| P.136/Royal Gull | |
|---|---|
 | |
| Piaggio P.136L-2 at Tamiami Airport near Miami in 1989 | |
| Role | Amphibious aircraft Type of aircraft |
| National origin | Italy |
| Manufacturer | Piaggio Aero |
| First flight | 29 August 1948 |
| Introduction | 1949 |
| Status | examples still flying in 2018 |
| Produced | 1948-1961 |
| Number built | 63[citation needed] |
| Developed into | Piaggio P.166 |
ThePiaggio P.136 is an Italian twin-engineamphibian flying boat designed and manufactured by aircraft companyPiaggio Aero. It is furnished with an all-metal hull,pusher propellers, agull wing, and retractable landing gear.
During late 1948, the P.136 prototype performed itsmaiden flight; roughly six months later, it reportedly completed certification tests, clearing the type's entry into service. The aircraft was marketed in the United States as theRoyal Gull by American distributorKearney and Trecker. During the late 1950s, a land-basedutility aircraft, thePiaggio P.166, was developed from the P.136 and shares many design similarities, despite the deletion of the hull in favour of a conventional fuselage.
During the 1940s, barely a year following the end of theSecond World War, Italian aircraft manufacturerPiaggio Aero, being keen to rebuild itself and its customer base in the post-war era, embarked upon the development of a newamphibian design. As noted by Aviation periodicalFlight International, this was no simple choice, as many aviation companies had been defeated in their ambitions to develop efficient flying watercraft and required ingenuity to achieve.[1] The design produced by Piaggio was of a relatively large aircraft, yet still being capable of operations from both relatively rough waters and fairly compact grass air strips. Furthermore, large portions of the aircraft, such as its three-bladedconstant-speed propellers, was internally designed by the company.[2]
During 1954, Francis K. Trecker, president of Kearney & Trecker Corporation, was impressed when he witnessed a P.136 in flight, and offered to bring the type to theNorth American market.[3] A new entity, initially known as theRoyal Aircraft Corporation, was formed to distribute the aircraft inCanada, theUnited States, andMexico. Trecker secured the right to build complete aircraft, but he typically imported partially-constructed P.136s from Italy and assembled them with additional American-sourced components and systems. Around 75 engineering modifications were made to the airframe to better suit North American requirements.[3]
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The Piaggio P.136 was a twin-enginepusher-type amphibian, being capable of carrying a maximum of five people withbaggage, or a pair ofstretchers and an accompanying medical attendant.[1] While the general configuration and systems remained largely the same across different models, there were some customisations present in the cabin to suit its customer and intended purpose; while military aircraft would often be fitted with alternative instrumentation andradio sets, as well as additional transparent panels in locations like the doors for greater external visibility, civil P.136s would be furnished with more comfortable seating and additional panelling for sound exclusion and heat retention purposes.[2] The aircraft's fuel is stowed in two large metal tanks housed within the hull.[2]
The P.136's pusher configuration confers several advantages, one being that both the propellers and engines are kept well clear of spray and the cabin doors.[2] Cooling of the engines is achieved via large scoops located above theleading edges of the wing. After passing through the engines, this heated air is then channeled at the propellers to keep them free ofice, making any specialde-icing apparatus unnecessary. Reportedly, operations revealed that even prolonged taxiing in tropical climates did not lead to any instances of overheating.[2] Another benefit of the aft positioning of the engines is that cabin noise is inherently lessened in the cabin, providing a quieter environment for passengers and pilot alike. The engines typically drove fixed-pitch propellers, althoughvariable-pitch propellers were available as an option for greater performance.[4]
Several features of the P.136 are to enhance customer convenience. Access to the cabin is eased by stepping on the spray dam set upon thechine, while a spacious baggage compartment is present to the rear ofthis cabin; some bulky cargo may also be stowed inside a large chamber accessed via a hatch located just aft of the wing.[2] The top of the fuselage has four hoisting points, intended for use bycranes to lifting the aircraft. For ease of maintenance, only a handful of moves are required to unclip the enginecowlings to directly access the aircraft's powerplants. A starboard windscreen panel controls all mooring and anchoring operations, while full nautical riding and navigation lights are fitted.[2] The aircraft has a total of six sealedbilge compartments, which can be pumped dry via a singlehydraulicpump; reportedly, it can remain buoyant even with two compartments flooded.[2]
In terms of its controls and handling, Flight International observed that the P.136's boat hull makes little imposition on its flight characteristics: "As a landplane, it behaves as well as any comparable light twin, except that it pays the penalty of slightly lower cruising speed incurred by its marine capabilities"; the publication also praised its "excellent manoeuvrability" and ability to perform a "very steepapproach".[5] All of the flight control surfaces had afabric covering, these typically being mass-balanced. As common amongst flying boats, both the control wheel and pedal travel are large, aiding in take-off runs to avoid water-based obstructions such asbuoys.[4] Water steering is achieved via a largerudder that is linked to cable of the aerodynamic rudder; it is extended by pulling a long wire out of the cabin roof. Highly-effectiveslotted flaps were positioned in sections on either side of the engine nacelles, full deployment of which rarely being used other than to rapidly decelerate.[2]
According to Flight International, theItalian Air Force was the first organisation to place an order for the type.[1] During the 1950s, theItalian Air Force opted to procure a fleet of 14 P.136s, where they were used to conductcoastal patrol andair-sea rescue missions. In addition to military sales, the P. 136 also received orders from civilian operators. A number were purchased by individuals and private operators.[1]
American aircraft manufacturerKearney and Trecker was appointed as awholesaler for the type, received three Italian-built P.136s along with the partially-assembled fuselages and components for the productions of another 29 examples of the type under alicensing arrangement. The company produced a handful of examples under theRoyal Gull brand.[6]
Data fromJane's All the World's Aircraft 1958-59[9]
General characteristics
Performance
Related development
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