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With three wheel gear it lands like a large plane
The large propeller gives long steady flights
Body is of four longeron construction
A MINIATURE FLYING SKYFARER
A Small Scale Reproduction of the Latest Light Plane -- Unusually Stable and suitable for Contest Flying
By Earl Stahl
In flight it is most spectacular
The frame is of simple design and very light
A faithful replica of the big ship
High wing and twin fins give unusual stability
Recognizing that the overwhelming proportion of all flying accidents are caused by errors of the pilot judgment, the General Aircraft "Skyfarer" was designed to anticipate and make inherently impossible these human mistakes. According to the designer, Otto C. Koppen, professor of Aeronautical Engineering at M.I.T., the Skyfarer cannot slip, skid or spin nor does it lose control when stalled. It is placarded as "characteristically incapable of spinning" by the C.A.A.
The Skyfarer is a high-wing monoplane, seating two passengers side-by-side; it is powered by a four cylinder Lycoming engine of 75 horsepower. Most unusual is the fact there is no rudder -- turns being made by the ailerons. The ailerons are operated by a steering wheel which also steers the front wheel of the tricycle landing gear in much the same manner as an automobile. The ship is equipped with flaps which contribute to the control of takeoffs and landings.
In performance the Skyfarer compares favorably with other lightplanes. With a geared Lycoming engine top speed is 100 miles per hour. It climbs at a rate of 550 feet per minute and cruises for 400 miles at about 20 miles to a gallon of fuel. Because of the tricycle landing gear and hydraulic brakes, landings can be made at speeds from 45 to 80 miles per hour. Other specifications are; Wing span 31 feet, 5 inches; length 22 feet. The useful load is 460 pounds, gross weight is 1350 pounds.
Because of its excellent proportions and interesting construction, this plane is ideally suited for a flying scale replica. The model was developed from data supplied by the manufacturer and is exactly to scale except for enlarged propeller and added dihedral. In spite of its snappy appearance, it flies very well. Standard construction methods are used throughout, so little difficulty should be experienced as your Skyfarer takes form.
A simple rectangular frame is the backbone of the fuselage structure; it is shown lightly shaded. Work directly over tracings of the plan and build two side frames, one atop the other to make certain they will be identical. While it is not absolutely necessary, it is best to steam or soak the longerons in hot water so they will dry with a natural curve, as required; this will aid in keeping the structure from springing out of shape. Hard grade wood is used and longerons and uprights are 3/32" sq. stock. Invert the completed sides over the top view and cement 3/32" sq. pieces to place at the body center; when dry, draw the backs inward and place the remaining cross-pieces. It will be necessary to crack the longerons so that they can be pulled into position at the front.
Cut the formers shown on page three of the plans from 1/16" sheet. Now, if the basic structure is dry, remove it from the workboard and attach the formers to their correct positions. The wing center section is constructed directly atop the fuselage; make this very accurately as the wing's correct placement is determined by its position. Since the stringers are merely fairing strips, they should be medium-soft balsa; they are cemented directly to the underframe except where there are formers, of course.
Before the nose can be completed it is necessary to attach the front landing gear fork. A full scale plan of the fork is given. Bend the halves from .034 music wire and then join them by soldering. Align the fork properly against former LG-1; then using needle and thread, firmly sew it to place. Apply several coats of cement over all the former and adjacent structure.
The rear landing gear strut can be made at this time also; it is bent from .040 music wire. The method of attachment is indicated by the perspective. A 5/16" deep piece of hard 1/16" sheet is cemented to the vertical members at section 5S. The wire strut is then fitted over this member and securely lashed to place by wrapping with thread. Add the triangular 1/16" sheet gussets, shown, and apply several coats of cement. Rubber tubing and balsa fairings are not added until later.
The nose is covered with light grade 1/32" sheet; all the shaded area, as indicated on the plan, is covered. Three or four individual pieces will be required. Cement the sheet to the adjacent frame, using pins and rubber bands to hold it in place until dry. The extreme front of the nose is made removable to permit the rubber motor to be stretched for winding. Roughly cut the nose block to shape, lightly cement to the fuselage and sand the entire front smooth and uniform. Remove the nose block and cement a piece of 3/16" sheet to the back so it will fit to the opening in section No. 1. The rather blunt tail piece is carved from a very soft balsa block; it is hollowed, as shown.
Construction of the tail surfaces is simple. First build flat frames for the two rudders - or rather fins - and stabilizer using 1/16" thick stock for the outlines and 1/16" sq. strips for the ribs. To give the stabilizer a streamline cross section, cement soft strips of 1/16" sq. to each side of each rib and then, when dry, cut them streamline. The fins are of flat construction. Trim and sand each structure to complete the tail surfaces construction.
