Q:

Re old (1993) US VFR sectional charts-- when did the term "Class E" first appear?

When did the phrase "Class E" or "Class E airspace" first appear on the legend of US VFR sectional charts, to identify the meaning of the thin dashed magenta line?  I'd like to narrow down the date as precisely as possible. Currently I'm aware that this phrase DID appear on the legend of a sectional chart (Hawaiian Islands) effective November 11, 1993, and did NOT appear on the legend of a sectional chart effective August 19 1993.  Please post the "effective date" of any US VFR sectional chart that you are aware of before November 11 1993 in which the phrase "Class E" or "Class E airspace" does appear on the legend, or the "effective date" of any US VFR sectional chart that you aware of after August 19 1993 in which the phrase "Class E" or "Class E airspace" does not appear on the legend.
Basically this question is just asking when the current "alphabet" system of airspace classification first appeared on US VFR sectional charts-- presumably the terms "Class A", "Class B", "Class C", "Class D", and "Class E" were all introduced at the same time.
When answering this question please disregard any reference to foreign (e.g. Canadian) airspace on the legend of the US VFR sectional chart-- the transition to the "alphabet" system of airspace classification may not have been simultanous between the US and all bordering countries.  

A:

According to this AOPA article, the change was made in Sept, 1993

In a move to simplify airspace classification, the FAA will rename the different airspace categories on Sept. 16, 1993. In order to fall in line with ICAO (International Civil Aviation Organization) practices, it will replace descriptive titles, such as Terminal Control Area, with alphabetical designators, such as Class B Airspace. This change will be phased in gradually. Charts and references will carry both designations until pilots get used to the transition.

https://www.aopa.org/members/ftmag/article.cfm?article=1054
And some more background

A Brief History of Aeronautical Charting
To understand the change that GIS has brought to the National Geospatial-Intelligence Agency (NGA), it is helpful to be familiar with the history of aeronautical charting.
Shortly after the Wright brothers made their historic first flights, the skies began to fill with aircraft. Visibility was the key navigational tool at that time. Aircraft were limited to short flights in clear weather and used transportation routes to navigate by, flying low to the railroads during reduced visibility. Early pilots began making personal notes to help them navigate to and land at increasingly distant airports, and enterprising pilots sold these notes to other pilots, but air travel remained limited by visibility.
In the 1930s, radio technology made it possible for pilots to navigate farther distances through unfamiliar surroundings in reduced visibility. In 1941, the first instrument approach and landing charts were developed, serving pilots with the need to land in low visibility.
By this time, aviation was a matter of interest worldwide. Many organizations began drafting standards for aviation-related maps, charts, and information. During World War II, the demand for charts increased dramatically. By 1943, production had increased from around 500,000 per year to more than 11 million. The U.S. Army and Navy air forces each built their own custom charts to fit their wartime needs.
By the end of the war, it was clear that standardized products and symbology were needed to support international air travel. The following years saw the establishment and maturity of many of the aeronautical- and aviation-related agencies and associations that we see today, such as the U.S. Federal Aviation Administration and the United Nations International Civil Aviation Organization (ICAO), each mandated to ensure the safe, efficient, and orderly evolution of international civil aviation.
Today, these organizations and others drive the look and feel of aviation products worldwide. They have also mandated an update cycle to ensure that all aircraft are flying on the same data. Depending on the region of the world, this cycle is effective every 28 days or multiples of 28 days. It is easy to see how a map of the world's airports and airways, updated every 28 days and limited by international standards, can become a huge challenge. This challenge is the mission of NGA's Aeronautical Division.

http://www.esri.com/news/arcnews/summer07articles/a-brief-history.html

A:

As indicated by CrossRoads it was on September 16, 1993 that the airspace classification structure changed. The decision was made in 1991, as can be seen in the US Library of Congress:  Federal Register: 56 Fed. Reg. 65415 (Dec. 17, 1991).

SUMMARY: 
This final rule amends the Federal Aviation Regulations (FAR)
  to adopt certain recommendations of the National Airspace Review (NAR)
  concerning changes to regulations and procedures in regard to airspace
  classifications. These changes are intended to: (1) Simplify airspace
  designations; (2) achieve international commonality of airspace
  designations; (3) increase standardization of equipment requirements
  for operations in various classifications of airspace; (4) describe
  appropriate pilot certificate requirements, visual flight rules (VFR)
  visibility and distance from cloud rules, and air traffic services
  offered in each class of airspace; and (5) satisfy the
  responsibilities of the United States as a member of the International
  Civil Aviation Organization (ICAO). The final rule also amends the
  requirement for minimum distance from clouds in certain airspace areas
  and the requirements for communications with air traffic control (ATC)
  in certain airspace areas; eliminates airport radar service areas
  (ARSAs), control zones, and terminal control areas (TCAs) as airspace
  classifications; and eliminates the term "airport traffic area." The
  FAA believes simplified airspace classifications will reduce existing
  airspace complexity and thereby enhance safety.
EFFECTIVE DATE: 
These regulations
  become effective September 16, 1993,
  except that ...

