NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: recommendation for slide rule ?
From: Greg Rudzinski
Date: 2009 May 21, 20:48 -0700
From: Greg Rudzinski
Date: 2009 May 21, 20:48 -0700
Paul, The 4080-3 K&E was gotten for a song so I am happy to have it for general use if it doesn't work out for CelNav. The Pickett N3 models seem to be going for more than the K&E 408x models. Of course condition is everything. If I catch the slide rule bug then I will be getting a N3 Pickett next. Greg On May 21, 4:00�pm, Paul Hirosewrote: > Greg Rudzinski wrote: > > Gary, > > > � � �It does appear as you have illustrated that the K&E 4080 has > > multiple advantages over the Pickett. > > The K+E 4080 family has the disadvantage that its rear (trig) side lacks > a C scale. While you can easily do 2 * sin 20�, or 2 / sin 20�, > something like 2 * 3 or 2 / 3 requires flopping the rule to the other > side. Also, if you simply want to read the value of sin 20�, you must > first align the S and D indices. > > Like most high-end rules, the Pickett N3 you mentioned has scales C and > D on both sides of the rule, eliminating the above annoyances. Scale S > is not adjacent to D as on the 4080 family, but this is a matter of > taste rather than computational power. > > The Pickett N3 is one of the few rules with a double tangent scale. > This doesn't give the rule any greater accuracy or range, but sure makes > life easier when dealing with tangents and arc tangents. > > Lest anyone think I'm a Pickett shill, let me say the only slide rule > I've ever liked enough to buy two identical ones is the 10 inch K+E > 4181! It's a nice competent workhorse with everything I need but no > frills. The shortcomings I pointed out above are charming blemishes. > Part of the fun is working around them. However, if using a slide rule > were just a job, I'd rather have an N3. > > I believe the Pickett "Eye-Saver" yellow was just a marketing gimmick. > It's not any easier to read, and I find a white rule more attractive. As > far as I can tell, readability is a tie. > > Note the Pickett doesn't necessarily mean yellow. Their high end rules > were all available in white. You'll find them on eBay, but expect to pay > more because they're less common. > > As far as I know, Pickett trig scales were always marked in decimal degrees. > > On the following simulator you can use a (white!) Pickett N3 to work > Gary LaPook's sight reduction example. Just drag the slide and cursor to > make the settings. The only difference is that where he says to "line > up" the S and D scales (bring their left and right indices into > coincidence), you use C and D. > > http://www.antiquark.com/sliderule/sim/n3t/virtual-n3-t.html > (The virtual slide rule requires that Javascript be enabled. After the > page loads, it's self-sufficient, requiring no Internet connection.) > > Note that Gary's azimuth computation has a mistake. The message text > says to set the cursor to cos 14�, but the picture and the final result > indicate it was set at cos 20� instead. > > Hein Bodahl wrote: > > The Faber Castell 2/83, or even better the FB 2/83N Novo Duplex, is by > > some said to be the best ever made. It is a desktop model of double > > length. Unfortunatly that makes it sensitive to temperature changes (or > > so "they" say). > > The famous Novo-Duplex, the so-called "ultimate slide rule", is dear to > collectors. But I wonder how many of these just sit in display cases. > They are so collectible, I'd hesitate to put one to work at home, never > mind take it to sea on a small craft. > > Recently I bought a Faber-Castell 63/82, which has several of the same > features:http://www.sliderulemuseum.com/Faber/P030_Faber-Castell_63-82_Biplex.jpg > > It looks impressive, but in actual use the 63/82 is cluttered and > gimmicky. Those auxiliary hairlines are the worst part. They're hardly > ever useful, and all those extra lines make it hard to read the scales > quickly. And the slide has too much friction and stick slip. Its feel is > the worst of any of my plastic rules. > > To be fair, I grew up with American slide rules. Fancy features like > extra hairlines, Pythagoras scales, etc. have never been popular here. > > Not that we always know better. One ridiculous practice, common on > American rules, is to chop off all scales to exactly the same length as > C and D. Look at the left end of ST in that N3 simulator. Wouldn't it > make sense to carry the scale down to .56�? The K+E 4080 family has the > same problem. > > As the picture of the Faber-Castell 63/82 shows, German makers often > extend such scales a little to end them at a sensible graduation. > > > > ns...@hotmail.com wrote: > > British brand UNIQUE offered several sliderules of cheap > construction, but > > interesting scale layouts. Among them was so called "Unqiue > navigational". In > > addition to normal log scales it featured sine and tangent scales > located both > > on slide rule body AND slide. Allegedly this would make certain trig > > calculations easy. > > That's true. For example, to compute sin A sin B on a rule with trig > scales on the slide only: > > 1. Align the indices, i.e., center the slide so the C and D scales coincide. > > 2. Set hairline to A on scale S. > > 3. Pull C index under the hairline. > > 4. Set hairline to B on scale S. > > 5. Read product on D at hairline. > > But with trig scales duplicated on slide and body, step 1 is unnecessary > if you use the S scale on the body for step 2. > > -- > --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---