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Much has been said and written about the potential boom in private flying, and, while it is true that young America is tugging to break the leashes of earthdom to soar through the air for pleasure and business, the great transformation to the predicted scene of clouds of private planes fairly darkening the skies is not yet at hand. For while thousands upon thousands of aviation minded persons are interested in furthering their individual flying aspirations, they are frustrated by the high purchase costs of planes as well as the rather great operating expenses.
At present the most modest sport plane costs about twice that of a prewar popular priced car, and while fuel and oil consumption compares favorably with these autos, costs of storage, maintenance, insurance, etc. boost the amount to the point where it makes flying an expensive luxury. Time will of course correct these conditions; mass production of planes structurally engineered to be fabricated in the fast manner of a car, lowering of maintenance and operating costs will go hand in hand and then, once this is accomplished, the flying age envisioned by many will perhaps be upon us.
Typical of the planes fast becoming available to the flying public of today is the Globe-Swift, a snappy looking, fast little sportster. Looking for all the world like a miniature fighter, the Swift gains many admirers because of its appearance. But that is not where the ship's appeal ends, for it is an easy-to-fly craft with exceptional performance. With pilot and passenger and an 85 hp engine, it cruises at 125 mph for 600 miles; a 125 hp engine can be installed and speed is even greater. The undercarriage retracts in flight but when it is lowers and the flaps are depressed, the Swift slows up so it eases to the runway at close to 45 mph. Staunchly built of metal, it is unusually safe and durable. All in all it is a sportsman pilot's dream.
We have attempted to capture the eye appeal and flight characteristics of the real ship in our model; how well we have succeeded can only be judged by building and flying one yourself. Building the model is not difficult as standard construction practices are followed throughout; before starting, though, study the text and drawings to fix the details in mind. Work carefully as the reward for this is a better appearing, finer flying model.
CONSTRUCTION-The manner of fuselage construction calls for the use of four keels cut to shape from I/16 sheet balsa. To obtain their shape trace the top, bottom and side outline shapes of the body. Bulkheads, likewise 1/16" sheet, are cut in accordance with the patterns given; two of each being required. Pin the top and bottom keels to the view and cement half of the bulkheads to place. Attach a side keel and when dry remove the structure from the plan and add the remaining bulkheads and keel. Stringers are 1/16" sq. stock; attach the ones nearest the side keels first placing them on opposite sides in pairs to keep from pulling the structure out of line.
Between formers C and F where the wing fits in, curved pieces are cut from 3/32" sheet and they are shaped so as to make the fuselage sides fit to the curvature of the wing's uppersurface. Other items to be attached to the frame are the 1/32" balsa cockpit outlines as well as the very hard 1/16" balsa blocks in the rear, which anchor the motor.
The nose block just forward of bulkhead A is made from pieces of 1/8" sheet cemented crossgrain. Cut out the center for the removable portion to fit into and cement the whole nose in so it can be roughly cut to shape and then finished with sandpaper.
A hard balsa or soft white pine propeller block is needed for the flying model. Drill the tiny hole for the prop shaft first, then cut the blank to size and shape shown. Cut away the back surface of the block until the undercamber is as desired, then thin the front until the blades are of the desired thickness. Round the tips and reduce the depth of the hub a bit as shown. Blades are brought into balance by sanding. A free-wheeling gadget that will permit the big blades to spin freely in the glide is recommended for better flights. On our original model we used a second propeller, a scale one. It was made to the shape shown and we used a number of laminations of contrasting color wood to make it look realistic.
Tail surface construction is elementary and both stabilize, and rudder are made in a like manner. Cut the outline shapes from 1/16" sheet balsa and spars and ribs are 1/16" sq. stock. When the flat frames are dry, lift them from the plans over which they have been assembled and cement very soft 1/16" sq. strips to each side of each rib. These are later, cut to the streamline rib shape shown. Be sure to notice that the stabilizer has dihedral; it is cracked in the middle and tips are raised to provide this.
