Pitts S-1S “Special”
Single-seat sporting biplane
Archive Photos ¹
Pitts (Pinkston) S-1S “Special” (N66YY, s/n 20P, 1975) c.1998 on display at the El Toro MCAS Air Show, MCAS El Toro, California (John Shupek photo copyright © 1998 Skytamer Images)
- Pitts S-1S Special
- Role: Aerobatic biplane
- National origin: United States of America
- Manufacturer: Aviat (current)
- Designer: Curtis Pitts
- First flight: September 1944
The Pitts “Special” (company designations S1 and S2) is a series of light aerobatic biplane designed by Curtis Pitts. It has accumulated many competition wins since its first flight in 1944. The Pitts biplanes dominated world aerobatic competition in the 1960s and 1970s and, even today, remains a potent competition aircraft in the lower categories.
Design and Development ²
Curtis Pitts began the design of a single-seat aerobatic biplane in 1943-1944. The design has been refined continuously since the prototype's first flight in September 1944, however, the current Pitts S2 still remains quite close to the original in concept and in design.
Several of the aircraft that Curtis Pitts built had a picture of a skunk on them and were called “Stinkers”. After she bought it, aerobatic performer Betty Skelton called the second aircraft that Curtis built, “Lil' Stinker”. The prototype S-2, which was the first two-seat Pitts, was “Big Stinker”, the prototype Model 11 (later called S1-11B) was “Super Stinker”, and the prototype Model 12 was the “Macho Stinker”.
In 1962 Curtis Pitts set up Pitts Enterprises to sell plans of the Pitts S-1C to home builders.
Operational History ²
All single-seat (S-1) and two-seat (S-2) Pitts “Specials” are variations on the basic design from 1944.
The aircraft was popularized by Betty Skelton, Caro Bayley and other air show performers, which led to the offering of plans in 1962.
Pitts produced limited numbers of aircraft during the 1940s and 1950s. It is widely accepted that the Pitts “Special” is the standard by which all other aerobatic aircraft are judged. After a number of home-built aircraft were produced from rough hand-drawn plans produced by Pitts, more professionally drawn plans went on sale in 1962. While many home-built aircraft were built in the 1960s, earning the Pitts S-1 a reputation as an excellent aerobatic aircraft, Pitts worked on the design of a two-seat aerobatic trainer version, the Pitts S-2, which first flew in 1967 and gained its type certificate in 1971. Factory-built aircraft produced by the Aerotek company at Afton, Wyoming were joined in production by the single-seat S-1S in 1973.
The design's popularity grew significantly following Bob Herendeen's participation on the USA Aerobatic Team in a Pitts “Special” in the World Aerobatic Competition in Moscow, Russia in 1966. In 1972, the US National Aerobatic Team won the World Championships flying only Pitts biplanes.
In 1977 Curtis Pitts sold his interests in the Pitts S-1 and S-2 to Doyle Child. Child later sold the rights in 1981 to Frank Christenson, who continued production at the Afton plant under the guise of Christen Industries. The rights for home-built versions of the Pitts were sold in 1994 to Steen Aero Lab, with the Afton factory and production rights being transferred to Aviat.
Curtis Pitts died in 2005 at age 89. At the time of his death, he was working with Steen on the prototype of the new Pitts Model 14, a brand-new, two-seat biplane designed for unlimited aerobatics powered by the 400 horsepower Vedeneyev M14P radial engine. The rights to the Pitts name is currently owned by Aviat which also owns the similar model to the Pitts in the Christen Eagle.
Current Versions ²
Certified versions of the compact Pitts are now produced by Aviat in Afton, Wyoming. It is available as an S-1 single-seater with up to 200 hp (150 kW) flat-4 Lycoming engine and a 17 ft 4 in (5.28 m) wingspan, or as an S-2 two-seater variant featuring a 260 hp (194 kW) flat-6 Lycoming and a 20 ft (6.1 m) wingspan. Pitts “Specials” have been equipped with engines of up to 450 hp (338 kW).
