View Full Version : Daimler Benz engined Hurricane...

03-21-2008, 02:47 PM

'Little is known of the Royal Yugoslav Air Force (JKRV) and its brief fight with the Luftwaffe and Regia Aeronautica in April 1941. Many Western historians have written it off as small and insignificant. It will surprise many to learn that the JKRV had over 800 aircraft on its strength at the time of the German invasion. By 1941 the JKRV had on its strength over 160 fighters, made up of 73 Messerschmitt Me-109Es, 44 Hawker Hurricane Is and 30 Hawker Fury IIs, as well as 8 Ikarus IK-2s and 12 Rogozarski IK-Zs, both locally designed and built.

Its bomber strength of 175 aircraft comprised 70 Dornier Do-17Ks, 60 Bristol Blenheim Is (both being licence manufactured in Yugoslavia by the State Aircraft Factory and Ikarus respectively) and 45 Savoia Marchetti SM-79s.

The situation whereby Yugoslavia had to acquire or manufacture aircraft from whatever source presented itself meant that by 1941, the JKRV was equipped with 11 different types of operational aircraft, 14 different types of trainers and five types of auxiliary aircraft, with 22 different engine models, four different machine guns and two models of aircraft cannon.

The Yugoslav manufactured Dornier Do-17K, for example, was a German aircraft with French engines, Belgian armament, Czech photo-recon equipment and Yugoslav instrumentation! It was a quartermaster's nightmare!

During 1938, The Yugoslav government concluded an agreement with Hawker to purchase 12 Hurricane Is for the Royal Yugoslav Air Force and followed this up with an order for 12 more together with a manufacturing licence to allow production of the fighter at the Rogozarski (orders for 60) and Zmaj (orders for 40) factories. These plants, together with the Ikarus concern, had been designing and manufacturing sporting and training aircraft since the 1920s.

Production was expected to reach eight per month from each assembly line by mid-1941. In the event, by the time of the German onslaught of April 1941 which put an end to further production, Zmaj had delivered 20 Hurricanes but Rogorzarski had delivered none.

The design team had been working on improved versions of the IK-Z. It had originally been planed to power later IK-Zs with new 1,100 h.p. Hispano-Suiza 12Y-51 engine. The German occupation of France had frustrated this plan, and it therefore become necessary to consider a British or German engine. The Air Ministry favored the DB 601 A, and as part of IK-Z development program, the Daimler-Benz engine was installed experimentally in a Hurricane airframe in 1940.

JKRV DB601 Hurricane

Engineers Ilic and Sivcev at the Ikarus plant, Zemun, outside Belgrade, made the conversion, by the fitting of new engine bearers, cowlings and cooling system manufactured at the Ikarus factory.

The one Hurricane fitted with a DB601A engine for comparison with the Merlin-engined version was tested early in 1941. The conversion was extremely successful, and experimental aircraft displayed better take-off performance and climb rate than either the standard Hurricane or the Bf 109 E-3 and was only slightly slower than the latter.

At the same time, a 1,030 h.p. Rolls-Royce Merlin III was installed in one of the IK-Z airframes, but this machine had only just been completed at the time of the German attack, and as enemy forces neared Belgrade it was destroyed by the factory workers, together with four other IK-3s undergoing overhaul or modification. JKRV pilots who flew the Hurricane conversion considered it to be superior to the standard model.'

WHat engine was in the RAF Hurricanes in 1941? wasnt it the Merlin XX?

I find it a bit odd that the Hurricane witht he same engine had a better climb rate than the Bf109E, but maybe thats because of its much bigger wing?

*Taken from the 'Unreal Aircraft' website.

03-21-2008, 03:05 PM
Same power for bigger wing area produces more lift.

I read the same thing about the Spitfire that Germans powered with a DB engine. It climbed quite a bit better then the 109.

03-21-2008, 03:07 PM
"""Spitfire Vb serial EN830 / NX-X fell into German hands late in 1942. It crash landed on November 18th 1942 while being flown by P/O (Sous Lt.) Bernard Scheidhauer of the Free French Air Force, attached to 131 "County of Kent" Sqn. RAF. He and his No.1, P/O Henri de Bordas, had been on a "rhubarb" to Normandy during the afternoon. EN830 was hit by light flak and made a forced landing in a turnip field at Dielament Manor, Trinity, Jersey.

