Experimental Results from a Static Stability and Pressure Test of the Minuteman Instrumented Payload Delivery System Launch Vehicle Configuration at Mach Numbers from 1.6 to 5.0

1976 ◽  
Author(s):  
E. E. Lindsay ◽  
D. H. Fikes
Keyword(s):  
Delivery System ◽  
Static Stability ◽  
Launch Vehicle ◽  
Experimental Results ◽  
Pressure Test ◽  
Mach Numbers ◽  
Vehicle Configuration

Effects of Molecularly Thin Liquid Lubricant Film Materials on Slider Hysteresis Instability in Hard Disk Drives

2007 ◽  
Author(s):  
Norio Tagawa ◽  
Daisuke Tanaka ◽  
Atsunobu Mori
Keyword(s):  
Hard Disk Drives ◽  
Disk Surface ◽  
Intermolecular Forces ◽  
Experimental Results ◽  
Disk Drives ◽  
Friction Forces ◽  
Liquid Lubricant ◽  
Pressure Test ◽  
Lower Mobility ◽  
The Difference

In this study, the difference in the touchdown and takeoff pressures was monitored by using three types of lubricant materials, namely, Zdol2000, Ztetraol2000 and A20H2000 by using the pump down pressure test. The results indicated that the touchdown pressures depended on the lubricant materials; it was greatest for Ztetraol2000 and smallest for A20H2000. The takeoff pressure was greater for a lubricant with lower mobility. Considering these experimental results, it was suggested that the variation in the touchdown pressure is due to a variation in the intermolecular forces, taking into account the lubricant pickup by a slider. Further, it was suggested that the variation in the takeoff pressure is caused by a variation in the friction forces between the slider and disk surface.

Blockage Corrections for Blunt-Based Bodies of Revolution

1968 ◽  
Vol 72 (696) ◽  
pp. 1058 ◽  
Author(s):  
W. A. Mair
Keyword(s):  
Correction Factor ◽  
Experimental Results ◽  
Base Pressure ◽  
Alternative Methods ◽  
Wind Tunnels ◽  
Maximum Diameter ◽  
Bodies Of Revolution ◽  
Blockage Correction ◽  
Mach Numbers ◽  
Experimental Values

Calvert has considered alternative methods of estimating the blockage corrections for blunt-based bodies of revolution in closed wind tunnels at low Mach numbers. His models were all of maximum diameter 152 mm, with an ellipsoidal nose section 203 mm long followed by a cylindrical afterbody. The ratio of overall length L to maximum diameter d varied from about 1.5 to 5.5. For each model the base pressure was measured in wind tunnels of two different sizes, so that the blockage correction factor e for the smaller tunnel could be derived for each model from the experimental results. These experimental values of e were compared with alternative theoretical estimates, using the methods given by Evans, Maskell and Pank-hurst and Holder.

Study of Airscrews for High Speed Aeroplanes

1940 ◽  
Vol 44 (352) ◽  
pp. 322-337
Author(s):  
Lucio Lazzarino
Keyword(s):  
Special Reference ◽  
Present Article ◽  
High Speed ◽  
Numerical Evaluation ◽  
Experimental Results ◽  
Aerodynamic Efficiency ◽  
Angular Velocities ◽  
Mach Numbers ◽  
High Mach

RésuméIt is demonstrated how, with increase in speed, the diameter of optimum efficiency and the maximum possible value of efficiency of an airscrew diminish. The efficiency of a system of two counter-revolving airscrews with different angular velocities is then determined, and the variation of efficiency with variation in the relation between the angular velocities of the two airscrews.With increase in the height and speed of flight, airscrew performance inevitably falls off, frequently in a marked degree; this being mainly due to the decrease in aerodynamic efficiency of the blade sections at high Mach numbers.The object of the present article is to analyse the influence exerted upon the performance of an airscrew by the various parameters that determine it, wit-h special reference to those connected with the speed and height of flight.A similar study has also been made of systems constituted of two counter-rotating airscrews, with a view to comparing them with isolated airscrews designed to absorb the same power under identical conditions.By the methods here described, an approximate numerical evaluation of the performance can be made, utilising the experimental results which are already to hand.

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