John A. Parker

The effect short-time protection of thermally sensitive substrates from the action of heat or impinging flames, coatings an be applied which will swell to form an insulating layer.

J.R. Kaye, T.J. Hogland, H.P. Weinberg

Twenty samples from small aircraft engine exhaust systems were investigated metallurgically to determine the differences, if any, between failures produced in a ground test program and failures from operating aircraft as de scribed in Technical Report ADS- 28. The work included samples fabricated from a new material (nickel-iron- chromium alloy) recommended as an improvement for applications such as exhaust systems. The purpose also requested further information regarding the metallurgical cause of failure of conventional stainless steel exhaust system components. The test failures and samples involving AISI 321 and 347 stainless steels were similar to the previously evaluated failures from operahonal.aircraft. The samples showed the effects of high temperature corrosion, carburization, sigma phase and delta ferrite. In most cases, these conditions were similar to those exhibited by the components from operational aircraft. Crack-type failures were attributed to a type of fatigue, which was also the conclusion drawn by the investigation of the components which failed on aircraft. Test results disclosed that a material composed of 21 per cent chromium and 32 per cent nickel was far superior to AISI 321 or 347 stainless steel in regard to high-temperature oxidation or corrosion in exhaust systems. Those failure s resulting from oxidation' could be significantly reduced or eliminated by incorporation of this material.

Dorothy Bulford

The bibliography consists of 578 references to technical reports, articles in periodicals, and books published during the past 17 years. Reference about other forms of turbulence such as that occurring with storms and airplane wake votices are not included.

The following summary of the FIREPAC Test Program. The initial testing and evaluation commenced on 24 January 1968 with the first series being completed on 14 March 1968.

John Marcy

Propulsion Section NA 542 - Data Report 62