All Aero

Designed by Pavel Beneš, the Beneš-Mráz Be-500 Bibi, Be-501 and Be-502 were Czechoslovak single-seater sports aircraft which were manufactured by Inž. P. Beneš et al. J. Mráz in 1936, at Choceň.

They were small single-seater aircraft with low fuel consumption. The dimensions differed minimally, and were equipped with different Walter engines. The Walter Atom engine was to be tested on the Be-500 prototype (but the prototype was not completed), the 20 cm longer Be-501 version had the Walter Mikron II engine (modified to fit a cylinder capacity of 2 l) and finally the Be-502 version. of the same length as the prototype Be-500, was equipped with the most powerful Walter Minor 4 engine. Both aircraft were specially built to participate in the 12-hour race in the city of Angers.

Shortly after the completion, the Be-501 and Be-502 successfully participated in the “12 heures d’Angers” race in France, when Josef Kalla and Karel Mareš won in their categories.

The aircraft was designed as a low-wing monoplane with a covered cabin. The self-supporting, wooden wings were complete and were inserted into the lower part of the fuselage. In the wooden, veneered fuselage, the cockpit was located in front of the main wing longitudinal. The cabin was accessible by opening most of the top cover and behind it was space for smaller luggage. The rudders were controlled by ropes, the ailerons by a rigid system of rods. The wide vertical tail surfaces were self-supporting, the rudder of which was somewhat cut above the continuous elliptical horizontal tail surface. The rudder with the keel surface has been moved forward to achieve favorable properties in the corkscrew.

The undercarriage with “trouser” covers, consisting of two separate parts, was fastened to the main wing side member and sprung with rubber cords. The spur was made of steel, leaf springs. Various motors with an output of 20-95 hp (15-70 kW) could be installed in the engine bed of steel tubes.

First flying in 1936, as of July 1, 1936, the Be-501 Bibi aircraft was assigned the registration mark OK-BEI and the Be-502 Bibi aircraft assigned the OK-BEL mark. In both cases, these were serial numbers 1. Both machines purchased by Aeroklub RČs. successfully participated in the race “12 hours of Angers” (12 heures d’Angers) in speed and reliability, organized by the West French Aeroclub in early July 1936. The machines and their pilots, Major Kalla and Lieutenant Colonel Mareš, gave their best, and they won in their categories. Major gen. no. Josef Kalla on the Be-502 Bibi won in the category of engine capacity up to 4 liters, when he flew 1229.04 km at an average speed of 204.04 km / h, and in the category up to 2 liters with a special Micron II Lt. Col. Karel Mareš on the Be-501 Bibi, when he flew 1001,968 at an average speed of 166,968 km / h. In the overall classification, regardless of the volume of engines, J. Kalla finished in 2nd place and K. Mareš in 6th place.

In May 1937, these aircraft completed high-speed flights of 100 and 1000 km. Pilot stkp. Štěpán with Be-501 on a shorter route reached a speed of 179.229 km / h and on a longer 170,809 km / h, on Be-502 a speed of 220.94 km / h was reached (ing. Šimůnek per 100 km) and 214.174 km / h (Capt. Pupil for 1000 km). In December 1937, Capt. Červinka on the Be-501 international altitude record 4658 m.

Further development of these aircraft did not continue, because the developers focused on the more advanced type Beneš-Mráz Be-550 Bibi, which was completed in late 1936. After the occupation of Czechoslovakia by Nazi Germany, the aircraft were used in Luftwaffe flight schools.

Be-500
Engine: Walter Atom, 18 kW / 25 hp
Propeller: two-bladed, wooden
Span: 8.5 m
Wing area: 9 m²
Length: 5.86 m
Height: 1.65 m
Empty weight: 170 kg
Max. takeoff weight: 285 kg
Wing load: 31.6 kg / sq.m
Cruising speed: 135 km / h
Max. ground speed: 155 km / h
Landing speed: 57 km / h
Range: 850 km
Ceiling: 4000 m
Climb to 1000 m: 9 min
Crew: 1

Be-501
Engine: Walter Mikron II, 33 kW / 45 hp
Propeller: two-bladed, wooden
Span: 8.5 m
Wing area: 9 m²
Length: 6.02 m
Height: 1.72 m
Empty weight: 340 kg
Max. takeoff weight: 600 kg
Wing load: 66.7 kg / sq.m
Cruising speed: 165 km / h
Max. ground speed: 190 km / h
Landing speed: 73 km / h
Range: 1700 km
Ceiling: 3300 m
Climb to 1000 m: 9 min
Crew: 1

Be-502
Engine: Walter Minor 4, 62 kW / 85 hp
Propeller: two-bladed, wooden
Span: 8.5 m
Wing area: 9 m²
Length: 5.86 m
Height: 1.65 m
Empty weight: 340 kg
Max. takeoff weight: 600 kg
Wing load: 66.7 kg / sq.m
Cruising speed: 200 km / h
Max. ground speed: 230 km / h
Landing speed: 87 km / h
Range: 1900 km
Access: 4000 m
Climb to 1000 m: 7 min
Crew: 1