PART I

By STEWART ROUSE

Man is fast becoming air-minded, and many are experiencing a desire to own an airplane. This is a very normal situation, for the airplane entered the field of practical carriers at the close of the World War, and since that time has gained public accept- ance. Contrary to popular belief, flying is not pro- hibitively expensive. The cost per passenger for any trip in the average five-passenger monoplane is about the Same as it would be for the Same trip in a large, high-grade, five-passenger automobile.

During 1924-1928 airplane manufacturers built a large number of very efficient two, three and five-

planes powered with the OX-5, 90 hp training plane motor. These airplanes sold for about the Same price as a very good automobile. The supply of new war- time motors is about exhausted now and the manu- facturers are powering their products with excellent new production motors, which, due to small produc-

The young man who wishes to build up the 200 hours of flying time necessary to obtain a license as a transport pilot will find the building and flying of a Heath Parasol a satisfactory means of acquiring the skill and kmwledge necessary to become a skilled pilot. This plane contains practically all the parts of a larger ship, and in building it the young pilot will obtain a thorough knowledge of airplane anafomy. The Heath Parasol is an unsually economical light plane to fly.

tion, and strong demand, are so expensive that the price of plane and motor together is at least double the cost with wartime motors of similar power.

This state of affairs has suddenly turned the at- tention of the air-minded to light one and two-pas- senger airplanes capable of flying with from 20 to 60 hp. Low power motors are comparatively inexpensive due to their small size and simplicity. There are large stocks of Anzani 30 to 60 hp motors available at very low prices. Several makes of motorcycle motors can be converted into successful light plane motors cap- able of astonishing performance. A light airplane can be constructed quite inexpensively, and its cheap power plant makes the complete plane within the reach of the industrious man of average means. I t is probably better to build a small airplane first, instead of a large one, for it takes much better engineering to make a large one strong; in fact, it is almost un- heard of for a light plane to prove weak. A light plane of modern design is quite safe to fly and cer- tainly a very inexpensive traveling machine, both to produce and maintain.

One strong objection to building a full-size plane is the great number of hours of labor necessary for completion. The author of this article spent three years of his spare time, with the aid of an assistant, in building a five-passenger ,monoplane to his own designs. This included nearly all Saturday afternoons, Sundays, and at least one night per week. I t took over 2,000 factory hours to build Lindbergh's "Spirit of St. Louis." An interested handy man should be able to build a successful light plane in a fraction of this time, provided he has accurate and complete plans, correct instruction and complete information.

Tom Nelson. Trans~ort Pi- nmate, "Para-

The purpose of this and the following two articles is to describe what is probably the most practical light plane yet built, and to present complete plans, details, and instructions for its construction.

This light airplane is the externally braced, sin- gle-seat monoplane, regularly powered with a Hender- son "Deluxe" motorcycle engine, converted for air- plane use, which is known as the Heath "Super-Para- sol" Sportplane, after E. B. Heath, who, with Claire Linsted, designed it. E. B. Heath built his first air- plane in 1908, and has operated a factory, building planes to his own designs ever since.

His first light plane which could be considered as of the modern series, of which the "Super-Parasol" monoplane is the latest, was the "Feather" built in 1918-1919, and powered with a 7 hp Thor Motor- cycle motor!

Considering its low horsepower this little biplane flew very well. Several other low power motors were

Fig. 1 of photos. This shows the first of the pres- ent day Heath string of wonderful light planes. The "Tomboy" is also shown on Page 32 round- ing the pylon at PiPila- delphia in the 1926 Nation- al Air Races.

tried in this plane with varying results. Using some of the data gained in the experiments with the "Feath- er", Heath designed and built in 1921-23 a biplane known as the "Favorite", powered with an OX-5, 90 hp motor. This plane is still one of the most efficient 90 hp planes in the world, and carries four large pas- sengers with ease.

I t created a sensation in 1923 by a flight with four passengers from Chicago to St. Louis, where it won all the races in its class for efficiency and speed at the 1923 National Air Races. After this triumph in low power weight carrying, Heath continued his light plane researches, and in 1925 he and Claire Linsted designed and constructed a new light plane, the "Tom- Boy" (see Fig. 1 above and photo on Page 32). This was a full cantilever monoplane racer (by canti- lever is meant that the wings and tail had no external brace, wires or struts) with about 78 sq. ft. of wing area; powered with a 32 hp Bristol "Cherub" motor, and capable of an extreme top speed of about 103 mph. It won the light plane races of the 1926 Na- tional Air Races at Philadelphia with great ease, un- der the skilled guidance of Heath. The prizes won, totaled $2,500.00!

