Q - American Bonanza Society

AND A FEW THINGSABOUT THEMBY JOHN M. MILLER. POUGHKEEPSIE. NEW YORKairplanes will enter aspin under certain conditions.principally whenairspeed is too low andthe airplane is stalled while in a turn ifrudder is used improperly. That is howwe deliberately enter a spin.However. a spin can result fromother misuse of controls, even abovepublished stall speeds. There was a timewhen regulations required pi lot cand i­dates to demonstrate proficiency inentering and stopping spin s. However.there were more spinning accidents duringinstruction in spins than in otherroutine flying. possibly due to thein structors' lack of proficiency orimproper loading of the aircraft.The selection of the wrong aircraft,suscept ible to bad spin qual ity such as atendency to progress from a normal spininto a nat spin. usually uncontrollable,was also the cause of accidents.One of the most common inadvertentspins occurs during an approach tolanding. This might occur when the airplanehas a tailwind on base leg and acrosswind on fi nal. The airplane overshootsthe nonnal approach path and thepilot starts a flat turn to get back in linewith the runway. The rudder is used toget back in line with the runway insteadof banking the tum properly. resultingin skidding which lowers airspeed aswell as puts the airplane in a yaw.That is a classic way to enter a spin.Pilots feel they are too low to correcttheir approach path by banking, so theyuse the rudder improperl y. Don't dothat! The result can be death.It is my belief that a pilot is notfully and truly competent unless he hashad training in spin recovery. I canunderstand that many are terrified byspins so avoid them . If a pilot is properlytrained in avoidance of spins, thatmay be enough to carry him safelythrough his entire career.Actually, a spin in an airplane thatspins well and safely is a lot of fun. Ican remember when we used spins justto get rid of altitude or to get downthrough a layer of clouds. Stories aboutsuch use of spins are not mere myth.Spins are required in the case ofsingle-engine airplanes for approval.However, full spins are not required fortwin-engine airplanes with enginesmounted on the wings. on ly quickavoidance from an incipient spi n duringa stall. The mass of the engines out thereon the wings increases the radius of gyrationof the airplane. In other words whenthose heavy engines are going around ina circle at high speed, in all probabilitythe rudder wi ll not have enough airspeedto stop them turning.A single-engine airplane does nothave that problem, except when thewing tanks and tip tanks are fu ll. Anyairplane loaded with a center of gravitytoo far back can be dangerous. Thatincreases the radius of gyration and thedifficulty in stopping the spin.That also can happen if the airplaneis loaded so that the CG is too far forward.If an airplane is modified with aheavier engine and propeller, and aweight is installed in the tail to balancethe airplane, there is real danger of anuncontrollable spin. With those twomasses flying around in a circle theytend to go farther out, thus lifting thenose and lowering the tail, resulting inan unstoppable spin.That very thing happened to afriend of mine when he installed a 300-hp engine in his airplane to replace thelighter 220-hp engine. He had to installa weight in the tail to get the CG with inlimits. During the required spin test. theairplane quickly entered a flat spin fromwhich he could not recover. He hesitatedtoo long before bailing out and had toride the plane down. It crashed on a privatehouse a mile or so east of TeterboroAirport, with the engine going downthrough the kitchen. He survived. Noone else was hurt. There were big damagesto the house and the plane. a NewStandard D-25, was demolished.During the first Florida Air Tour inwhich 42 airplanes participated, one ofthe airplanes was a single-engine, twoplace,low-wing cabin type withretractable landing gear. It was the firstretractable landing gear I had ever seenon a passenger airplane. (There hadbeen one on a racing plane, and ofcourse amphibious airplane. hadretractable landing gears.)That little airplane was built inColorado by the Eaglerock Company. Iwas given a ride in it and it was wonderfulfor its early day. far ahead of anyother airplane. At that time most ai r­planes were open COCkpit biplane types.•Page 8715www. b o nanza .orgABS Nove mbe r 20041