The Arado Ar 80, an aircraft developed before World War II, was intended to participate in the Luftwaffe’s initial fighter contract competition.
However, the Ar 80’s performance was lacklustre, and it encountered several setbacks.
Ultimately, the Messerschmitt Bf 109 emerged as the victor in the contest, while the Ar 80 prototypes were repurposed as test aircraft.
The completion of the design, now referred to as the Ar 80, was achieved without the assistance of Rethel.
In 1934, Rethel departed from the company to join BFW, leaving Blume in charge of the project.
The aircraft was specifically designed to accommodate the Jumo 210 engine, which would power a wooden two-blade fixed-pitch propeller.
However, since this engine would not be available until after the contest was scheduled to end, all participants sought alternative engines to fill the void.
In this particular case, Arado had the upper hand, as they had already acquired a 391 kW (525 hp) Rolls-Royce Kestrel VI engine for their Ar 67 design.
Unfortunately, the engine’s suboptimal supercharging resulted in underwhelming performance for the Ar 67.
The V1 prototype successfully completed its maiden flight in the spring of 1935, marking an early achievement in the competition.
Unfortunately, a few weeks later, a company test pilot lost control of the aircraft at a low altitude, leading to the decision to write off the V1.
The landing gear posed a significant challenge during the initial weeks of testing.
Despite efforts to address the issue, the gear would often get stuck halfway when retracted.
Fortunately, it functioned properly during landing.
After numerous unsuccessful attempts to identify the root cause, it was discovered that air pressure on the front strut caused the oleo to jam in its tube, preventing rotation.
During the construction of the V1, it was discovered that Rethel’s monocoque technique was unexpectedly heavier than anticipated.
This was partly due to the design requiring thick sheets running the length of the plane, as well as the need for a higher number of rivets than initially planned, resulting in the aircraft being overweight.
Despite being rushed to completion, V2 still faced the challenge of the unavailable Jumo engine.
To provide contestants with a suitable engine, the RLM exchanged an He 70 for four 518 kW (695 hp) Kestrel V engines from Rolls-Royce.
Although similar to the VI engine, the Kestrel V boasted superior supercharging and was considered the most powerful inline engine at the time.
Various companies vied for access to these engines for their prototypes, with BFW receiving two, Arado and Heinkel one each, and Focke-Wulf missing out entirely.
By autumn of 1937, V2 was completed with the Kestrel and underwent company testing.
However, the fixed gear once again posed a problem.
Blume, who had always been sceptical of the design, immediately blamed Rethel for all the issues.
In an attempt to offset the performance problems caused by the fixed gear, the Ar 80 reverted to using a well-spatted and faired set of gear similar to their biplane designs.
Unfortunately, this conversion resulted in several months of lost time.
Despite the expectation of saving weight, the use of fixed gear did not yield the desired results.
The plane still exceeded the design weight by 16%, weighing 1,630 kg (3,590 lb) when empty.
Even without armament, the fully loaded plane weighed 2,100 kg (4,630 lb), making it underpowered even with the Kestrel V engine.
Additionally, the drag was higher than anticipated.
Consequently, the plane’s performance was highly disappointing, reaching a maximum speed of only 410 km/h (255 mph).
In the early months of 1936, the long-awaited Jumo engines finally made their appearance.
The 210 model, although possessing less take-off power compared to the Kestrel, showcased a similar performance at higher altitudes.
However, it did experience a decline in low-level speed and climbing performance.
Arado proposed that equipping the aircraft with a constant speed propeller would enhance both aspects, resulting in a speed of 425 km/h (264 mph).
Unfortunately, this modification was not implemented before the plane was dispatched for the competition.
Despite being among the first aircraft to take flight, the Ar 80 faced persistent issues with its gear and engine supply, causing it to be one of the last contenders to arrive for the head-to-head fly-off.
It was transported to Travemünde on 8th February 1936 and later relocated to Rechlin-Lärz Airfield in March to join the rest of the aircraft.
It was evident from the beginning that the Ar 80 stood no chance against the superior designs of Heinkel and BFW.
Arado received official confirmation of this fact merely a month after the competition commenced.
By this stage, V3 had already been completed.
To reduce weight, the gull-wing was removed and replaced with a “flat” wing, necessitating slightly longer landing gear.
Additionally, the Jumo 210C engine with a constant-speed propeller was installed, increasing the speed to 410 km/h (255 mph).
At this point, the RLM had abandoned the project, so the aircraft was not sent for testing and instead stored at the Arado plant.
In 1937, V3 was brought back to life as a flying test platform for various experiments.
A second seat was added behind the pilot for an observer, along with an enclosed canopy.
The aircraft was initially used to test a 20 mm cannon firing through the spinner, making it the first German cannon-armed fighter.
This system, known as the “motorkanone” – a concept first seen on the 37 mm cannon-equipped French SPAD S.XII during World War I – would later become a standard feature on most German inline engine fighter designs throughout the war.
In 1938, the V3 underwent another reconstruction to evaluate a new Fowler Flap design that Arado planned to implement on their Ar 198 and Ar 240 aircraft.
The tests revealed the flap’s remarkable effectiveness, causing a significant shift in lift distribution across the wing.
Consequently, a supplementary adjustment was made to lower the ailerons in conjunction with the flaps.
Extensive testing was conducted in this configuration, leading to the development of the “Arado travelling aileron” and “Arado landing flap.”.
Specifications
Crew
1
Length
10.30 m (33 ft 10 in)
Wingspan
10.89 m (35 ft 9 in)
Height
2.65 m (8 ft 8 in)
Wing area
21.0 m2 (226 sq ft)
Aspect ratio
5.65
Empty weight
1,642 kg (3,620 lb)
Gross weight
2,125 kg (4,684 lb)
Powerplant
1 × Junkers Jumo 210C,
Liquid cooled V12 engine,
480 kW (640 hp) at 2,700 m (8,858 ft)
Performance
Maximum speed
415 km/h (258 mph, 224 kn) at 2,700 m (8,850 ft)
Range
800 km (497 mi, 432 nmi)
Rate of climb
9.5 m/s (1,870 ft/min)
Armament
Guns
2× 7.92mm MG 17 machine guns.
Sources Arado Geschichte Eines Flugzeugwerks-Jorg Armin Kranzhoff. Aircraft of the Luftwaffe 1935-1945, An Illustrated Guide-Jean-Denis GG LaPage. The Official Monogram Painting Guide to German Aircraft, 1935-1945-Kenneth A Merrick & Thomas H Hitchcock.
