KRIERS CLIPPED CUB
KRIERS CLIPPED CUB
Harold Krier 'Clipped' 1941 Piper Cub initiating a 'hammerhead' turn over the Kansas countryside.
To 'clip' a Cub, there were several changes that had to be made, the most significant was to take the inner forty inches of the wing off, thus the 'clipped' part of the name. This improvement made the airplane roll much faster and handle much higher 'g' loading for aerobatics while having the expected performance detriments that one would expect.
Harold Krier, a Kansas native and renowned aerobatic pilot who tragically lost his life when a parachute failed to deploy during spin testing on an experimental design in the 1970's started his aerobatic career in 'clipped' cubs. He built two of his own, and this was one of them.
The 'Hammerhead' is a classic and seemingly easy aerobatic maneuver that is performed regularly with additionally twists thrown in from time to time. It does however have its little quirks, and if not performed correctly can end in some surprising unusual attitudes. First set your upline looking out to the left wing to hold it straight up vertically. Your airspeed will of course slow rapidly as the ever present force of gravity begins to take over. You know the time is right when you can hear the fabric of the fuselage start drumming and the controls quickly get a soft muddy feeling. You then quickly but smoothly apply full left rudder while simultaneously adding full right aileron and forward rudder to counter act the torque of the spinning propeller as depicted in the illustration above. Wait too long and you'll start going backwards. Don't apply enough elevator or aileron and you could end up spinning inverted. But, do it all right and you end up with one of the most thrilling maneuvers that I think is in the books. The nose falls through the horizon, you set the same vertical downline and your airspeed once again quickly builds with the RPM's of the propeller. Gently and smoothly ease back on the stick and you are once again flying on the horizontal axis, ready to pull up to the vertical to do it all once again... fun. The first time you do it solo is a right of passage.