Rogozarsky IK-3

Assisted by Ing. Zrnić, the design team initiated the design of a single-wing fighter that would be a marked improvement over the biplane fighters then in use. They began work in 1936 under strict secrecy. Wind tunnel testing work was carried out in France, before they submitted the design to the Yugoslav Air Ministry, who then approved construction of a single prototype. Construction of the IK-3 was assigned to Rogožarski A. D. in Belgrade.

Prototype

The prototype first flew in the spring of 1938.

The IK-3 prototype was powered by a Hispano-Suiza 12Y-29 liquid-cooled supercharged V12, rated at 890 hp (664 kW) for take-off and at 920 hp (686 kW) at 11,810 feet (3600 m) altitude. The prototype was armed with one 20 mm Hispano-Suiza HS-404 cannon and two 7.92 mm FN-Browning machine guns mounted over the engine in the forward fuselage. The aircraft was of mixed steel tube, wood, and fabric construction with the retractable landing gear of Messier design. Its construction was similar to the British contemporary Hawker Hurricane fighter. Six test pilots flew the prototype in a mostly-successful test program (alterations were required to the retractable landing gear and to the engine installation) before the airplane was destroyed in a fatal crash. On January 19, 1939 the test pilot, Captain Milan Pokorni, after a series of aerobatic maneuvers, entered a terminal velocity dive from which he did not recover. The subsequent accident investigation could not find an aircraft-related cause for the accident, and the Yugoslav Air Ministry ordered an initial production lot of twelve aircraft.

 IK-3 Production

Several changes were added to the production version of the IK-3:

More structural members were added to the rearward-sliding canopy enclosure;

Bulletproof glass was incorporated into the windshield;

Use of a Czech-built version of the Hispano-Suiza engine used in the prototype, the Avia H.S. 12Ycrs.

The first IK-3s were delivered in the summer of 1940 to an experimental fighter squadron whose pilots preferred it to the Messerschmitt Bf 109E-3 and the Hawker Hurricane, as the IK-3 was more maneuverable and could make tighter turns. Additionally, the aircraft was found to be very maintainable.

With the success of the IK-3, planning began for licensing manufacture in Turkey as well as increased production by Rogožarski - a second production batch of 25 aircraft were ordered. However, production of the second batch had just started when Germany invaded Yugoslavia on April 6, 1941.

Planned design improvements to the IK-3

As production of the IK-3 proceeded the design team was working on improved versions of the IK-3 and other designs. Among the IK-3 improvements in work was installation of a more powerful engine. Engines that were considered:

An upgraded 1,100 hp Hispano-Suiza 12Y-51;

The Daimler-Benz DB-601A;

The 1,030 HP Rolls-Royce Merlin III engine

Also, Rogožarski was pursuing a new fighter design, the IK-5 [1] , that was to be powered by two Hispano-Suiza 12Y engines. Two versions of the design were planned, a single seat interceptor and a two seat long range “destroyer” with heavy nose mounted armament. Models of the IK-5 had been tested in wind tunnels and construction of a prototype begun when the German invasion ended this and all other efforts.

The Ikarus S-49 fighter, prodced after the Second World War, was based on the IK-3.

Operational history

At the beginning of the April war, only 6 out of 12 IK-3 from the first production series were operational. One aircraft was lost in a fatal accident before the war (it dived into the Danube River under power; investigators concluded the pilot had blacked out), four were grounded for scheduled services and repairs and one aircraft was undergoing modification to Series II IK-3 standard in the Rogozarski airplane factory. The six remaining IK-3s were assigned to 161st and 162nd fighter squadron (3 IK-3 each) of the 51st Fighter group. The 51st fighter group was part of the 6th fighter regiment of Royal Yugoslav Air Force which was tasked to defend Yugoslav capital, Belgrade. Both fighter squadrons were stationed at Zemun airport. One source [2] states: " . . the IK-3s put up a valiant resistance against the Luftwaffe, scoring a number of "kills" before they were finally destroyed in combat." Another source [3] claims 11 victories for the IK-3, with Narednik (Flight Sergeant) M. Semiz as most successful (4 victories).

General characteristics
Crew: 1
Length: 27 ft 5 in (8.38 m)
Wingspan: 33 ft 10 in (10.33 m)
Height: 10 ft 8 in (3.23 m)
Wing area: 179 ft² (16.6 m²)
Empty weight: 4,123 lb (1,874 kg)
Loaded weight: 5,291 lb (2,405 kg)
Powerplant: 1× Avia-built Hispano-Suiza 12Ycrs V-12 liquid-cooled engine, 920 shp (686 kW)
Performance

Maximum speed: 327 mph (526 km/h) at 17,715 ft (5,401 m)
Range: 310 miles (496 km)
Service ceiling: 26,250 ft (8,000 m)
Wing loading: 29 lb/ft² (113 kg/m²)
Power/mass: 0.17 hp/lb (0.29 kW/kg)
Armament
Guns:
1× 20 mm Hispano-Suiza HS-404 cannon
2× 7.92 mm FN-Browning machine guns

Fokker T.VIII-W

Designed to Netherlands naval air service specifications for a torpedo-bomber/reconnaissance aircraft suitable for home and the Netherlands East Indies service, the Fokker T.VIII-W floatplane was built in three versions: the T.VIII-Wg of mixed wood and metal construction, the T.VIII-Wm which was all metal and the T.VIII-Wc, a larger version of mixed construction.

