Intelligent Repeatable Release Hold Back Bar (IRRHB)

Period of Performance: 05/08/2008 - 11/08/2008


Phase 1 SBIR

Recipient Firm

Michigan Aerospace Corp.
1777 Highland Drive Suite B
Ann Arbor, MI 48108
Principal Investigator


The Repeatable Release Holdback Bar (RRHB) is a device that is used to hold aircraft in place just prior to launching them with a catapult. These bars are about 3 feet in length and attach to the front landing gear and hold it to a cleat on the flight deck. Once the catapult is fired a pre-determined force is reached and the holdback bar lets go of the aircraft allowing it to be accelerated down the deck. There have been some problems in the past with these holdback bars letting-go of aircraft prematurely, caused by worn parts or a failure of the bar to be properly reset after a previous launch. The result is that the aircraft moves down the deck unexpectedly and too slowly for a successful launch. Michigan Aerospace Corporation (MAC) proposes a way to record the number of shots fired on the bar, read the force acting on it during each launch and monitor reset conditions. In doing so, money can be saved in preventative maintenance by detecting early signs of a failure. During use, the holdback bar goes through high shock loads, which MAC is well-equipped to address in the design of this new system.