Whimpy Too (oz6485)

About this Plan

Whimpy Too. Radio control sport model.

Quote: "Whimpy Too is a friendly little fellow, capable of entertaining you with whatever type of flying you want to do. It is honest with no surprises. Whimpy Too by Roger Tennyson.

A lot of air has gone through the prop since I did Whimpy (oz6124) over eleven years ago, and I've learned a lot about flying and designing since then. Sometimes, though, I think that I haven't learned as much about myself as I have about the flying and the designing, and the lessons which brought about the original model have been mislaid or forgotten, over the years, in the usual pursuit of contest wins and trophies. The hobby used to be more fun, but, of late, the constant practice of aerobatics, while challenging and interesting, was becoming the same type of thing at which I spend my work days - and the stress level wasn't much different, either. I was coming home from the flying field in the same shape as I was when I came home from the office.

Nearly everybody at the field stood by to take a turn flying Whimpy that day, and we had a hell of a time. I can't remember a more enjoyable day of flying. Part of it was, of course, the ego trip of having my stuff remembered and appreciated after so long a time, but what was really neat was rediscovering the pure joy of flying, not of flying to impress the judges, or anyone else for that matter - of exploring the parameters of an airplane - of seeing if it would slip, or skid, or whatever - of can you do this? I got so stoked-up that I began designing on the way home from the field.

Whimpy had been designed to have a positive stability envelope. In those days, I needed that, and even now, it wasn't a bad characteristic for an airplane to have. Whimpy would fly hands-off, once trimmed. If I got into trouble, I could always let the airplane do the flying. Go to Plan B: Take your dumb thumbs off of the box. The airplane would undoubtedly do a better job than I was doing. Left alone, the fool thing could absolutely land itself, if the field was big enough.

It turned out that an airplane with a wide stability range wasn't much fun to fly for very long, so after I got bored, I had added ailerons to the original three channel design, and in an effort to exceed the stability envelope, utilized bigger control throws as well as that additional third axis of control.

So now, nine years later, as we experimented with Whimpy's flight characteristics again, this addition turned out to be most fortuitous, because the trailing edge now could be 'reflexed,' ie the ailerons adjusted up at their trailing edges. This did some neat things to the bottoms of the loops, and also delayed the daylights out of the stall. In fact, at full back stick and idle, the aircraft simply mushed happily along, with nary a sign of a wing drop in sight. At this point, we figured that we simply had an airplane with inadequate elevator throw to stall it. Of course, the way to find out if there is adequate elevator deflection is to see whether or not the plane will spin or snap-roll, once rudder is applied. Yes, Virginia, there is a Santa Claus. The little guy spun tightly in either direction! We were indeed able to exceed the stability envelope. We found out something else, though, which we certainly didn't expect. When returning to 'Plan B' (take your hands off the sticks, dummy), the airplane stopped spinning, and pulled itself out of the dive, leveled itself off and happily flew off in whatever direction it was pointed! This maneuver always evoked large numbers of open mouths, gasps, and assorted cusswords from the onlookers, who couldn't believe that they really saw that. If you really want to blow their brains out, start a spin, and then just set the transmitter down and walk away - believe me, that'll do it every time! It began to look as if we could have our cake and eat it too.

And so with the parameters of 'Whimpy One' in mind, I began to think about what I could do to make a machine which would be 'more fun,' while still retaining a lot of those desirable characteristics we so enjoyed in the original model. As there are certain drawbacks inherent in any high wing aircraft, I felt that I wanted to go with a low wing design, providing that I could still retain the general shape and thereby the character of 'One.' I also felt that a powerplant change was in order. I opted to go to a 4-stroke, for the usual reasons (noise, sound, fuel economy, and less mess to clean up), but also because the design had a relatively short nose moment, and it could easily carry the extra weight up front. I chose the Saito .45-II because I wanted no surprises, and we have several fliers at the field who know these engines inside and out, thanks to Ernie Aubert, who taught me to set the valves frequently and tightly (Saito specifies 0.03 - 0.1mm, and supplies you with a 0.1 feeler), and Rico Dalmau who taught me to never underpitch the beastie, I am ecstatic over the engine's reliability and performance. I've got a lot to learn about 4-strokes, so I certainly don't consider myself to be an expert on the matter, but so far I've had great luck. I'm running an 11 x 6 for the short runways, and an 11 x 7 in areas where I don't care about how long the landing run is.

Whimpy Too is not, then, a beginner's aircraft in the sense that it will fly completely by itself, but it's close. You can easily exceed its stability envelope to do all the maneuvers in the IMAC pattern (albeit not as precisely as a ship which is designed to be an acrobatic platform) but it won't snap-roll on final approach if you get a bit slow or use too much elevator, as an acrobatic ship will. You can fly 'Too' when a lot of guys are sitting on the ground, waiting for the wind to quit. Like its older brother, it is a friendly little fellow, capable of entertaining you with whatever you might want to do; it is a thoroughly honest airplane with no surprises. No one who has flown it has felt the least bit uncomfortable..."

Direct submission to Outerzone. Scanning by Don at EAC, cleanup by theshadow.

Supplementary file notes

Article pages, text and pics, thanks to DavidTerrell.

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