"Ed Rasimus" wrote in message
...
On Sun, 11 Jan 2004 09:50:00 -0800, "Tarver Engineering"
wrote:


"Ed Rasimus" wrote in message
.. .
On 11 Jan 2004 01:19:53 GMT, (B2431) wrote:

From: Ed Rasimus

Not sure what "roll steering" is.

The only place I have ever seen the terms "roll steering" and "pitch
steering"
was in reference to the bars on an ADI.

Not even there, Dan. The ADI terminology was "bank steering" and
"pitch steering".

That would be because most INSs produse "roll command" and you would not
have "roll steering" in an F-4.


Dan's post refers to the nomenclature for the Attitude Director
Indicator. The two bars, one horizontal and one vertical, provide cues
for flying instruments, similar to the "bug" in more current displays.
They can offer commands related to navigation guidance such as turns
to headings or cues for flying ILS approaches or even be linked to
weapons release computers for fly up for lofted weapons deliveries.

What roll steering refers to is a navigational error signal. From which the
flight director roll computer would use roll steering and other parameters
to produce roll command, usually displayed as a CMD bug on a flight director
attitude display.

The vertical bar on the display was called the bank steering bar
because it displaced left or right of center and when the proper
amount of bank was initiated, it returned to center. When your course
change was complete it displaced the opposite direction to return you
to wings level flight.

Or a bug can be used to play pilot chase the needles, or just have George do
it.

The horizontal bar was termed the pitch steering bar and it commanded
pitch inputs to achieve the proper climb or dive angles.

Same idea, except roll steering is only part of the equation that produces
command.

The nomenclature has nothing to do with the Inertial Navigation
system. The ADI is not specific to the F-4, but is the generic
attitude indicator display and was the same in the F-105, F-4, and
T-38, as well as a a number of other US aircraft which I don't have
several thousand hours in.

Ed, an INS usually produces roll command directly and does not use the
flight director calculation for roll command. The nomenclature is
different.

Let me give you an example of some 747 navigation changes we have
facilitated:

A certain head of state aircraft wants to have a glass cockpit and selects a
company with an FMS that integrates several flight management systems into
their computer. (PMS, Flight Director, DADC, Primary Display) For this
system integration we provided a converter from digital to Analog Roll
Command, so that the FMS could drive the aircrft's roll command input.

Another head of state has a 747 where there was a desire to integrate a
Trimble 2101 I/O for approach. In this case, we provided a signal such that
the HSI could output "roll steering" from signals derived from the GPS and
the DG.

So, it is a matter of where the signal is in the system as to what it is
named and you would not normally use roll steering with an INS, but I have
heard of some INSs that are the other way.