (5.58 ft)
Sweepback Upper 13 deg
Gap 2.10 m (6.89 ft)
Stagger 0.69 m (2.26 ft)
Total Wing Area 38.5 sq m (414 sq ft)
General: Length 8.70 m (28.54 ft)
Height 3.25 m (10.66 ft)
Track 2.05 m (6.73 ft)
Empty Weight 840 kg (1852 lb)
Loaded Weight 1225 kg (2701 lb)
Maximum Speed: 122 km/hr (76 mph)
Climb: 1000m (3,281 ft) in 11 min 5 sec


Lohner B.VI Series 16.1

  After the Lohner B.V failure, the LFT required Lohner to redesign the remaining 18 aircraft on order to meet the performance specifications. Known as the Type H2, the airframe was lightened throughout and fitted with a shorter, plywood-covered fuselage replacing the fabric-covered one of the B.V. The wing cellule had a reduced span, sweepback and stagger. These new aircraft were designated Lohner B.VI series 16.11 to 16.28 (AE 107-124). Delivered after a year's delay, the Rapp-engined B.V and B.VI biplanes were assigned directly to training units. In June 1916, the training command was forced to ground all of them because of recurrent carburetor fires. After corrective measures, limited flying was resumed at Fleks 2-6, 8, 9, and 14. In the fall of 1917, the remaining aircraft (17 or 18) were assigned to Flugpark 1 and sporadically flown until June 1918, when a fatal crash attributed to an engine fire caused the B.V and B.VI biplanes to be withdrawn from service altogether. Several were used as non-flying instructional airframes at the officer flying school in Wiener-Neustadt through 1918. According to one report, aircraft 16.01 was fitted with the experimental Praga engine in August 1916 for flight testing.
  
Lohner B.VI Series 16.1 Specifications
Engine: 140 hp Rapp
Wing: Span Upper 12.80 m (41.99 ft)
Span Lower 11.40 m |37.40 ft)
Chord Upper 1.78m (5.84 ft)
Chord Lower 1.78 m (5.84 ft)
Sweepback Upper 6 deg
Gap 1.90 m (6.23 ft)
Stagger 0.39 m (1.28 ft)
Total Wing Area 38.45 sq m (414 sq ft)
General: Length 7.60 m (24.93 ft)
Height 3.00 m (9.84 ft)
Track 2.05 m (6.74 ft)
Empty Weight 802 kg (1768 lb)
Loaded Weight 1205 kg (2657 lb)
Climb: 1000m (3,281 ft) in 10 min 15 sec


  
Lohner B.VII Series 17

  The last and most-successful Pfeilflieger design was the Lohner B.VII (Type J), built in greater number than any other Lohner landplane. Conceived as a load-carrying aircraft (Lastflugzeug), the Type J was a development of the Type D series 13 but fitted with the more powerful 150 hp Daimler engine. On 17 January 1915, the LA gave Lohner a contract for one prototype (10.17) and 24 Type J production aircraft designated B.VII 17.01 to 17.24 (AE 202-225). An additional 24 B.VII (U) Pfeilfliegers were ordered from UFAG in March. Lohner deliveries were scheduled to commence in April 1915 and continue at a rate of four aircraft per week, but the first machine was not accepted until August 1915. The fabric-covered fuselage was fitted with the favored common cockpit that provided staggered seating for the pilot and observer. Armament consisted of hand-held weapons until early 1916, when some aircraft were retro-fitted with a single machine gun mounted on a simple pivot fixture. With an observer aboard, the bomb load was about 80 kg (176 lb). A maximum bomb load of 220 kg (485 lb) could be carried in lieu of the observer, but there is no record of aircraft operated in this configuration.
  The B.VII began to reach squadron service in August 1915, replacing the Lloyd C.I and C.II biplanes stationed in mountainous terrain. The B.VII series 17 Pfeilfliegers were assigned to Fliks 6, 9, and 15 in the Balkans and to Fliks 7, 16, and 17 in South Tirol and Karnten. Judging by early combat reports, Lohner had designed a rugged machine that was highly regarded for its load-carrying ability and performance. Years later, Julius Arigi remembered the Lohner B.VII as being "the first series aircraft that was totally effective in high mountains and, most importantly, an aircraft that we, as pilots, fully trusted." Between August 1915 and mid-1916, the B.VII series 17 performed numerous long-range reconnaissance and bombing raids, some of five or six hours duration. However, the reliability of the 150 hp Daimler engine left much to be desired. After the outspoken commander of Flik 16, Hauptmann Raoul Stojsavljevic, voiced his displeasure during a visit to Vienna in November 1915, his squadron was the first to receive the more powerful Lohner B.VII series 17.3 in December 1915.


