United Aircraft Corporate, Pratt & Whitney Canada, and Sikorsky Aircraft Collaborated in the Past to Conquer Land, Sea and Air Assault Support Patrol Boat (ASPB) Turbo Train ABC uring the lean production years of the mid 1960s to the mid 1970s, Sikorsky Dand corporate entities developed the Turbo Train, the Assault Support Patrol Boat, the S-58T and the Advancing Blade Concept (ABC) Helicopters. All of these systems were powered by specifi c versions of the Canadian Pratt & Whitney PT-6 shaft turbine engines. S-58T April, 2010 Visit us at Sikorskyarchives.com (203) 386-4356 I (203) 386-4218 Contact us at [email protected] Newsletter © 2006. The Igor I. Sikorsky Historical Archives Inc. All rights reserved. April, 2010 2 April, 2010 3 The TurboTrain was conceived by United weight Canadian Pratt & Whitney ST-6 shaft turbine Aircraft Corporate Systems, and was developed by engines located in the Power Dome Car per Figure the Surface Transportation Systems of Sikorsky Air- (1) provide the power to the drive system. Single craft. In January 1966, United Aircraft was awarded a axle truck installations result in low track friction. contract by the U.S. Department of Transportation for Improved passenger ride comfort was achieved by two three-car TurboTrains to operate between Boston supporting the cars from above through a pendulum and New York. Shortly thereafter, Canadian National structure shown in Figure (2). This arrangement Railways signed a contract for fi ve seven-car trains causes the car body to bank inward on curves like an to operate between Montreal and Toronto. The trains airplane. Separate spring devices were provided for could be operated in tandem sets of 14 cars with a vertical and lateral forces. The center of gravity of the total capacity of 600 passengers. cars as shown in Figure (3), is lower than convention- al railroad cars. This further improved the passenger Amtrak TurboTrain showing Power Dome Cars at each end The basic design philosophy of the Turbo Train was ride comfort. This system produced a speed advantage to produce a light weight system with aerodynamic to operate on curves at speeds up to 40% greater than body lines to achieve 160 miles per hour. Two light that possible with conventional trains. CONVENTIONAL TURBO TRAIN Amtrak TurboTrain Canadian National TurboTrain Figure 2- Pendulous Suspension System COMPARATIVE DIMENSIONS & Single Axle Truck Installation Figure 3 The Canadians called the TurboTrain the Rocket was to end its association with the train efforts for ST-6 Turbine Engine Figure 1-Power Dome Car Model Train. It was unquestionably the most technically business reasons. Sikorsky Aircraftʼs surprised deci- advanced high speed train for the period while it was sion to end its TurboTrain operations drew sharp con- TURBOTRAIN MAIN FEATURES used in both United States and Canada. In 1974 the gressional criticism, and zeroed in on the delays and -Passenger carrying Power Dome Cars on each end -40% greater speeds around turns United States Department of Transportation and Am- “foot-dragging” by Amtrak and DOT in the turbine -Light weight turbine engines -All cars have room for 50 passengers trak were evaluating a French train company against powered train decision. Senator Abraham Ribicoff, -2-1/2 feet lower than conventional cars -Increased passenger comfort the United Aircraft and Sikorsky team for procure- charged that DOT and Amtrak had “derailed” Sikor- -Lower center of gravity -Fastest and smoothest train at the time ment of additional trains to be used in the Chicago skyʼs effort to get into the train business. Thus ended -Pendulous suspension system -Potential speeds up to 170 mph depending corridor. Negotiations fell apart and UAC/Sikorsky the 10 year TurboTrain program. -Guided single axle wheel trucks on condition of tracks Aircraft decided not to bid. The Sikorsky decision -Banks inboard around curves Visit us at Sikorskyarchives.com Contact us at [email protected] Visit us at Sikorskyarchives.com Contact us at [email protected] April, 2010 4 April, 2010 5 The air venture with Pratt & Whitney Canada and The sea venture with United Aircraft, Pratt & Sikorsky Aircraft started in 1969 when S-58 commercial Whitney Canada and Sikorsky Aircraft started in the helicopter operators requested that the radial piston engine mid 1960s when marine gas turbine engines were under be replaced with a modern turboshaft engine to improve development for high speed boats. and extend the useful life of the aircraft. After a techni- A Thunderbird hull was designed and built by Alliance cal evaluation of the engines available that met the power, Machine Company. United Aircraft Corporate Systems configuration cost and reliability requirements, the Pratt PT6 Turboshaft Engine provided the technology for installation of twin ST-6 & Whitney Canada PT6T Twin Pac turboshaft engine was gas turbine engines. The Thunderbird design goal was to selected. A small “Skunk Works