<s>
The	O
E6B	B-Device
flight	B-Device
computer	I-Device
is	O
a	O
form	O
of	O
circular	O
slide	O
rule	O
used	O
in	O
aviation	O
and	O
one	O
of	O
the	O
very	O
few	O
analog	O
calculating	O
devices	O
in	O
widespread	O
use	O
in	O
the	O
21st	O
century	O
.	O
</s>
<s>
They	O
are	O
mostly	O
used	O
in	O
flight	O
training	O
,	O
because	O
these	O
flight	B-Device
computers	I-Device
have	O
been	O
replaced	O
with	O
electronic	O
planning	O
tools	O
or	O
software	O
and	O
websites	O
that	O
make	O
these	O
calculations	O
for	O
the	O
pilots	O
.	O
</s>
<s>
These	O
flight	B-Device
computers	I-Device
are	O
used	O
during	O
flight	O
planning	O
(	O
on	O
the	O
ground	O
before	O
takeoff	O
)	O
to	O
aid	O
in	O
calculating	O
fuel	O
burn	O
,	O
wind	O
correction	O
,	O
time	O
en	O
route	O
,	O
and	O
other	O
items	O
.	O
</s>
<s>
In	O
the	O
air	O
,	O
the	O
flight	B-Device
computer	I-Device
can	O
be	O
used	O
to	O
calculate	O
ground	O
speed	O
,	O
estimated	O
fuel	O
burn	O
and	O
updated	O
estimated	O
time	O
of	O
arrival	O
.	O
</s>
<s>
They	O
are	O
frequently	O
referred	O
to	O
by	O
the	O
nickname	O
"	O
whiz	B-Device
wheel	I-Device
"	O
.	O
</s>
<s>
Flight	B-Device
computers	I-Device
are	O
usually	O
made	O
out	O
of	O
aluminum	O
,	O
plastic	O
or	O
cardboard	O
,	O
or	O
combinations	O
of	O
these	O
materials	O
.	O
</s>
<s>
Electronic	O
versions	O
are	O
also	O
produced	O
,	O
resembling	O
calculators	B-Application
,	O
rather	O
than	O
manual	O
slide	O
rules	O
.	O
</s>
<s>
Manual	O
E6Bs/CRP	O
-1s	O
remain	O
popular	O
with	O
some	O
users	O
and	O
in	O
some	O
environments	O
rather	O
than	O
the	O
electronic	O
ones	O
because	O
they	O
are	O
lighter	O
,	O
smaller	O
,	O
less	O
prone	O
to	O
break	O
,	O
easy	O
to	O
use	O
one-handed	O
,	O
quicker	O
and	O
do	O
not	O
require	O
electrical	O
power	O
.	O
</s>
<s>
In	O
flight	O
training	O
for	O
a	O
private	O
pilot	O
or	O
instrument	O
rating	O
,	O
mechanical	O
flight	B-Device
computers	I-Device
are	O
still	O
often	O
used	O
to	O
teach	O
the	O
fundamental	O
computations	O
.	O
</s>
<s>
This	O
is	O
in	O
part	O
also	O
due	O
to	O
the	O
complex	O
nature	O
of	O
some	O
trigonometric	O
calculations	O
which	O
would	O
be	O
comparably	O
difficult	O
to	O
perform	O
on	O
a	O
conventional	O
scientific	O
calculator	B-Application
.	O
</s>
<s>
The	O
graphic	O
nature	O
of	O
the	O
flight	B-Device
computer	I-Device
also	O
helps	O
in	O
catching	O
many	O
errors	O
which	O
in	O
part	O
explains	O
their	O
continued	O
popularity	O
.	O
</s>
<s>
The	O
ease	O
of	O
use	O
of	O
electronic	O
calculators	B-Application
means	O
typical	O
flight	O
training	O
literature	O
does	O
not	O
cover	O
the	O
use	O
of	O
calculators	B-Application
or	O
computers	O
at	O
all	O
.	O
</s>
<s>
In	O
the	O
ground	O
exams	O
for	O
numerous	O
pilot	O
ratings	O
,	O
programmable	O
calculators	B-Application
or	O
calculators	B-Application
containing	O
flight	O
planning	O
software	O
are	O
permitted	O
to	O
be	O
used	O
.	O
</s>
<s>
Many	O
airspeed	O
indicator	O
(	O
ASI	O
)	O
instruments	O
have	O
a	O
movable	O
ring	O
built	O
into	O
the	O
face	O
of	O
the	O
instrument	O
that	O
is	O
essentially	O
a	O
subset	O
of	O
