National Champion Lew McFarland's Shark "45"
October 1961 American Modeler

October 1961 American Modeler Table of Contents These pages from vintage modeling magazines like Flying Aces, Air Trails, American Modeler, American Aircraft Modeler, Young Men, Flying Models, Model Airplane News, R/C Modeler, captured the era. All copyrights acknowledged.

The Jetco Shark 15 was my very first built up control line airplane. Before that they had all been plastic Cox models. As did many kids in the 1960's and 1970's I learned to fly on a Cox PT−19 Trainer (summer of 1969, about the time Apollo 11 landed on the moon). Before building the Shark 15, my experience with built-up models was with rubber-powered free flight. Mustering enough money for a Shark 15, a Fox 15 C/L engine, and covering materials was not easy in those days. The Shark 15 flew very nicely when I could get the Fox 15 started and running properly. Loops, wingovers, and inverted flight were much more satisfying than with the Cox models, whose .049 engines had a nasty habit of quitting during inverted flight. I resolved to someday step up to a Shark 45 once I had enough spare cash, but to this day I still have never owned one. The largest engine I've ever had on a C/L model was a Fox 35 (equally temperamental and frustrating) on a Sterling Ringmaster.

National Champion Lew McFarland's Shark "45"

Do you feel your stunt flying is in a rut? I did until K&B introduced their .45 featuring R.C.F. (rear counterbalancing flywheel) which makes it very adaptable to stunt. My previous efforts with .59 and .60 ships proved impractical due to the 900 sq. in. of wing area required and the 6 oz. of fuel needed to complete a decent pattern. Moreover I feel that 70 ft. of lines is not enough for a hot .60. However, additional length would create additional drag which in all probability would cancel out any theoretical advantages. (This brings up one of my pet peeves. Why should .45 powered shills be handicapped by having to fly under the same requirements as those governing .60's?)

The "Shark" is not an overnight wonder. It is the result of ten years of designing and flying stunt ships in an effort to make others obsolete or "shark bait." I feel that a "Shark" gives its owner an edge before the engine is even started.

Patterns should be scored in respect to the perfect geometric figures flown, but let's not kid ourselves - judging sometimes is as imperfect as most of our flights. Judges' impressions of you and your model are important as they can get points or ·take them away whether you and the judge are conscious of it or not.

With these facts in mind and a few hours at the drawing board my dream ship was born. A shift from military to civilian life necessitated a six month wait to see if it would live up to my expectations. I must say that I have never been more pleased with first flights than those of the "Shark." It gave a constant pull on the lines in all maneuvers, was not too fast and did round and square maneuvers equally well. I have never seen a ship square so well and not lose flying speed. My goal of ten years had finally been achieved. No modifications were necessary.

The "Shark" gives the thrill of a sixty ship and at the same time has all the maneuverability of a good thirty-five. The performance of the K&B .45 amazed me more with each flight. A very smooth run without any change of sound or rpm even in the most violent maneuvers. There are many good .35 ships but they have approached their optimum performance as can be noted by the fact that planes designed 10 years ago are still consistent winners. My optimism grew and the 1960 contest season proved the "Shark" worthy of my enthusiasm. Two firsts were won in Louisville, Ky., another in Cincinnati, Ohio, plus a Tester's Best Finish Award. At the Nationals, the "Shark" was given the most appearance points but the bellcrank pulled out on the pull test.

All wins were by large enough margins to make second flights unnecessary.

One feature incorporated in this ship that is not new but is seldom used is variable position lead-outs. Although this is not absolutely necessary, there is no other way of insuring that the lead-outs are coming out the right location and spacing for the particular design, wind conditions or slight variations in balance. Although there are several ways in which this may be accomplished, I chose to make a portion of the lower half of the tip removable. Slotted pieces of white pine in each half make changes both simple and quick.

Before we get into the construction, let's remember that the success of any design depends upon the model builder. Care must be used in selecting wood to get strength without excess weight. Don't be afraid to use the knife and sandpaper on portions that are not needed for strength. The original model weighed 57 oz. which compares very favorably with its little brothers. This ship can be built in about 10 percent more time than a .35 job but will give back 100 percent more fun and wins. A good investment in any book.

I shall dwell only on the construction points that are not too conventional or need some clarification. However, in performing each step let's ask ourselves a few questions. Is there a way to improve this? How does this affect flight?

The wing can be built very easily in an inverted position once the ribs and spars have been pre-notched. The same number of ribs are used in both wing panels with 1/8" wider spacing on the inboard panel thus increasing its length by 1 1/4". Care should be taken to make good splices. Double plank the center portion of the leading and trailing edges. A double plywood bellcrank mount is recommended. The upper pieces being inserted after the system has been installed in the normal manner. A longer 1/8" bolt is required to extend up through the second platform. Forty-five pound pull tests are hard on any model so take care and cement well.

