THE HITTLE WORLD RECORD MODEL
(SINGLE TRACTOR MONOPLANE, 116 seconds DURATION RISING FROM WATER)
The Hittle World record model hydroaëroplane, designed and constructed by Mr. Lindsay Hittle of the Illinois Model Aëro Club, is perhaps one of the most interesting types of models yet produced. The establishing of this record illustrates the value of careful designing and construction and offers to the beginner an example which might be followed if good results are sought. In having broken the world’s model hydroaëroplane record with a tractor type model Mr. Hittle accomplished a feat of twofold importance. First, in having advanced the possibilities of the tractor model, and, second, in illustrating the value of scientific construction. The previous record for this type of model has been but 29 seconds, just one-fourth of the duration made by Mr. Hittle’s model.
Mr. Hittle’s model shows many new and original features not hitherto combined on any one model. Note [diagram 12]. The model is of extremely light weight, weighing complete but 1.75 ounces. The floats and their attachments have been so designed as to offer the least possible wind resistance. In fact every possible method was utilized in order to cut down weight and resistance on every part of the model. As a result of this doing away with resistance an excellent gliding ratio of 8³⁄₄ to 1 has been obtained.
For the motor base of the model a single stick of white pine ⁵⁄₆″ deep and 45″ in length is used. On the front end the bearing for the propeller is bound with silk thread and a waterproof glue of the constructor’s own composition being used to hold it secure. For the bearing a small light weight forging somewhat in the shape of the letter “L” is used, this being made streamline. At the rear end of the engine base is attached a piano wire hook for the rubber. The stabilizer consisting of a segment of a circle measuring 12″ × 8″ is attached to the under side of the engine base. The rudder measuring 3¹⁄₂″ × 3¹⁄₂″ is attached to the stabilizer at the rear of the engine base.
The wing is built up of two beams of white pine with ribs and tips of bamboo and has an area of 215 square inches.
The wing which has a total span of 43″ and a chord of 5¹⁄₈″ is built up of two beams of white pine with ribs and tips of bamboo and has a total area of 215 square inches. The wing is given a small dihedral and the wing tips are slightly upturned at the rear.
The trailing edge is longer than the entering edge the ribs being placed somewhat oblique in order to secure an even spacing. The wing is attached to the frame by two small bamboo clips which hold it rigidly and permit easy adjustment and is set at an angle of about 4 degrees with the line of thrust.
Diagram 12
Both the floats which take practically the whole weight of the machine are situated directly under the wing just far enough behind the center of gravity to prevent the model from tipping backward. These floats are attached to the engine base by means of streamlined bamboo struts. Bamboo is also used in the construction of the float frames. A single float of triangular sections is situated just behind the propeller. The entire weight of the floats and their attachments is but .23 ounces.
The propeller which consists of four blades is built up of two propellers joined together at the hubs and securely glued, the completed propeller having a diameter of 10″ with a theoretical pitch of 14″. The blades are fairly narrow, tapering almost to a point at the tips. The propeller is driven by five strands of ³⁄₁₆th″ strip rubber at about 760 r.p.m. when the model is in flight. At the time when the model made its record flight of 116 seconds the rubber was given 1500 turns which is not the maximum number of turns. At other times the model has flown satisfactorily with less turns of the rubber. While in the air the model flies very slow and stable notwithstanding its light weight and large surface. On three occasions the model has made durations of approximately 90 seconds which rather dispenses the possibility of its being termed a freak.