AirTalk.org

James Ricks · Guest

Just curious. Where did the term E6B come from? I've looked in various places
for an origin and come up dry. Was it perhaps a military designation for a
flat, slide rule type flight computer?

I know that in the overall scheme of things this is unimportant, but. . . .

Thanks.

Dudley Henriques · Guest

Not exactly sure about the origin, but I believe it was the Weems Co. back
in the early forties. I think they had a contract with the government to
supply a universal navigation hand computer and the E6B was the result.
As I say, I'm far from being certain about it. I'm sure the historians will
know a bit more.
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot; CFI; Retired
dhenriquestrashatearthlinktrashdotnet
(take out the trash Smile

"James Ricks" <jtricks (AT) cableone (DOT) net> wrote

Dudley Henriques · Guest

Not exactly sure about the origin, but I believe it was the Weems Co. back
in the early forties. I think they had a contract with the government to
supply a universal navigation hand computer and the E6B was the result.
As I say, I'm far from being certain about it. I'm sure the historians will
know a bit more.
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot; CFI; Retired
dhenriquestrashatearthlinktrashdotnet
(take out the trash Smile

"James Ricks" <jtricks (AT) cableone (DOT) net> wrote

Icebound · Guest

"James Ricks" <jtricks (AT) cableone (DOT) net> wrote

kdarling@basit.com · Guest

After spending several years in research, thousands of dollars, plus
reading Dalton's personal letters, here is a fairly definitive history
of the E-6B:

Philip Dalton (1903-1941) was a Cornell graduate who joined the Army as
an artillery officer, but soon resigned and became a Naval Reserve
pilot from 1931 until he tragically died in a plane crash with a
student practicing spins. He, with the support of the Navy and the
godfather of modern marine/air/space navigation, P.V.H. Weems,
invented, patented and marketed a series of flight computers.

Dalton's first popular computer was his 1933 Model B, the circular
slide rule with TAS and Altitude corrections that we know so well. In
1936 he put a double-drift diagram on its reverse to create what the US
Army Air Corps (USAAC) designated as the E-1, E-1A and E-1B.

A couple of years later he invented the Mark VII, again using his Model
B slide rule as a focal point. It was hugely popular with both the
military and the airlines. Even Amelia Earhart's navigator Fred Noonan
used one on their last flight. But Dalton himself felt that it was a
quickie design, and wanted to create something more accurate, easier,
and able to handle higher flight speeds.

So he came up with his now famous wind arc slide, but printed on an
endless cloth belt moved inside a box by a knob. He applied for a
patent in 1936 (granted in 1937 as 2,097,116). This was for the Model
C, D and G computers widely used in WW-II by the British Commonwealth,
the US Navy, and even copied by the Japanese and Germans. You see many
of these old square metal and phenolic boxes for sale on eBay.

But the US Army Air Corps decided the endless belt computer cost too
much to manufacture, so later in 1937 Dalton morphed it to a simple
straight wind slide, with his Model B circular slide rule included on
the reverse. He called it his Model H. In 1938 the Army wrote formal
specs for it (the E-6A). Then the USAAC had him make a few changes,
which Weems called the Model J. This "E-6B" was introduced to the Army
in 1940, but it took Pearl Harbor for the Air Corps (by then the Army
Air Forces) to put in a really large order. Over 400,000 E-6Bs were
manufactured during WW-II, mostly of the plastic type which glows under
black light.

The base name "E-6" was totally arbitrary, as there were no standards
for stock naming at the time. The "B" simply meant it was the
production model. If you ever see Copyright 1933 on older models, that
was for his circular slide rule only.

Interestingly, the designation "E-6B" was only used for a couple of
years. By 1943 the Army and Navy changed the marking to their joint
standard, the AN-C-74 (Army/Navy Computer 74). The USAF later called
updates the MB-4 and then the CPU-26. But navigators stuck with the
original "E-6B" name.

After Dalton's death, Weems (www.weemsplath.com) tried updating the
E-6B and calling it the E-6C, E-10, and so forth, but finally fell back
on the original name which was so well known by 50,000 WW-II Army Air
Force navigator veterans. After the patent ran out, many manufacturers
made copies, sometimes using a marketing name of "E6-B" (note the moved
hyphen).

Dalton was still inventing when he was killed. It's sad that he died
without knowing his E-6B design would last for over sixty years.

"My eyes are dim I cannot see,
I have not got my E-6B with me,
Over the Valley of the Ruhr."
- WW-II USAAC ditty

Kevin Darling

James Ricks · Guest

Thanks to all who replied. I'm not sure I didn't find out more than I needed
to know, but did suspect the origin was early military and the designation
continued into civilian use.

The knowledge available in this forum never ceases to amaze me.

Thanks again...... Jim

Paul Hirose · Guest

[email]kdarling (AT) basit (DOT) com[/email] wrote:

CryptWolf · Guest

"Dudley Henriques" <dhenriques@noware .net> wrote in message

kdarling@basit.com · Guest

kdarling@basit.com · Guest

C J Campbell · Guest

"James Ricks" <jtricks (AT) cableone (DOT) net> wrote

kdarling@basit.com · Guest