Team” was organized and package speed, endurance and reliability into a marine Thunderbird in action given the full authority of Sikorsky to design, build test, system capable of winning an open ocean race against develop, and certify the aircraft. the world’s top performance competitors. The 172 mile The Twin Pac turboshaft engine was unique providing Sam Griffith Memorial Race on February 22, 1966 pro- more than sufficient power required with the additional fea- vided this opportunity. Waves averaged 8 to 10 feet and ture of dual engine reliability. The Twin Pac was a configu- visibility was poor between Miami and Bimini. Of 31 ration of two PT6 engines connected to a combining gear- boats starting only two finished. Thunderbird crossed the box with a single horizontal output drive shaft. The original finish line after 4 hours, 48 minutes, as the winner aver- piston engine was mounted with its output shaft center PT6T Twin Pac Turboshaft Engine aging 36 mph in the roughest seas ever encountered in line on an angle. This required Sikorsky to design an angle this race. The only remaining competitor finished 2-1/2 gearbox with an output drive shaft on the same angular hours later. center line as the original S-58 aircraft’s piston engine. The engine installation requirements of structural mounting, In 1967 Sikorsky Aircraft Surface Transportation Systems won a U.S. Navy contract to develop controls, fuel, lubrication, instrumentation, accessories, fire a high speed Assault Support Patrol Boat. The ASPB was designed, developed and delivered to protection, inlet and exhaust systems were designed and the U.S. Navy with the following specifications: manufactured as conversion kits to be installed at Sikorsky or at the customer’s facilities. First flight was in 1971 and -3 Canadian Pratt & Whitney ST-6 turbine engines -3 water jet pump propulsion systems FAA certification occurred approximately one year later. -Speeds up to 50 miles per hour -Bar grill armor mounted 3 to 4 feet away from hull S-58T -Maneuver in water depth of 4 feet -small machine gun in bow -105 millimeter howitzer -20 millimeter automatic cannons HSS-1 (S-58) Engine Compartment S-58T Engine Compartment Military surplus HSS-1, H-34 and commercial S-58 impressive record is a testament to the Sikorsky he- aircraft have been converted with the PT6T Twin Pac licopter technology of that era. The Pratt & Whitney engines and are operating around the world today. Canada PT6 family of turboshaft engines has a similar The S-58 was launched in 1952 and the basic aircraft impressive record of utilization in the aerospace, mari- ASPB Starboard side view ASPB port side view has been in worldwide service for over 58 years, This time and industrial industries. Visit us at Sikorskyarchives.com Contact us at [email protected] Visit us at Sikorskyarchives.com Contact us at [email protected] April, 2010 6 April, 2010 7 The Air Venture with Pratt & Whitney Canada The Air Venture with Pratt & Whitney Canada and and Sikorsky Aircraft continued into the 1970s with the Sikorsky Aircraft continued with the S-76B and S-76D™ he- introduction of the Advancing Blade Concept (ABC) licopters. The search for the optimum engine for the Sikor- helicopter. Sikorsky Aircraft won a contract with the U.S. sky S-76 helicopter started during the initial design stage in Army for the development of a high speed helicopter uti- the mid 1970s. The engine selected for the S-76A was the lizing the ABC concept. An essential part of developing Allison Model 250-C30, rated at 650 SHP for Take-Off at S-76A the ABC as a high speed helicopter required an engine Sea Level Standard Day conditions. Maximum Take-Off that was fully developed and reliable while producing the gross weight for the aircraft is 10,500 pounds. Aircraft basic power required. The PT6T-3 Twin-Pac was the engine weight empty is 6,306 pounds. selected to drive the two counter rotating rotors. Auxil- The S-76B design was initiated to improve the utility of iary propulsion was provided by two Pratt & Whitney the aircraft at higher gross weights at high altitude hot day J60-P3A engines, each mounted on opposite sides of the conditions. Pratt & Whitney Canada PT-6B-36A turboshaft fuselage. engines were selected. The engine was rated at 981 SHP for The aircraft design, fabrication, test and development ABC Test Aircraft with auxiliary propulsion Take-Off at Sea Level Standard Day conditions. Maximum S-76B culminated in a fi rst fl ight approximately two weeks after Take-Off gross weight for the aircraft is 11,700 pounds. the S-58T fi rst fl ight. An extensive fl ight test program Aircraft basic weight empty is 7,623 pounds. was initiated with various aircraft confi gurations. The The S-76C design incorporated a lightweight turboshaft development and fl ight test programs continued to 1981 engine with lower fuel consumption providing improved achieving maximum speeds of 276 mph in level fl ight, payload characteristics.