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How did pilots program gyroscopic 'Sperry' autopilots?


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Afternoon guys,


I've recently been flying a few older aircraft within FSX recently as I do enjoy the more manual side of flying, although one thing I've never quite understood is how pilots would program the old-style autopilot you would find in aircraft like the BAC 1-11 or Boeing 707 as this was a time before the FMC.


My only guess would be that pilots manually programmed radio frequencies whilst flying, but I don't think this is the case - could someone explain to me how the old system worked?


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My only guess would be that pilots manually programmed radio frequencies whilst flying, but I don't think this is the case


Then you've guessed right and think wrong. The time of the 707 is before digital computers were a common thing (and the few that existed were huge). They did, indeed, set the radio freqs manually on the radios. They also had to manually turn the OBS on the VOR or rotate the pointer on an ADF.


There were inertial nav systems, but they weren't tied to radios, and the navigator had to periodically check them, since they would drift some over time. I'm not sure when the inertial systems went from analog (such as the bomb/nav on the B-47 and B-52, both of which had a separate bombardier/navigator to manage the system) to digital, but it still wasn't an FMC, in the modern sense. And these systems were BIG and HEAVY (the B-47 system would take up a fair sized room on the ground), with just one of the many, many boxes often taking two people to carry. The system was mostly servo mechanisms, gear trains, 3 dimensional cams and a few tube-type amplifiers. The navigator used a periscope (yes, that's not a misprint) with a tracking handle (similar to a joystick) to set winds into the system (later they tied in doppler radar for that).


As far as the autopilot controller you depict above, the one you've labeled "Horizontal Mode Selector" switched between a HDG mode (manually set the heading bug on the DG), the MAN mode (manually twist the turn selector (which you've labeled Bank Angle Selector, though it doesn't control bank, just the rate of turn)), LOC/VOR (localizer/VOR), GS (glide slope) and Auto(matic). INS may mean Inertial Nav System. The one you labeled Altitude Hold Switch is the on/off to hold the altitude set by a bug on the altimeter.


In other words, you did most of the stuff manually, without computer control.


Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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When I first started simming in FS 5.1, we didn't have fancy GPS systems where we could program in a course for the sim to fly. I kind of 'created' my own system that I used to get from place to place. Didn't have the moving map either.


I would tune the freq, then turn the VOR to capture it. Exactly as you describe.

Spent way too much time using these sims...

FS 5.1, FS-98, FS-2000, FS-2002, FS-2004, FSX, Flight, FSW, P3Dv3, P3Dv4, MSFS

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He knows there was no FMC involved. The only reason he asks these 'type' questions is to post his link to his YouTube videos. Troll post. Click bait. Annoying.

Chuck B


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