"Mike Marron" wrote in message
...
"Mortimer Schnerd, RN" wrote:
Mike Marron wrote:

In any event, other than NDB's, what type of
instrument approaches were generally available back in WW2?

Radio ranges. Pilots flew along a beam listening to dots and dashes. The
tone
changed if you drifted off the beam. Some of the old timers here can explain
this a lot better than me since I didn't start flying until the late 1970's.

Since I qualify as one of the old timers, this is how it worked as best as this
over the hill WWII airplane driver can remember it:

Try to visualize two intersecting lines creating the form of a cross, which is
the radio range with
its station at the intersection. Each of the opposing quadrants broadcasts
either an "a" or an "n"
in Morse code, i.e.- ".-" or "-." Where the adjacent quadrants come together,
the signals merge
and become a solid tone, which becomes one of the legs of the range. The merger
was never abrupt as
I recall, so if you were flying at right angles to a leg, you heard a clear "n"
as you approached a
leg, and then slowly started to hear a solid tone in the background. The closer
you got to the leg,
the less you were able to hear the "n" until it completely disappeared as you
flew over the leg.
When you started to pick up the "a" over the solid tone of the leg, you were
outbound from the leg.

Let down procedures were published, just as they are now. So, whatever your
heading happened to be,
the first thing you did was to ID the station, which broadcast its unique
identifier in Morse every
minute or so (I don't recall how often). Then, you'd identify the quadrant you
were in, as well as
which leg of the range you were approaching (by the solid tone becoming louder
or lower), each of
which had its own published let down headings and altitudes. Work this out on a
piece of scratch
paper, and I think it'll make more sense to you than just trying to visualize it
from words.

Reverse turns were almost always initially done by flying outbound on a leg,
then a 45 degree turn
(all turns single needle width) either left or right and fly for a minute on
that heading, then a
180 in either direction until the leg was again intercepted, followed by a 45
degree turn to the
inbound heading.

Somewhere along the line, somebody discovered that if you did a 90 degree turn
to the left of the
outbound leg heading and then a 270 to the right as soon as you hit the 90
heading, you'd end up at
the same place inbound on the leg and didn't have to time your outbound leg
after the 45 turn, which
was useful when your clock was inop or at night when your cockpit lighting
wasn't what it should
have been.

When RDBs became available, they simplified the process because you had a visual
pointer to help you
identify the station location, instead of having to rely on the clarity of audio
radio reception
which, when you were far enough from the station and in bad wx or over poor
radio reception terrain,
could be a challenge.

At any rate, after a while, stations were lined up so that their legs were in
what were the
forerunners of airways, so that you could navigate over distances simply by
flying from the legs of
one station on to those of another ahead of you. I once ferried a gooneybird
from the east coast to
someplace near Riverside, Cal. for a major overhaul by flying radio ranges all
the way.

I hope that helped explain how the system worked. I hope I didn't have too much
screwed up, but
it's the best I can do with the memory available to me of details I used 60
years ago or so.

Please feel free with the questions if I've left something muddy or otherwise
unclear. I may or may
not be able to clarify it, but I will try.

George Z.