TESTING METHOD AND APPARATUS FOR SIMULATING ACCELERATION FUNCTIONS

• US 3,845,665 A
• Filed: 11/09/1973
• Issued: 11/05/1974
• Est. Priority Date: 04/25/1972
• Status: Expired due to Term

• Current Assignee: Joseph G. Cappetta, Steven H. Langdo
• Original Assignee: Joseph G. Cappetta, Steven H. Langdo
• Inventors: Cappetta, Joseph G., Langdo, Steven H.
• Primary Examiner(s): Gill, James J.
• Application Number:
  US05/414,563
• Time in Patent Office: 361 Days
• Field of Search: 73/1D,1DC,12,432SD
• US Class Current: 73/865.3
• CPC Class Codes: F42C 21/00 Checking fuzes; Testing fuzes
• CPC Class Codes: G01M 9/00 Aerodynamic testing; Arrangements in or on wind tunnels

Abstract

A testing method and apparatus for simulating acceleration functions experienced by a missile or a projectile during launch. The method comprises the steps of mounting a test piece on a test fixture so that its normal flight axis is perpendicular to the fixture'"'"''"'"'s direction of travel, propelling the loaded test fixture along a straight path until a desired level of speed is obtained, guiding the fixture into an arcuate path, maintaining the speed of the test fixture constant while in the arcuate path, guiding the test fixture along a second straight path which forms a continuation of the first arcuate path, maintaining the speed of the test fixture and the test piece affixed thereto constant while traversing the second straight path, guiding the test fixture into a helical path, maintaining the speed of the fixture and the test piece constant while in the helical path, while maintaining constant speed for a number of revolutions depending upon the duration of the radial acceleration desired. The test piece is held in a rolling test fixture which is initially propelled within a rectangular shaped closed track by a blast of compressed air. The speed of the test fixture is adjusted in the straight sections by a plurality of controlled motordriven belttype friction stabilizers which synchronize the speed of the test fixture with the speed in centrifuge sections located in an arcuate path and helical path.

Claims

1. A testing method for simulating on a test piece acceleration environments characterized by the rapid turn on and off of a plurality of acceleration pulses which comprises:

mounting said test piece in a test fixture so that its normal flight axis is perpendicular to the direction of travel of said fixture;

propelling said fixture along a first linear path from a stationary position to a predetermined speed at the end of said path;

guiding said fixture having said speed into an arcuate path;

maintaining the speed of said test piece constant while said test piece is in said arcuate path so that said test piece has a constant radial acceleration;

guiding said test piece along a second linear path which forms a continuation of said arcuate path;

synchronizing the speed of said test piece with said predetermined speed at the ends of said first and second linear paths;

guiding said test piece into a circular helical path;

maintaining the speed of said test piece constant while said test piece is in said helical path for a number of revolutions depending upon a duration of constant radial acceleration simulation desired.

2. Testing apparatus for simulating said acceleration environments which comprises:

mounting means for holding said test piece so that its normal flight axis is perpendicular to the direction of travel of said mounting means;

means for propelling said mounting means along a first linear path from a stationary position to a predetermined speed at the end of said path;

first means for guiding said mounting means having said speed into an arcuate path;

first means for maintaining said velocity of said test piece constant while said test piece is in said arcuate path so that said test piece has a constant radial acceleration;

second means for guiding said test piece along a second linear path;

stabilizer means for synchronizing the speed of said test piece to said predetermined speed at the ends of said first and second linear paths;

third means for guiding said test piece into a circular helical path; and

means for maintaining the speed of said test piece constant while said test piece is in said circular helical path for a number of revolutions depending upon a duration of a constant radial acceleration simulation desired.

3. An apparatus as recited in claim 2 wherein said mounting means comprises:

a carriage having a plurality of wheels mounted on the bottom of said carriage, a pair of longitudinally-positioned rollers on the top of said carriage, a plurality of slide pads located on the sides and top of said carriage for reducing the frictional losses, said carriage having a cavity for holding said test piece therein.

4. An apparatus as recited in claim 2 wherein said means for propelling comprises:

an air compressor having a gas reservoir connected thereto;

a quick opening valve having one end pneumatically connected to said air compressor for rapidly releasing air therefrom;

a first rectangular tubular linear track section having one end connected to the other end of said quick opening valve;

a hinged loading door attached to Said linear track which permits said mounting means to be inserted therein.

5. An apparatus as recited in claim 2 wherein said first guiding means comprises:

a cylindrical housing having rectangular tubular input and output port sections connected thereto;

an arcuate tubular track of rectangular cross section supported in said housing intermediate said input and output ports and communicating therewith, said arcuate track having an opening in the inner arcuate track wall;

6. An apparatus as recited in claim 2 wherein said first means for maintaining velocity comprises:

a cylindrically-shaped drum concentrically supported in said housing and having a peripheral surface which protrudes through said opening of said arcuate track, said surface contacting said rollers of said carriage as said carriage passes through said arcuate track;

a motor connected to said drum rotating said drum, which in turn frictionally drives said carriage so that said test piece will have said constant radial acceleration impressed thereon.

7. An apparatus as recited in claim 2 wherein said stabilizer means comprises:

a pair of rotatably supported pulleys;

an endless belt engaging said pulleys and frictionally contacting said rollers of said mounting means;

an electric motor connected to said pulleys for rotating said pulleys to move said belt;

an electronic controller connected to said motor for adjusting the speed of said motor and to synchronize the speed of said belt and said mounting means with the tangential speed of said test piece in said first and third guiding means.

8. An apparatus as recited in claim 2, further comprising means for braking said mounting means when said mounting means exits from said helical path.