Ribs W-1 and W-2 on the inboard side in line with the center of the bellcrank, when inverted on a flat surface, make the wing appear to have a little dihedral or at least prevents the drooped appearance of tapered ribs. The slots for the gear spar are cut out after the wing construction has been completed except for center planking and cap strips. The 1/8" wire and gear spar (yardstick) are inserted separately and "J" bolts inserted into pre-drilled holes. A small piece of 1/32" sheet aluminum or tin is inserted behind the gear wire at the bottom of the spar so that any shock received will be spread over a larger area. Note that ribs W-3 and W-4 are 1/8" to give the system added strength. Selection of very light balsa for the wing flaps is very important.

The fuselage construction is fairly conventional but here again the finer points will make the difference between a bunch of square boards glued together and a sleek "Shark." Fuselage area, thickness and moments have considerable effect on all maneuvers. The fuselage has been designed to be more than just a motor mount. Its sweeping curve, in overhead maneuvers, acts as a wing. To keep the balance point from being too far back, much care is required in selecting wood for points aft of the C.G. Hollowing out the weighty parts where shown is also important in this respect. Note the concave shape of the elongated fin which is similar to the Navy's Fury.

The nose section is built around a 4 1/2 oz. rectangular semi-pressure baffled fuel tank. Good solid oak or hard maple motor mounts and liberal use of fiberglass resin where they join the wing and other stress points is advisable. Fiberglasing the nose section is also strongly recommended but the use of nylon externally and 1/16" plywood internally is a good substitute. The cowling is built from 3/4", blocks with the engine mounted. A large opening is not required as long as the air flow is forced around the cylinder head.

The rudder, stabilizer and elevators are made of light 1/2" sheet balsa with the 1/16" sheet ribs inserted and sanded to proper airfoil. Note that the elevators and stab are symmetrical while the rudder has its outboard side flat. This lifting rudder, plus the slight curve (2 degrees) built into the fuselage, achieves the desired constant pull on the lines. The tail surfaces are covered with light 1/16" sheet. Additional ribs and paper covering may be substituted without sacrificing flying characteristics if you prefer or have difficulty in procuring light wood.

I feel that the control system is the heart of any stunt ship. For this reason I went all out and used ball bearings at all push rod fittings and in mounting the bellcrank. The original utilized a homemade 4" bellcrank to insure enough leverage to turn a big ship but this is not an absolute must since the "Shark" turns so easily. The ratio of 30 degrees flap movement to 40 degrees elevator gives excellent results. 7/8" movement of the leads gives the desired degrees of movement.

The control horns were made by inserting small ball bearings into an enlarged version of the conventional type. Instead of using two on the flap horn, the second was mounted on the elevator push rod which was in turn mounted on the flap push rod which extends through the flap horn. If ball bearings are not available, good results can be obtained by fitting the system with nylon or teflon bushings.

The plywood guides on the fuselage formers are also important. It is fool-hardy to put in a system that will wear out in a few flights. A set of smooth responsive controls helps keep you f:om getting in those tight spots and gives more positive control under slack lines or upwind conditions. The. semi-balanced elevators are also factors in making this ship so easy to control.

The "Shark" was meant to look like a real jet plane so realistic colors were chosen. A light gray top and light blue approaches official Navy colors and that of a real live shark. Cockpit details help make a more realistic ship and also help in picking up a few of those all important appearance points.

The wing should be covered with heavy Silkspan and the rest of the ship with medium weight. I find that wood fillets give less trouble. It should be noted that the exaggerated fillets at the leading edge of the wing and stab are not only for appearance but add considerable strength at these stress points.

Be sure your .45 is well broken in before attempting any serious stunting. Excellent results were obtained with an 11/6 Top Flite prop but full power was not required permitting a slightly rich run and insuring a longer engine life. If you find your .45 has power to burn as I did, a very small restrictor in the intake will cause a slight reduction in power and improve fuel economy.

Well, I guess we are set to go hunting for some "Shark Bait."

Shark 45 Plans, by Lew McFarland

"Shark" Bill of Materials

Balsa: Eleven sheets 1/16" x 3" x 36"; two sheets 3/32" x 3" x 36"; four sheets 1/8" x 3" x 36'" (1) 1/2" x 3" x 36"; (1) 3/4" x 3" x 36"; (4) 3/16" x 3/16" x 36"; (2) 5/16" x 5/16 x 36'" (2) 1/4" x 3" x 36"; (4) 1/8" x 1/4" x 36 ;

(4) 1/8" x 1/2" x 36"; (2) 1/4" x 1/2" x 36"

Also: (2) 1/2" x 3/8" oak motor mounts; 3/16" x 1 1/8" x 17 5/8" white pine or yard-stick; 1/8" plywood; 1/16" plywood; Blind mounting nuts; (6) 4-40 bolts; Berkeley F8F Bearcat Canopy; 1/8" wire; 3/32" wire; 1/16" wire; one pair 2 1/2" wheels; (1) 2" wheel; Aero Gloss Fillercoat; Silkspan; fiberglass cloth and resin; tin can stock; 1 3/4" brass tubing; 1 3/4" Veco spinner; Veco prop extension.

Posted March 4, 2023