A 1977 high performance flexible wing. The Dave Cronk designed Cumulus has folding tubes for truncated wingtips. There are no battens, and the flying wires are adjustable for seated or prone.
The Cumulus V is a high-aspect ratio Rogallo hybrid with tip extensions, shaped keel and large, tapered, leading edge pockets. It is controlled solely by means of weight shifting. It is characterised by a higher wing loading and a faster cruise speed than for a standard Rogallo, giving it improved penetration. The stall is described as being gentle, with the nose dropping through at about 16 mph.
Take down and set up times should be within 10 minutes and the Cumulus V may be folded and transported like a standard Rogallo.
The Cumulus 5B continues the development started in October 1974 and features a very lightweight frame, shaped keel, squared wing tips, and a roached sail with two battens per side. A fully battened sail was optinal. The light frame and small sail area gave fast and responsive control.
All aluminium components are fully anodised, and the triangle bar is adjustable to two positions for seated or prone flying. Spar saddles are brushed onto tubes for better distribution of loads, and tensioners are used on the top rigging, replacing turnbuckles. Wingpost blades are standard equipment, eliminating spar deflection.
The Cumulus 5B airframe main tubes are 2044-T3 1.75in x .035 aluminium with the exception of the crossbar which is 6061-T6 1.75in x .049. All tbes are clear anodised, and all stress points are internally sleeved. Triangle bar is 6061-T6 1in x .083 black anodised aluminium.
Rigging cable is 3/32in vinyl coated stainless steel throughout. All ends are double nico pressed. Clip locking AN turnbuckles are used on the wingpost wires. All fittings are polished stainless steel and black anodised aluminium. Nuts and bolts are to AN specification.
The Haowe & Bainbridge 3.8oz stabilised dacron sail was available in 11 colours. A nine foot leading edge pocket was applied to eliminate bias stretching, all seams double zig-zag stitched, and all stress points heavily reinforced. Clear windows, special inserts, logos, air brushing, extra battens etc were available on request.
Seated harness and supine harness use individual leg straps and a wide back strap is used on both systems with the supine having fibreglass stiffeners added to aid comfort. The prone harness fully supports the pilot and is padded at all pressure points. It can also be flown for short periods in a seated position. Both systems use 5500 lb tested nylon webbing in load carrying positions.
1975 world champion David Cronk organised a mass drop of eight Cumulus VB’s from a 320 ft high hot air balloon over California.
Cumulus V
Wingspan: 29 ft 6 in
Wing area: 165 sq.ft
Aspect ratio: 5.2
Keel length: 12 ft
Leading edge length: 18 ft
Nose angle: 109 degrees
Billow: 2.5 degrees
Empty weight: 39 lb
Max flying weight: 240 lb
Useful load: 201 lb
Best L/D: 7-1
Min sink: 250 fpm
Stall speed: 16 mph
Cruise: 25 mph
Cumules 5B 16
Leading edge: 16 ft
Keel length: 9.5 ft
Wing span: 26.1 ft
Wing area: 136 sq,ft
Aspect ratio: 5.0
Nose angle: 110˚
Sail billow: 2˚
Weight: 37 lb
Pilot weight: 100-140 lb
Takeoff speed: 12-15 mph
Stall speed: 15-16 mph
Max speed: 35 mph
Best glide ratio (L/D): 7-1
Best L/D speed: 25 mph
Min sink: 250 fpm
Cumules 5B 17
Leading edge: 17 ft
Keel length: 9.5 ft
Wing span: 28 ft
Wing area: 145 sq,ft
Aspect ratio: 5.4
Nose angle: 110˚
Sail billow: 2˚
Weight: 38 lb
Pilot weight: 120-160 lb
Takeoff speed: 12-15 mph
Stall speed: 15-16 mph
Max speed: 35 mph
Best glide ratio (L/D): 7-1
Best L/D speed: 25 mph
Min sink: 250 fpm
Cumules 5B 18
Leading edge: 18 ft
Keel length: 10.5 ft
Wing span: 29.5 ft
Wing area: 165 sq,ft
Aspect ratio: 5.3
Nose angle: 110˚
Sail billow: 2˚
Weight: 41 lb
Pilot weight: 150-200 lb
Takeoff speed: 12-15 mph
Stall speed: 15-16 mph
Max speed: 35 mph
Best glide ratio (L/D): 7-1
Best L/D speed: 25 mph
Min sink: 250 fpm
Cumulus 10
Wing span: 10.2 m
Hang glider weight: 20 kg
All Aero 