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1002-20-1(706 April 25, 1953 £1)714

Fourth

Progress Report

on

FIRh mTMlOH ID AIRCRAFT ENGUK MA0ELIM

by

0. &* i-loCaeiy and Vstew I . oeser

Covering period 25 January, 1953 to 25 April, 1953

for

Headquarters

•'.ri.-ht Air Development Center

v. ri ght-P at terson Air force Rase

Dayton, Ohio

Project ; o. 52-66GALS

mtM1-3

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Fir© Detection in

Aircraft Engine Faeelle©

by

c . S, 1 cC stray and m * .

• -.defter

1. Summary

Measurements of the spectral distribution of radiation, the

frequency of the flicker, and the amplitude of the flicker from

various type* of flames are being made In five spectral bands

coverin. the ran e 0.23 to 3 ,u. Arrangements are being made to study the limitations of

ler tubes and of thermistor bolometers in fire detecting systems, fh© feasibility of util! sin.- fusible electrolytes

in fire detec tiny systems ie also be in*, studied.

Z, mediation from, 'lames

Measurements are beiht made of the radiation characteristics

of flames in five different spectral bands coverin the range 0.23

to 3 u with a calibrated spec troradiome ter in conjunction with a

low frequency wave analyzer and a continuously recording oscillograph. These measurements yields 1} the spectral distribution of

tits radiation; Z) the frequency of the flicker; and 3) the amplitude of the flicker. Although, measurements made thus far have

to fit vari g flames in still air, it is planned to make similar measurements on

flames in air moving at various speeds .

3. Qei rer-fculler Tube

An ultra-violet sensitive Geifcr-Hullor tube and the necessar:

accessory circuits have been assembled for experiments to determine

the applicability of such tubes to fire detection.

k • 'itemi s tor Bolome ter

One of the major problems encountered in the deal,, n of radiation type fire, detector© is the inability of existing photoelectric

detectors to retain their sensitivity at the high ambient temperatures encountered in engine spaces. A cursory investigation of a
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radiation receiver known as a ** thermistor bolometer” indicates

that it may retain its* sensitivity at high temperatures. Arrangements have been made to obtain and test such a bolometer.

There arc certain chemical compounds which, in the solid

state, produce no perceptible electrolytic effect but which, :

the liquid state, become active electrolytes, the use of such

a material in conjunction with two dissimilar metals to form a

battery when the temperature is raised above the melting point

has been used in a number of applications and has recently been

proposed for use in fire detecting, systems. This principle may

be adapted to either a "spot*1 or "continuous” type system.

Demonstrations with relatively simple equipment indicate

that it is possible to obtain the required time of response with

such a system, tfo study has been made of the materials required

to withstand the reaction that may take place at the very high

temperatures attainable in flames. One possible objection to a

system of this type is that, once Installed in an engine nacelle,

the temperature at which it operates cannot be altered because

the melting point of the electrolyte is an inherent property of

the material.

$ • Fusifel e Elee trolyte

6. financial Condition

Expenditures and commitments on this projects

April 25 through December 31, 1952

January 1 through March 31 , 1953

10,733.37

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Total through March 31, 1953 1: 00 . f
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