Wings are easily assembled in two halves; the builder will, however, have to make a left wing drawing as there was insufficient room on the magazine pages for it. Ribs are cut from 1/32" sheet except No. 3 which is 1/16" thick; sand them carefully to exact size and cut the notches for the spars. Spars and leading edge are cut from sheet balsa and the trailing edge is a strip of 1/8" x 3/8" balsa tapered in correction. With pins hold the various parts and place over the plans, and when they are finished fit the two halves together with 1‑3/8" dihedral at each tip.
A sketch shows the landing gear detail. The strut is .040" diameter music wire bent as shown to attach to the wing structure. This type gear has been used on dozens of models by the author and none has ever failed nor has a wing ever been damaged because of the gear's ruggedness. Sew the strut to the wing and cement the area liberally. Scale effects of the gear are represented by slipping rubber tubing obtained from electrical wiring over the strut. Wheels may be purchased but they are made so easily from laminated balsa disks that it is hardly necessary. Remember to cement washers or bearing to the wheels so they will turn freely.
Covering is probably the most important item for a neat looking model but the underframe must be carefully built and sanded to prepare for this. Use colored tissue for lightness and work carefully using banana oil or thin dope to make the tissue stick. Use a separate piece of tissue for each side of each wing half and tail surface section. For the fuselage numerous small pieces of tissue neatly lapped are required to avoid unsightly wrinkles. Water spray the covering lightly to tighten it but do not apply any dope until the whole ship has been assembled.
Assembly of the components should follow this procedure: Slip the wing into place and cement it fast. Align the stabilizer with the wing and attach it, too. Now finish underside of the wing-to-fuselage opening as well as the stabilizer top with strips of 1/16" balsa and tissue. Fix the rudder perpendicular to the stabilizer, offsetting the leading edge about 1/32" for a right turn in the glide. One or two coats of light dope or banana oil may be applied to the covering to tighten it further and toughen it.
Now for the more minor finishing details. The cockpit enclosure is made from thin celluloid and cleaned photo film may be used for this purpose. Make paper patterns for each section of the windshield before cutting them from the celluloid. When cementing the sections fast, be careful to avoid cement smears. The structural details are represented by doping thin strips of dark tissue to the transparent surface. Incidentally, it should be noted for exact scale builders that the aft section and middle top portion of the cockpit enclosure are colored Plexiglas on the real plane to lessen the effects of the hot sun. Finish the undercarriage and tail wheel assembly by painting, etc. License numbers, radiator grill, wing walks and the like are effectively simulated by colored tissue skillfully used. Exhausts and other minor details are fashioned from scraps and help much to improve the appearance without increasing the weight appreciably.
Installation of the rubber motor makes the little Swift ready for a test hop. Since each model will vary in weight and efficiency, the proper amount of power must be determined for each; in all probability four strands of 1/8" flat brown rubber will be right for an average model but six strands may be required for a heavier one. Lubricate the rubber before placing it within the fuselage. The strands are hooked to the prop shaft and the other ends are dropped through the fuselage where they are held in the rear by the tiny bamboo pin.
Flight performance depends in a measure on how carefully the model has been built. On the other hand, though, no model regardless of how well constructed will give maximum performance without proper adjustment. With this in mind strive to get the most from your Swift in the way of flying satisfaction. First, roughly adjust the center of gravity by adding a small amount of weight within the nose or tail as may be needed to bring the ship into balance when held under the wing spar. Then make any further adjustments by gliding from shoulder height. If it stalls, add weight to the nose; if it dives, remove some of the weight or place a bit in the extreme tail.
First power flights should be made with just a few turns, and as performance improves and confidence is gained increase the power. Tilting the thrust line down will eliminate a tendency to stall while under power, while right or left thrust will control the power circles. As flights become satisfactory use a mechanical winder and stretch the strands of rubber out the nose before starting to build up maximum power. Most low wing scale models fly best when they are adjusted for a large left hand circle while under power and then once the motor is exhausted the turn should veer to a sweeping right one; this is typical of the Swift.
Incidentally, take care where you launch your Swift for Mrs. Murphy will surely resent your climbing over her roof to retrieve it and birds frown upon the practice of model planes nesting upon the branches with them. You have quite an investment of time and effort in your Globe so protect it with reasonable judgment.
from January, 1947
Model Airplane News
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