The Pitts held sway over the aerobatic world championships until the rise of the monoplane, though it remains very competitive in all levels of competition and remains a favorite of air show performers worldwide. The first monoplane to topple the Pitts from the top of unlimited aerobatic competition was the Russian-built and designed Yak-50.
Today, the single-seat Pitts S-1S plans are available from Aviat Aircraft. The S-1C and derivative S-1SS plans and kits are supplied by Steen Aero Lab in Palm Bay, Florida. The S-1 continues to provide extremely high performance at a relatively low cost. Many hundreds of home-builders have successfully completed and flown the Pitts since plans became available in 1960.
S-1: Basic single-seat Pitts aerobatic biplane with a flat M6 aerofoil section and lower wing ailerons only, fitted with a variety of engines. Two were built, the first named Special and the second Li'l Stinker.
S-1C: Amateur-built S-1 single-seat aircraft, flat bottom wing with ailerons on lower wing only, designed for 100 to 180 hp (75 to 134 kW) engines. First flown in 1960, the S-1 is currently available as a plans-built aircraft from Steen Aero Lab.
S-1D: Amateur-built S-1C with ailerons on all four wings, generally similar to S-1S.
S-1E: Amateur-built S-1C using factory-produced kits. Uses symmetrical airfoil.
S-1F: Outside derivative homebuilt, with the Falcon wing. Square tips, 25% more aileron span. In the UK, this model is fitted with a 200 hp (149 kW) Monty Barrett engine, and a lightweight Hoffmann VP propeller.
S-1S: Aerotek-built certified S-1C for competition aerobatics, round aerofoil section, four ailerons and powered by a 180 hp (134 kW) Lycoming AEIO-360-B4A; 61 built. This model is also available from Aviat Aircraft as a plans-built aircraft.
S1-SS: Similar to the certified S1-S “Roundwing”. 180 to 200+ hp (134 to 149 kW), single-seat, homebuilt, symmetrical wing, four symmetrical "Super-Stinker" style ailerons, 300 degree/s roll rate, fixed pitch propeller. This model is available in plans and components form from Steen Aero Lab.
S1-1T Aerotek-built S-1C with a 200 hp (149 kW) Lycoming AEIO-360-A1E and minor changes; 64 built. Four-aileron, single-seat, factory-built, symmetrical wing, symmetrical ailerons, constant speed two- or three-blade Hartzell propeller. The top wing was moved forward compared to the S-1S for weight and balance. This model is in production in 2008 from Aviat Aircraft as an "on-demand" manufacture product.
S-1-11B: Known as Model 11 “Super Stinker”, 300+ hp (220 kW) Lycoming, four-aileron, single-seat, experimental-plans or factory-built and factory component parts, symmetric airfoil, three-blade constant speed prop, rolls better than 300 degree/sec, climbs better than 3,000 ft/min (15.3 m/sec).
S-2 Scaled up S-1 with tandem two-seat fuselage and powered by a 200 hp (149 kW) Lycoming AEIO-360-B4A piston engine.
S-2A: Aerotek-built S-2A with a 200 hp (149 kW) Lycoming AEIO-360-A1A or -A1E piston engine, constant speed propeller, later builds has a longer landing gear and a 2-inch-wider (51 mm) front cockpit; 259 built.
S-2B: Aerotek-built S-2A with a 260 hp (194 kW) Lycoming AEIO-540-D4A5 engine, and upper wing auxiliary fuel tank, the landing gear and upper wings were moved forward six inches; 196 built. The aircraft is out of production but is supported by Aviat Aircraft.
S-2C: Four aileron, two-seat, factory-built, symmetric airfoil, 260 hp (194 kW) Lycoming driving constant speed three-blade propeller, current production model. This was an evolution of the S-2B model, with improved ailerons and rudder, flat bottom fuselage, lower profile bungee gear, better inverted handling and certified for +6 -5g. It is in production in 2008 by Aviat Aircraft.
