Friday, January 19, 2007

Teaching the Chandelle -- It works in the sim too

The chandelle is one of the maneuvers in the single-engine commercial flight test. It is a maximum performance 180°climbing turn and was developed during World War I by French pilots. They would fly to enemy ground troops and toss their bombs out of the cockpit, and then perform the chandelle in an effort to avoid ground fire.

The maneuver is divided into two parts. During the first half of the maneuver, through 90° of heading change, the bank angle is held constant, and the pitch is slowly increasing. During the second half of the turn, the pitch is held constant and the bank angle is slowly rolled out. The graphic attempts to show the changes in the maneuver, where the gradually darkening magenta represents the increasing pitch, and then held constant during the second half, and the same for the changing bank angle, represented in blue. It is steady throughout the first half and decreases throughout the second half of the maneuver.

A road that is parallel to the wind serves as a good visual reference for teaching the chandelle. Fly towards the road at normal speed. When you cross the road, quickly turn into the wind, rolling to 30° of bank angle. Then simultaneously add full power and start to pitch up. At the 90° point in the maneuver you will be parallel with the road. You should still have 30° of bank angle and to have reached the maximum pitch attitude. During the second half of the maneuver, hold the pitch attitude constant while slowly rolling out bank angle. When you cross the road again, now in the opposite direction, you should have rolled to wings level and be just above a stall. Complete the maneuver by slowly lowering the pitch attitude to regain your airspeed. Lots of right rudder is needed during the second half of the maneuver, and at the 180° point, all of those left turning tendencies will be in full force.

In teaching the chandelle, I see two very common errors. The most common is uneven roll out of bank angle. The tendency is to keep most of the bank angle in until you are through about 170° of turn and then roll it out all at once. The second most common error is not maintaining the pitch attitude. It takes increasing back pressure to maintain it, and the tendency is to let it flatten out. How much pitch attitude is needed? That varies from plane to plane, and you just have to experiment to find out how much is needed to give you the desired airspeed at the completion of 180° of turn.

Because uneven bank angle roll out is such a common error, I teach the chandelle in two parts. The first part is simply learning to manage the bank angle – don’t do any of the pitch and power changes. Start on a cardinal heading and quickly roll into a 30° bank angle. When you have completed 90° of heading change, start slowly and smoothly rolling out the bank angle. As a guide, at 120° of heading change, you should have about 20° of bank angle. At 150° of heading change the bank angle should be down to about 10°. Practice this until you can handle the roll-out smoothly. The last 10° of roll out feel like you will never get the plane around to the desired heading, but it will happen – just very slowly. When you have the roll-out under control, you can now add the pitch and power. Just be sure when you do the complete chandelle that you make the quick roll to 30° of bank angle first, and then add power and start the pitch change.


Today for the first time I actually taught the chandelle in the sim. It would not have occurred to me to do so in the sim, but I had a request from a CFI student to go over them in the sim. First I watched him do the maneuver, with it set to VFR conditions and configured as a C172. I saw the same mistakes that I see in a plane. So we did the two-part learning process. We worked strictly on bank angle management until he had that down pretty well. Then we added the pitch and power. We only spent 0.8 hour in the sim, but at the end of that short session, he was doing much better. The airplane would never have been that efficient. Now on Sunday we’re going to tackle Lazy 8’s in the sim. This should be fun!


Linda said...

I conquered the chandelle maneuver to CFI PTS in .8 hours in the simulator,
based on past performance it would have taken about 3 hours and over 525.00
in an airplane, weather providing to do what was accomplished in Linda's
sim. Thank you and nice work.


john said...

Thank God you're back. I read your earlier Blog enties avidly. I always found some useful tidbit.
I sorely missed your blog. Can you put your older entries on yor archive list. please do.

Linda said...

Thanks for the compliment, John. I will work on restoring the older entries.


Max said...

Why learn the chandelle? I'm not working toward a commercial ticket right now, but might someday and would like to know why it is necessary. Thanks anyone.

Linda said...

Max, the only real answer I can give you as to why you learn to do the chandelle is because it is required on both the ASEL Commercial and ASEL CFI practical tests. The same question could be asked as to why learn to do lazy 8's or 8's on pylons? Because you have to do it on the practical test. All of these maneuvers teach the pilot coordination, smoothness of control inputs, situational awareness, and division of attention.


Dad Smith said...

The chandelle can also be used to get yourself out of a tight spot when Mountain flying! (best to stay our of tight places though).

snoboy 58 said...

Outstanding lesson Linda. Thank you. I can't wait for the 8s on Pylons lesson.