Good Morning,
It's snowy here in Northern California so I thought it would be a good day to catch up on my recreational reading and the first magazine I picked up was Plane&Pilot. As I read an article by Budd Davisson entitled 'SPINS' it occurred to me that I had read some dangerous misconceptions about coordinated turns in posts under the "Would This Concept be Legal" thread.
It seems that some pilots were talking about the use of rudder only for making turns in some situations, which can be done, but not without understanding there can a good deal of risk involved, especially at low altitudes. One post even stated that the rudder only turn was used to avoid "loss of lift" and this is wrong. Since I'm not a wordsmith I'm going to quote Budd on this subject;
"The very fact that the airplane is in a turn raises the stall speed, BUT CROSSING THE CONTROLS SPOILS SOME LIFT AND FURTHUR INCREASES THE STALL SPEED. So, even if the nose stays down, the margin between you and stall speed has decreased. Furthermore, because of the decreased lift, the nose wants to go down, so some back pressure is applied to keep it from falling. A really bad situation is in the making!"
Airplanes turn because bank angle causes the wing to "lift" you in the direction of the bank.
When you are making a coordinated turn, the rudder is used to match centrifugal force and bank angle so that for all practical purposes, what you FEEL (the sensation on your butt) is like level flight with an increase in G-force, or the same sensation as climb initiation.
I used to demonstrate spins to my primary students (if they wanted--I never forced them) and I usually did this in a base to final configuration with at least 3,000 AGL so they see how much altitude was lost (usually about 400 feet) before recovery even though we were anticipating the stall/spin.
Most were impressed at how low the nose appeared to be on the horizon at the stall and how fast the airplane snapped over the top into a spin.
I highly recommend getting your hands on a March 2006 Plane&Pilot and reading the article. I would love to see further illumination and comments by anyone interested.
Jim
