Phoenix 5 (oz7774)

About this Plan

Phoenix 5. Radio control pattern plane, for .60 power.

Quote: "As maneuver and radio requirements changed, this eight-year-old design has undergone continuous development. A great flyer. Phoenix 5, by Don Lowe.

I designed the Phoenix (oz5864) to meet a need for something different and beautiful, as well as for aerodynamic advantage - thus the swept-wing design. Other requirements were good rough air stability, equal stability upright and inverted, and being groovy (whatever that means). Having fulfilled those prime objectives in 1963, the Phoenix design has been refined ever since.

The early configuration was an advanced design concept for accomplished modelers and never was intended for the beginner, although many Phoenix 1's have been built and successfully flown by the novice. As with all highly-swept wing designs, the stall was a little nastier than a straight wing, but certain features, such as a 17 to 19 percent root to tip wing taper for softening the stall, were incorporated. Some say swept-wings are too nasty to fly, but I feel any experienced flier who can recognize a stall condition and can handle a Taurus (oz612) or Kwik Fli (oz6526) can safely fly the early Phoenix design. For those less accomplished or for the advanced flier, the present Phoenix is easy to fly and has stall characteristics second to none!

Over the years, the design has had many modifications, such as varying sweep from 12 to 25 degrees (per panel); raising wing and lowering thrust line; changes in nose and tail moments; changes in wing section and area; changes in fuselage profile, offset thrust, etc. The Phoenix 5 is designed primarily for best performance in the AMA and FAI patterns, and no weaknesses in executing current competition maneuvers (including snap rolls) are apparent. (See chart for chronology of the Phoenix design evolution.)

Phoenix 2 and 3 basically explored the effect of sweep variations. Primary findings indicated that increasing sweep may improve lateral stability but hurts performance in pitch. Increasing sweep also hurts performance for the wingover or Figure M, since it decreases the tail moment - unless the fuselage is lengthened or tail area increased considerably.

Phoenix 4 was a move toward the AMA 'grab-bag' maneuvers where high maneuverability and snap rolls were required. The airplane also was made smaller to increase speed. The faster they fly, the more impressive they are, and the better they roll. (Ever watch a Formula I or II do axial rolls? Beautiful!) A switch to a symmetrical airfoil improved the outside, and reduced sweep made it more docile and helped pitch and yaw. Results were gratifying. The Phoenix 4 was very fast, yet had terrific slow speed characteristics. The airplane also knife-edged extremely well, even without the wide fuselage.

Phoenix 5 employs the successful Phoenix 4 wing. The nose moment was increased to improve looks; and the tail moment was increased to help pitch and yaw. The horizontal tail was lowered and the wing raised to get thrust, and to get the wing and tail more in line. Fuselage depth was increased to help knife-edge and all rolling maneuvers. Results? As far as I'm concerned, there isn't a better airplane around. A number of good designs are available and can win, but the big difference these days is the pilot.

My present fixed-gear Phoenix 5 with Marvelite-covered foam wings weighs 7 lb. My son's ship with cardboard-covered foam wings weighs 7-1/4 lb. Another Phoenix 5 with fiberglass fuselage, balsa-covered foam wings, and retract gears weighs 8 lb. This one is extremely fast and is not nasty, but it does land faster than the 7-lb. model. Seven lb is about the best flying weight, since the airplane is good in a wind, lands easily and flies through the manuevers easily with a good 60 up front.

Construction: Only a few construction details need discussion, since |I believe in structural simplicity..."

Supplementary file notes

Article pages, text and pics.

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