In November, 1925, the first real "~arasol" was designed and built by Ed Heath and Claire Linsted. It had a fuselage of small steel tubing, simple steel fittings and aircraft wire. The wings were a pair of Thomas-Morse Army Scout lower wings, externally braced with steel tubes and bracing cables. The "Para- sol" flew strongly with a Henderson motorcycle en- gine, converted for airplane use. The flight testing of this light plane was done by Thomas E. Nelson, a transport pilot of the National Air Transport. He was Lindbergh's roommate at Maywood, Ill., before the latter's meteoric rise to fame. At that time he kept a Henderson engine, which he was converting for light plane use, under his bed. Subsequent work on conversion methods by Heath refined this "Heath-

34

Henderson'' motor to an efficient little aviation motor, and such motors are giving fine service as the stock motor equipment of the present "Super-Parasol."

E. B. Heath decided to make a racer for the 1927 National Air Races at Spokane. He used just a refined 'rParasol" with a modern wing, and a 32 hp Bristol "Cherub" motor. This neat little monoplane was known as the "Spokane Super-Parasol", and won the light and sport plane races, and' $1,000.00 in prizes, although its speed was not as great as the "Tom-Boy's", being about 90 mph. However, the "Tom Boy" is a true racer, while the "Spokane Su- per-Parasol" is a practical plane and easy to fly. The "Super-Parasol" is exactly the same as the "Spokane Super-Parasol", with the two exceptions of having a slightly larger wing area, and a "Heath Henderson" 27 hp engine, instead of the 32 hp Bristol "Cherub" motor. The Bristol "Cherub", though a more power- ful motor, is not recommended for installation in homebuilt planes because of its cost and the difficulty of obtaining Parts, which come from England.

In the spring of 1928 Heath designed and built his "Baby Bullet." This is the smallest airplane in the world, and certainly one of the fastest, as its top speed, with pilot alone, is 150 mph when opened up. Small size, a small frontal area, extremely refined streamlining, and a light, reliable motor are re- sponsible for this tremendous speed. The fuselage is constructed of steel tubing and wire in the front half, and duralumin tubing and wire in the rear. The wings are of conventional constmction excepting for the ailerons, the hinge lines of which are diagonal to the rest of the wing structure. There are no shock absorbers save the tires. The wing tmss is made of eight streamline wires, the lower four of which pul1 directly from the Centers of the hubs. The hubs are fastened together by a larger streamline wire in place of an axle.

With this racer Heath won the light and sport

Here she is! This shows the prof i le o f the Heath Super-Parasol l ight air- plane which Modern Me- chanics is presenting its "how to build" fans! The men are drawn to scale so that a good comparison of relative sizes can easily be made. She's a f ine ship!

Figure 4 . . . -C*---_... . . .*. . . . . -.. . .

i i r ur iP'.iro* "Si"0 ),>L <O(ll,

' SUPER PAWASOL

SCALE IN FEET S W l P L A N E

LIDE V l E W

Details fo r laying out the f loor i i g fo r fuselage bui lding are given here w i t h a l l necessary notations and dimensions, together w i t h a scale b y means of which the sizes of parts not clear may be readily deterrnined. Follow the plans carefully. Do not Change a Single thing!

Two men are here drawn to scale and foreshortened iust a b i t to show how the "Super-Parasol" would look f rom the prop end of the ship. Note the splendid visibi l i ty which the p i lo t has! Small f rontal area, weights hung low, and good ta i l length make the "parasol" simple to fly.

. . .

plane races a t the 1928 National Air Races at Los Angeles, California. The prize money amounted to $1,500.00. The "Baby Bullet" was unofficially timed about the five mile triangular Course at 142 mph. Its official time for the 50 mile race was 112 mph, car- rying a weight of 75 lbs. in addition to the pilot. See accompanying box for measurement data.

Parasol Easy to Fly The "Super-Parasol", being easy to fly and eco-

nomical in maintenance, is an ideal plane to use in acquiring the 200 hours flying time it is necessary to have before one can become a tramport pilot, which is the highest air license one can get. Possessing practically every part found in a large plane, it is just as educational to build. The safety factor is about 10 to 1; that is, all parts are about 10 times as strong as necessary for level flight, making it very safe for stunting if carefully assembled. In cross-country work it is very economical, consuming but 1 to 1% gals. of gasoline per hour and traveling about 60 to 65 mph at cruising speed. The cockpit is roomy and can be upholstered to suit the taste. Visibility is very good, the parasol type being the best ship obtainable in this respect. The controls operate with ease, and the ship is possessed of great inherent stability. I t is Safe to fly in any weather that is Safe for a 90 hp JN4 or Standard training plane.

