HFB 320

The Hansa-Jet HFB-320, the first German business jet, was designed under the direction of Dipl. Ing. Hans Wolcke at the Hamburger Flugzeugbau (HFB) in the early 1960s. The all-metal aircraft, which was designed to carry twelve passengers, successfully completed its 45 minute maiden flight on April 21, 1964 in Finkenwerder, Hamburg.

Because of its tremendous high maximum speed of up to 850 kilometers per hour, the Hansa-Jet was well suited as a comfortable aircraft for commercial travelers. A unique feature this business and passenger aircraft were the swept-forward wings, which had already been used, likewise by Wocke, at end of the Second World War for the four-jet bomber Junkers Ju 287, which at that time created a sensation.

Forward-swept wing designs appear to offer selected aerodynamic performance improvements over conventional aft-swept wings, such as higher lift-drag ratios, lower trim drag, and better stall/spin characteristics. In addition, these designs may allow for improved fuselage-volume arrangements, by having the wing box located more rearwar.

Two powered, forward-swept wing aircraft, both of German design, are known to have been built to take advantage of these improvements. These aircraft include the World War II vintage Junkers Ju 287 and a 1960's business jet. In the postwar era perhaps the most successful FSW incarnation was the German Hamburger Flugzeugbau HFB 320 Hansa jet transport, whose design was led by the same Hans Wocke who brought the Ju 287 to life nearly two decades earlier. This notable design first flew on April 24, 1964, and subsequently enjoyed limited sales success (despite the loss of the prototype in an accident in 1965).

The moderately FSW planform of the Hansa business jet reflected the structural constraints of incorporating a FSW planform constructed of conventional metal structure. Even so, Wocke believed the configuration offered significant advantages for an aircraft intended to have low drag, a speed of 500 miles per hour, and a range of 1,600 miles. Additionally, it enabled an unobstructed cabin, an important consideration for passenger comfort. Traditional straight or rear swept wing design would have either necessitated wing spar location in the cabin area to the detriment of passenger accommodations or, possibly, a larger diameter fuselage, which would add to drag and weight.

The Hansa’s forward swept wing placed the wing-fuselage juncture aft of the main passenger cabin, allowing smaller dimensions that yielded better performance. The design also enabled the use of a smaller horizontal tail than a traditional planview would call for, and this further reduced drag. Teardrop wingtip tanks projecting well ahead of the wing on the Hansa helped tame wing twisting and bending. The Hansa jet was a vindication of Hans Wocke’s vision for FSW technology, and a total of 47 were built for civil and military use.

The passenger compartment was very spacious due to the unusual wing root behind the pressurized cabin, so that the passengers could not only stand up easily, but also could enjoy easy freedom of movement because of the missing wing spar. The following models of the first prototype experienced only minor changes.

Predominantly European partners participated in manufacturing this German business jet. The Hamburger Flugzeugbau was responsible for the fuselage and the section center as well as the engine pods and the control system. Fokker (The Netherlands), Casa (Spain) and Lockheed were gained as partners for this project. General Electric produced the propulsion system for the HFB-320.

In February 1967, this passenger jet aircraft was certified by the "Luftfahrtbundesamt", the German Aviation Authority. Two months later, on April 7, 1967, the Hansa-Jet could be used worldwide thanks to the international certification. The Hamburger Flugzeugbau expected numerous orders especially from the USA. These hopes were based on the fact that the much praised HFB-320 could serv not only as a passenger aircraft, but also as an aerial photogrammetry aircraft, an airborne simulator, a trainer and a transport aircraft.

Altogether 47 machines were manufactured in Finkenwerder; some of them are still in service in the USA and Turkey. The strong competition of international aircraft manufacturers and the decline of the US Dollar put a stop to the further development of the Hansa - Jet at the end of the 1960s.

Until recently, serious consideration has not been given to forward-swept wing designs because forward sweep has led to an unfavorable static aeroelastic characteristic, namely, static divergence. Potential gains in aerodynamic performance were more than offset by the increase in structural mass required to provide sufficient stiffness to insure adequate divergence speed margins. In the early 1970's, however, developments in composite structures technology appeared to offer a solution to the problem of structural mass increases required in the design of forward-swept wing.

Technical data

HFB320

Power plant

2 General Electric CJ610-5 with 12.80 kN each

Performance

Top speed	850 km/h
Cruising speed	704 km/h
Fuel	3,310 kg
Range	2,410 km

Weight

Empty weight	4,420 kg
Take-off weight	9,200 kg

Dimensions

Span	14.49 m
Length	16.61 m
Height	4.94 m
Wing span area	30.14 qm

Passengers

12 persons