S-2E: Amateur-built S-2A from factory-produced kits.
S-2S: Aerotek-built S-2B with a single cockpit and a twin tank fuel system. The fuselage is shortened by 14 inches (35 cm) forward of the cockpit to allow the installation of the heavier 260 hp (194 kW) Lycoming AEIO-540-D4A5. The wingspan is 20 ft, 0 inches (6.10 m); 17 built. This model is currently out of production, but supported by Aviat Aircraft.
S-2SE: Amateur-built S-2S from factory-produced kits.
Specifications (S-1S) ³
- Single-seat sporting biplane.
- Braced biplane type, with single faired interplane strut each side of N-type cabane struts.
- Dual streamline flying and landing wires.
- Wing section M6.
- Thickness/chord ratio, 12%.
- Dihedral, 0° on upper wing, 3° on lower wings.
- Incidence 1° 30' on upper wing, 0° on lower wings.
- SweepBack at quarter-chord 6° 40' on upper wing only.
- Wooden structure, with fabric covering.
- Frise-type ailerons on both wings, of similar construction to wings.
- Welded steel tube structure, covered with fabric.
- Wire-braced steel-tube structure, fabric-covered.
- Fixed-incidence tailplane.
- Trim tab in each elevator.
- Non-retractable tailwheel type.
- Rubber-cord shock-absorption.
- Cleveland main wheels with 6-ply tires, size 5.00-5, pressure 30 psi (2.10 kg/cm²).
- Cleveland hydraulic disc brakes.
- Steerable tailwheel.
- Glassfiber fairings on main wheels.
- One 180 hp at Lycoming IO-360-B4A four-cylinder horizontally-opposed air-cooled engine.
- Sensenich type 76EM8-O-52/62 two-blade metal fixed-pitch propeller.
- Fuel tank aft of firewall, capacity 20 US gallons (75 liters).
- Refueling point on upper surface of fuselage, immediately forward of windscreen.
- Oil capacity 2 US gallons (7.5 liters).
- Inverted fuel and oil systems standard.
- Single-seat in open cockpit.
- Wing span, upper: 17 ft 4 in (5.28 m)
- Wing chord (constant, both): 3 ft 0 in (0.91 m).
- Wing aspect ratio: 5.77
- Length overall: 15 ft 6 in (4.72 m)
- Height overall: 6 ft 3 in (1.91 m)
- Tailplane span: 6 ft 6 in (1.98 m).
- Propeller diameter: 6 ft 4 in (1.93 m)
- Wings, gross: 96.5 ft² (9.15 m²)
- Weight empty: 720 lb (326 kg)
- Maximum take-off weight: 1150 lb (521 kg)
- Maximum power loading: 6.38 lb/hp (2.89 kg/hp)
Performance at Maximum Takeoff Weight:
- Maximum never-exceeding speed: 203 mph (176 knots; 326 kmh)
- Maximum level speed at sea level: 177 mph (154 knots; 285 kmh)
- Maximum cruising speed at sea level: 141 mph (122 knots; 227 kmh)
- Stalling speed: 64 mph (56 knots; 103 kmh)
- Maximum rate of climb at sea level: 2,677 ft/min (816 m/min)
- Service ceiling: 22,300 feet (6,795 m)
- Take-off to 50 ft (15 m): 1,085 ft (331 m)
- Range with maximum fuel, no reserve: 315 miles (273 nm; 507 km)
- Photos: Shupek, John A., copyright © 2004 Skytamer Images
- Wikipedia, Pitts Special
- Taylor, John W. R. (editor). “Pitts S-1 Special”, Jane's All The World’s Aircraft 1975-76, Jane's Yearbooks, Franklin Watts Inc., New York, 1975, ISBN 0-531-03250-7, pg 430c
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