be made by varying the current to achieve the desired voltage drop across 

 the base 1/4 inch. At the design heat load, a copper cylinder 1/4 inch 

 thick has a At of about 2°F. All other potentially useful materials are 

 of lower conductivity, so they will have a greater temperature drop; for 

 aluminum, this is 3.6°F. 



The actual resistance paper used for these and most later iterations 

 is shown in Figure 9, and includes not only the field with pricked points 

 at the grid intersections, but a varying resistance area allowing sinula- 

 tion of the resistance provided by the film coefficient, h. By biasing 

 the outer border to 40°F with an external electrical resistance it is 

 possible to obtain direct voltage readings at any point on the surface 

 which are equivalent to the temperature. Figure 10 shows the same cross 

 section, with temperatures plotted for a first single nodule designed 

 to provide a prototype for the full-scale 12-module system, shown in 

 Figure 11. This single module is shown schematically in Figure 12 in 

 partial section full size, and in elevation l/4th size, with some details 

 of its construction. Its method of construction allowed two desirable 

 features: a complex, 'ideal' shape at low cost, and a copper sheath to 

 which could be directly attached a single constantan wire forming a 

 thermocouple junction by which precise surface temperatures could be 

 obtained. The succession of steps followed in checking the design was: 



(a) Prepare, bias, and take readings of a preliminary resistance 

 paper half section, four times full size. 



(b) Build the prototype, lead-filled single module and equip with 

 electric heaters and a heat transfer liquid consisting of approximately 

 two parts water an' one part ethyl alcohol, enough to cover the electric 

 heaters while in the vertical position. 



(c) Test the lead-filled prototype in a snail tank at two tempera- 

 tures of water--one at about 70°F, ambient fcr the Port Hueneme area, 

 and one at about 40°F, using ice water. 



(d) Repeat the ambient water tests with the module tilted 30 and 

 60 degrees from the vertical (a small trunnion was used to main '.n 

 stability). 



(e) Fill in the f^eld of temperatures, using an electrical bias 



to reproduce the measured values. Figures 10(a) and 10(b) show the section 

 temperatures at mid -elevation; the temperatures underlined are measured. 



The values obtained are recorded in Tables 4 and 5. There was no 

 indication of local overheating or insufficient cooling in any of these 

 first tests. 