Lohner B.VII Series 17.3

  The B.VII series 17.3 was powered by the improved 160 hp Daimler engine that had been test flown in the Lohner 10.17 and was just coming into production. Sixteen B.VII series 17.3 biplanes, numbered 17.31 to 17.46 (AE 808-823), were ordered and although the contract was not signed until 20 March 1916, acceptances had already begun in December 1915 and ended in March 1916, only one month behind schedule. The B.VII series 17.3 began to arrive at the Front in December 1915 and served with Fliks 7, 8, 16, and 17 and singly with Fliks 12 and 19 on the Isonzo Front.
  The B.VII's range and bomb load presented the LFT with the opportunity to attack targets deep in Italian territory. Among the most notable was the bombing raid against the Milan electro-generating works undertaken on 14 February 1916. While older Lohner B.VII and Lloyd C.II machines performed a diversionary raid on Schio, twelve B.VII series 17.3 would attack the prime target. Aircrews of Fliks 7, 17, and 16, based at Gardolo and Pergine, prepared for a round trip of about 380 km (236 miles) over imposing mountainous terrain that presented a formidable obstacle. Hauptmann Eugen von Steinner-Goltl, commander of Flik 17, recalled:
  We took off with 270 liters fuel and 80 kg bombs and assembled at 1600 meters in the dawning light. My Gral II took the lead, steering a straight compass course so we would quickly reach Milano without undue fuel consumption. At 3000 meters we crossed the enemy lines some 700 meters below us. We were met by murderous artillery fire. After our compass froze, we navigated by the distinctive lakes and valleys. On the way the squadron dispersed entirely. After one and a half hours, the Lombard plain greeted us. My heart laughed, so much flatland - so many landing possibilities. Finally my observer picked out Milan in the haze.
  Gral II only just got home. Spending almost five hours in the air "we landed with a stalled engine; inspection showed a broken crankshaft." Given the conditions, it is remarkable that the target was hit at all and that no aircraft were lost. Of the 12 aircraft that took off from Pergine, nine reached Milano and damaged the Porta Volta power station, one bombed Monza by mistake and two made forced landings in friendly territory. Of the few B.VII that carried a machine gun, one succeeded in shooting down an Italian aircraft. Other attacks under similar circumstances were undertaken in 1916. Flik 7 lost two B.VII (17.40 and 17.41) behind the Italian lines during a squadron attack on the Piave bridges on 27 March 1916. In the course of an attack on Udine, aircraft 17.42 became Baracca's second victory on 16 May 1916. Only two B.VII aircraft served on the Russian Front, one when Flik 7 was transferred to Galicia and one with Flik 26.

