WEIGHING ENGINES AND AIRCRAFT By Richard Finch, EAA 102503
341 Cambridge Dr.
For several years I have used the beam multiplication or division method for weighing heavy things in my workshop. Currently, I have a large fish scale weighing device that will directly weigh up to 300 Ibs. by hanging things on the lower hook of the scale. But when I want to weigh an engine that weighs 350 to 400 pounds, I hook up my divider beam that divides the weight equally between the scale and my ceiling hook. The scale extends as it measures the weight, so I have an adjustable turnbuckle on the other end of the beam to keep the beam level for more accurate readings. This beam division principle works for 1-to-1, 2-to-1 or other ratios as you wish. For a 1-to-1 ratio, I weigh a 340 pound engine and read 180 pounds on the scale. I subtract 10 pounds tare for the 1-to-1 beam and the handcrank hoist that lifts the engine from the bottom of the dividing beam. Before I lift the engine, I read the tare on the scale so I know what to subtract. Then I add the scale reading (multiply it by 2) and come up with a reading of 340 pounds, which is what the engine actually weighs. I could even weigh my 2600 Ib. car with my 300 Ib. fish scale, by using a 10 to 1 beam multiplier setup. And, as is often the case, a race car engineer has designed a simple weighing system for weighing race cars, and he has also developed a version for weighing airplanes. Joe Ruggles of Ruggles Scales Company has designed a simple, "drive-on" set of beams and scales that operate on the same principle as my fish scale setup. A new method of weighing light aircraft weighing under 4,000 Ibs. has just been developed. This newly designed
scale set weighs only 30 Ibs. complete, and will easily store in a plastic case used for carrying milk cartons. When the airplane is on the scales for weighing, the tires are only 2" off the hangar floor. One man can pull the airplane onto the scales in less than a minute, using short wooden ramps made from 2x4s, and by using the airplane's nosewheel tow bar. No jacking of the airplane is required. A complete set of Ruggles Scales costs only $295. The scales were originally designed for race car weighing where one pound over the legal limit, or under the legal limit, could cause the race car to be disqualified and cost the driver thousands of dollars in prize money. Joe Ruggles says the scales are accurate to 1 pound. The photo shows a Mooney Aircraft nosewheel sitting on one of the three portable Ruggles Scales. For
further information, contact, J.P.R. Development (Ruggles Scales Co.), 1747 E. Avenue Q, Unit D-5, Palmdale, CA 93550, phone 818/992-5375. Ceiling Beam
"50% of Weight Fish Scale 50% of — Weight
The Ruggles beams and scales. SPORT AVIATION 59