An initial order for five aircraft was placed, and all were completed by June 1939, when a further batch of 26 was ordered, most of them intended as replacements for T.IVs in the East Indies, but none was delivered there. A total of 36 T.VIII-Ws was built, these comprising 19 T.VIII-Wgs, five T.VIII-Wcs and 12 T.VIII-Wms, the difference of five being accounted for by a Finnish order which was not delivered. These were of the T.VIII-Wc variant which had a 1.83m longer fuselage, 2.01m increase in wing span, an additional 8.00m2 of wing area, and power provided by 664kW Bristol Mercury XI engines. In the event, the Fokker factory was overrun by the Germans before completion of this order, but the aircraft were finished and subsequently delivered to Germany along with 20 ex-Netherlands navy aircraft. A one-off landplane variant, the T.VIII-L built for Finland, was also seized by the Germans.

Meanwhile, eight T.VIII-Ws had been flown to England along with other Dutch floatplanes on 14 May 1940, and on 1 June 1940 No. 320 (Dutch) Squadron RAF was formed at Pembroke Dock, to operate the T.VIII-Ws on convoy escort work. These aircraft carried RAF markings, plus a small Dutch triangle badge. Three of the aircraft were lost, and with no spares available the remaining aircraft were flown to Felixstowe for storage. They were joined by another in May 1941, when four Dutchmen escaped from Amsterdam and brought their T.VIII-W down on the sea near Broad-stairs. German navy operations with their group of T.VIII-Ws were confined mostly to patrol work in the Mediterranean.

Fokker G.1A

In November 1936 the prototype Fokker G.I heavy fighter caused a sensation when exhibited at the Paris Air Show, which in those days did not have a flying display but only a static exhibition in the Grand Palais. The concept of a twin-boom twin-engined fighter (later adopted for the Lockheed P-38 Lightning) was revolutionary at the time, and the new aircraft was the centre of much critical appraisal, leading it to be called Le Faucheur or Grim Reaper, in part to its devastating armament.

After the Show, the Fokker G.I was taken to Eindhoven/Welschap airfield, from where its first flight was made on 16 March 1937. The G.I was then powered by two 750 hp (559 kW) Hispano-Suiza 80-82 counter-rotating radial engines, but problems with these prototype units resulted in a change to similarly rated Pratt & Whitney SB4-G Twin Wasp Juniors during reconstruction, after the G.I suffered brake failure and rammed a hangar at Schlphol on 4 July 1937.

Demonstrations had already been given to the Netherlands army air corps at Soesterberg, and considerable interest was shown, resulting at the end of the year in an order for 36 aircraft to be designated G.IA. In order to ease the spares situation, it was stipulated that these must have 830 hp (619 kW) Bristol Mercury VIII engines, which were also to power the T.V bomber and D.XXI fighter already on order for the air corps.

This decision brought delay because although G.IA production began immediately there was a hold-up in the supply of engines. Thus the first production aircraft to fly, actually, the second of the batch, became airborne only on 11 April 1939. It remained with the makers for production testing and modifications, and the first aircraft was delivered to Soesterberg on 10 july 1939.

Possibilities of export orders followed the aircraft's debut at Paris and a number of foreign pilots came to Fokker to fly and evaluate the G.lB export version. Orders were placed by Finland (26), Estonia (9), Sweden (18) and Republican Spain(12), while a licence-production agreement was in negotiation with Denmark and another with Manfred Welss in Hungary. The Dutch embargo on weapon exports before World War II killed the Spanish order, but the Finnish batch was under construction when war broke out and a ban was then placed on its export. After lengthy negotiations a contract was drawn up to permit the G.IB's export on 17 April 1940, by which time 12 had been completed, apart from armament.

When Germany attacked the Netherlands on 10 May 1940, 23 G.Is were in service. 12 with the 4th Fighter Group at Alkmaar and 11 with the 3rd Fighter Group at Rotterdam/Waajhaven, The G.Is were successful in destroying several Junkers Ju 52/3ms during the early stages of the German invasion, but by the fifth day, when Dutch resistance ended, only a single example remained airworthy.

The Germans occupied the Fokker factory, ordering completion of the 12 G.Is intended for Finland, and these were used subsequently by the Luftwaffe as fighter trainers. Test flights from the factory were made under German supervision, but on 5 May 1941 two Dutch pilots succeeded in evading an escorting German-flown G.I and escaped to England. Their G.IB was taken to the Royal Aircraft Establishment, Farnborough, for examination, and used subsequently by Phillips and Powis (Miles Aircraft) at Reading for research into wooden construction.

