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H. Julian Allen's Blunt-Body Concept

H. Julian Allen's Blunt-Body Concept

Image creditNACA / NASA Ames Research Center
Public domain ↗

H. Julian Allen's Blunt-Body Concept

Year
1951
Creator
H. Julian Allen, Alfred J. Eggers Jr.
Company
NACA Ames Aeronautical Laboratory
Location
Moffett Field, California

Description

In 1951 Julian Allen at Ames found that a blunt nose protects a warhead or capsule better than a sharp nose during reentry. The blunt shape makes a shock wave that keeps most of the heat away from the body.

Importance

The concept reduced the reentry heat problem that delayed the development of ballistic missiles in the United States. Julian Allen and Alfred Eggers described it in a 1953 NACA report, and NACA released later versions in 1957 and 1958. It also gave the Mercury capsule its shape, and the photograph shows Allen at a blackboard with a drawing of a bow shock.

Interesting fact

For Mercury, Alfred Eggers suggested a lifting body without wings, but NASA chose the blunt shape of Julian Allen because engineers could build it sooner.

Sources

  1. Atmosphere of Freedom: 75 Years at the NASA Ames Research Center (SP-2014-4314) ↗NASA History Program Office (Glenn E. Bugos) · 2014
  2. NACA RM A53D28 (original research memorandum) ↗NASA Technical Reports Server · 1953-08-25
  3. NACA TN 4047 ↗NASA Technical Reports Server · 1957-10
  4. A Study of the Motion and Aerodynamic Heating of Ballistic Missiles Entering the Earth's Atmosphere at High Supersonic Speeds (NACA Report 1381) ↗NASA Technical Reports Server · 1958
  5. H. Julian Allen with Blunt Body Theory (NASA photo ARC-1957-A-22664 and caption) ↗NASA via Wikimedia Commons · 1957