MAR 2015

Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.

Issue link: http://experimenter.epubxp.com/i/471466

Contents of this Issue


Page 36 of 36

EAA Experimenter 37 deliberately low, the opposite can happen when the prop acts like an air brake. Avoid practicing deadstick landings at public airports that have traf c. Even if you can hit the spot every time, it's disrup- tive for other pilots when you fl y steep close approaches. Never do deliberate engine-of landings to a runway only wide enough for one airplane. Even if you are self-announcing on the radio, another aircraft may appear low on fi nal approach. Worse yet, I have had an aircraft taxi out and begin a downwind takeof after I announced on the radio and stopped the engine. Fortunately I can do an in-air restart most of the time, and the runway had plenty of room for me to land in the grass alongside. Begin each practice session with an idle power approach even if the conditions are safe for engine-of landings. It pro- vides a chance to check out the actual wind conditions, aircraft performance, instruments, and the nut holding the stick (the pilot). I learned it the hard way. I had completed a series of engine-of landings the previous day and was anxious to resume some testing. The wind sock was hanging straight down that morning, so I blasted of the same direction as yesterday, climbed quickly to 1,000 feet, and confi dently shut down the engine. Something looked wrong immediately. I suspected trim speed or airspeed error and worried I wouldn't make it back to the run- way. I was crawling along on downwind and losing altitude fast. The base leg drift revealed the wind had changed from yesterday and everything above 200 feet was blowing the other way! I made a downwind deadstick landing, went very long, and barely got it stopped at the far end with inches to spare. IT'S NOT A GLIDING CONTEST In a real emergency when the engine quits in fl ight, slow down to best glide speed and pick a spot you can reach easily, but don't think of it as a gliding contest. Never try for anything at the margins, because landing short is unacceptable. As soon as the target is selected, increase the speed to slightly faster than best glide. When fl ying at best glide and coming up short, anything you can do makes it worse. If you are a little faster, you might be able to stretch the glide by slowing down. The faster fl ying speed also reduces the displacements caused by turbulence and thermals. I prefer to fl y the entire approach at a constant airspeed so I have consistent glide performance and a good platform for observing ground drift. Success depends entirely on where you make the turns. It's not a gliding contest. My essential tools for practicing engine-of landings are an altimeter set to the surface, a clock, and established sight lines. Practicing from a standard altitude establishes the ideal height at every point in the approach. A stopwatch on the descent gives additional information. The average glide time from 1,000 feet in a contest is about 90 to 100 seconds. We start directly overhead, but you can begin anywhere. The halfway point even with the target on downwind is my fi rst important benchmark where I should still have 600 feet. Established sighting points on the airframe help to set the desired angle downward to the runway at midpoint and on the turn from downwind to base leg. Once on base leg, you adjust or play the turn to fi nal to hit the target. Don't be bashful about extending base leg beyond the runway centerline if you are too high. If you never have to extend the base leg, you are either very good or perhaps cutting it too close. With practice, engine-of landings are easy if the wind is calm. Wind gradients, sinking air over cool marshes or green fi elds, and gusts that halt your ground speed help to make it a mental challenge. In a real emergency (or a contest), an engine-of landing may be required in strong crosswinds, or strong headwinds, and in either direction. Pilots of side-by-side aircraft should consider how well they can perform engine- of with a right-hand landing pattern. I thought practicing in winds up to 15 mph was enough until I had to do one in France in an honest 18- to 20-mph straight-on headwind, with gusting. It was humiliating to be 200 feet short, but I had some com- pany. All gliding practice in strong conditions should be at idle power for safety, and keep the engine ready to go. TOO HIGH ON FINAL You should always be too high after turning on fi nal approach. Regardless of pilot skill, bad things happen on a deadstick fi nal that can't be fi xed. The fi nal glide should be a short, getting- rid-of-altitude contest. It needs to be long enough to identify the likely landing point, dump any excess altitude, and then complete the touchdown. Any major FAI microlight engine- of competition will provide an amazing display of slips, use of fl aps, spoilers, S-turns, parachute turns, and trike bar pumping. Almost everyone starts high and then skillfully sheds altitude. A few may arrive very high and do multiple S-turns of the end of the runway until it looks right, though contest rules tend to discourage the practice. They do this because in contests and in real life, coming up short is unacceptable. To pen a phrase, "The ditch in front of the runway is a mortal threat, but the ditch at the far end will only scratch the paint." Contests are commonly scored based on the actual land- ing spot (after any bouncing), though occasionally stopping distance is rewarded. A wheel-type landing with extra speed works best. When the target is made for certain at about 50 to 75 feet of altitude, drop the nose and descend smartly into ground ef ect. Skim along 1 or 2 feet of the ground with good control, plant it when the chalk line arrives, and enjoy your gold medal. Gliding down slowly and hoping for the best is less predictable. Dropping low and skimming can also help to gain a little distance in strong headwinds when raising the nose will make things worse. I hope you enjoy some careful gliding experiments. May your emergency landings be in your favorite direction, and may you always be high on fi nal. Please send your comments to dangrunloh2@gmail.com . Dan Grunloh, EAA 173888, is a retired scientist who began fl ying ultra- lights and light planes in 1982. He won the 2002 and 2004 U.S. National Microlight Championships in a trike and fl ew with the U.S. World Team in two FAI World Microlight Championships.

Articles in this issue

Links on this page

Archives of this issue

view archives of Experimenter - MAR 2015