Sherwood KUB (SSDR)

Definition of a SSDR is a single seat aircraft with a stall speed of less than 35 knots and a M TOW of 300kgs in the UK, 115 and 120kg empty weight in other countries

The KUB is a tail dragger configuration SSDR aircraft perfectly at home on a farm strip or tarmac runway. The KUB has a really wide cockpit with good size door, getting in and getting comfortable is an easy process even when wearing winter clothing. Whilst not being the fastest of aircraft the KUB is not slow either when compared with other SSDRs about and with a 3 hour duration and average range of 180 miles touring is a real possibility, and if you want to go further just put in the optional second tank.

Although the KUB is an SSDR it is a great handling 3 axis aircraft, which is easy to maintain, cheap to operate and has the benefit of requiring no official oversight, NO C of A’s and NO permit to fly.

It’s folding wings are operated single handed, 2 minutes to operate and no disconnected flying controls, and if you base your KUB at home and transport it to the airfield by trailer its 5 minutes from applying the handbrake to pre-flight inspection.


Single seat tail dragger monoplane with rapid wing fold, 10 minute from trailer to flight prep
Wings – constant-chord
Tail – conventional
Flight controls – Pitch control by elevator on tail; yaw control by fin-mounted rudder; roll control by Frize-type ailerons.
Flaps 3 stage
Wing bracing – wings braced steel streamline struts
Landing gear – Undercarriage has three wheels in tail dragger formation bungee suspension on main wheels, bungee suspension on steerable tail wheel
Ground handing via steerable tail wheel, rudder and differential cable-operated brakes.
Construction welded 4130 aerospace steel space frame, aluminum tube, wood and fabric
Fuselage mounted engine driving tractor propeller

External dimensions and areas

Length overall 16.5 feet 5 m
Length wings folded 20 feet 6.1 m
Height overall 5 feet 2 inches 1.58 m
Wing span 29 feet 3 inches 8.9 m
Width wings folded 8 feet 2.46 m
Constant chord
Dihedral 1.5 degrees
Total wing area 113 sq ft 10.5 m²
Wing loading 23.8kg/m²
Elevator span 7′ 10″ 2.35 m
Aspect ratio 7.64:1
Fuel Cap. 23.5l 5.1 gals, optional second tank same size 47l 10.3 gal total cap.

Wheel track 12′ 7″ 3.86 m
Wheelbase 4′ 7″ 1.42 m
Main wheels dia. Overall. 6″ with disc brakes
Tailwheel dia. Overall 4″ solid

Power plant

Polini Thor 250 36.5 hp single cylinder 2 stroke water cooled. The Polini has twin spark ignition, centrifugal clutch and is ultra smooth with integral balance shaft.

Hirth 50hp opposed 2 cylinder 2 stroke twin carb with oil injection, electric start and twin spark options

Weights and Loadings

Empty weight from 115kg, 253 lbs(Builder and engine dependant)
Max. take off weight 300kg, 660lb..
Load factors,+4 -2 limit load , +6, -4 ultimate.load


Cruise speed 55 knts 60mph Polini (7 l/h)
Cruise speed 60 knts 70 mph Wankel (7 l/h).
Never exceed speed 86 knts 99mph. .
Stall speed Clean 29 knts 33mph.
Stall Speed Flaps 22knts 25mph
Max. climb rate at sea level (engine dependant)
Take off roll 50 m
Landing roll 50 m
Service ceiling N/A.
Range at average cruising speed miles. 3 hours or approx. 180 miles
Noise level N/A. (engine dependant)