Radio Control: Old Timers
JOHN Tedford of Spearville, Kansas is flying his "Utility" in the free-flight mode, using a 1.5 cc Cox, but anticipates converting to 2 or 3 channels in the near future. The Utility should make a superior trainer for his first attempts at R/C Old Timer flying. Although a 2.5cc powerplant would be SAM legal in the model, the concept of powering this design with a Cox Conquest or a Rossi 15 strikes fear in my heart. The resultant climb should surely rival that of an FAI power ship, even at an increased wing loading of 10 oz./ft.2 rather than the 6.55 of the FAI rules. Construction of Hackers Utility is typical for the period. The wing ribs are 1/16 sheet, the spars 1/8 × 1/2 and 3/16 × 3/8, the leading edge 1/4 × 1/4, and the trailing edge 1/8 × 1/2. I would recommend substituting a larger T.E. and use of four spruce spars if a larger powerplant is contemplated. Tail surfaces are of 1/8 outlines with a 1/4 spar, the semi-symmetrical section sanded in after assembly. The fuselage is a 3/16 sq. box with formers and stringers contouring the bottom. I would consider substituting spruce for the longerons. The nose is carved from 1/2 balsa sheet. The undercarriage could be improved upon with a Kadet type torque rod main gear, or a torque-bend type as used on U/C models.
Radio Control: Old Timers
MANY builders of Old Timer RC-assisted models have successfully scaled designs up or down from the original. I have had gratifying results reducing the Powerhouse to 85%, the Ole Reliable to 60%, and the Westerner and Scram to 50%. I have also been satisfied after enlarging the Viking and the Panther. However, such scaling does not always result in a model with the same flight characteristics as the original. This month's feature illustrates such a deleterious result. In 1940 Henry Struck designed a new model to meet the requirements of the 1940 rules. Wing loading requirements had been removed and an 80-oz./cu. in. of displacement rule introduced for 1940 competition. Struck named his model the New Ruler. With a .60, the model was required to weigh 48 oz.
Radio Control: Old Timers
REPEATEDLY over the last few weeks I've begun to compose this report only to question my objectivity in light of overwhelming enthusiasm. Can the Davis Diesel conversion heads actually alter the characteristics of a glow motor to the extent my testing indicates? Do these conversions represent a valid improvement in power, torque, economy, and utility, or am I allowing my fondness for diesel powerplants to cloud my judgement? Admittedly, I am certainly not an engine expert, do not possess the equipment to accurately measure performance, nor have I ever been very interested in modifying engines. In the final analysis, the only important measurement of any powerplant is its performance on a flying model. This is exactly where the astonishing performance change comes in with the Davis head and the answers are all decidedly positive. The Original Buccaneer in the photo spans 84 in., has a chord of 14 in., weighs nearly 7 pounds, and will take off short grass in less than 10 feet! It will gain altitude at 60% throttle, cruise at 40%, and with the Semco muffler is barely audible 100 yards away. The powerplant is turning a 13 × 6 Rev-up prop 10,000 rpm, idling at 1800 (measured with Heath-kit tach). Now for the incredible number. This "Bucc" is not powered with the usual 60 glow; the engine is a ST 35 Stunt!! Unbelievable you say! Not with a Davis head.
Panther II
HAVE you ever noticed most model airplane "freaks" tend to doodle drawings of fanciful aircraft whenever they are listening to boring lectures? They tend to drive their teachers insane by drawing instead of taking notes, marking the edges of church programs with far-out designs, and generally filling any blank piece of paper with whimsical dream designs. Back in 1938 Walter Schutz was also inclined towards doodling, the important difference being that he followed up by building a model of one of his dream designs. As kitted by Peerless of Cleveland, the Panther was so unlike the usual slab-sided high-winged designs of that era that it stood out like a man in a tuxedo at a nudist convention. That it flew as a free-flight is testimony to his excellent understanding of aerodynamics. Combined with a heavy undercarriage and sub-rudder, the poly-dihedral wing places the center of lift close to the center of mass and provides surprisingly good stability-particularly for a model that looks so much like a "pursuit plane" of that era.
Radio Control: Old Timers
S.A.M. RULES as printed in the AMA rule book require a minimum of 225 sq. in. of area for each .10 cu. in. of engine displacement. This is an effort to strike a balance between "screamers" and "floaters." The majority of pre- 1942 designs must be either scaled up or down to reach the required 900 sq. in. for use with the popular 40-size engines. This month's feature model is an exception. The Riser Rider has slightly over the minimum area and handles the power very well. Joe Percy of Fort Worth has powered his with a K&B 6.5 cc to create a model possessed of an astounding climb and a slow lazy glide. I had the privilege of observing Joe's creation at the Southwestern Regionals in Ft. Worth, and am highly impressed. The glide is dead flat and the sink rate almost negligible. The model seemingly will stop in mid-air, hanging like a parachute. It rides lift very well, showing little tendency to tighten up or fall out of the thermal.
