HPK SP-1

HPK SP-1
Role	Homebuilt aircraft
National origin	United States of America
Manufacturer	HPK Aircraft Associates, a division of Engle Flying Service, Inc.
Designer	Harold Hayden, Art Payne, Robert Kinney, Norman R. Benner
First flight	23 August 1957
Introduction	1957
Number built	1

The HPK SP-1 aka "Some Pisser-1" is a single seat homebuilt aircraft.^[1]

Design and development

Engle Flying Service members, Harold Hayden, Art Payne, Robert Kinney, and Norman R. Benner developed the HPK SP-1 over the course of five years. Plans for a two-seat side by side, and four seat variants were not completed.^[2]

The SP-1 is a single-place, all-metal, low-wing aircraft with conventional landing gear and partial span split trailing edge flaps. The cowling is from a Piper Tri-Pacer.^[3]

Operational history

The aircraft was built and tested at Three-M airfield in Pennsylvania, home of Kaiser-Fleetwings Company.^[4] The prototype has been registered for over 50 years.^[5]

Specifications (HPK SP-1)

Data from sport aviation

General characteristics

• Length: 19 ft 1 in (5.82 m)
• Wingspan: 25 ft (7.6 m)
• Height: 8 ft 1 in (2.46 m)
• Wing area: 99 sq ft (9.2 m²)
• Airfoil: 4412
• Empty weight: 1,300 lb (590 kg)
• Powerplant: 1 × Lycoming O-235-C1 , 115 hp (86 kW)
• Propellers: 2-bladed

Performance

• Maximum speed: 139 kn; 257 km/h (160 mph)
• Cruise speed: 126 kn; 233 km/h (145 mph)
• Stall speed: 43 kn; 80 km/h (50 mph)
• Wing loading: 13 lb/sq ft (63 kg/m²)

References

1. "Abandoned & Little-Known Airfields: Pennsylvania - Northeastern Philadelphia area". Retrieved 17 June 2011.
2. Sport Aviation. February 1959. Missing or empty |title= (help)
3. Frederick Thomas Jane. Jane's all the world's aircraft.
4. "Abandoned and little known airfields". Retrieved 17 June 2011.
5. "N65X". Retrieved 17 June 2011.