A total of 62 Fokker G.Is are believed to have been built, and none survived the war

Specifications (Fokker G.1A)

Type: Two or Three Seat Heavy Fighter & Ground Support

Design: N. V. (Nederlandsche Vliegtuitenfabriek) Fokker Design Team

Manufacturer: N. V. (Nederlandsche Vliegtuitenfabriek) Fokker in Amsterdam

Powerplant: (G.IA) Two 830 hp (619 kW) Bristol Mercury VIII 9-cylinder radial engines. (G.IB) Two 750 hp Pratt & Whitney R-1535-SB-4 Twin Wasp Junior 14-cylinder radial engines.

Performance: (G.IA) Maximum speed 295 mph (475 km/h) at 9,020 ft (2750 m); cruising speed 221mph (355 km/h) at 9,020 ft (2750 m); service ceiling 30,500 ft (9300 m), climb to 16,405 ft (5000 m) in 8 minutes 0 seconds.

Range: (G.IA) 945 miles (1520 km); (G.IB) 913 miles (1469 km) on internal fuel.

Weight: (G.IA) Empty 7,410 lbs (3360 kg) with a maximum take-off weight of 10,582 lbs (4800 kg); (G.IB) Empty 6,930 lbs (3143 kg) with a maximum take-off weight of 10,520 lbs (4772 kg).

Dimensions: Span 56 ft 3 1/4 in (17.15 m); length 37 ft 9 in (11.50 m); height 11 ft 2 in (3.40 m); wing area 412.26 sq ft (38.30 sq m).

Armament: (G.IA) Eight 7.9 mm (0.312 in) FN-Browning forward firing machine guns in the nose and one similar gun on pivoted mount in tail cone, plus up to 882 lbs (400 kg) of bombs. (G.IB) Two 23 mm Masden cannon and two 7.9 mm (0.312 in) FN-Browning machine guns in the nose, plus up to 882 lbs (400 kg) of bombs.

Variants: G.IA (three seat with the addition of a radio operator), G.IB (export - two seat only).

Avionics: None.

History: First flight 16 March 1937; service delivery May 1938.

Operators: Netherlands, Sweden, Denmark.

Fokker D XXI

Aircraft: Fokker D.XXI
Nation: The Netherlands
Manufacturer: Fokker
Type: Fighter
Year: 1938
Engine: Bristol Mercury VIII  9-Cylinder radial ari-cooled, 780 hp each
Crew: 1

Among the effective aircraft produced by Fokker in the years immediately prior to the war.  The D.XXI fighter deserves a place of honor.  It was a transitional plane, still retaining fixed landing gear, although particularly efficient and advanced for its time nevertheless.  Above all, it had great potential, and only the course of the war prevented this from being developed

PZL P-37B

Aircraft: P-37B
Nation: Poland
Manufacturer: Pantstwowe Zaklady Lotricze
Type: Attack
Year: 1938
Engine: PZL Bristol Pegasus XX, 9-Cylinder radial ari-cooled, 918 hp each
Crew: 4


Paradoxical, the PZL P-37 the most modern aircraft in service in the Polish air force when the war broke out, was never produced in any great quantity.  The fate of this elegant, two-engine bomber was decided by the members of the Genearl Staff who, after heated argument, gave priority to the construction of other types of aircraft.  As a result only a few month before the out-break of the war, production programs were reduced by a third, and only 36 of the final P-37B version were operational at the time of the German invasion.

PZL P-23B

Aircraft: PZL P-23B
Nation: Poland
Manufacturer: Pantstwowe Zaklady Lotricze
Type: Attack
Year: 1937
Engine: PZL Bristol Pegasus VIII, 9-Cylinder radial ari-cooled, 680 hp
Crew: 3
  
The plane was developed to replace Breguet 19 and Potez 25 aircraft in the Polish Air Force. Main designer was Stanisław Prauss of PZL works. The works started in 1931 and were based on a passenger plane project PZL.13, that remained in sketches. The plane was of modern all-metal construction, wings were built around light closed profiles instead of spars (introduced first in PZL.19). The first prototype flew on 1 April 1934, followed by the second prototype.

PZL P-24G

Aircraft: PZL P-24G
Nation: Poland
Manufacturer: Pantstwowe Zaklady Lotricze
Type: Fighter
Year: 1935
Engine: Gnome-Rhone 14 N7 14-Cylinder radial air-cooled, 930 hp
Crew: 1

Typical example of a fighter that marked the transition between the monoplane and the biplane, the biplane, the PZL P-24 represented the final stage in the evolution of a successful series of battle planes developed by Zygmunt Pulawski who up to March 1931 was chief designer at Panstwowe Zaklady Lotnicze, the Polish State aeronautical factory.

Avia B 534

Aircraft: Avia B 534

Nation: Czechoslovakia

Manufacturer: Avia

Type: Fighter

Year: 1935

Engine: Avia-Hispano-Suiza 12Ydrs.  12 cylinder V. liquid-cooled 850hp.

Fast easy to handle and well armed, the Avia B534 represented one of the best examples of the biplane.  Its qualities were fully revealed at the International Aeronautical Meet held in Zurich in 1937.