by: The_Migrant [ ]
Originally published on:
The Wright R-3350 Duplex-Cyclone was one of the most powerful radial aircraft engines produced in the United States. It was a twin-row, supercharged, air-cooled, radial engine with 18 cylinders. Power ranged from 2,200 to over 3,700 hp (1,640 to 2,760 kW), depending on the model. Developed before World War II, the R-3350's design required a long time to mature before finally being used to power the Boeing B-29 Superfortress.
Following the war the Turbo-Compound system was developed to deliver better fuel efficiency. In these versions, three power-recovery turbines (PRT) were inserted into the exhaust piping of each group of six cylinders and geared to the engine crankshaft by fluid couplings to deliver more power. The PRTs recovered about 20 percent of the exhaust energy (around 450 horsepower (340 kW) that would have otherwise been wasted, but reduced engine reliability (Mechanics tended to call them Parts Recovery Turbines, since increased exhaust heat meant a return of the old habit of the engine eating exhaust valves). The fuel burn for the PRT-equipped aircraft was nearly the same as the older Pratt and Whitney R-2800, while producing more useful horsepower. Effective 15 October 1957 a DA-3/DA-4 engine cost $88,200.
The R-3350 Turbo-Compound engine was installed in the following aircraft:-
Lockheed P2V-7 Neptune
Martin P5M-1 and -2
Fairchild C-119F and G
Lockheed Super Constellation
(Adapted from Wikipedia)
Plus Model recently released its 1/72 EC-121 Warning Star kit, (reviewed here on Aeroscale by Matthew Robson). Basically the old Heller kit with a bunch of resin, photo-etch and decal upgrades, the most obvious omission was a resin engine. The company has now rectified this by releasing the R-3350 as a separate kit, which is also useful for modellers of the subjects listed above.
Securely blister-packaged and cushioned with a block of foam rubber, there was no damage to any of the parts in transit. These are cast in light grey resin, and are nothing short of exquisite, with every detail replicated. The twenty cylinders are all separate components, as are the various lengths of exhaust piping, so assembly is going to require some careful alignment. All the parts are numbered on the casting blocks, their positions being clearly indicated on the instruction sheet.
A brass photo-etched sheet includes the ignition harness, although wire would look more convincing, as shown on the kitís cover photo. The valve push-rods must be cut from the length of copper wire supplied.