Viper (oz4974)

About this Plan

Viper. IC Pattern plane. American Aircraft Modeler, January 1973.

Quote: "The 1972 Toledo design and finish winner is a state-of-the-art pattern ship. Fast, predictable, and smooth even in gusty winds. It is a model for the expert builder and flier.

The word 'intention,' according to Webster's 'often applies to little more than having an idea in mind, or the will to act or do a certain thing. With this in mind, it would seem that most modelers are inherently blessed with all manner of 'good intentions/ideas.' In most cases, the only catalyst required to convert these intentions into reality, is simply ample free time applied towards the varied types and numbers of model subjects in mind for the future.

More often than not, we do complete some of our model-intentions. Some require the passing of more time than others before completion. Then there are those which are just passed over due to the advancements in the State-of-Art, or forgotten over the years. I have dropped a few intentions along the way, as most of us have. On the other hand, I have managed to complete some which date back a few years. Recently, for example, I completed an intention of twelve years - that of restoring a full-size aircraft. Today I am the very proud owner of a classic 1947 Stinson-Voyager, N-12-DB (Best Stinson Classic, 1971 EAA Convention). The original intention was easy to come by; the time for actual restoration was sumpin' else. The model presented here, though a new design, is really the completion of another intention that dates back to 1969.

Ostensibly, Viper began as only an intention while completing the research covering the North American P-51 Mustang for an ultra-scale model (another good intention). As so often one project is shelved in lieu of another, so went the Mustang. My scale deHavilland Hornet took its place, as did the Stinson restoration project. The Mustang remains shelved, but that intention is the prime contributor and factor of this design.

Obtaining the airfoils and sections employed on the Mustang was a feat in itself. Once accomplished though, these laminar flow designs really turned me on. I became intrigued by the rather unusual curves and reflexes of these high-speed sections. Thus Viper-intention began. Someday I would experiment with these sections on a non-scale design, or at least before completing the Mustang.

There were many long discussions about this project with other modelers. Seldom, if ever, were there any encouragements. Many had doubts and fears. The laminar-flow sections almost became more challenge than intention. Certainly obvious was the fact that a non-scale design would provide the best test vehicle in the least amount of time. My next pattern design would begin around these airfoil sections.

Undoubtedly, from the onset, there could be more gained than lost in the experimentations. If the sections proved to be another bag of worms, the test model could always be fitted with another wing - a small price to pay should it someday save the early demise of the still intended Mustang. Needed then was only the free time to begin. Sound familiar?

Inadvertently, as accidents occur, three fractured fingers left me with all sorts of time late in 1971. This period was not what I'd consider 'good time,' but I was grounded and idled. So I began the roughest of unnatural, lefthanded sketches for Viper. Now there was time to incorporate new ideas and methods into those older one's learned through experience.

The only design parameters that can provide the exacting performance required of our pattern competition models are those found by the tried and proven methods. This will include many hours of testing, modifying and testing again. Reynolds Numbers, lift-drag ratios/coefficients, scale effect, etc have little effect on RC as we know it today. Designs based upon these terms generally turn out poorly.

About the same results can be expected of the 'Averager Design,' a phrase coined recently by one well-known RC editor, in which the averages compiled from some sixty-odd good models are used in achieving the ultimate in design. However, when employing average design methods, one should expect an average, not ultimate, model. Averagers can only lead to averages! Those items or combinations of items which perform well for one model seldom, if ever, perform well in combination with another set of conditions. I am not proposing that all designs begin on a hit-or-miss basis. In the Viper, other than the laminar-flow sections, combinations known and learned through experience were the only guidelines. Inspired by the new wing sections, it lead to some newer approaches toward the overall design. The six available weeks helped, too. The completion of the drawings and the arrival of New Years Eve, 1972 were simultaneous.

The Toledo Conference was but 56 days off as the first balsa sheets were cut. Things went along smoothly even though some of the construction techniques were slightly unorthodox (foam ailerons), in an effort to maintain alignment and retention of the laminar sections. This Toledo-bound model was first presented, unpainted, at the January meeting of the Milwaukee Flying Electrons, nine days after its start. It was not alone - another member also displayed Viper Number Two the same night. The old doubts and fears were more in evidence that night than the models themselves.

Of the remaining 47 days before Toledo, 37 passed during the final assembly and finishing. Five more days passed for the display stand, leaving four days for some needed arm resting before the long drive to Toledo. Friday night in the Rec-Hall Viper made its formal debut, as yet, unflown!

The model stirred more than just casual interest. I noticed the apprehensive faces of the onlookers, who were aware of its distinctive airfoils, knowing it still was earthbound. My spouse, who was in charge of babysitting my models, began to have her own doubts of the venture, after overhearing the comments of the viewers..."

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