Designer Kevin McGrath wanted to produce an aircraft which could be flown regularly even in British weather conditions, so he deliberately made the wing loading as high as possible within the British microlight definition and gave the aircraft a snug cockpit. The transparent canopy at the front hinges at the top to allow entry and exit and can be removed completely for summer days. Another novel feature is that behind the pilot is a compartment suitable for 13 lb (6 kg) of baggage.
Introduced in prototype form at the beginning of 1983, the Aeolus is most notable for its fully enclosed glass fibre fuselage; this is a structural part of the aircraft rather than just a pod, and supports the engine at the rear.
A single seat, single engined high wing mono¬plane with conventional three axis control. The wing has unswept leading and trailing edges, and constant chord, with a conventional tail. Pitch control is by elevator on the tail; and yaw control by fin mounted rudder; roll control is by full span ailerons; with control inputs through stick for pitch/roll and pedals for yaw. The NACA 63412 profile; 100% double surface wing is braced from above by struts and cables, from below by struts. The undercarriage has three wheels in tail dragger formation; steel spring suspension on the tailwheel and aluminium spring suspension on the main wheels. No ground steering (tailwheel castors) or brakes are fitted. The glassfibre fuselage is totally enclosed, and the engine is mounted below the wing, driving a pusher propeller.
The prototype machine was to be modified for production, using V belts instead of a toothed belt reduction drive. Other changes for production included a 25% increase in tailplane and elevator areas, a reduction in aspect ratio from 7.3 to 5.6/1, a more rigid wing of composite construction with heat shrunk fabric skin and strut bracing, plus replacement of the coil spring suspension on the main wheels by a wire-braced aluminium cantilever arrangement.

Prototype
Engine: Robin EC34PM, 30 hp at 7500 rpm.
Max static thrust: 160 lb, 73 kg.
Propeller: 53 x 36 inch, 1.34 x 0.91 m.
Reduction: Toothed belt ratio.
Length overall: 17.0ft, 5.18 m.
Height overall: 5.5ft, 1.68m.
Power/unit area: 0.21 hp/sq.ft, 2.3 hp/sq.m.
Fuel capacity: 6.0 USG, 5.0 Imp gal, 22.7 lt.
Wing span: 32.0ft, 9.76m.
Constant chord: 4.4ft, 1.34m.
Dihedral: 2 degs
Sweepback: 0 degs
Tailplane span: 7.5ft, 2.29m.
Fin height: 4.0ft, 1.22m.
Total wing area: 140 sq.ft, 13.0 sq.m.
Aileron area: 9.0sq.ft 0.84 sq.m.
Fin area: 3.0 sq.ft, 0.28 sq.m.
Rudder area: 5.0 sq.ft, 0.46 sq.m.
Tailplane area: 15.0sq.ft, 1.39 sq.m.
Elevator area: 10.0 sq.ft, 0.93 sq.m.
Wing aspect ratio: 5.6/1.
Wheel track: 4.0ft, 1.22m.
Wheelbase: 11.0ft, 3.35m.
Tailwheel dia: 4 inch, 102 mm.
Main wheels dia: 12 inch, 305 mm.
Empty weight: 280 lb, 127kg.
MTOW: 550 lb, 249kg.
Payload: 220 lb, 100 kg.
Max wing load: 3.92 lb/sq.ft, 19.1 kg/sq.m.
Max pwr loading: 18.3 lb/hp, 8.2kg/hp.
Load factors: +4.0, 2.0 design; +6.0, 4.0 ultimate.
Max level speed: 65 mph, 105 kph.
Vne: 80 mph, 129 kph.
Max cruise: 58 mph, 93 kph.
Economic cruise: 58 mph, 93 kph.
Stalling speed: 28 mph, 45 kph.
Max climb SL: 550 ft/min, 2.8 m/s.
Best glide ratio: 11/1 at 45mph, 72kph.
Take off dist: 200ft, 60m.
Landing dist: 200ft, 60m.
Service ceiling: 10,000ft, 3050m.
Range ave cruise: 120 mile, 193km.

Double-surface mono-wing and tail of aluminum tube, Dacron. Conventional 3-axis controls with spoilers. Undercarriage: Tricycle, aluminum. Price 1984: $6,262. Sold through dealers only.

Engine: Cuyuna 430cc, 43 hp
Wood prop: 72in x 30in
Wingspan: 35 ft 3in
Wing area: 162 sq.ft
Empty weight: 300 lb
Gross weight: 750 lb
Cruise speed: 50-55 mph
Stall speed: 25 mph
Vmax: 65 mph
Climb: 1000 fpm
Takeoff run: 50-100 ft
Landing roll: 100 ft
Setup time: 25 min

The Cobra was a completely new design according to the releases from Advanced Aviation. The wing is totally new and, although the aircraft still has a cruciform empennage, it has been completely changed to fit it for its role as a three axis device. The Cobra was presented for the first time at the 1982 Oshkosh and was next shown at the Sun ‘n’ Fun event at Lakeland the same year.

