Pepper (oz4270)

About this Plan

Pepper. Radio control sport model, for electric power. Wingspan 22 in, wing area 85 sq in. Plan shows a 5v DC can motor used with a 4.2:1 gearbox and 5in prop.

Update 14/4/2023: Added article, thanks to theshadow.

Quote: "Pepper. A 3-channel flyer to spice up yopur backyard. By Dave Robelen

The Pepper is a result of a weakness of mine. You see, I am attracted to low-wing designs in RC models. The recent availability of tiny control equipment and small, powerful, electric drive systems nudged me toward a micro, low-wing, 3-channel model. Pepper is quite capable of looping, rolling and performing a very sharp stall turn along with smooth, low and slow flying. At present, I do not have access to an indoor site; however I have flown Pepper inside a marked area representing the dimensions of a standard gym - no problem!

Pepper is not a scale model of any particular airplane, even though various features of the design have been seen many times before. A primary design consideration was the desire to fly in very small spaces and still be able to handle a moderate breeze.

Pepper has a usable range of flying speeds from about 11 to 25mph. The low end of the speed range is established primarily by the wing loading and airfoil used. The maximum speed is basically established by the motor/battery combination.

A wing area of 85.8 square inches combined with a weight of 75 grams set the wing loading at 4.4 ounces per square feet, and I chose a modified Benedeck airfoil because of previous good experiences with it. The WES-Technik DC 5-2.4 motor is a perfect match when teamed with a 4.2:1 gear set from Kenway. This combo is powered with a 7-cell, 50mAh Ni-Cd pack. Maximum flight times are around 7 minutes in still air, and the duration at con-tinuous maximum power is about 4 minutes.

The above-mentioned performance very much depends on matching the correct propeller to the airplane/motor combo. I spend quite a bit of enjoyable time designing and shaping props for my projects. Because this is a personal thing and not many folks are this zealous about their projects, I will refrain from a lengthy discussion of prop construction. The best commercial option is to trim a 6-inch-diameter Peck propeller to 5-inch diameter. The prop should turn about 6,500 static rpm on a fresh charge.

To get maximum performance, I have used the smallest and lightest equipment available. In a few cases, the cost was fairly high. Pepper has a reasonable tolerance for weight increase without trashing its flight qualities; if you feel inclined to make substitutions, be careful of the increases in weight. The maximum flying weight I recommend is 85 grams. I covered my Pepper with plastic film, but some weight could be saved by using Japanese tissue and clear lacquer instead. Actually, if you plan a fair amount of work with lightweight models, I recommend that you use a decent gram scale; mine is a reasonably priced, triple-beam mechanical scale from a scientific supply house. Several electronic scales also do a fine job.

Tools and Materials: Because you are considering a moderately complex project in Pepper, I will assume some basic skills on your part. Tools for these small projects can make a large difference to the outcome, so use only the sharpest blades and the best sandpaper. I use mostly 150-grit..."

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