The Avia B.135, also known as the Av.135 according to the RLM designation, was an advanced fighter aircraft with a cantilever monoplane design originating from Czechoslovakia.
This particular aircraft served as the finalised production model of the Avia B.35, which was developed in the period leading up to the war.
The B.135 incorporated several notable improvements compared to its predecessor, including a retracting main undercarriage and a newly designed all-metal wing.
The B.135/1 prototype captured the interest of Bulgarian Air Force officials during their visit to the Avia plant, resulting in the signing of a production contract for 12 aircraft and 62 engines.
Additionally, a licence was granted to DAR for the construction of an additional 50 airframes under the designation DAR 11 Lyastovitsa.
Unfortunately, DAR’s production facilities were found to be inadequate for manufacturing the aircraft, leading to only the 12 Czech-built models being produced.
The RLM intervened by halting plans for further production and ceasing engine deliveries after 35 units.
Subsequently, the Bulgarian Air Force was advised to acquire the Messerschmitt Bf 109 instead.
The B.135s encountered persistent engine issues during their service and were subsequently assigned to training duties.
Nonetheless, four of these aircraft were involved in combat on 30 March 1944, when they intercepted formations of USAAF bombers that had intruded into Bulgarian airspace following an attack on Ploieşti.
Some Bulgarian sources attribute the destruction of a B-24 Liberator to Lieutenant Yordan Ferdinandov on that morning.
According to Bílý, all four Avias, under the leadership of Captain Atanasov, participated in the potential downing of a four-engined bomber on that day.
The downed aircraft ultimately crashed in the vicinity of Tran and Breznik, as documented in Lieutenant Yordan Ferdinandov’s log.
Specifications
Crew
One
Length
8.5 m (27 ft 11 in)
Wingspan
10.85 m (35 ft 7 in)
Height
1.6 m (5 ft 3 in)
Wing area
17 m2 (180 sq ft)
Empty weight
2,063 kg (4,548 lb)
Max take-off weight
2,547 kg (5,615 lb)
Powerplant
1 × Avia (Hispano-Suiza) 12Ycrs,
V-12 liquid cooled piston engine,
641 kW (860 hp)
Propellers
2-bladed wooden fixed pitch propeller
Performance
Maximum speed
535 km/h (332 mph, 289 kn) at 4,000 m (13,000 ft)
Cruise speed
460 km/h (290 mph, 250 kn)
Range
550 km (340 mi, 300 nmi)
Service ceiling
8,500 m (27,900 ft)
Rate of climb
13.5 m/s (2,660 ft/min)
Armament
Guns
1 × 20 mm (0.79 in) MG FF cannon
2 × 7.92 mm (0.312 in) Vz. 30 machine guns.
Sources
Czechoslovakian Air Force, 1918-1970, Aircam Aviation Special 05-Richard Ward, Zdenek Titz & Gordon C. Davies.
AVIA B-35 & B-135-MBI- M Bily, D Bernad & C Kucera.
