Piaggio P.136

Piaggio Aero

Industry	Aerospace
Founded	1940s
Headquarters	Italy
Products	Aircraft, including Piaggio P.136 amphibious flying boat

Template:Infobox aircraft

The Piaggio P.136 represents an Italian amphibious flying boat powered by twin engines, engineered and produced by the aerospace firm Piaggio Aero. It features an all-metal hull construction, employs pusher propellers, incorporates a distinctive gull wing design, and is equipped with retractable landing gear.

The prototype of the P.136 took to the skies for the first time in late August 1948; within approximately six months, it had successfully passed certification trials, enabling its entry into operational service. In the American market, the aircraft was sold under the name Royal Gull through the distributor Kearney and Trecker. Later in the 1950s, Piaggio developed a land-based utility aircraft derived from the P.136—the Piaggio P.166—which retained many design elements but replaced the hull with a conventional fuselage.

Development

In the years following the conclusion of the Second World War, specifically during the 1940s, Italian manufacturer Piaggio Aero sought to reestablish its presence and clientele by initiating development of a new amphibious airplane. As highlighted by Aviation magazine Flight International, this undertaking was particularly challenging since numerous aviation companies had struggled to create effective flying boats, demanding considerable innovation. The resulting design was relatively large yet capable of operating from both rough water surfaces and small grassy airstrips. Additionally, significant components such as its three-bladed constant-speed propellers were developed in-house by Piaggio.

In 1954, Francis K. Trecker, president of Kearney & Trecker Corporation, became impressed after observing a P.136 flight demonstration and proposed introducing the aircraft to markets in North America. To facilitate distribution across Canada, the United States, and Mexico, a new company initially named Royal Aircraft Corporation was established. While Trecker obtained rights to manufacture complete aircraft, his usual practice involved importing partially assembled P.136 airframes from Italy and completing assembly with American-made parts and systems. Approximately 75 engineering alterations were implemented to adapt the airframe to North American specifications.

Design

File:PiaggioatBF (4447275790).jpg

A Piaggio P.136

The Piaggio P.136 featured a twin-engine amphibious design with a pusher propeller arrangement, capable of accommodating up to five passengers along with luggage, or alternatively, two stretchers and a medical attendant. While the overall layout and systems were consistent across variants, cabin configurations were tailored to meet specific customer requirements and mission profiles; military versions often included specialized instrumentation and radio equipment, as well as additional transparent panels in areas such as the doors to enhance external visibility. In contrast, civilian models prioritized passenger comfort with upgraded seating and extra insulation panels aimed at noise reduction and thermal retention. Fuel was stored in two substantial metal tanks integrated within the hull.

The pusher engine setup offered several benefits, notably positioning the propellers and engines away from spray and cabin door areas. Engine cooling was managed by sizable scoops placed above the wing leading edges. The warmed air exiting the engines was directed toward the propellers to prevent icing, eliminating the need for dedicated de-icing systems. Operational experience indicated that even extended taxiing in hot tropical environments did not cause overheating issues. Another advantage of mounting the engines aft was reduced noise levels inside the cabin, contributing to a quieter atmosphere for both crew and passengers. The powerplants generally drove fixed-pitch propellers; however, variable-pitch propellers were available as an option to enhance performance.

File:PiaggioP136L1Takeoff.jpg

P.136 L-1 during takeoff

Several design elements aimed to improve user convenience. Cabin access was facilitated by a spray dam located on the chine, while a roomy baggage compartment was situated behind the cabin; larger cargo could be stored in a spacious hold accessible through a hatch positioned just aft of the wing. Four lifting points on top of the fuselage allowed cranes to hoist the aircraft when necessary. Maintenance was simplified by requiring only a few steps to detach engine cowlings for direct access to the powerplants. Mooring and anchoring operations were managed from a designated panel on the starboard windscreen, and comprehensive navigation and riding lights were installed. The hull contained six sealed bilge compartments that could be emptied using a single hydraulic pump; the aircraft was reportedly able to stay afloat even if two compartments were flooded.

Regarding handling and controls, Flight International noted that the boat hull imposed minimal impact on flight performance: "As a landplane, it performs comparably to other light twins, aside from a slight reduction in cruising speed due to its marine capabilities." The publication also commended its "superb maneuverability" and capacity for executing "very steep approaches." All flight control surfaces were fabric-covered and typically mass-balanced. Consistent with flying boat design norms, both control wheel and pedal travel were extensive to aid during takeoff runs by helping avoid water obstacles such as buoys. Water steering was accomplished through a large rudder connected via cables to the aerodynamic rudder; it was deployed by pulling a long wire extending from the cabin roof. Highly effective slotted flaps were installed in sections adjacent to each engine nacelle, though full flap deployment was seldom used except for rapid deceleration purposes.

Operational history

Flight International reports that the Italian Air Force was the initial entity to place a procurement request for this model. Throughout the 1950s, the Italian Air Force acquired a total of 14 P.136 aircraft, utilizing them primarily for coastal surveillance and air-sea rescue operations. Beyond military demand, the P.136 also attracted interest from civilian sectors, with several units purchased by private individuals and commercial operators.

The American firm Kearney and Trecker was designated as a wholesale distributor for the aircraft. This company received three P.136s constructed in Italy, along with partially assembled fuselages and components to assemble an additional 29 units under a licensing agreement. Kearney and Trecker manufactured a limited number of these planes under the name Royal Gull.

Variants

File:PiaggioP136L1.jpg

P.136L-1

P.136F

Equipped with Franklin engines, this version was predominantly built for the Italian Air Force, with 18 units produced.

P.136L

Featuring Lycoming GO-435 engines, two were constructed, alongside one conversion from a P.136F.

P.136L-1

A five-seat amphibious flying boat powered by two 201-kW (270-hp) Avco Lycoming GO-480-B engines; 18 units were manufactured.

P.136L-2

Also a five-seat amphibian flying boat, but fitted with two 254-kW (340-hp) Avco Lycoming GSO-480 piston engines; 24 were assembled in the United States using kits supplied from Italy.

Royal Gull

The Kearney and Trecker Corporation marketed both the P.136-L1 and P.136-L2 versions within the United States.

Military operators

Template:ITA

• Italian Air Force operated 22 aircraft in total—14 Piaggio P-136F and eight Piaggio P-136L-1 models—from 1951 until 1961.

Template:PER

• Peruvian Air Force – operated four aircraft comprising one P.136 and three P.136L-2 variants.

Template:BGD

• Bangladesh Army – operated a single P.136L-1, registered as AP-ALV.

Civilian

Template:GRC

• Olympic Aviation utilized two P.136 L2 aircraft, including SX-BDC, which tragically crashed during takeoff from Athens (Ellinikon Airport) on 22 January 1973, resulting in the death of Alexander Onassis.

Template:HKG

• Macau Air Transport Company (Hong Kong) Limited operated one P.136 L2.

See also

Bibliography

• Lambert, C.M. "Flying the Piaggio P.136-L." Flight International, 11 April 1958. pp. 486–488.

External links

• footage of a P.136 in flight on Youtube.com