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Bygrave position line slide rule
From: zvidoron---COM
Date: 28 Feb 2004 16:01

---

Hello,
Henry Hughes & Son of London, England used to make a cylindrical 3 part
position line slide rule for astro navigationsometims called "Bygrave" that
worked on the principal of solving two right angle triangels instea of the
complete PZX in one calculation. Francis Chichester used one on his epic
solo flight across the Tasman Sea (1931) and Weems in his book "Air
Navigation - British Empire Edition" gives a drawing and a few details. I
could not find any reference to it on the web.
Has anyone - ever used one? got one? seen one? knows if they can be had and
for how much? Any information will be gratefuly received.
Thanks
Zvi

Re: Bygrave position line slide rule
From: danallen46---NET
Date: 28 Feb 2004 20:48

---

Zvi Doron wrote on Saturday, February 28, 2004 8:02 AM:

Henry Hughes & Son of London, England used to make a cylindrical 3 part
position line slide rule for astro navigationsometims called "Bygrave" that
worked on the principal of solving two right angle triangels instea of the
complete PZX in one calculation. Francis Chichester used one on his epic
solo flight across the Tasman Sea (1931) and Weems in his book "Air
Navigation - British Empire Edition" gives a drawing and a few details. I
could not find any reference to it on the web.
Has anyone - ever used one? got one? seen one? knows if they can be had and
for how much? Any information will be gratefuly received.

---

I found one thing from Google:

http://home.ecn.ab.ca/~jsavard/other/sr03.htm

The Otis King Slide Rule

This slide rule consists of a body with a helical scale, on which a sleeve
with a similar helical scale could both slide and rotate. An outer sleeve
then slid and rotated on that sleeve at one end, and at the other end was
constricted to slide directly on the body. Marks at the two ends of that
sleeve constituted the cursor of the slide rule; thus, instead of placing
the two helical scales in coincidence, points on the two scales separated by
the distance between the two cursor marks were treated as corresponding.

The Otis King cylindrical slide rule was perhaps the most popular and
inexpensive circular slide rule made.

A special-purpose cylindrical slide rule made for use in sight reduction for
celestial navigation, the Bygrave position-line slide rule, was based on the
same principle.

---

As a mathematician, I simply turned your problem into a different one: what
the heck is an Otis King slide rule?  Sounds very interesting!

Dan
Re: Bygrave position line slide rule
From: zvidoron---COM
Date: 29 Feb 2004 09:00

---

Hi Dan Thanks for that - the Otis King is British made to the best of my knowldge. It has chrome scales and a black handle, two models were make, the K and the L, with different scale sets. They appear from time to time on eBay UK, the better deals have the instructtions and the box. They can fetch somewhere between 30-100 GBP. Excellent scans of one of these can be seen on the website of Mr. Atsushi Tomozawa of Japan. http://www5b.biglobe.ne.jp/~tomozawa/sr-annex/cat/other/otis-king/otis-kinge .htm You can also download instructions from the following website to understand how to operate one. http://sliderule.ozmanor.com/man/man-download.html The Bygrave has a roughly similar mechanical construction ()according to the one drawing I have) but the scales are dedicated to a two step process of solving the PZX triangle. Kind regards Zvi

AW: Bygrave position line slide rule
From: koeberer---DE
Date: 1 Mar 2004 20:28

---

Dear Mr. Doron,

the Bygrave Slide Rule, a cylindrical slide rule like the Fuller or the Otis
King, was invented in the 1920s to solve the navigational triangle in
position line navigation. The ?Admiralty Navigation Manual?, Vol. III
(London 1938) describes it on p. 128:

?The Bygrave Slide Rule consists of three concentric tubes, the innermost
carrying a scale of logarithmic tangents and the one next to it a scale of
logarithmic cosines, both scales being arranged in spiral form. This
construction is made possible by dropping a perpendicular from X on the side
PZ of the spherical triangle, as in the Ageton method, and solving the two
right-angled triangles thus formed.?

Another description can be found in the 1977 edition of the ?American
Practical Navigator?, Vol. I, p. 604, in the historically interesting
chapter on ?Comparison of various methods of Sight Reduction.There is also a
picture of this slide rule on this page.

