Slow, but skillful: Although the operative word here is ‘slow‘, lazy eights are usually the final VFR maneuver introduced to commercial pilot aspirants. The best way to describe the flight path for one is to say it would be like skywriting the letter “S” (forwards or backwards) on the earth-facing side of a huge cylinder laid on its side in the sky. Another way to describe it is a series of opposing 180-degree turns combined with climbs and descents. Like the chandelle, lazy eights keep you busy! Although flown slowly (read: not aggressively), lazy eights call for a skilled choreography of pitch, bank, airspeed, and altitude — all continuously changing. It is not a figure for aerobatic competition (neither is the chandelle). Its extreme form might be two back-to-back wingovers.
The practical use of Lazy Eights has historically been marginal (it was flown by faster fighters in WWII to stay with the slower bombers). The best reason to perform these so-called “performance” maneuvers other than for the SEL commercial checkride is that they are also pilot performance maneuvers. They make you work — just as important, they make you understand your airplane!
What It Looks Like: Seen from above, the 180s in the lazy eights maneuver would look something like this upper diagram. As with the chandelle, you start with a ‘clean‘ airplane at maneuvering speed (or the manufacturer’s recommended maneuver entry speed), no lower than 1500’ AGL. As with any air work, clear the area first! To help further describe how it’s flown, it helps to look at pitch and bank at 45-degree intervals. (Both the upper figure and the plot beneath are meant to be read beginning from the left.)
I find that the simplest way to visualize what’s going on is with a diagram of pitch and bank vs. heading change, which I’ve here referenced at 45-degree intervals. Each 180-degrees, you’re rolling into and out of a 30-degree bank, greatest at the 90-degree points. Pitch goes up and down twice in that time — highest in the first quarter or turn, level at 90 degrees, max nose-down at 135, level again at 180. In a typical trainer, pitch angles will range between about 15-degrees nose up, to 15 nose down. Altitude, of course, will be changing. However, you’ve got to keep it within 100 feet at all “level pitch” points. (That means between successive 180 degree points 1 & 5, as well as the same maximum altitude at the “#3” 90 degree points.) The PTS says “plus or minus 100 feet” by the way, but that’s most often interpreted to mean that the difference between highest and lowest must be within 100 feet — not a 200-foot swing! The airspeed has to be within plus-or-minus 10 knots (same deal) at all successive similar 90 degree points, as well. At the top (half-way point) of each turn, your airspeed should be about 1.2 times Vs1. The heading tolerance at each 180-degree point is 10 degrees. (If you were to plot airspeed in addition to pitch and bank, qualitatively, it would mirror the bank curves about the X-axis.)
Make It Look Easy: Doing all this smoothly takes some finesse — which is the whole point. Believe it or not, but it’s easier to do without explicitly trying to account for all the defining variables. If you find yourself consistently off, then focus on one aspect at a time in some order that works for you (e.g. match pitch, then match airspeed, then match bank, then match heading criteria…).
By Mastering Details: P-factor is constantly changing, and you’ll need to respond with varying amounts of right rudder — more during the 45-to-90 points when turning right, less when turning left. The PTS tolerances on altitude and heading are explicit, but there is no specific target on the absolute maximum altitude gain, nor of what maximum pitch and bank you can use. (I don’t know anyone who’s taken a commercial checkride in a Pitts S2C, but I’ll bet it could be interesting.) Done right, it’s a tough act to follow. The PTS says “at least two 180-degree circuits”… but there’s nothing to stop you from doing more.
BOTTOM LINE: Sometimes having fun means becoming a better pilot. If you don’t have to fly the maneuver for a checkride, you can still fly it for fun. Set your goals and give yourself time to reach them. Perfection may be unattainable, but patience is not and the skills you’ll learn thoroughly through the second are forever applicable in search of the first.
References:
‘Pilots Handbook of Aeronautical Knowledge’ Advisory Circular 61-23C (1997)
Jeppesen Instrument/Commercial Manual
Commercial Pilot PTS, FAA-S-8081-12A (1997)
telephone conversation with my friendly local DPE
