Centurion (oz7803)

About this Plan

Centurion. Free flight power model from 06-66 Flying Models magazine. 1965 FAI winner at the Nationals.

Quote: "1965 FAI Winner at the Nationals. FAI Centurion, by Roger Simpsons

The Centurion was my first try at an FAI power model with elliptical surfaces. Other modelers claimed it made a cleaner model which should be faster in the climb. I was curious to find if such was the case, as no matter how good the model you are flying, something can be done to make a better model.

I decided to design a new model with elliptical surfaces, as the model I was flying had been developed just about as far as possible in regards to its climb, without changing its layout, moment arms, airfoils, etc. Also the glide was good but one is always looking for some way to improve it.

The model would have more total area than my previous design (600 square inches projected, instead of 570), slightly different airfoils, and less dihedral in the wing. These three changes I believed would improve the glide. I used a shorter tail moment as the new stab would have a much higher lifting airfoil and too long a moment arm with the planned airfoil could result in a disasterous over-the-hill climb or prolonged pullouts.

The model was first flown in March 1965. I can't say the model flew per-fectly from the start. I didn't have enough left thrust in it for its first flight and it went straight up and straight back down to its right. After I repaired the fuselage and put in an-other washer increment of left thrust I got it flying pretty fine. More flights resulted in taking out some incidence and adding some downthrust to achieve the straight-away climb I use.

After I got the Centurion trimmed out, it has been a very consistent model. Flying in Air Force competition, you fly in all different parts of the country. The model was trimmed out here in California, flown in two Air Force contests in Texas, where it placed first in one and second in the other. It was then flown at the Nats at Willow Grove NAS, Pa., where I won 1st in Open FAI power for the second year in a row. Back home again here at Sacramento, I flew the Centurion in a NCFFC contest on Sep-tember 19th and set an AMA record of 34 minutes 45 seconds. In as much as most of the design features incorporated into the Centurion were aimed at improving its glide, plus the fact that it is a larger model, I believe the model is quite an improvement over the previous design, as it climbs as high, if not higher, and certainly out-glides it.

Construction. Wing: Be sure you use spruce for the spars, as you will need the strength it gives, and the same thing applies to the use of plywood for the dihedral braces. The tips can either be laminated..."

Direct submission to Outerzone.

Supplementary file notes

Article pages, text and pics.

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