SAWE Report - Cal Poly San Luis Obispo

TSFC
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0 0.5 1 1.5 2 2.5 3
Mach Number
Sea Level
Alt 5,000 ft
Alt 10,000 ft
Alt 20,000 ft
Alt 25,000 ft
Alt 30,000 ft
Alt 36,089 ft
Alt 43,000 ft
Alt 50,000 ft
Alt 55,000 ft
Alt 60,000 ft
Alt 70,000 ft
Figure 6.3 - Military TSFC Curves for Altitudes from Sea Level to 70,000 ft (21,300 m)
Once the engine deck had been established the engine dimensions were once again considered.
The fan face diameter of the new engine was assumed to be that of the RFP. Low bypass
turbofans typically have smaller fan face diameters however as the bypass ratio increases the fan
face diameter would increase as well. Since future technology is being taken into account it is
likely that the engine that would produce this thrust would have a larger bypass ratio but smaller
core keeping the fan face diameter comparable to that of the RFP. The length of the engine was
estimated based off of previous trends in engines. Engines used to plot this data include the
F100, F101, F110, F404 JT3D, JT8D and TF30. This data can be seen plotted in Figure 6.4
below. Logarithmic trendlines were fitted to the data and then extrapolated out past 30,000 lbs
(133,500 N). For a thrust of 30,000 lbs (133,500 N) the engine would have a maximum diameter
of 60 inches (152 cm) and a maximum length of 220 inches (559 cm).
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