A similar gadget called ?Höhenrechenschieber MHR1? was produced by Dennert &
Pape in Germany before and during WWII. Although they must have been
produced in sizable numbers most appear to have been lost during the war
and/or thrown away as outdated later on; so they seem to be quite scarce
these days: One ?MHR 1? reportedly was sold on e-bay for $ 1080 a couple of
years ago. The ?Deutsches Museum? shows a couple of ?Höhenrechenschieber? in
their new department on ?Computing? (shelf mark 78/255). I could also send
you a picture of my ?MHR1? off-list, if you like.

W. Köberer

Re: Bygrave position line slide rule
From: zvidoron---COM
Date: 18 Mar 2004 22:14

---

Hello, Based on the information and images Mr. Koberer kindly sent me and on some details and a drawing from Weems' book Air Navigation I have now built a fully working model of the Bygrave position line slide rule. It is 2-3 times larger than the original and is quite accurate, giving calculated positions to within about 1' of arc (1 nautical mile) with the inputs being Dec, Lat and LHA, so in effect it replaces the normal sight reduction tables. It took some 8 hours of work to make. Do contact me if you are interested in details. Kind regards Zvi

Bygrave slide rule
From: wnmpiccer---NL
Date: 11 Dec 2005 14:00

---

Is it possible to put a drawing/picture of this slide rule on the forum?

 

I have been looking on the web but cannot find anything

 

Thanks

 

Willem Piccer

Re: Bygrave slide rule
From: zvidoron---COM
Date: 11 Dec 2005 13:44

---

I have collected some .PDF files and phographs regarding both the original Bygrave slide rule and its German copy MHR1 (some came from other members of this forum). However, I don't know how they can be posted on the web for all to see - maybe the mediator of the forum has a aord of advice?

 

I have been toying with the idea of posting a webpage of my own covering the Bygrave and other items of interest to navigators and slide rule collectors but again don't know were to start.

 

Re: Bygrave slide rule
From: zvidoron---COM
Date: 11 Dec 2005 13:44

---

I have collected some .PDF files and phographs regarding both the original Bygrave slide rule and its German copy MHR1 (some came from other members of this forum). However, I don't know how they can be posted on the web for all to see - maybe the mediator of the forum has a aord of advice?

 

I have been toying with the idea of posting a webpage of my own covering the Bygrave and other items of interest to navigators and slide rule collectors but again don't know were to start.

 

Bygrave position line slide rule
From: zvidoron---COM
Date: 28 Feb 2004 16:01

---

Hello,
Henry Hughes & Son of London, England used to make a cylindrical 3 part
position line slide rule for astro navigationsometims called "Bygrave" that
worked on the principal of solving two right angle triangels instea of the
complete PZX in one calculation. Francis Chichester used one on his epic
solo flight across the Tasman Sea (1931) and Weems in his book "Air
Navigation - British Empire Edition" gives a drawing and a few details. I
could not find any reference to it on the web.
Has anyone - ever used one? got one? seen one? knows if they can be had and
for how much? Any information will be gratefuly received.
Thanks
Zvi

Re: Bygrave position line slide rule
From: danallen46---NET
Date: 28 Feb 2004 20:48

---

Zvi Doron wrote on Saturday, February 28, 2004 8:02 AM:

Henry Hughes & Son of London, England used to make a cylindrical 3 part
position line slide rule for astro navigationsometims called "Bygrave" that
worked on the principal of solving two right angle triangels instea of the
complete PZX in one calculation. Francis Chichester used one on his epic
solo flight across the Tasman Sea (1931) and Weems in his book "Air
Navigation - British Empire Edition" gives a drawing and a few details. I
could not find any reference to it on the web.
Has anyone - ever used one? got one? seen one? knows if they can be had and
for how much? Any information will be gratefuly received.

---

I found one thing from Google:

http://home.ecn.ab.ca/~jsavard/other/sr03.htm

The Otis King Slide Rule

This slide rule consists of a body with a helical scale, on which a sleeve
with a similar helical scale could both slide and rotate. An outer sleeve
then slid and rotated on that sleeve at one end, and at the other end was
constricted to slide directly on the body. Marks at the two ends of that
sleeve constituted the cursor of the slide rule; thus, instead of placing
the two helical scales in coincidence, points on the two scales separated by
the distance between the two cursor marks were treated as corresponding.

The Otis King cylindrical slide rule was perhaps the most popular and
inexpensive circular slide rule made.

A special-purpose cylindrical slide rule made for use in sight reduction for
celestial navigation, the Bygrave position-line slide rule, was based on the
same principle.

