NavList:

   

Reply

Paul wrote:

"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."



You're right I said to set it to cosine 14 in step fifteen but in fact 
it was set to the declination of 20 since the first movement was to set 
it to the the LHA of 14. The illustrations were correct and produced the 
correct answer. Thanks for the correction.

gl




Paul Hirose wrote:
> 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.
>
>
> nsg21@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
-~----------~----~----~----~------~----~------~--~---

   

Reply