Wren 460, the Ultimate STOL

By:      Norm Goyer

The Wren 460 is one of most advanced STOL aircraft ever. It was just too slow for most pilots.

The Wren 460 is one of most advanced STOL aircraft ever. It was just too slow for most pilots.

Thanks Wikipedia for supplying the technical information for the Wren 460. NG

The Wren got its beginning from the STOL Skyshark aircraft by Jim Robertson in the late 1950s. The Skyshark incorporated a number of novel features, most notably a canard with elevators and rudders attached the nose of the aircraft and in the prop wash. It was a technological success, but too expensive to produce. However many of the ideas worked well and  Robertson incorporated some of them into the Wren Aircraft Company’s Wren 460. The Wren 460 was a conversion of the Cessna 182 airframe. The conversion added full-span double-slotted flaps, movable spoilers to assist the ailerons with roll control and a movable high-lift canard. Later models offered a reversible pitch propeller for steeper approaches, and shorter landing runs. The aircraft was marketed as the only safe STOL aircraft. This was because it did not achieve its STOL characteristics through dangerous high angles of attack and by depending on a powerful engine to pull the aircraft upward (operating “behind the envelope”). At full gross weight, the Wren’s take-off and landing distances were 300 ft. At idle power the aircraft could loiter at slow speed with outstanding]stall resistance and over-the-nose visibility. It could also make steep turns immediately after take-off. Because of the low approach speed, the Wren was approved for landings under Category II conditions (1/4 mile visibility and 100 foot ceilings on Instrument Landing System approaches). The company was seeking approval for landings under conditions of zero visibility shortly before the company went into bankruptcy in the late 1960s. However, there are reports that several “Wrens” did service with “Air America”.

Note the "Wren's teeth" on top of the wing. These vector airflow over the surfaces.

Note the “Wren’s teeth” on top of the wing. These vector airflow over the surfaces.

In 1980 Todd Peterson acquired the Supplemental Type Certificate for the Wren and produced a number of under the designation 460P. Under Peterson the Wren design became the Peterson 260SE. On the 260SE the wing modifications are absent. The aircraft depends on the high-lift canard and a more-powerful fuel-injected 260 HP Continental engine to achieve STOL capabilities. The additional power and speed modifications permit a cruise speed in excess of 150 knots. A canard-only conversion, the 230SE, is also available for about 1/3 the price of the canard/engine combination. The 230SE has inferior take-off performance compared to the 260SE but both aircraft have a stall speed of 35 knots.

The heart of the Wren STOL system is the canard attached the cowling area in the prop air flow.

The heart of the Wren STOL system is the canard attached the cowling area in the prop air flow.

General characteristics WREN 460

  • Crew: 1
  • Capacity: 3 passengers
  • Length: 27 ft 4 in (8.33 m)
  • Wingspan: 35 ft 10 in (10.92 m)
  • Height: 9 ft 0 in (2.74 m)
  • Wing area: 175.4 sq ft (16.30 m2)
  • Empty weight: 3,741 lb (1,697 kg)
  • Gross weight: 2,800 lb (1,270 kg) (normal)
  • Max takeoff weight: 3,650 lb (1,656 kg) (restricted category)
  • Fuel capacity: 80 US Gallon (303 L)
  • Engine:    Continental IO-470-R air cooled flat-six, 260 hp (190 kW)

Performance

  • Maximum speed: 160 mph (257 km/h; 139 kn) (max cruise)
  • Cruise speed: 140 mph (122 kn; 225 km/h) (econ cruise)
  • Stall speed: 29 mph (25 kn; 47 km/h) (flaps down, power off)
  • Range: 980 mi (852 nmi; 1,577 km)
  • Service ceiling: 19,200 ft (5,852 m)
  • Rate of climb: 1,080 ft/min (5.5 m/s)
  • Take-off to and landing from 50 ft (15 m): 560 ft (171 m)

[The Zenith CH701 and the Ch 801 ( four place) are experimental homebuilts.  Some versions are also available as LSA legal.

Fans of STOL aircraft currently do not have many to choose from. The Maule is fully certified and does have good STOL performance, but not of the quality of the WREN. For homebuilders, the Zenith folks in Canada have been producing a kit for a two passenger experimental (homebuilt) CH-701 for many years now. This is a very good performing STOL. A few years ago, Zenith modified the CH-701 into the four-plane CH-801.The aircraft look the same but both are completely different from each other. The 801 has a larger engine and better weight lifting performance. The designs are avail in homebuilt kits as well as an LSA aircraft. This is a very popular design.

Zenith CH-801 Specifications

  • Crew: one pilot
  • Capacity: three passengers
  • Length: 24.5 feet (7.5 m)
  • Wingspan: 27.0 feet (8.3 m)
  • Wing area: 167 sq ft (22.0 sq m)
  • Empty weight: 1150 lb (523 kg)
  • Loaded weight: 2200 lb (998 kg)
  • Useful load: 1050 lb (475 kg)
  • Max. takeoff weight: 2200 lb (998 kg)
  • Engine:  Lycoming O-360, 180 hp (135 kW)

Performance

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