Hamburger HFB.320 Hansa

Interest in forward-swept wing was revived in the early 1960s when the German Hamburger Flugzeugbau (HFB) company made market studies on the prospects for business jet aircraft. These studies indicated a potential demand for a seven-seater and that a forward-swept wing offered advantages for this particular size of aircraft. The HFB chief designer was Hans Wocke. Designer of the wartime Junkers Ju 287, and the commercial sales manager of HFB was Sieffiried Holzbaur, the Ju 287 test pilot.

In the development of the Hansa Hamburger Flugzeugbau GmbH co-operated with several other companies, the Dutch Fokker concern being responsible for the typical forward-swept wing and the Spanish CASA concern for the rear fuselage and tail.

The Hansa 320 is identified by the 15-degree forward sweep of the wings. In addition to providing the low-speed flying characteristics desired, the adoption of forward sweep enabled the wing to be mid-mounted, this position permitting the use of a fuselage of optimum diameter (81 in). A mid-wing layout is impractical with conventional aft-swept wings, as it involves the main spar passing through the cabin. On the HFB 320 Hansa Jet, the cabin is forward of the main spar.

The Hansa Jet prototype D-CHFB first flew on 21st April 1964, for 73 minutes. The wing provided the flying charac­teristics hoped for. Control during the approach to, and in, the stall was excel­lent. During trials the aircraft was held in a full stall with an indicated angle of attack of 19 deg., and banked with the normal application of aileron. Warning of stall is consistent and readily evident.

Production of the Hansa was initiated by Hamburger Flugzeugbau and carried the name of Messerschmitt- Bolkow-Blohm (MBB) when the two German aircraft companies merged in 1969. The first production Hansa Jet flew on February 2, 1966, and received FAA certification on April 7, 1967. However, the problem of providing the exceptional wing torsional stiff-ness required, without excessive weight penalty, was not entirely overcome. To prevent the main landing gear bay breaking into the vital lower wing skin, the legs are stowed in fuselage fairings, ahead of the forward wing root. This results in a narrow track. To keep the air flowing over the heavily loaded inboard end of the wing, short span slats are fitted to the inner section of the wing. Without such a device, a forward-swept wing will generate less lift than one swept aft.

A US test pilot, Loren W. Davis, was engaged for the initial flight programme.

In the second part of 1968, after three HFB-320 were ordered for the RLS, the Hansajet became well known at Groningen-Eelde. HFB directed a number of brand-new HFB-320 Hansa jets to Groningen Airport Eelde in the Netherlands for test flying and training.

In spite of the good low speed qualities, the Hansa Jet did not initiate a business jet fashion. The theoretical aerodynamic advantages were in practice too deeply eroded by the increased wing weight, its complexity and cost.

A parachute brake in the tail is used for short or icy runways. About 50 were built in executive, cargo and quick-change versions.

Hamburger Flugzeugbau HFB 320 Hansa Jet
Engine : 2 x General Electric CJ610-1, 12704 N / 1295 kp
Length : 54.462 ft / 16.6 m
Height : 15.748 ft / 4.8 m
Wing span : 47.572 ft / 14.5 m
Max take off weight : 18742.5 lb / 8500.0 kg
Max. speed : 486 kts / 900 kph
Service ceiling : 38058 ft / 11600 m
Range : 1253 nm / 2320 km
Crew : 2+12

Engines two 3,108-lb. s.t. General Electric turbojets.
Gross wt. 20,280 lb.
Empty wt. 11,960 lb.
Fuel capacity 1,099 USG.
Top speed 513 mph.
Cruise 420 mph.
Stall 111 mph.
Initial climb rate 4,250 fpm.
Range 1,472 miles.
Ceiling 40,000 ft.
Takeoff distance (50') 2,740 ft.
Landing distance (50') 4,429 ft.
Seats 15.