The following stories from the March 23, 2007, edition of AOPA ePilot were provided to AOPA members who expressed an interest in the particular subject areas. Any AOPA member can receive information tailored to their areas of interest by updating their preferences online.
My ePilot – Student Interest, Training Tips
MAPPING THE POWER CURVE
Performance charts in your trainer's pilot's operating handbook reflect results of test flights in your make and model aircraft. Student pilots study the airspeeds, power settings, and configurations the charts say to use in various flight phases. One of the most educational lessons you can have is to create a performance diagram. This diagram will tell you just what level-flight airspeeds to expect at the various power settings. And it will show you the airspeed at which your airplane is flying at the angle of attack (AOA) that produces the maximum lift for the total drag created—known as L/D max. The result will be a graph resembling the total-drag curve in Figure 3-5, Chapter 3 of the Pilot's Handbook of Aeronautical Knowledge. The chapter notes: "If the airplane is operated in steady flight at L/D max, the total drag is at a minimum. Any angle of attack lower or higher than that for L/D max reduces the lift/drag ratio and consequently increases the total drag for a given airplane's lift."
On your next dual lesson, take along a pencil and a pad to come up with a power curve for your aircraft. In the same exercise, explore how your aircraft behaves when flying "on the backside of the power curve," an expression you may have heard. Here's what to do, wrote Larry Randlett in the January 2002 AOPA Flight Training feature "Behind the Power Curve": "Trim the aircraft for level flight at a given power setting. Write down both the airspeed and power setting. Then reduce your airspeed in 10-kt increments without changing your altitude and continue to record airspeed and power settings. Eventually, you will reach a point at which more power is required to maintain a slower airspeed. You are now officially 'behind the power curve.' Once you know you're on the back side, push the nose over and observe what happens. Then raise the nose and make some similar observations."
An aerodynamic point to remember: On the backside of the power curve, it is induced drag that increases rapidly with increased AOA. Check out "Flying Forces" on AOPA Online, in which AOPA Pilot Editor at Large Thomas A. Horne discusses the types and effects of aerodynamic drag.
My ePilot – Training Product
SHORT VIDEOS FOR ON-THE-GO LEARNING
For those who like to have something to do while waiting in an airport terminal or a doctor's office, add CFI Jason Miller to your list of downloads. Miller, creator of The Finer Points series of aviation audio podcasts, has produced several short subjects in high-definition video. The focused content is available in 5- to 15-minute segments. Subjects so far include Class C and D airspace communications, as well as segments introducing you to an airplane's flight controls and systems, and paperwork. The downloads are $1.99 each and are available at the Web site.
Note: Products listed have not been evaluated by ePilot editors unless otherwise noted. AOPA assumes no responsibility for products or services listed or for claims or actions by manufacturers or vendors.
My ePilot – Student Interest, Final Exam
Question: With daylight-saving time starting earlier in the year than it has in previous years, I plan to take advantage of the additional daylight to schedule my lessons after work. If by chance I have a flight that doesn't end until after dark, how do I determine how much of my flight time can be considered night when logging my time?
Answer: FAR 1.1 defines "night" as the time between the end of evening civil twilight and the beginning of morning civil twilight as published in the American Almanac converted to local time. For the purposes of logging time, you will need to determine when evening civil twilight has ended in your specific geographical area. The U.S. Naval Observatory has a helpful sunrise/sunset calculator that calculates the exact civil twilight starting time for any location in the country. For additional information on this subject, see "Pilot Counsel: Night Flying and the FARs" in the October 2005 AOPA Pilot.