For Openers
Editors of model airplane magazines share one "in" experience, in that so many people tell them that, gee, it must be fun to have your job. Some fun. Editors are regarded as literally rolling in new radios, wonderful kits, hot engines, and with little more to do than dash out on sunny days to happily tweak the control sticks. But there are certain advantages. In endless reading of copy and proofs, the white-hat guys are force-fed the latest state of the art, in every category of modeling. The reader may peruse only what concerns him, and skip lightly over the rest. That's a shame. The stuff buried in what all these writers are saying is a mind-boggling accumulation.
For example, Ron Van Putte this month (pg. 21) is deeply into the obscure things that happen when the RC model rolls. We aren't about to meddle with this dialogue between Ron and his erudite readers. Most of us sport fliers aren't on that level, but we will be reminded of strange things we have seen.
Consider the vertical tail. It can be baffling. How so? Well, its size for one thing. It isn't news to say that area of the vertical tail varies with the type of machine, especially in relationship to nose and tail length, and dihedral. It might be huge—see Ken Bates' Windlord (pg. 15), or very small—Carl Goldberg found on his free flights that it could be as small as 4% of the wing area.
Carl also noted, a long time ago, that when wash-in is cranked into the inside wing tip, the model turns in the expected direction only if the vertical tail is big enough, or too big. If it is shy on area, the model can turn the wrong way! This is easily demonstrated. Before Aeronca added a small dorsal to the Champion, the yaw exerted because of the drag of the down aileron required heavy rudder pressure to force the turn. Without rudder, the ship would simply yaw. Keep easing over the stick, say for a left aileron turn, one ended up looking ahead out of the side window!
We all know that too large a vertical tail will make most models drop their noses in the turn—a free flight, for example, may wind into the ground. But it isn't that simple. Oh, it can be "proved." One Wakefield winner used a half stabilizer for a fin. If the model turned crosswind, the wind would not allow the low wing to raise, and down the ship would go. In easy air, the fault was not evident. But when dihedral was added, without changing the fin, performance was perfect regardless of wind.
So when one argues that vertical area is too big, he must ask "how much dihedral?" To be directionally stable, a weight-lifting model requires more dihedral. As weight is increased, so must the dihedral (if hands-off stability is required) go up, and up, and at about 10 to 12 degrees, the machine has to be constantly controlled to avoid falling off—and it can wind in, in either direction, to either side. At this stage a modeler-engineer decreed, "The fin is too big, the ship is dropping its nose in a turn." So the fin was reduced—and the airplane became totally unflyable.
Illusions may be at work—basic laws seem contradicted, but by the time some end point is reached, these will always be verified. A free-flighter added downthrust to correct a power stall, then the model looped—he then believed that downthrust caused stalling. But had he added enough downthrust, results would have been what the "law" decreed.
One may suppose that the downthrust made the ship fly faster, causing more lift, thus explaining the illusion of contradictory results. Jim Cahill once observed that the weaker the power, the more downthrust that is required to correct a power stall. Which can be so!
Evaluating what we see can be difficult at times. Weight was added to the nose of an RC job to speed up a slow glide; but then, a very slight, partial stall occurred. Nose weight was added two more times, and the stall grew worse with each addition. Did adding nose weight make the ship tail-heavy? With sufficient nose weight, the glide was as desired. May we suppose that as weight was added, the ship actually moved faster, developing more lift, making the stall worse? Add slight down-trim to an RC with a flat bottom wing, and under power it may nose down, only to nose up again at higher speed. Does "down" mean up? Keep adding slight elements of down trim and eventually the nose stays down.
Ken Willard tells of adding a small weight off center on a wing, making the model turn the wrong way—by moving the weight more toward the tip, the model was made to turn correctly. It's a matter of asymmetric drag. (Ten bucks says we'll hear from Ken.)
So, having "proved" the dihedral and fin relationship, consider Walt Mooney who has made good flying gas free flights without dihedral! In a forward cockpit he located a huge profile of a comic pilot. Like an auxiliary forward fin, it keeps the nose up on a turn. And in Peanut, the Lacey and the Fike have wings as flat as ironing boards. Impossible, everyone once agreed. (The magic is in adjustments.)
We don't say that these things relate to pattern machines, which is what got us started. Those guys are into really advanced things—do note that Ron Van Putte is into another dimension while talking of rolling flight. We fell off at the last turn.
