Hannover AFH 4
Type
Single seat high performance glider
Dimensions
Length 6,5 m, height 1,82 m, span 15 ,0 m, wing area 10 m2, aspect ratio 22,5
Weights
Empty 170 kg, max.flying weight 270 kg, wing loading 27 kg/m2
Performance
Max. speed 300 km/h, landing speed 32 to 91 km/h, lowest sink 0,72 m/sec. at 69 km/h, glide ratio 1:33,6
Type
Werk.Nr
Registration
History
       
Profile at wingroot NACA 23014, mid NACA 23012, tip 23012
The AFH-4 sailplane was built by the Tech­nical Flight Section of the Hanover Tech­nical School. It was designed by Eppmann and Vol­lmer, and the idea behind it was to produce a glider  with the greatest possible speed range. In its planning,  special consideration was given to high cruising speed  and good turning qualities. It is a full cantilever mid­ wing with remarkably thin wing depth and employing a  modified Fowler auxiliary wing.
The elliptical wing is of gulled design with a sweep  forward of 2.5° with the 23012 section thickened at the  root by Lt'. The two wing panels are connected to  the fuselage by five bolts apiece. A good stiffness (164  oscillations per minute) was achieved in spite of the  thinning depth (10.6 em. max.).
In order to increase the speed range even more than  the best previous designs at the lower speeds, the ship  was fitted with a landing flap which combines the ad­vantages of the German Junker and the American  Fowler auxiliary wings. This flap lies in an entering  relationship to the wing section and can be pushed out  like the Fowler flap, whereby the wing area is increased  by 14.4%, but in contrast to the Fowler wing, in which  a special supporting wing angle is fixed every time the  flap comes out; in this construction the supporting arm  can be placed so that the flap can be set anywhere be­ tween 5° and 40° down like the junker's wing when  it is fully extended. In this way, it is possible to  utilize the best position of this extra wing area for con­trolling the rate of descent and the minimum flying  speed. Placed further down, it can be used as a brake  flap to steepen the gliding ratio.
The whole movement of the flap (pushing out as  well as down) is controlled with one lever. The ailerons  can be trimmed down 10°, the trimming being done  through lifting the rear end of the tortion tube with a  spindle. Elevator and aileron controls are mounted in  ball-bearings.
The fuselage is wood monocoque construction with  landing skid mounted on tennis-balls. The large,  Plexiglas cockpit cover gives unusually good vision for the pilot with practically no distortion or reflection. It  was made by Kopperschmidt and Sons, Hamburg.
The high lying, pendulum elevator is fastened with  a bolt to one of the girders at the side of the vertical  fin. It is controlled through a push-pull rod and can  be trimmed from the cockpit by an adjustable Flettner  tab. The rudder construction is symmetrical with its  turning axis ahead of the trailing edge of the fin.
SPECIFICATIONS
Span 15 m. Aspect Ratio 22.5 (19.7)  Length 6.5 m. Weight Empty 203 kg. Wing Area 10 m'  (11.4 m') Gross Weight 263 kg.  Wing Loading 26.3 kg/m'  (23 kg/m') Gliding Ratio 1:33.6