Advanced Aviation Cobra / King Cobra Article

Recognition points include a rectangular plan form wing with triangular wing tips and double skin fabric over the whole chord. It has spoilerons of single thickness cloth and the trailing edge is notched between each batten, giving the impression of a batwing. Options are a braked steerable nosewheel, wheel fairings, reserve petrol tank, floats, skis, a parachute and an instrument panel. A single seat, single engined, high wing mono¬plane with conventional, three axis control. The wing has unswept leading and trailing edges, and constant chord except for triangular wing tips; cruciform tail. Pitch control by elevator on tail; yaw control by fully flying rudder; roll control by half span spoilerons; control inputs through stick for pitch/roll and pedals for yaw. The wing was braced from above by kingpost and cables, from below by cables; wing profile; 90% double surface. Undercarriage has three wheels in tricycle formation; torsion bar sus¬pension. Optional push right go right nose¬wheel steering connected to yaw control. Optional brake on nosewheel. Aluminium ¬tube framework, without pod. Engine mounted above wing driving pusher propeller. Tubing used is 6061T6 anodized aluminium; wing covering is Dacron. Rigging is vinyl ¬coated stainless steel cable. Price (January 1983) $4995 in kit form.

The two seat King Cobra debuted at 1983’s Sun ‘n Fun. The two seat trainer version of the Cobra and has side-by-side seating configuration, with dual flying and engine controls for instructional purposes. The nose wheel is steer¬able on both models, in-line planetary gear, optional floats.

Cobra
Engine: Cuyuna ULII-02 (429 cc) 35 hp.
Static thrust: 225 lb.
Empty wt: 250 lb.
Wing span: 35ft.
Wing area: 152 sq.ft.
Aspect ratio: 8.0.
Height: 9ft 3in.
Length: 17ft 6in.
Fuel cap: 5 USG.
Max wt: 525 lb.
Stall: 26 mph.
Max speed: 63 mph.
Vne: 70 mph.
Design limit: +5, -3g.
Climb rate: 800 fpm @ 38 mph.
Glide ratio: 9-1.
Wing loading: 3.39 lb/sq.ft.
Power loading: 15 lb/hp.
Construction: Aluminium, Dacron.

Engine: Cuyuna 430RR, 30 hp at 6500 rpm.
Propeller dia/pitch: 54x28in, 1.37×0.71m.
Reduction, ratio: 2.1/1.
Power per unit area: 0.20 hp/sq.ft, 2.1 hp/sq.m.
Fuel capacity: 4.8 US gal, 4.0 Imp gal, 18.2 lt
Wing span: 35.0ft, 10.7m.
Constant chord: 4.3 ft, 1.30 m.
Sweepback: 0 Degs
Total wing area: 152 sq.ft, 14.1sq.m.
Wing aspect ratio: 8.0.
Empty weight: 235 lb, 107 kg.
Max take off weight: 525 lb, 238 kg.
Payload: 290 lb, 132kg.
Max wing loading: 3.45 lb/sq.ft, 16.9 kg/sq.m.
Max pwr load: 17.5 lb/hp, 7.9 kg/hp.
Max level speed: 65 mph, 105 kph.
Vne: 70 mph, 113 kph.
Max cruising speed: 55 mph, 88 kph.
Economy cruise: 50 mph, 80 kph.
Stalling speed: 24 mph, 38 kph.
Max SL climb: 1000 ft/min, 5.1 m/s.
Best glide ratio: 9/1.
Take off dist: 60 100ft, 18 30m.
Landing distance: 100 ft, 30 m.
Service ceiling: 9900ft, 3000m.
Range at cruise: 130 mile, 209 km.

Cobra B
Engine: Rotax 447
Empty wt: 250 lb
Max wt: 625 lbs
Wing span: 35ft
Wing area: 140 sq.ft.
Wing loading: 3.6 lb/sq.ft
Power loading: 13.13 lb/hp
Max speed: 60 mph
Cruise: 52 mph
Stall: 25 mph
Vne: 75 mph
Seats: 1.

King Cobra
Engine: Rotax 532
Empty wt.: 325 lb
Max wt.: 775 lb
Wing span: 34ft 6in
Wing area: 146 sq.ft.
Wing loading: 5.3 lb/sq.ft
Power loading: 12.11 lb/hp
Max speed: 65 mph
Cruise: 50 mph
Stall: 31 mph
Vne: 75 mph
Seats: 2

Engine: Rotax 447
Empty weight: 265 lbs
Max wt: 550 lbs
Wing span: 27ft 8in
Wing area: 134 sq.ft.
Cruise mph: 60
Stall mph: 26
Vne mph: 85
Max speed: 75 mph
Wing loading: 4.1 lb/sq.ft
Power loading: 13.75 lb/hp