The Ramp-Head Merlin

Sometime in the latter half of 1933, George Albert Elliott, Rolls-Royce Chief Engineer, informed the PV-12 development team of his decision to change the engine’s cylinder heads to the ramp type. This announcement would have been greeted with astonishment, amazement and probably, dismay by the engineers involved. They already had major problems to contend with and the introduction of an untried, untested modification to a brand new engine had the potential to add significantly to their woes.

The MASM Gnome Omega Engine

Early in the 20th century James Shannon Stephens and his engineer son Ralph became interested in designing an aircraft, a common interest of engineers in the first decade of the century. They subsequently designed the Steco (Stephens Engineering Company) aircraft which has been variously described as a hydroaeroplane or Aerohydroplane. Stephens was granted a patent on his aircraft and its design inventions in 1915.

As with many aircraft designs of the era, the designer tried unique control systems to get around the Wright patents. Also, the science of aircraft stability and control was poorly known at the time, and while we have no detailed data from the flight tests, we can surmise that the Steco was a handfull to handle. Like many early aircraft, the plane was set up to be neutrally stable in both pitch and yaw.

The aircraft and its Gnome Omega engine have been restored by the Minnesota Air & Space Museum.

Turbocompounding the Wright Way

Engine designers have a long history of trying to extract as much power as possible from a given engine, and this is especially true of aircraft engines since there is a large penalty for carrying extra weight, be it fuel, engine, or airframe mass. There is significant energy in the engine exhaust stream, and it is an art form trying to put that energy to efficient use. Stanley Hooker reported that the jet efflux from a Rolls-Royce Merlin engine was worth up to 150 hp (10% of power output) at high power settings. While this is a valuable and relatively simple way to put exhaust energy to work, turbo-supercharging, which uses the pressure of the exhaust gas, and turbocompounding, which uses primarily the velocity of the gas stream, are other ways to boost efficiency.

As large-displacement piston engine technology peaked in the late 1940s and early 1950s, turbocompounding was studied by a number of manufacturers including Allison, Pratt & Whitney, and Napier, to increase horsepower, but even more importantly, specific fuel consumption (sfc) of their engines. More power on less fuel meant larger loads carried over longer distances for the same-size airplane, an efficiency mantra that drives design even today.

Power Recovery Turbine Images

Assembled	Outlets	On Stand with Parts	With Cap	Without Cap
Hood, Cap and Clamps	Underside of Cap	Buckets and Guide Vanes	Turbine Wheel Showing Cooling Holes and Knife Cuts	Underside

Aero Engine Drawings by Frank Munger

Balzer-Manly 1903 Engine

The Impact of the Engine on the Airframe
Schedule Effects — German Jet Engine Development in WWII
Part 2: The Aircraft

Aircraft engine development requires more time than does airframe development, usually about 60 percent more. This truism is sometimes forgotten in the desire to achieve program goals. Perhaps the most dramatic example of the consequence of such forgetfulness occurred in Germany in World War II when the jet engine not-so-quietly arrived on the scene.

Part 1 of this series discussed German jet engine development during WWII. Part 2 covers the manned turbojet-powered aircraft that actually flew in Germany before WWII ended. Jet aircraft that flew in wartime Germany used first-generation engines, and many aircraft were on the drawing boards using second-generation engines such as the He 011, BMW 018, BMW 028, Jumo 012, Jumo 022, and ramjet engines.

Conceive, Construct, Configure, then Run Your Demo Engine
Or, How I Got My V-1710 Running

Most of us have a favorite engine, one that we have always wanted to get "close and personal" with. In many cases such engines are only operable in rare and expensive Warbirds, airplanes whose owners will not willingly let just anyone into the cockpit, let alone operate the engine. This is where the committed enthusiast will look for an alternative, for me that meant one that was affordable and restorable.

Those of us who are running and demonstrating old aircraft engines are often asked, sometimes incredulously, "Why?", others want to know "How?", and some others say, "I’ve always wanted to run one of these things.". This article intends to give the reader some insights as to how I got my V-1710 up and running, along with some of the lessons learned.