The serious RC sailplane pilot can appreciate Ken Bates' achievement in the Windlord. There have been flying wings before, but never one quite like this. We first saw it at Toledo, and the hunch paid off handsomely. During the summer of '77, the Windlord won a first, a second, three thirds, a fourth (at the GLSL Championship), and an eighth, 11th and 12th. That fourth in the GLSL was attained in spite of Ken's not attending the last contest. He was second in the rankings up until then. At the Ft. Wayne man-to-man, Windlord maxed on
Continued on page 60 each round, beating out others — including two Open Class ships in a 15-minute round. But Ken could not get it down under an 11-minute max (no points rule on a 10-minute flight). Incidentally, Ken discovered that inverted flight is an excellent way to get the Windlord out of a boomer. So, it has been proved that flying wings can compete successfully in sailplane competition.
Neil Liptak's plans for the Windlord are a collector's item. MA had just about despaired of getting the plans right, when glider-man Liptak came to the rescue. And how nice it was that Al Meyers engaged Liptak to make that magnificent plan (pg. 27) of his Mustang CL Sport-Scale/Stunter. Alas — for us — Neil is about to build a house. He put away his drawing pen.
One guy we would love to fly with is Doc Mathews who recently took over RC Old-Timers from Jack Bolton, whose business travels filled his time. Not only does Doc grind out those wonderful old gassies, but he flies high, wide, and handsome. His enthusiasm would regenerate the moribund. Doc is a 45-year-old family dentist (you can't hurt us anymore, Doc) in a small farming community of 2,000 souls, Galesburg, KS. His wife, Joann, "is a very patient lady." Two sons, Mark, a pre-law Senior, and Bruce, a HS Senior who "thinks the world is shaped like a basketball." Daughter Shelly is a sophomore, an honor student in engineering. Both boys show up at widespread FF contests. Between them, the men folk have garnered a cabinet full of trophies in everything but Indoor.
Doc has been modeling since seven. He first flew an O&R 23 Fireball, got into RC in 1952. An avid competitor, he's been at 11 Nats, and uncountable local meets (within 400 miles). His first OT was a 3-channel Bombshell eight years ago, which he describes as a trainer (many sporting old-timers call these things superb trainers). He likes RC Assist because smaller, close-in flying fields can be used, for not needing complicated launching apparatus, no long walks for retrieval, or the fence climbing we all so well remember. Most of all, he is "turned on by the esthetic purity of model thermaling." Which says it very well indeed.
How often have you heard the word "penetration?" The ability of a ship to cleave through the wind is a prized quality in RC. It is hardly a factor any more in the case of high-powered, heavy, clean, pattern models, or pylon racers. But it is important for much sport flying. In the rudder-only days, from whence the word "penetration" has been inherited, single-channel models seldom could make progress into the wind. They ballooned, and stalled, and galloped, and blew away — often out of sight — as the flier did his damndest. But engine and elevator control have made life half liveable when the gales blow.
Now there is a fascinating letter from Joe Tschirgo (Letters, pg. 6) who is commenting on a Wischer column, making his point that lightly loaded scale models can fly, and win, in the wind. Both gents know what they are talking about, so it isn't a question of "you are wrong, I am right," but one of viewpoint. No one is wrong (and we expect Bob will be talking again on this question).
What tickled us was Joe's general assertion that it is a fallacy that light models can't fly in the wind. Big, small-engined load carriers flying empty (like 6- to 8-ft. on an .09/.15) have bested the wind. Ground turbulence might require quick stick work with a lightly loaded model to stay on an even keel, but once up, they can bore smoothly into the wind. Proper balance and trimming, plus elevator trim control allow; but if you crank too much positive into a stab to compensate for wind, decalage is decreased, sometimes to the point of reaching a negative pitching moment. In other words, that stab is less effective in countering increased wing CL with increasing angles of attack, and will stall before the wing. This isn't to say that a light airplane is desirable for wind, but don't mumble that it can't have penetration. Tschirgo may be the first to dare say so.
The recent AMA membership renewal period witnessed a 20% increase in the number of Open members who take Model Aviation. So for the second year in a row, MA has increased its readership by a significant amount. Over 75% of the AMA adult membership now take the magazine. No member is required to subscribe to MA. Every member has the option of declining the magazine, or subscribing to it. Each who opts for it pays the full subscription price because he wants the magazine. We are pleased that so many people find the contents worthwhile. Thank you.
Transcribed from original scans by AI. Minor OCR errors may remain.
