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Mitchell P-38 / AG-38

mitchp-38
P-38


Single-seat single-engined mid-wing mono-plane with conventional three-axis control. Wing has unswept leading and trailing edges, and constant chord; two-fin tail. Pitch control by fully flying tail; yaw control by fin-mounted rudders; roll control by full-span ailerons also usable as flaps; control inputs through stick for pitch/roll and pedals for yaw. Wing braced from above by struts, wing profile NACA 23015; double-surface. Undercarriage has three wheels in tricycle formation, with addi-tional tailskids; steel-spring suspension on nosewheel and glass-fibre suspension on main wheels. Push-right go-right nosewheel steer-ing connected to yaw control. Brake on nosewheel. Aluminium-tube/wood/steel-tube framework, with optional pod. Engine mounted above wing driving pusher propeller.

The P-38 was designed by Jim Meade and christened Lightning after the famous twin-boom fighter of the Second World War. The prototype appeared at the end of 1980 and the first P-38 was sold during the second quarter of 1981. The prototype was fitted with a 26.0ft (7.92m) span wing having a 4.0ft (1.22m) chord, giving 104sq.ft (9.7 sq.m) of wing area using the same NACA 23015 profile as the B-10. With 200 lb (91 kg) empty weight and 450 lb (204 kg) maximum gross weight, this machine carried 250 lb (113 kg) useful load with a wing loading of 4.32 lb/sq.ft (21.1 kg/sq.m).

On the production models, the wing span was increased to 28.0ft (8.53m) and the chord also increased.
Initially fitted with a Honda Odyssey engine of 250 cc giving 20 hp, or as an option a Zenoah G25B also of 20 hp, the P-38 was in 1983 powered by the twin-cylinder Cuyuna 430RR 30 hp engine. Its characteristics and performance figures do not allow its classification as an ultralight, so it is therefore necessary to hold at least a private pilot's licence to fly the Lightning in the US.

The complete kit, requiring 80 h for assembly, has less than 200 pieces, the principal components being prefabricated and partly assembled. The wing ribs are wood, bonded with epoxy to the tubular Duralumin spar, while the leading edges are of polyurethane foam shaped and then covered with birch plywood. On the P-38, the 'flaperons' - a combination of flap and aileron - are made with ribs every 6 inch (15 cm). Like the other Mitchell models, this one is also available as an economy kit or as plans only.

Units delivered by June 1981 35 kits and plans.

The AG-38 is the crop-spraying version of the P-38 Lightning, to which it is very similar except a pod is fitted. The prototype AG-38 was shown to the public during the EAA Convention at Oshkosh in August 1982. This aircraft is fitted with Micron X15-100 variable-speed rotating nozzles, which are said to control droplet size and so reduce the amounts of chemical and water required. They are supplied from a shaped tank which carries 14.0 US gal (11.7 Imp gal, 53.0litre) of spray chemical. The tank is fitted under the seat and central wing section, between the legs of the main landing gear. An electric pump feeds the spray booms which are fitted with 19 fan nozzles across the full wing span. For a better spread, the two spray bars are placed at not the trailing edge as is usual, but 9.5 inch (24 cm) below the level of the wing.

At 50mph (80kph) the AG-38 spray swath varies from 20ft (6m) wide at 6ft (2m) altitude to 45 ft (14 m) wide at 15 ft (5 m) altitude. With the equipment set for maximum delivery, the AG-38 can deliver 48oz/acre (3.4 litre/hectare) and can treat 37 acre (15 hectare) per load. Reloading is required every 30 min, allowing an average coverage of 60 acre/h (24 hectare/h). At the other end of the scale, the machine can be set up for maximum acreage, when it will deliver 6oz/acre (0.42 litre/hectare) and treat 300 acre (120 hectare) per load. Reloading is required approximately every 2h, giving an average coverage of 140 acre/h (56 hectare/h).

P-38
Engine: Cuyuna 430RR, 35 hp at 5500 rpm
Power per unit area 0.29 hp/sq.ft, 3.1 hp/sq.m
Length overall 17.0ft, 5.18 m
Height overall 5.0ft, 1.52m
Wing span 28.0ft, 8.53m
Constant chord 4.3 ft, 1.29 m
Sweep forward 5 deg
Total wing area 120 sq.ft, 11.2 sq.m
Wing aspect ratio 6.5/1
Wheel track 5.0 ft, 1.52 m
Nosewheel diameter overall 10 inch, 25 cm
Main wheels diameter overall 10 inch, 25 cm
Empty weight 305 lb, 138kg
Max take-off weight 700 lb, 317kg
Payload 395 lb, 179kg
Max wing loading 5.83 lb/sq.ft, 28.4 kg/sq.m
Max power loading 20.0 lb/hp, 9.lkg/hp
Load factors; +4.0, -4.0 ultimate
Max level speed 65 mph, 105 kph
Max cruising speed 55 mph, 88 kph
Stalling speed 32 mph, 51 kph
Max climb rate at sea level 500 ft/min, 2.5 m/s
Min sink rate 400 ft/min, 2.0 m/s
Best Wide ratio with power off 7/1
Take-off distance 210ft, 64m
Landing distance 250ft, 76m
Service ceiling 12,000ft, 3660m
Range at average cruising speed 110 mile, 177 km

AG-38
Engine: Cuyuna 430RR, 35 hp at 5500 rpm
Power per unit area 0.29 hp/sq.ft, 3.1 hp/sq.m
Length overall 17.0ft, 5.18 m
Height overall 5.0ft, 1.52m
Wing span 28.0ft, 8.53m
Constant chord 4.3 ft, 1.29 m
Sweep forward 5 deg
Total wing area 120 sq.ft, 11.2 sq.m
Wing aspect ratio 6.5/1
Wheel track 5.0 ft, 1.52 m
Nosewheel diameter overall 10 inch, 25 cm
Main wheels diameter overall 10 inch, 25 cm
Empty weight 325 lb, 147kg
Max take-off weight 700 lb, 317kg
Payload 375 lb, 170kg
Max wing loading 5.83 lb/sq.ft, 28.4 kg/sq.m
Max power loading 20.0 lb/hp, 9.lkg/hp
Load factors; +4.0, -4.0 ultimate
Max level speed 65mph, 105kph
Stalling speed 35mph, 56kph
Max climb rate at sea level 500ft/min, 2.5 m/s
Take-off distance 275 ft, 85 m
Landing distance 325 ft, 100 m

 

 

 

 


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