From our very first, a very important part of Backyard Flyer (now Electric Flight Magazine) has been our “Homebuilt” articles where we feature scratch-built RC aircraft designs that our readers can build. The model designers who produce the working plans and develop the models put a great deal of effort into their final products. Pat Tritle of Pat’s Custom Models is no stranger to Scratch Building and we’ve featured several of his lightweight, electric-powered scale planes. When he submitted his newest plane, the Fleet Biplane, (article and plans coming soon!) we asked him to fill us in on the back story.
(Above) Pat Tritle is a talented and very busy model airplane designer and builder and flyer. He blends oldtime stick n tissue construction techniques with modern day CAD and laser technology to bring the hobby great new designs and short kits!
The Fleet Biplane is a classic Golden Age biplane. What about it did you like enough to choose it as your next design?
Pat Tritle: The Fleet Trainer has always been among my favorites in the biplane realm, and has been on my design “short list” for a long time. Scale monoplanes have been growing in popularity, so to change course a little, I figured the Fleet Biplane would be a welcome diversion. The main thing about the Fleet is that it’s a good flyer, both in full scale, as well as a scale model. This one definitely lives up to that reputation.
While designing your RC version, was there anything about the scale design you needed to change? Why?
PT: My Fleet was designed exactly in outline to the full-scale 3-view drawings that I used, right down to the airfoil-shaped horizontal stabilizer and the relatively small vertical tail. The bottom wing’s dihedral is scale. Even the wing’s airfoil is nearly scale in outline, though the bottom was flattened a bit to make it easier to build. I also reduced the number of wing ribs to lower the parts count and to help keep the airframe weight to a minimum without sacrificing structural integrity.
What are the most important things a design has to have for it to be really successful?
PT: There are two ways of looking at what makes a design “successful.” One is from the standpoint of sales and marketing. From that angle, for a kit or scratch-built plan to even stand a chance in the marketplace, the subject matter has to be well known and the full-scale airplane has to be reputed to fly well. The Fleet has both. The other is that the specific design has to prove itself well to be a good flyer. When it does, word travels fast.
When it comes to designing a nice-flying model, I think that for park-flyer types like the Fleet, flying weight is without a doubt, the most important factor. When building a slow, gentle flyer that is well behaved and can be easily flown in relatively small parks and flying fields, a light wing loading is absolutely essential.
There are also some tradeoffs in that a lightly loaded model can’t handle the same windy blustery conditions that faster, more heavily loaded models can. But for those cool mornings and calm evenings, making laps around the patch, or shooting landings at scale speeds, a light model simply can’t be beat.
Finally, the model has to be powered properly. With these lightly loaded, slow flying and very docile-type park flyers, too much power isn’t almost enough, it’s just “too much.” Lightly loaded models like the Fleet that are designed specifically for slow flight, simply don’t like to fly fast; and with too much power, more often than not, they’ll get “twitchy” and fly way too fast. And when that happens, the charm of these wonderful, old slow-flying biplanes can be so easily lost.