Close this search box.

Stroukoff YC-134 Avitruc

The Stroukoff YC-134, which was conceptualized in 1956, drew significant inspiration from the Fairchild C-123 Provider, a creation of Michael Stroukoff.

In order to enhance the aircraft’s capabilities, the United States military enlisted the services of Stroukoff Aircraft Corporation to integrate advancements from the YC-123D and YC-123E models.

By 1956, Stroukoff had accumulated significant expertise through his involvement with the C-123 Provider, having successfully fulfilled two contracts utilizing that particular airframe.

One notable innovation introduced by Stroukoff was the incorporation of a Boundary Layer Control (BLC) system into the C-123B, resulting in the creation of the YC-123D variant.

This ingenious system involved directing pressurized air over the upper wing surfaces of the aircraft, effectively simulating a higher airspeed during flight.

Consequently, this enhancement brought about substantial improvements in the aircraft’s landing and take-off capabilities, expanded its gross weight capacity, and notably reduced the stall speed of the C-123.

The YC-123E was a further attempt to enhance the C-123’s operational capabilities in various environments.

It incorporated Stroukoff’s innovative Pantobase system, which consisted of two durable skis attached to the lower fuselage, floats mounted on the wingtips, and improved sealing of the fuselage.

As a result, the YC-123E possessed the capability to operate not only on water, but also on ice, snow, and other challenging terrains.

Additionally, with the inclusion of the Boundary Layer Control (BLC) system from the previous YC-123D model, this new aircraft could effectively take off and land on runways of different surfaces and even on shorter airstrips.

The YC-134, derived from a C-123B aircraft produced under a US Air Force contract in 1956, underwent significant modifications by Stroukoff Aircraft.

These modifications included the installation of new engines, improved control surfaces, enhanced landing gear, and a revised fuel storage system.

The YC-134 was equipped with two powerful Wright Turbo Compound R3350-89A radial engines, each generating 3,500 horsepower, and featured four-blade, thirteen-foot Aeroproducts constant-speed fully feathering propellers.

To enhance directional stability, endplates were added to the horizontal stabilizers, giving the aircraft its distinctive three-tail appearance.

The landing gear was also upgraded, with the addition of a third wheel to both main gears, improving weight distribution.

Furthermore, the fuel storage was relocated from the rear of the engine nacelles to an expanded center-wing fuel tank.

Additionally, two hardpoints were incorporated into each wing, allowing for the attachment of 550-gallon drop tanks.

Notably, the YC-134 was equipped with Stroukoff’s own Boundary Layer Control (BLC) system, and it was intended that all three aircraft, if delivered, would be fitted with the Pantobase equipment specifically designed for the YC-123E variant.

The YC-134 boasted several enhancements that resulted in a significant increase in its empty weight from 31,058 lb (14,088 kg) to 37,965 lb (17,221 kg), as well as a maximum loaded weight increase from 60,000 lb (27,000 kg) to 74,700 lb (33,900 kg).

In terms of speed, the aircraft’s cruising speed was 219 mph (352 km/h), which was notably faster than the C-123B’s 190 mph (310 km/h).

Additionally, the YC-134 had an impressive range of 1,600 miles (2,600 km) with a 24,000 lb (11,000 kg) payload.

The BLC system also allowed for a shorter take-off distance of 750 feet (230 m), which was comparable to that of the YC-123D.

Despite these advancements, the U.S. Air Force ultimately determined that the YC-134 did not offer significant improvements over the C-123 and did not require a piston-engined amphibious assault transport, opting instead to purchase the Lockheed C-130 Hercules.
82 ft 0+3⁄4 in (25.013 m)
110 ft 0 in (33.53 m)
34 ft 8+1⁄2 in (10.579 m)
Wing area
1,234.9 sq ft (114.73 m2)
Aspect ratio
Empty weight
40,391 lb (18,321 kg) (equipped)
Gross weight
74,700 lb (33,883 kg)
Fuel capacity
1,032 US gal (859 imp gal; 3,910 L) internal fuel
1,000 US gal (830 imp gal; 3,800 L) in underwing float tanks
2 × Wright R-3350-89A Turbo Compound 18-cylinder 2-row air-cooled radial engines,
3,500 hp (2,600 kW) each
4-bladed Aeroproducts Model A644FN-C2 fully feathering constant-speed propellers
Cruise speed
250 mph (400 km/h, 220 kn) at 10,000 ft (3,000 m)
1,610 mi (2,590 km, 1,400 nmi) with 24,000 lb (11,000 kg) payload
Take-off distance on land
740 ft (230 m)
Take-off distance on water
1,250 ft (380 m)
Landing distance on land
550 ft (170 m)
Landing distance on water
750 ft (230 m)
Fifty Years of Flight: A Chronicle of the Aviation Industry in America, 1903-1953-Welman Austin Shrader.
Chase C-123 Provider-Squadron Signal 1124.

Share on facebook