E1

E1, E01, E.I or E-1 may refer to:

Transport

Trains and locomotives

Aircraft

Submarines

Roads

U.S. uniformed services pay grades

Pay grades are used by the uniformed services of the United States to determine wages and benefits based on the corresponding military rank of a member of the services. While different titles or ranks may be used among the seven uniformed services, pay grades are uniform and equivalent between the services and can be used to quickly determine seniority among a group of members from different services. They are also essential when determining a member's entitlements such as basic pay and allowances.

Pay grades are divided into three groups: enlisted (E), warrant officer (W), and officer (O). Enlisted pay grades begin at E-1 and finish at E-9; warrant officer pay grades begin at W-1 and finish at W-5; and officer pay grades begin at O-1 and finish at O-11. Not all of the uniformed services use all of the grades; for example, the Navy does not use the grade W-1, the Air Force discontinued use of the warrant grades in the 1960s, and both the Public Health Service and National Oceanic and Atmospheric Administration do not use any of the enlisted or warrant grades.

Rocketdyne E-1

Rocketdyne's E-1 was a liquid propellant rocket engine originally built as a backup design for the Titan I missile. While it was being developed, Heinz-Hermann Koelle at the Army Ballistic Missile Agency (ABMA) selected it as the primary engine for the rocket that would emerge as the Saturn I. In the end, the Titan went ahead with its primary engine, and the Saturn decided to use the lower-thrust H-1 in order to speed development. The E-1 project was cancelled in 1959, but Rocketdyne's success with the design gave NASA confidence in Rocketdyne's ability to deliver the much larger F-1, which powered the first stage of the Saturn V missions to the Moon.

History

Genesis

In July 1954 the Air Force Scientific Advisory Board's ICBM working group advised the Western Development Division (WDD) on their doubts about the Atlas missile that was then under development. Atlas used a number of unconventional features in order to meet its performance goals, and they felt that there was undue risk that if any of these proved unworkable in practice then the entire design would fail. The group suggested that a second ICBM project be started as a risk mitigation effort.

Grumman E-1 Tracer

The E-1 Tracer was the first purpose built airborne early warning aircraft used by the United States Navy. It was a derivative of the Grumman C-1 Trader and first entered service in 1958. It was replaced by the more modern E-2 Hawkeye in the early 1970s.

Design and development

The E-1 was designated WF under the old US Navy system; the designation earned it the nickname "Willy Fudd". Since the S-2 Tracker was known as S2F under the old system, that aircraft was nicknamed "Stoof"; the WF/E-1 with its distinctive radome gained the nickname "Stoof with a Roof." The E-1 featured folding wings for compact storage aboard aircraft carriers. Unlike the S-2 and C-1 in which the wings folded upwards, the radome atop the fuselage necessitated the E-1 to fold its wings along the sides of the fuselage.

Radar

The Tracer was fitted with the Hazeltine AN/APS-82 in its radome and fuselage. The radar featured an Airborne Moving Target Indicator (AMTI), which compares the video of one pulse time to the next in reflected radar energy to distinguish a flying aircraft from the clutter produced by wave action at the ocean's surface. The energy reflected from an aircraft changes position rapidly compared to the energy reflected from the surrounding sea. Separating a moving object from stationary background is accomplished by suitable hardware.