[MineralMan]

"I was a personnel clerk in the USAF reserve in 1972 stationed at Ellington AFB (same home base as Bush). We had "better" equipment than the TANG had. They usually got our hand-me-downs. We had 0 (zero) electric typewriters in the person el headquarters for the group.

I know this because I spent a good part of the day typing re-assignment orders.

All our typewriters were manual.
"

Interesting. I was also in the USAF, from 1965-69. Every typewriter I typed on was an IBM Selectric. Some had Cyrillic balls, since I had to type in Russian part of the time.

In the headquarters office for our detachment at Ft. Meade in 1969, there were three IBM Executive typewriters...the very ones that produce proportional spacing like this. They were used for all sorts of documents.

These memos are not official memos, to be disseminated. They're memos for this person's personal file...I suppose to be use to cover his butt under some circumstance.

I'm not saying they aren't faked. I'm saying that they could have been prepared using the equipment at the time.

BTW, the IBM Executive I used to use to typeset that little magazine had a couple of interesting characters. Two of them were a "th" and an "st" as upper case on the number row. They were smaller than the regular font and printed in superscript position. Very useful.

[igoramus987]

from link...

The IBM Executive typewriter I found at a garage sale was magnificent, and (having been long since replaced by the Selectric), dirt cheap. Only somebody with a PhD in secretarial skills could operate it. It was a proportional spacing machine: an 'm' was five spaces wide, an 'i' was two. There were two separate space bars (two and three spaces respectively). To correct a mistake, you had to know the width of all the characters involved so that you could backspace the appropriate amount (backspace was the only single-space key on the machine). There was an arcane procedure for producing justified type which involved typing a page a first time (while using a special guide to measure where the lines ended), noting the extra spaces that needed to be added, marking the copy to show where two-width spaces would be replaced with three-width spaces (or, in the worst case, two two-width spaces), and typing the page a second time. Even loading the ribbon (it was one of the first carbon ribbon machines on the market) was a major challenge: its rimless reels would spill their contents at the slightest mishandling, and the thin (less than 1/2" wide) tape had to be threaded through bewildering series of slots, grooves, carriers, and guides. It was a machine only a fanatic could love, and I did. I made regular trips to Santa Barbara's IBM parts center, and spent hours with tweezers, probes, hooks, needle-nosed pliers and other fine tools, getting it working right.

The IBM Executive IBM Model D 1967 could do proportional spacing

c.f. link 1 and link 2

Later models of Selectrics replaced inked fabric ribbons with "carbon film" ribbons that had a dry black or colored powder on a "once-thru" clear plastic tape. These could be used only once but they were in a cartridge that was simple to replace. They also introduced auto-correction, where a sticky tape in front of the print ribbon could remove the black-powdered image of a typed character, and introduced selectable "pitch" so that the typewriter could be switched among pica ("10 pitch"), elite ("12 pitch"), and sometimes agate ("15 pitch"), even in one document. Even so, all Selectrics were monospaced -- each and every character was the same width. Although IBM had produced a successful typebar-based machine, the IBM Executive, with proportional spacing, no proportionally-spaced Selectric office typewriter was ever introduced. There was, however, a much more expensive proportionally-spaced machine called the Selectric Composer which was considered a typesetting machine rather than a typewriter.