---

As a mathematician, I simply turned your problem into a different one: what
the heck is an Otis King slide rule?  Sounds very interesting!

Dan
Re: Bygrave position line slide rule
From: zvidoron---COM
Date: 29 Feb 2004 09:00

---

Hi Dan Thanks for that - the Otis King is British made to the best of my knowldge. It has chrome scales and a black handle, two models were make, the K and the L, with different scale sets. They appear from time to time on eBay UK, the better deals have the instructtions and the box. They can fetch somewhere between 30-100 GBP. Excellent scans of one of these can be seen on the website of Mr. Atsushi Tomozawa of Japan. http://www5b.biglobe.ne.jp/~tomozawa/sr-annex/cat/other/otis-king/otis-kinge .htm You can also download instructions from the following website to understand how to operate one. http://sliderule.ozmanor.com/man/man-download.html The Bygrave has a roughly similar mechanical construction ()according to the one drawing I have) but the scales are dedicated to a two step process of solving the PZX triangle. Kind regards Zvi

AW: Bygrave position line slide rule
From: koeberer---DE
Date: 1 Mar 2004 20:28

---

Dear Mr. Doron,

the Bygrave Slide Rule, a cylindrical slide rule like the Fuller or the Otis
King, was invented in the 1920s to solve the navigational triangle in
position line navigation. The ?Admiralty Navigation Manual?, Vol. III
(London 1938) describes it on p. 128:

?The Bygrave Slide Rule consists of three concentric tubes, the innermost
carrying a scale of logarithmic tangents and the one next to it a scale of
logarithmic cosines, both scales being arranged in spiral form. This
construction is made possible by dropping a perpendicular from X on the side
PZ of the spherical triangle, as in the Ageton method, and solving the two
right-angled triangles thus formed.?

Another description can be found in the 1977 edition of the ?American
Practical Navigator?, Vol. I, p. 604, in the historically interesting
chapter on ?Comparison of various methods of Sight Reduction.There is also a
picture of this slide rule on this page.

A similar gadget called ?Höhenrechenschieber MHR1? was produced by Dennert &
Pape in Germany before and during WWII. Although they must have been
produced in sizable numbers most appear to have been lost during the war
and/or thrown away as outdated later on; so they seem to be quite scarce
these days: One ?MHR 1? reportedly was sold on e-bay for $ 1080 a couple of
years ago. The ?Deutsches Museum? shows a couple of ?Höhenrechenschieber? in
their new department on ?Computing? (shelf mark 78/255). I could also send
you a picture of my ?MHR1? off-list, if you like.

W. Köberer

Re: Bygrave position line slide rule
From: zvidoron---COM
Date: 18 Mar 2004 22:14

---

Hello, Based on the information and images Mr. Koberer kindly sent me and on some details and a drawing from Weems' book Air Navigation I have now built a fully working model of the Bygrave position line slide rule. It is 2-3 times larger than the original and is quite accurate, giving calculated positions to within about 1' of arc (1 nautical mile) with the inputs being Dec, Lat and LHA, so in effect it replaces the normal sight reduction tables. It took some 8 hours of work to make. Do contact me if you are interested in details. Kind regards Zvi

Bygrave slide rule
From: wnmpiccer---NL
Date: 11 Dec 2005 14:00

---

Is it possible to put a drawing/picture of this slide rule on the forum?

 

I have been looking on the web but cannot find anything

 

Thanks

 

Willem Piccer

Re: Bygrave slide rule
From: zvidoron---COM
Date: 11 Dec 2005 13:44

---

I have collected some .PDF files and phographs regarding both the original Bygrave slide rule and its German copy MHR1 (some came from other members of this forum). However, I don't know how they can be posted on the web for all to see - maybe the mediator of the forum has a aord of advice?

 

I have been toying with the idea of posting a webpage of my own covering the Bygrave and other items of interest to navigators and slide rule collectors but again don't know were to start.

 

Re: Bygrave slide rule
From: zvidoron---COM
Date: 11 Dec 2005 13:44

---

I have collected some .PDF files and phographs regarding both the original Bygrave slide rule and its German copy MHR1 (some came from other members of this forum). However, I don't know how they can be posted on the web for all to see - maybe the mediator of the forum has a aord of advice?

 

I have been toying with the idea of posting a webpage of my own covering the Bygrave and other items of interest to navigators and slide rule collectors but again don't know were to start.