Some silly screwing around ended with my running the Cub off the runway. Still trying to fully understand how it happened so abruptly. It was dead calm and I was screwing around (obviously for no good reason) with one wheel landings and holding it on one wheel as it rolled out. I've done this before no problem, but this time I let it slow down as much as possible with full left aileron applied, and tailwheel on the ground, until the other (right) wheel fell to the ground. Prior to this, I was rolling straight down the pavement, with very little rudder input keeping it straight. Felt pretty balanced and stable. I admit I let the right wheel fall fairly firmly rather than easing it down.
What happened next was a bit of a shock that I'm still trying to understand completely. As soon as the right wheel came down, while the plane was rolling dead straight without any significant rudder deflection, the plane made an immediate and hard swerve to the right. It did not develop - it was instant as if the right wheel followed a sharp switch on a railroad track as soon as it touched. The plane was so slow that there was very little rudder authority, and immediate opposite left rudder and hard left brake (not that the brakes work great) did nothing. Went off the runway and did almost a full slow speed groundloop to the right in the grass. The right wheel never came up as it went around, and no damage. Not happy with myself at all for letting this happen. First groundloop in a decade of flying tailwheel airplanes pretty much nonstop...and was caused by stupid f'n around.
All I can figure is that as the right tire came down firmly, that the added friction against the pavement caused the hard turn to the right. There was no turning or instability before the tire came down. But even with the added friction of the tire coming down, I can't believe it would have caused such a hard, uncontrollable swerve. The other times I have done this have involved the wheel settling down at higher speeds and a little smoother. Never noticed any swerve at all. Just curious if anyone had any explanations or theories that would shed a little more light.
Aside from it happening in the first place, it bothers me that I was so caught off-guard with no anticipation of such a potential upset in the stability of the landing roll. The Cub has always seemed so laid back and lackadaisical in the landing department, that it came as a shock how hard it bit me. Almost seemed like it became momentarily possessed.
Goes to show that even a J-3 will only put up with so much disrespect. I honestly didn't think I could be surprised by, or unable to handle anything in a taildragger at this point. Boy was I proven wrong...and by a Cub no less! Not to be repeated.
What happened next was a bit of a shock that I'm still trying to understand completely. As soon as the right wheel came down, while the plane was rolling dead straight without any significant rudder deflection, the plane made an immediate and hard swerve to the right. It did not develop - it was instant as if the right wheel followed a sharp switch on a railroad track as soon as it touched. The plane was so slow that there was very little rudder authority, and immediate opposite left rudder and hard left brake (not that the brakes work great) did nothing. Went off the runway and did almost a full slow speed groundloop to the right in the grass. The right wheel never came up as it went around, and no damage. Not happy with myself at all for letting this happen. First groundloop in a decade of flying tailwheel airplanes pretty much nonstop...and was caused by stupid f'n around.
All I can figure is that as the right tire came down firmly, that the added friction against the pavement caused the hard turn to the right. There was no turning or instability before the tire came down. But even with the added friction of the tire coming down, I can't believe it would have caused such a hard, uncontrollable swerve. The other times I have done this have involved the wheel settling down at higher speeds and a little smoother. Never noticed any swerve at all. Just curious if anyone had any explanations or theories that would shed a little more light.
Aside from it happening in the first place, it bothers me that I was so caught off-guard with no anticipation of such a potential upset in the stability of the landing roll. The Cub has always seemed so laid back and lackadaisical in the landing department, that it came as a shock how hard it bit me. Almost seemed like it became momentarily possessed.
Goes to show that even a J-3 will only put up with so much disrespect. I honestly didn't think I could be surprised by, or unable to handle anything in a taildragger at this point. Boy was I proven wrong...and by a Cub no less! Not to be repeated.