Lohner B.VII Series 17.3 Specifications
Engine: 160 hp Daimler
Wing: Span Upper 15.40 m 150.52 ft}
Span Lower 11.20 m (36.74 ft)
Chord Upper 2.00 m (6.56 ft)
Chord Lower 1.83 m (6.00 ft)
Sweepback Upper 13 deg
Gap 2.21 m (7.25 ft)
Stagger 0.352 m (1.15 ft)
Total Wing Area 44.0 sq m (473 sq ft)
General: Length 9.50 m (31.17 ft)
Height 3.75 m (12.30 ft)
Track 2.22 m (7.28 ft)
Empty Weight 990 kg (2183 lb)
Loaded Weight 1441 kg (3177 lb)
Maximum Speed: 121 km/hr (75 mph)
Climb: 1000m (3,281 ft) in 7 min 41 sec


Lohner B.VII(U) Series 17.5

  Following the successful tests of the Lohner B.VII prototype (10.17), UFAG was given a contract to build 48 Lohner B.VII(U) biplanes on 30 March 1915. Deliveries were scheduled to start on 30 April and end on 2 July 1915. In March 1915, the contract was reduced to 24 aircraft in favor of the Brandenburg G.I(U) series bomber. After four aircraft were accepted, production was stopped in August 1915 to repair unacceptable welds, for which UFAG was penalized. The last of 24 Lohner B.VII(U) biplanes, numbered 17.51 to 17.74 and powered by 150 hp Daimler (MAG) engines, was delivered in January 1916. Because of the unreliable MAG-built engines, the aircraft were declared unfit for frontline service. Beginning in November 1915, the UFAG-built B.VII biplanes were flown as secondary trainers with Fliks 2 and 19 as well as Fleks 2-6, 8, and 9 and Schulkompagnie 1 and 2. Five were still in use as trainers when the war ended.


Lohner B.VII Series 17.8

  Nine older B.VII series 17 machines (known are 17.01-05, 09, 12, and 20) were rebuilt by Lohner to take the 160 hp Daimler engine. Fitted with a new motor mount and fuselage frames and a machine gun ring for the observer, the modified aircraft were designated Lohner B.VII series 17.8, numbered 17.81 to 17.89. These aircraft arrived at the Front in February-March 1916. They were assigned to Fliks 12 and 23 on the Isonzo Front and Fliks 7, 8, and 17 in the Tirol.
  With the appearance of the Brandenburg C.I, the B.VII aircraft were withdrawn and assigned to Fleks 3-5, 7-9, and 13 for advanced pilot training. As of July 1917, thirty-seven B.VII aircraft were listed in LFT inventory and by October 1918, this number had been reduced to eight damaged B.VII aircraft stored at Flep 2.

Lohner B.VII Series 17.8 Specifications
Engine: 160 hp Daimler
Wing: Span Upper 15.40 m (50.52 ft)
Span Lower 11.20 m (36.74 ft)
Chord Upper 2.00 m (6.56 ft)
Chord Lower 1.83 m (6.00 ft)
Sweepback Upper 13 deg
Gap 2.21 m (7.25 ft)
Stagger 0.35 m (1.15 ft)
Total Wing Area 44.0 sq m (473 sq ft)
General: Length 9.50 m (31.17 ft)
Height 3.75 m (12.30 ft)
Track 2.22 m (7.28 ft)
Empty Weight 941 kg (2075 lb)
Loaded Weight 1392 kg (3069 lb)
Maximum Speed: 124 km/hr (77 mph|
Climb: 1000m (3,281 ft) in 9 min

E.Hauke, W.Schroeder, B.Totschinger Die Flugzeuge der k.u.k. Luftfahrtruppe und Seeflieger 1914-1918

10. Flugzeuge der Fabrik Jacob Löhner & Co. Wien, Floridsdorf
10.17 Löhner DD J-01 Dm 160
10.28 Löhner DD Type JS Pr 150
16.01 — 16.06 Löhner B.V (Type H) Rp 145
16.10 — 16.28 Löhner B.VI (Type JCR) Rp 145
17.01 — 17.25 Löhner B.VII (Type J) Dm 150
17.30 — 17.46 Löhner B.VII (Type J) Dm 160
17.51 — 17.76 Löhner B.VII (U) Dm 150
17.81 — 17.89 Löhner B.VII (Umbau Ba 17) Dm 160