SAWE Report - Cal Poly San Luis Obispo
SAWE Report - Cal Poly San Luis Obispo
SAWE Report - Cal Poly San Luis Obispo
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Other traits were looked at before choosing a two shock compression inlet. Figure 6.7 illustrates<br />
the area ratio compared to Mach number for the two and three shock inlets. The jumps in the<br />
curve, illustrate the Mach numbers at which the engine will work the hardest because they are<br />
the locations at which the shocks occur. Both of which will occur before the cruise Mach number<br />
of 1.6 therefore occurring during the climb portion of the mission.<br />
Area Ratio vs. Mach<br />
Area Ratio<br />
1.4<br />
1.35<br />
1.3<br />
1.25<br />
1.2<br />
1.15<br />
1.1<br />
1.05<br />
1<br />
0.95<br />
0.9<br />
0.8 1 1.2 1.4 1.6 1.8 2<br />
Mach Number<br />
2 Shock 3 Shock 6 deg and 6 deg<br />
Figure 6.7 - Inlet Area Ratio<br />
Figure 6.8 shows a rough cost relationship between different type inlets. As can be seen there is a<br />
lower cost associated with a two shock inlet. There are drawbacks to having more shocks, in that<br />
they drive the inlet to be larger, longer, and send multiple radar returns. The above traits do not<br />
show enough of a benefit to go with a three shock inlet therefore a two shock inlet was chosen.<br />
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