McDonnell XP-67

The McDonnell XP-67 "Bat" or "Moonbat" was a prototype for a twin-engine, long-range, single-seat interceptor aircraft for the United States Army Air Forces. Although the design was conceptually advanced, it was beset by numerous problems and never approached its anticipated level of performance. The project was cancelled after the sole completed prototype was destroyed by an engine fire.

Design and development

Origins

In 1940, the U.S. Army Air Corps issued Request for Proposal R-40C, requesting designs for a high-speed, long-range, high-altitude interceptor intended to destroy enemy bombers. The specifications were very bold, encouraging manufacturers to produce radical aircraft that would outperform any existing fighter in the world at the time. The aerospace parts manufacturer McDonnell Aircraft, eager to begin manufacturing its own aircraft, responded to the proposal with drawings and specifications of the proposed Model I, which would be powered by an unusual geared drivetrain with a single Allison V-3420 engine buried in the fuselage powering twin wing-mounted pusher propellers in the wings. However, 22 other manufacturers also issued proposals to meet the Army’s request; the McDonnell proposal had relatively unimpressive anticipated performance, and its odd drivetrain was unproven. The Model I fell in 21st place when the 23 proposals were examined and scored. The proposals that were accepted included the similarly ill-fated XP-54, XP-55, and XP-56. Despite the apparent setback, Air Corps leaders were impressed by the nascent company’s efforts, and granted McDonnell a $3,000 contract to re-engineer the aircraft.

Metasyntactic variable

A metasyntactic variable is a placeholder name used in computer science, a word without meaning intended to be substituted by some objects pertaining to the context where it is used. The word foo as used in IETF Requests for Comments is a good example.

By mathematical analogy, a metasyntactic variable is a word that is a variable for other words, just as in algebra letters are used as variables for numbers. Any symbol or word which does not violate the syntactic rules of the language can be used as a metasyntactic variable. For specifications written in natural language, nonsense words are commonly used as metasyntactic variables.

Metasyntactic variables have a secondary, implied meaning to the reader (often students), which makes them different from normal metavariables. It is understood by those who have studied computer science that certain words are placeholders or examples only and should or must be replaced in a production-level computer program.

Bat (guided bomb)

The ASM-N-2 Bat was a United States Navy World War II radar-guided glide bomb which was used in combat beginning in April 1944.

Background

In January 1941 RCA proposed a new TV-guided anti-shipping weapon called Dragon for which an operator would use the TV image sent from the nose of the weapon and operate aerodynamic controls during the weapon's fall. The National Bureau of Standards (NBS) would provide the airframe for use with a standard bomb, and was the same guidable ordnance airframe design used for the earlier, abortive Project Pigeon weapons program. The Pelican was a June 1942 modification to instead drop depth charges against submarines using semi-active radar homing. By mid-1943, the design was changed again to use a new active radar homing system from Western Electric with a 2,000-pound (907 kg) general-purpose (GP) bomb, the same basic ordnance unit as used for the heavier USAAF VB-2 version of the Azon radio-controlled ordnance. This Pelican version entered testing in summer 1944 at Naval Air Station New York, where it hit its target ship in two out of four drops.