The Roswell Report: Fact vs. Fiction in the New Mexico Desert

change in motor speed of five percent or more from the preceding rotation, the pressure value should be rejected. A slow, continuous change in speed from minute to minute may be neglected since it is probably a uniform change throughout the rotation period. The motor speed will decrease during the flight, as a result of the low temperatures and the drop in battery voltage. This of itself does not decrease the value of the record, as long as the speed does not change suddenly.

(e) Olland-Cycle Pressure Element Specifications

(1) Pressure range: 1050 to 5 mb.

(2) Desired accuracy: Surface to 300 mb $ \pm 5 $ mb. 300 mb to 50 mb $ \pm 2 $ mb. 50 mb to 5 mb less than $ \pm 2 $ mb, $ \pm 1 $ mb if possible.

Highest accuracy and readability desired on low pressure end. Temperature compensation, as required to meet pressure accuracy requirements for temperature, range $ + 30^{\circ} $ to $ - 70^{\circ} \mathrm{C} $ or equivalent for medium and high altitude flights. Mean operating temperature required more than $ 0^{\circ} \mathrm{C}. $

(3) Helix:

Cylinder--made of insulating material with low temperature coefficient. Diameter 3/4 inch to 1 inch, length $ 2^{\frac{1}{4}} $ inch.

Spiral--made of nickel or other metal which does not corrode in the atmosphere, .010 inch or less in diameter. Eight turns per inch on cylinder.

Check-points--Six points located between turns of spiral, starting with 9th turn, 60 degrees apart.

Made of the same material as the spiral. In the electrical circuit of the pressure signal.

Suggested shape 1/16 inch diameter, round pin, flush with surface of helix.