Re: Re: Rubber weight and size

From: <leop_at_lyradev.com>
Date: 30 Dec 2015 16:35:45 -0800

My comments on units was just to point out the mixing of Imperial (actually, US standards today) and metric. Vlad comes from Europe although he lives in Canada (which has completed metrication but still usesImperial units at times). So, I thought that mixing unit systems might seem a bit odd to him. Our fellow European fliers use grams/inch for a single strand to specify their motors as does Aki.

 I do things a bit differently (what a surprise). I specify my motors using grams per meter but I use the length of the motor rather than the length of the strand that makes the motor. For the usual two loop motor, my linear density is just twice that of the European method. Why do this you ask. Well, look at some of Bill Gowen's motors. They use three strands. One cannot compare a three strand motor with a two strand motor using just the strand linear density without knowing how many strands are in the motor. A motors properties are directly related to the total linear density of the motor. So, to account for an "any" strand motor, I use the total linear density.
 

 Anyway, I always ask for (and record for my motors) the mass and length of the motor. That way I can easily translate and can work things out for those classes which do n ot have a maximum motor weight. The hard thing in the US today is that many of the high school students use metric units nearly exclusively (and even more so in a college town with many students from foreign countries). I do everything (including balsa density and stiffness, and motor torque) in metric units for the Science Olympiad students I coach.
 

 LeoP
 

Received on Wed Dec 30 2015 - 16:35:46 CET