Known primarily for his significant contributions to aviation technology, Leonard Michael Greene (1918-2006) was an American inventor who held over two-hundred patents. Many of Greene’s patents are related to aviation, with one of the most noteworthy being his Aircraft Stall Warning device which, as the name suggests, warns pilots of imminent aerodynamic stall. This is where the critical angle of attack, typically around 15 degrees, of the foil is exceeded resulting in a sudden reduction in lift. The warning device makes pilots aware that the airflow over the wings is not providing lift, allowing them to take the necessary action.
Greene’s invention was prompted by his witnessing an aircraft crash caused by stall when he was working as an aerodynamicist and engineering test pilot for Grumman Aircraft Corporation during World War II. At that time aerodynamic stalls were the cause of the majority of aviation accidents deaths and by the mid-1940s Greene had developed a way of warning the pilot timeously. His first warning device was powered by flashlight batteries, consisting of threaded bolts, a bicycle horn and an assortment of other components – rudimentary, but a step in the right direction. Greene filed to patent his device in 1944, with the patent being issued in 1949. In 1946, Greene founded the Safe Flight Instrument Corporation in White Plains, NY, where he developed, refined and marketed the aircraft stall warning device. The company went from strength to strength and has remained dedicated to the production of aviation safety and performance equipment for sixty years, with its principle products, many of which were invented by Greene,including FAA approved Stall Warning Systems, Angle-of-Attack Systems, Speed Control Systems, Speed Command of Attitude and Thrust (SCAT) systems, AutoPower, Airborne and Wind Shear Warning Systems and N1 Computer Systems.
Leonard Greene’s 2001 book Inventorship: The Art of Innovation details how he found creative inspiration in the simplest of things, with an example being his invention of a device to prevent the sonic boom caused by a supersonic aircraft when breaking the sound barrier by using a hollow fuselage and ducts to suck in, compress and release air through the aircraft’s tail – with his inspiration being the lowly earthworm’s method of moving through dirt by eating and excreting it.
Greene remained actively involved in Safe Flight Instrument Corporation until he passed away in 2006. His inventions and dedication to making flight safer has benefited millions of people who today view air travel as routine.
The science of Biomimicry is not new to the scientific world, but every now and then it is taken to a whole new level. While aircraft have long been roughly designed in imitation of birds, they has always had certain set characteristics that set them apart. It seems all that is about to change.
Airbus has teamed up with Pratt & Whitney to conduct a series of flight tests designed to evaluate the PW1000G technology demonstrator engine. The engine features Pratt & Whitney’s patented Geared Turbofan (GTF). This is one of a number of tests that will be conducted by Airbus along with various major engine manufacturers.
The striking new Cirrus Vision SJ50 V1 has already managed to accumulate 25 hours of test flight since it first took to the skies on July 3. Now it seems that it is ready to undergo a rather rigorous test campaign, which will ultimately help to validate the technology required to finish off the aircraft.
Aerodynamics is the study of the motion of air and other gases and their effects on a body in movement, as well as the effects of moving air on stationary objects. The word aerodynamics is derived from the two Greek words: “aerios”, relating to air, and “dynamis”, meaning force. The principles of aerodynamics have been utilized in many industries, such as the automobile industry, heating and ventilation and various aspects of engineering, as well as in the field of sports, notably cycling. Without a doubt though, since the invention of “heavier-than-air” flight, air travel is the leader in the field of aerodynamics.
Some would argue that radio controlled (“RC”) airplanes are the domain of those who didn’t have what it took to become a pilot. But the ever-expanding fan-base of people who participate in this hobby will tell you that that is not true. Many RC Airplane controllers are skilled pilots while others have never even flown before.