the	O
flight	B-Device
computer	I-Device
.	O
</s>
<s>
Just	O
like	O
on	O
the	O
flight	B-Device
computer	I-Device
,	O
the	O
ring	O
is	O
aligned	O
with	O
the	O
air	O
temperature	O
and	O
the	O
pressure	O
altitude	O
,	O
allowing	O
the	O
true	O
airspeed	O
(	O
TAS	O
)	O
to	O
be	O
read	O
at	O
the	O
needle	O
.	O
</s>
<s>
In	O
addition	O
,	O
computer	O
programs	O
emulating	O
the	O
flight	B-Device
computer	I-Device
functions	O
are	O
also	O
available	O
,	O
both	O
for	O
computers	O
and	O
smartphones	O
.	O
</s>
<s>
The	O
front	O
side	O
of	O
the	O
flight	B-Device
computer	I-Device
is	O
a	O
logarithmic	O
slide	O
rule	O
that	O
performs	O
multiplication	O
and	O
division	O
.	O
</s>
<s>
This	O
is	O
one	O
area	O
where	O
the	O
E6B	B-Device
and	O
CRP-1	O
are	O
different	O
.	O
</s>
<s>
The	O
wheel	O
on	O
the	O
back	O
of	O
the	O
calculator	B-Application
is	O
used	O
for	O
calculating	O
the	O
effects	O
of	O
wind	O
on	O
cruise	O
flight	O
.	O
</s>
<s>
This	O
part	O
of	O
the	O
calculator	B-Application
consists	O
of	O
a	O
rotatable	O
semi-transparent	O
wheel	O
with	O
a	O
hole	O
in	O
the	O
middle	O
,	O
and	O
a	O
slide	O
on	O
which	O
a	O
grid	O
is	O
printed	O
,	O
that	O
moves	O
up	O
and	O
down	O
underneath	O
the	O
wheel	O
.	O
</s>
<s>
To	O
solve	O
this	O
problem	O
with	O
a	O
flight	B-Device
computer	I-Device
,	O
first	O
the	O
wheel	O
is	O
turned	O
so	O
the	O
wind	O
direction	O
(	O
C	O
)	O
is	O
at	O
the	O
top	O
of	O
the	O
wheel	O
.	O
</s>
<s>
The	O
mathematical	O
formulas	O
that	O
equate	O
to	O
the	O
results	O
of	O
the	O
flight	B-Device
computer	I-Device
wind	O
calculator	B-Application
are	O
as	O
follows	O
:	O
</s>
<s>
Although	O
digital	O
E6Bs	B-Device
are	O
faster	O
to	O
learn	O
initially	O
,	O
many	O
flight	O
schools	O
still	O
require	O
their	O
students	O
to	O
learn	O
on	O
mechanical	O
E6Bs	B-Device
,	O
and	O
for	O
FAA	O
pilot	O
written	O
exams	O
and	O
checkrides	O
pilots	O
are	O
encouraged	O
to	O
bring	O
their	O
mechanical	O
E6Bs	B-Device
with	O
them	O
for	O
necessary	O
calculations	O
.	O
</s>
<s>
The	O
device	O
's	O
original	O
name	O
is	O
E-6B	O
,	O
but	O
is	O
often	O
abbreviated	O
as	O
E6B	B-Device
,	O
or	O
hyphenated	O
as	O
E6-B	O
for	O
commercial	O
purposes	O
.	O
</s>
<s>
He	O
,	O
with	O
P	O
.	O
V	O
.	O
H	O
.	O
Weems	O
,	O
invented	O
,	O
patented	O
and	O
marketed	O
a	O
series	O
of	O
flight	B-Device
computers	I-Device
.	O
</s>
<s>
This	O
was	O
for	O
the	O
Model	O
C	O
,	O
D	O
and	O
G	O
computers	O
widely	O
used	O
in	O
World	O
War	O
II	O
by	O
the	O
British	O
Commonwealth	O
(	O
as	O
the	O
"	O
Dalton	O
Dead	O
Reckoning	O
Computer	O
"	O
)	O
,	O
the	O
U.S.	O
Navy	O
,	O
copied	O
by	O
the	O
Japanese	O
,	O
and	O
improved	O
on	O
by	O
the	O
Germans	O
,	O
through	O
Siegfried	O
Knemeyer	O
's	O
invention	O
of	O
the	O
disc-type	O
Dreieckrechner	O
device	O
,	O
somewhat	O
similar	O
to	O
the	O
eventual	O
E6B	B-Device
's	O
backside	O
compass	O
rose	O
dial	O
in	O
general	O
appearance	O
,	O
but	O
having	O
the	O
compass	O
rose	O
on	O
the	O
front	O
instead	O
for	O
real-time	O
calculations	O
of	O
the	O
wind	O
triangle	O
at	O
any	O
time	O
while	O
in	O
flight	O
.	O
</s>
