WesWorld

The prototype of the Soko Jastreb single-seat fighter for the Royal Yugoslav Air Force was flown successfully on 20 September 1939.



Low mid-wing cantilever monoplane. Wings have a constant taper and almost square tips. All metal flush-riveted stressed skin construction. Entire trailing edge is hinged, the inner sections acting as camber-changing flaps and the outer sections as ailerons. Flaps and ailerons have a welded aluminium frame and fabric covering.

Fuselage is an oval section all-metal monocoque structure with flush-riveted smooth metal skin.

Tail unit is of the cantilever monoplane type. Fin is built integral with the fuselage. Metal structure with metal-covered fixed surfaces and fabric-covered control surfaces. Trimming tabs in right elevator and rudder.

Retractable-type undercarriage. The shock-absorber legs are hinged to the lower fuselage members and retract backwards into the fuselage, the hinged doors covering the aperture – closing both while the landing gear is fully lowered as well as when retracted. Retractable tail wheel.

Powerplant is one 1,200hp Yugoslav-built Pratt and Whitney R-1830-S4C4-G Twin Wasp fourteen-cylinder two-row radial air cooled engine enclosed in a long-chord cowling with trailing edge controllable gills. Air intake and oil cooler apertures in leading edge of wing roots. Three-bladed controllable pitch airscrew. Fuel is carried in self-sealing tanks within the fuselage and wing.

Enclosed cockpit with sliding transparent canopy top over the centre of the wing. Bullet-proof windshield and armour behind the pilot.

Armament consists of four 13.2mm M40 machineguns with 400 rounds per gun – two guns being carried in each wing outside the propeller arc. Racks under each wing for up to 100 kg of bombs.

Wingspan 10.0 metres. Length 7.8 metres. Height 3.6 metres. Wing area 16 square metres. Empty weight 2,050 kg. Loaded weight 2,835 kg.

Maximum speed 575 km/hr; cruising speed 340 km/hr; landing speed 140 km/hr. Initial rate of climb 8.4 metres per second. Operational ceiling 9,300 metres. Range 1,270 km.

Looks like a FFVS J 22. This one would probably be a little faster than the historical aircraft, since the historical aircraft had a 1065 hp engine vs your 1200 hp engine.

Yes, it is a clone of the J22.

As for horsepower, depends on the number you choose to use. The 1,200 hp rating is for takeoff, and sustained military power would be around 1,050 hp. In the data I've found on the J22, I'm not certain whether the 1065 hp quoted was a takeoff or a sustained military rating. The speed might be a bit more, but given the data gap, I will merely quote the historical performance.

And I've gone with an all-metal structure vice steel and plywood - so the structure is a bit lighter but what impact that would have I am uncertain how to estimate.

Why choose over the OTL IK-3?

Quoted

Originally posted by Vukovlad
Why choose over the OTL IK-3?

From my personal perspective - the IK3 had inferior performance and did not meet my needs for a fighter-bomber vice an interceptor. Secondly, the engine technology I obtained was better than that of the HS - more synergy for other design programs.

From a practical perspective - I had more data on the development timeline of the J22.

I see, the other programs being clones of the SAAB B-17 & 18 ? Too bad about the Ik-3 an aircraft that I like and with a
great development potential (DB & RR engines, and the the postwar S-49 & S-49C)

Quoted

Originally posted by Vukovlad
I see, the other programs being clones of the SAAB B-17 & 18 ? Too bad about the Ik-3 an aircraft that I like and with a
great development potential (DB & RR engines, and the the postwar S-49 & S-49C)

Assumptions are dangerous things.

Huh? What assumptions?