Radio Control: Soaring
Byron Blakeslee 3134 N. Winnebago Dr. Sedalia, CO 80135
Byron Blakeslee's column continues this month with the reprint of "Landing With Flaps" by Bob McGowan:
Landing With Flaps — Bob McGowan
Going by reader response, "Tips from the Experts" is the most popular material in the column. This month we are indeed fortunate in having a super article from the Master — two years in a row! As Don McColgan described, Bob won the 1991 Masters over a very impressive roster of expert pilots. Typical of contests where most pilots have no trouble getting flight times, the Masters was won with consistently high-precision landings. Bobby flew his Standard Class Falcon 800, which he prefers because of its outstanding landing characteristics. Bob's article first appeared in the Diablo Valley S.S. newsletter (Greg Vasgerdsian, editor).
I think it's safe to say that trailing-edge flaps have replaced spoilers as the method of landing control preferred by most contest pilots. Oh, there are still a few die-hards out there who have not been convinced that you can be consistent with flaps, but their numbers are shrinking.
Making the transition to flaps for a veteran spoiler flier is a frustrating task. They're opposite in nature. A completely new landing style must be learned. Unlike spoilers, flaps help by slowing the glider down — often too slow.
If you are in the process of learning to land with flaps, you are probably making some of the best landings of your life, with the plane practically hovering up to the spot and settling in. Unfortunately, they are probably mixed with landings that fall embarrassingly short of the landing circle. Don't worry; consistency will come with time.
Full-size sailplane pilot and modeler Bob Wakerly taught me the secret many years ago. He said, "When your flaps are out, keep the nose pointed at the ground." It's a simple rule. Follow it and you will find it to be the key to consistent landings. That's really all you need to know, but I'll elaborate just a little further.
You have to remember that with the flaps deployed your wing has more camber and its stalling speed is reduced. You can now fly slower than is possible with the flaps neutral. This is where you can get yourself into a no-win situation. You may need to retract the flaps to avoid landing short... but you know that if you do, the plane will stall out instantly. To avoid this problem, keep the nose down and don't go slower than your plane could fly with the flaps neutral. It's tempting to go slower, but try to resist getting super slow until just prior to touching down. Don't underestimate the importance of keeping your speed just right throughout the whole approach pattern. Flying speed is every bit as important to a controlled landing as altitude.
There are as many styles of approach patterns as there are pilots. I'll describe the one I use to give you some ideas. It's tailored to my flying style and the capabilities of my equipment: the Flite Lite Composites Falcon 800 (Standard Class) with an Airtronics Vision 8SP radio. The main thing is to fly the same approach — one that works for you — every time.
I like to see my Falcon come over my shoulder and begin the downwind leg at 20 seconds to go. At this point I'm about 60 feet high and have half flaps deployed (about 45 degrees). At around 13 seconds to go (depending on wind conditions), I begin a 180-degree turn and line up on final. At this point I find it very helpful to get the fuselage precisely aimed at the spot and level the wings. Now I lock it on course by using the aileron-coupled rudder to keep the wings level. This is done quickly and gently so heading problems are avoided before they occur. The Falcon comes in on rails.
On final I work the flaps between half and full and adjust altitude, speed and approach timing. The Vision's automatic flap-elevator compensation is set to keep the nose pointed down, so the elevator stick remains neutral. If I'm way too high, add down elevator. With full flaps, dive away excess altitude and resume a normal approach angle. Try to leave enough distance to the spot so you have time to bleed off excess speed. If on final approach you look way too low, retract the flaps a ways. Leave out a little to help avoid the possibility of stalling about 25 feet above the spot.
If three feet high, start to level off and begin the flare. Allow speed to drop almost to the stall. If you haven't already, deploy full flaps now. Just right — instant — a foot or less off the ground, jab the down stick. Simultaneous flap retraction puts the nose right on the spot.
Although a little off subject I'd like to mention crow function. Both ailerons deflected up may be used independent of flaperon mix for maximum versatility, or coupled with flaps for simplicity. The more crow deflection you have, the higher the sink rate. Some people like as much as 45 degrees. I have my Falcon set to couple about 1/4 inch of crow to 90 degrees of flap. This small amount has only a subtle effect so I can still float it in as if I had flaps only. It's just enough to keep from floating excessively — and right past the spot with full flaps deployed.
With my Vision radio, reverse aileron differential is switched in automatically. This still allows the down-going aileron to deflect below the wing despite the fact that the neutral point is slightly above the wing in crow. This helps maintain maximum roll rate which is critical on landing approach.
One last note on control setup. Make sure you have lots of down elevator throw. You'll find that the typical amount needed for normal flying will not allow the fuselage to rotate downward very quickly with 90 degrees of flap application. I have the elevator end-point adjustments on the Vision set to give me twice as much down as up.
Just to add a bit to what Bob said about crow, I have always thought of it as the combination of flaps down and ailerons up. If your glider has ailerons and flaps, it's most effective to couple them together for optimum glide-path control (assuming, of course, you have a Vision, X-347 or similar computer radio that can do this trick). However, some gliders have ailerons but no flaps or spoilers. Many F3E and other electrics are set up this way. In this case, up ailerons (half crow) are the only means of speed braking.
That's it for this month. Send questions or comments to:
Transcribed from original scans by AI. Minor OCR errors may remain.