Construction of the "Super-Parasol" should pre- sent no difficulty for the practical man. Ordinary hand woodworking tools are needed, as are a few files, cold chisels, pliers, small end wrenches, hand drill, punches, heavy tin snips, soldering material, small dies, and a hack saw with plenty of blades! There is a small amount of brazing to be done on certain joints, which can be done cheaply in any locality. A small machinist's vise is necessary. Follow the plans with care, and remember that the structure must not only look strong, but it must be strong. Put no unnecessary scratches on any of the material for "Strength re- sides in the surface." If any part is in any way imper- fect discard it and obtain another.

How Motor I s Converted The back end of the Henderson "Deluxe" motor

becomes the front in the airplane conversion. The fly- wheel cover is sawed off ahead of the flywheel, and the flywheel is removed from the crankshaft end. The crankshaft extension is riveted on the crankshaft fly- wheel flange, and the extension is machined integral with the crankshaft according to drawings in Part 11. The end of the crankcase is then faced to make a seat for the Heath-supplied cover plate. The cover plate carries a ball thrust bearing to take the propeller thrust. The propeller hub slides onto the extension and is held in place by a key and an end nut. Closed type engine bearings are used, instead of the regular Open type Henderson engine bearings. This raises the oil pressure to 75 or 100 lbs., instead of the usual 5 or 10 lbs. Heath Airplane Co., 1727 Sedgwick St., Chicago, Ill., is probably able to do the machining better than other agencies, as they have special equipment for this job.

"BABY BULLET" DATA

Span . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 ft. Length . . . . . . . . . . . . . . . . . . . . . . . . . . 13 ft. Height . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 ft. Weight . . . . . . . . . . . . . . . . . . . . . . . . 235 Ibs. Chord . . . . . . . . . . . . . . . . . . . . . . . . 3 ft. 6 in. Wing Section . . . . . . . . . . . . . . . . . St. Cyr 52 Area . . . . . . . . . . . . . . . . . . . . . . . . . 5 0 sq. ft. Landing speed . . . . . . . . . . . . . . . . . . 55 mph Top speed (pilot only) . . . . . . . . . . . . 150 mph Motor . . . . . . . . . . . . . . . 32 hp Bristol Cherub Propeller-Heath . . . . . . . 4 ft. 4 in. diameter,

3 ft. 6 in. pitch

The propeller is designed to utilize the 27 hp available to the fullest advantage, and the maker's price for it is so low as to make carving it almost a waste of time.

The Fuselage

The fuselage is truly the backbone of the air- plane. In the "Super-Parasol" the engine mount is the nose of the structure, as shown in the drawing on

Page 35. Just back of this and just beneath the mono- plane wing is the pilot's cockpit. At the extreme rear of the fuselage, the .tail group or empennage is attached. The landing gear is so attached that its axle is almost below the leading edge of the monoplane wing. The fuselage must be made very carefully, for surprisingly great strains develop in an airplane's structure during landings. I t must be durable, as it must stand years of Service.

As it is impractical to show all dimensions on an airplane plan, it will be well to thoroughly ac- quaint oneself with the use of the draftsman's scale. You can obtain one of these little triangular cross- sectioned rulers from anyone selling drawing ma- terial~, and they or any architect or draftsman can, in a few minutes, show you how to determine the size of any Part in the plan. As these plans have been greatly reduced in size for publication, it is best to obtain a Set of the large blueprints from the manu- facturer, as the large drawings make scaling accurate and easy.

Floor Jig Required The first operation is to draw, with chalk, a full

size, complete and accurate plan of one side of the fuselage (See Figure 4-A) on a level wooden floor. Use double lines to show the struts (the vertical tubes) and the longerons (the main tubes running fore and aft). Do not include the motor mount A C D, as this is constructed separately, being detachable; the wing supporting tubes, or the landing gear struts. Now prepare a quantity of wooden blocks about 1 in. by 1 in. by 2% in., and nail these in pairs one on each side of the outlines at about 18 in. intervals. The purpose of this is to make the floor jig in which long- erons and struts can be placed in order to have every- thing fit perfectly before the installation of strap fit-

tings, bolts, rivets, wire and turnbuckles. Shelby seam- less steel tubing is used throughout the structure. The longerons require a splice at J and K (see Figure 4-B). This requires the rear tube to be slipped into the front tube about 5 in., and then held by three two- penny shingle nails passed clear through both tubes and riveted. I t is well to braze the end of the front tube to the wall of the rear tube. Lay the top longeron in the jig. I t will require no bending for it runs straight from C to R. Next put the bottom longeron in the jig. I t requires a slight bend at K. Before this bend is made, it is best to make struts bC , JK, stern- post RS, and the necessary sheet meta1 fittings to hold these struts in place.

