We'd just taken off for the seventh or eighth time when I had the epiphany: My up-until-now lazy feet were over-controlling the rudders.
|Taildragger lesson number three. Allow me to brag that of the 13 landings|
we did, I made 11 all by myself! And two of them were actually good.
Allow me to explain.
During take-off, pilots must account for engine torque and "P-factor," the tendency for a plane to yaw or veer left due to interaction between the propeller's thrust and the airframe. Practically, this means pilots must compensate for a left turning tendency by applying opposite rudder to keep the airplane's nose straight. Yours truly, and a lot of pilots, according to Mr. T, distill this down to: "Right rudder on take-off." (You know, to keep going down the middle of the runway and not barrel off to the left.)
But learning to fly a taildragger has made me consider the reasons for rudder control more carefully.
Up until now, take-offs have been variations on the following: Advance the throttle smoothly, use right rudder to stay on center line, and apply a little back pressure to the yoke so the plane flies off the runway at the appropriate speed.
What was initially the easiest part of flying for me to learn has gotten mighty complicated in the taildragger. Now it's: Stick neutral, advance the throttle smoothly, use rudder control to stay on center line, gently push the nose over/raise the tail, USE MORE RUDDER CONTROL TO STAY ON CENTER LINE, and apply back pressure on the stick so the plane flies off the runway. There's an extra step where the tail comes up off the ground before the airplane lifts off. And, once that happens, the tailwheel that was formerly helping keeping the plane straight is now useless as it hangs a foot or two off the ground.
Mid lesson, I realized that I was trying to take off in the Rans just like I would in the Cessna 182 I normally fly. I remembered right rudder when I put the power in, but felt surprised when after I pushed the nose over, it seemed to kick right aggressively. Taking off in a taildragger requires nimble control of the rudder in both directions.
|Flying the Rans S-7S along the California countryside. |
If you read about my first taildragger lesson, then you know that a taildragger will try to go any which way if the pilot isn't in control at all times. But understanding carefully the forces acting upon the plane makes it easier to anticipate which way the beast will try to move, and thus how to use more accurate rudder inputs. One of those forces is gyroscopic precession, which up until this lesson, I hadn't much considered.
Think of a spinning bicycle wheel or a top. The spinning motion causes stability, which is incidentally why you can ride a bicycle with no hands. When the gyroscope is tilted, however, it creates a force acting 90 degrees from the axis. This is precession. (Check out this video which explains gyroscopes and vectors with visuals.)
In the taildragger, raising the tail tilts the gyroscope that is the propeller. This gets the nose going left even more than normal, which requires even more right rudder to keep things going straight. But once the tail is up and the plane is just rolling along on the main wheels, the right rudder needs to be relaxed since the precession has also stopped. When it's time to lift the nose and get airborne, a little more right rudder is needed as precession becomes a factor once more. See what I mean about being nimble on the controls?
Now this epiphany isn't earth shattering just as my explanations of P-factor and gyroscopic precession aren't technical or in-depth. But! I wouldn't have reached this realization--connecting book read theory to real life experience--so early in my flying career had I not ventured into the world of taildraggers. Thus, I continue to be thankful for this experience and think that every pilot should get a few taildragger lessons at some point.
Questions? Comments? Leave a note below or email bluestmuse (at) gmail (dot) com.
P.S. Big thanks to Mr. T for his editorial help and continued explanations of precession and P-factor and torque. Dinners are always exciting at our house!
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Labels: aerodynamics, airplanes, center line, control, female, Fly Girl, flying, gyroscopic precession, P-factor, personal, physics, pilot, plane, Rans, rudder, student, tail wheel, taildragger, take-off, Veritasium