Sous Lt Scheidhauer was taken prisoner by the Germans and, like his aircraft, was transported to Germany. On March 24th, 1944 he and 80 other RAF officers escaped from Stalag Luft 3. He was captured along with his escape partner Sq. Ldr. Roger Bushell in Saarbrucken. The were both shot for their part in the "Great Escape" on 28th March 1944. His aircraft was captured virtually intact, and in good enough condition to be flown in November 1943, with black crosses in place of RAF roundels, to Rechlin for testing.

Enlarge image (will open in a new window)In early spring of 1941, another Spitfire had been tested here. A suggestion that it be tested with a Daimler-Benz engine to enable a more direct comparison with the Luftwaffes' Messerschmitt Bf.109 led to it being flown to the Daimler-Benz facility at Backnang, near Stuttgart, on April 24, 1941. There it was to receive a DB 601 engine. This work proved to difficult and the project was abandoned. That aircraft returned to Rechlin on September 9, 1942.

Enlarge image (will open in a new window)The acquisition of the second Spitfire, EN830, revived the idea. The Spitfire was sent to Echterdingen, south of Stuttgart, where Daimler-Benz operated a flight testing division. Flugkapitän Willy Ellenreider and his staff were responsible for testing to improve performance of other current aircraft, and a number of types served as flying test-beds. Among them were Ju.52s with a DB 605 engine in the centre position; He.111s, Hs.130s, Bf.109s and 110s, a Ju.87 and an Fi.167.

Spitfire EN830 was repainted to German standards, dark green above and pale blue below, with bright yellow tail control surfaces and large, black crosses. Radio code letters CJ+ZY were painted on each side, below and, unusually, above the wings; and the British serial transferred to the fin above the swastika.

The Spitfire reached Echterdingen minus guns and ammunition, with the gun ports closed. The radio had been replaced with ballast, but it still had its original Merlin 45 engine. Several flights were made by Daimler-Benz pilots before conversion was attempted. A decision was made to replace the intruments and the entire electrical system with standard German equipment, because the Luftwaffe used a 24 volt system, whilst the RAF used a 12 volt standard.

After the Merlin engine was removed, it was discovered that the Spitfire's front fuselage cross-section was very close to that of the standard Bf.110G's engine cowling. A new engine support was designed, and a standard DB 605A-1 engine (Wk-Nr 00701990) was mounted to the fire wall. The work was completed at the Sindelfingen Daimler-Benz factory, near Echterdingen.

A 3.0 m. diameter Bf.109G propellor was added, together with the carburettor scoop from a Bf.109G. This made the modified Spitfire's all-up weight, without armament, 6,020 lb. (2730 kg). The armament weight was an estimated additional 661 lb. (300 kg.). Its weight with armament, before the engine modification, had been 6,680 lb. (3030 kg.).

After a couple of weeks, and with a new yellow-painted nose, the Spitfire returne to Echterdingen. Ellenreider was the first to try the aircraft. He was stunned that the aircraft had much better visibility and handling on the ground than the Bf.109. It took off before he realised it and had an impressive climb rate, around 70 ft. (21 m.) per second. Much of the Spitfire's better handling could be attributed to its lower wing loading.

The Spitfire's wing area was about 54 sq. ft. (5m²) greater than that of the Bf.109. The Messerschmitt was faster at low altitude, but at 11,000 ft. (3350 m) the speeds evened out. The DB 605A engine gave better performance, according to the test group, than the Merlin, which was rated 150 hp below the German engine. It gave the Spitfire a ceiling of 41,666 ft. (12700 m.), about 3,280 ft. (1000 m.) more than a Bf.109G with the same engine and 5,166 ft. (1475 m.) more than that of a Spitfire Mk.V.

After a brief period at Rechlin confirming the performance data, the modified Spitfire returned to Echterdingen to serve officially as a test bed. It was popular with the pilots in and out of working hours. Its career ended on 14th August, 1944, when a formation of US bombers attacked Echterdingen, wrecking two Ju.52s, three Bf.109Gs, a Bf.109H V1, an FW.190 V16, an Me.410 and the Spitfire. The remains of the hybrid Spitfire were scrapped at the Klemm factory at Böblingen. """