With the hacksaw cut off the struts about i/8 in. longer than apparently necessary. Slip a 21/q, in. length of the next size smaller tube of the Same gauge into the end of the strut. Heat the strut end cherry red with a blow torch or gas burner, and squeeze the last in. or so flat in the vise while red. All strut and tube ends are prepared in this way. Do not flat- ten the ends any farther than just past the end of the sheet steel fittings, as further flattening would weaken the joint. The reinforcement is absolutely necessary (See Figure 4-C). Flatten both ends of each strut in the Same way. Then lay the struts in their correct places in the jig. They should just fit with each end against a longeron. Correct the errors with hacksaw and file.

T o make a typical 20 gauge sheet steel fitting to clamp a strut to a longeron, cut with the tin snips

GENERAL SPEClFlCATlONS OF THE "SUPER-PARASOL" SPORTPLANE

Span . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5 f t . Chord . . . . . . . . . . . . . . . . . . . . . . . 4 ft. 6 in. Angle of incidence . . . . . . . . . . . . . . . . 3 deg. Wing area . . . . . . . . . . . . . . . . . . . 110 sq. ft.

. . . . . . . . . . . . . . . . . . Aileron area 10 sq. ft. . . . . . . . . . . . . . . . . . Elevator area 5.2 sq. ft.

Stabilizer area . . . . . . . . . . . . . . . . 5.5 sq. ft. Fin area . . . . . . . . . . . . . . . . . . . . . 1.0 sq. ft.

. . . . . . . . . . . . . . . . . . Rudder area 3.8 sq. ft. . . . . . . . . . . . . . . . Length over oll 16 ft. 9 in. . . . . . . . . . . . . . . . Height over oll 5 ft. 1 0 in.

Weight, empty . . . . . . . . . . . . . . . . . 260 Ibs. Useful load . . . . . . . . . . . . . . . . . . . . 300 Ibs. Gas capacity . . . . . . . . . . . . . . . . . . . . . 5 gal. Oil capacity . . . . . . . . . . . . . . . . . . . . . 3 qts. High speed . . . . . . . . . . . . . . . . . . . . . 70 mph Landing speed . . . . . . . . . . . . . . . . . . 2 8 mph Cruising radius . . . . . . . . . . . . . . . . . 120 miles

MOTOR SPECl FlCATlONS

a rectangular piece large enough to encircle the long- eron and then clamp flat, covering the flattened Part of the strut end. Make it a little large; it can be cor- rected with hacksaw and tin snips. Bend it around a short piece of tube the Same size as the longeron, put the free ends of the sheet steel in the vise with the tube still in place, and then squeeze flat. A neat fitting, only needing a little trimming and drilling for bolts and rivets will result (see Figure 4-D, Fig- Ure 3).

Now install struts CD and JK with their sheet steel fittings and secure each fitting to its longeron with a rivet made of a two-penny shingle nail passed entirely through the tube and fitting. Now put the bend at K in the bottom longeron very carefully. Install the stern post. Next install all the other struts according to Figure 1, Figure 3.

Next in order is the installation of the hard wire and turnbuckles. This should be done with the frame lying in the jig for easy accuracy. The method of making hard wire ends is shown in Figure 4-T. Two JA in. bolts are secured firmly in the vise, and the wire is slipped through the space between them. Slip two ferrules on the wire before bending, one for each end. The wire is bent into an end loop as shown with the ferrule to hold the end together. Never bend any wire more than once in a place, and See that the wire has no scratches or splits, no matter how small. The shoulders should be rather' sharp, and the ferrule slipped up snugly against them; finally the wire end is hooked sharply to hold the ferrule in place, and filed off. Each brace wire consists of two lengths of hard wire with a turnbuckle at the Center. The wires for the front Part of the fuselage, back to the strut JK are 12 gauge plated hard wire, with No. 324 double- eyed turnbuckles. Their ends are held in the fuselage joint fittings by 3/16 in. machine screws passing through the sides of the fitting and the loop end of the wire. From the strut JK to the stern post, the brac- ing is 14 gauge plated hard wire, with No. 322 double- eyed turnbuckles, with the wire ends held in the fu- selage fittings with yu in. machine screws.

. . . . . . . . . . . . Type 4-cyl., vertical air-cooled Horsepower . . . . . . . . . . . . . 27 at 3,000 rpm

. . . . . . . . . . . . . . . . . . . . Oil pressure 75 Ibs. Gas consumption . . . . . . . . . . . . . . . 1 Y2 gph Propeller . . . . . Special Heath wood propeller

of 4 ft. 6 in. diameter