Only the right wing plan is shown so it will be necessary to prepare an accurate plan of the left wing in order that construction can be done directly atop it. With exception of the two 1/16" thick end ribs, all wing ribs are cut from 1/32" sheet. Taper and sand the tailing edges before pinning them into position over the plan. Pin the ribs to their respective positions, then attach the leading edges and spars. Assemble the tip pieces which are cut from 3/32" sheet and cement the tips to place. Once the leading edges and tips are cut and sanded to shape the wing frames are completed.
The propeller blank is shown in perspective on the plan. Select a hard block of the proper size and shape the blank as indicated. Drill the tiny hole for the prop shaft before starting to carve a right-hand prop. The hardness of the balsa will determine the blades' thickness, the shape of which can be seen in the photos. Thoroughly sand the propeller and apply several coats of clear dope with light sanding between each coat to produce a nice smooth finish. Equip the prop with some kind of free-wheel device so the glide will be improved. Cement a washer to the back of the propeller, too.
Bend the propeller shat from .040 music wire. Place several washers between the prop and nose block and then bend a loop on the shaft front into which a mechanical winder can be hooked.
Being a scale model, it is necessary for the covering to be nearly perfect. With this in mind carefully sandpaper all the structure to remove every bit of roughness. Colored tissue is used and since this is a commercial plane, most any color combination will be correct; our original model was very attractive with its red and black color scheme. Cement cellophane side windows to place before starting to cover the fuselage. The use of numerous small pieces on curved parts will help avoid wrinkles; use only enough banana oil adhesive to stick the extremities of the area being covered. Individual pieces of tissue should be lapped neatly. The balsa cowling and similar wood parts are tissue covered, too. Use a separate piece of tissue for each side of each wing half, stabilizer, rudder, etc.; wing tips require individual pieces, also. Once covered, all parts are lightly sprayed with water to tighten the covering; to keep the wings and tail surfaces from warping they should be pinned to a flat surface until dry. Clear dope is not applied until later.
The various parts are now assembled. A half windshield pattern is given; cut a complete paper pattern and make certain it will fit your model exactly before cutting one from celluloid. Avoid cement smears when attaching the windshield.
The landing gear is completed next. Rubber tubing of the correct diameter is slit and slipped over the upper portion of the front fork. Cement the seam and then neatly wrap light twine or heavy thread about the strut to represent the coil spring on the real ship. Tubing of smaller diameter is slipped over the fork portion of the strut. The structure at the strut rear is represented by thin balsa or bamboo strips. Cut the rear strut covers from 3/16" sheet; these members are of streamline cross section. Cut 1/16" deep grooves in the struts to hide the wires, cement the wires fast; do not, however, attach the tops of the struts to the fuselage. Cover the struts with several layers of colored tissue.
Wheels are made from three laminations of 1/8" sheet or they may be purchased. Cement washers to the wheels so they will revolve accurately and smoothly. Before the wheels are attached to place they should be color doped. The front fork will spring apart far enough to admit the front wheel; rear wheels are held in place by washers soldered to the axles.
Assemble the tail surfaces by cementing the rudders to the stabilizer; cut enough tissue from the rudders so a solid gluing surface will be had. Remove enough tissue from the stabilizer undersurface so the tail surfaces can be fitted accurately to the fuselage at the position indicated. Attach the wings -- this will be an easy matter since the exact position and angle has already been determined. Tips are elevated to the extent of 1-1/4". Now that the model is assembled, a coat of clear dope can be applied to all the covered surfaces.
Add the various more minor details to "dress-up" your model Skyfarer and construction is finished. License numbers, fuselage strips and similar decorations are cut from contrasting tissue; ailerons, flaps, elevator, doors etc., are effectively represented by thin strips of black tissue. The single wing struts are cut from 3/32" sheet; they are of streamline cross section and join the wing at "X". Struts, propeller and other exposed wood parts are color doped. Air intake openings in the cowl, exhausts and similar details found on photos of the real ship can be added without harming the model's flight ability.
Either 8 strands of 1/8" rubber or 6 strands of 3/16" rubber should be used to power the Skyfarer. Measure the strands to correct length and then attach them to the loop on the prop shaft; drop the rubber through the fuselage and slip the bamboo pin through the fuselage so as to attach them in the rear.
To prevent damage to the model at this crucial stage, test flights should be made in a field of tall grass, but if none is available make first flights R.O.G. with a few turns. The descent from a hand glide should be flat and smooth before power is applied, so a small corrective weight may be required to obtain the desired results. Once the glide is good, all further adjustments are made by offsetting the thrust line. A small sliver of wood between the nose block and fuselage, tilting the thrust line down at a slight angle, will help eliminate a tendency to stall, while right or left thrust will make the ship turn as desired. Use a mechanical winder for long flights -- stretch the rubber strands about 2-1/2 times normal length and store up power. Now that your Skyfarer is completed we are sure you will be more than pleased with its performance. Our original ship proved to be a consistent and capable flyer; it is exceedingly fast in climbing and gains considerable altitude for a ship of its size. The glide is flat and covers surprising distances from high altitudes to come in for easy, realistic landings on the tricycle gear. Happy landing!
from November, 1941
Model Airplane News
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