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This table looks like simple dynamic pressure.

The third report referenced in Chris Z's post (NACA RM A50E02) provides pressure recovery ratios for various mass flow ratios (discussion on p 5, plots on pages 14-20). While it appears nothing was tested to ratios around zero (1/4 dia wing tank vent lines at 15gph and 200 kts are in the 0.005 range--essentially zero), extrapolating a bunch makes me think we should expect mass flow ratios of 0.5 to 0.8. This is based on -2 to +2deg angle of attack at 0.3 Mach. So divide in half the pressures in the table below for a (maybe) conservative estimate.

- Kyrilian

Sky2high@aol.com wrote:

Mike,

Pressure in Units

IAS mph

Knots

"H2O

"Hg

PSI

40

34.8

0.79

0.06

0.028

50

43.4

1.23

0.09

0.044

60

52.1

1.77

0.13

0.064

70

60.8

2.41

0.18

0.087

80

69.5

3.15

0.23

0.114

90

78.2

4.00

0.29

0.144

100

86.9

4.94

0.36

0.178

110

95.6

5.98

0.44

0.216

120

104.3

7.12

0.52

0.257

130

113.0

8.37

0.62

0.302

140

121.7

9.72

0.71

0.351

150

130.3

11.17

0.82

0.403

160

139.0

12.72

0.94

0.460

170

147.7

14.39

1.06

0.520

180

156.4

16.15

1.19

0.583

190

165.1

18.03

1.33

0.651

200

173.8

20.01

1.47

0.722

210

182.5

22.10

1.62

0.798

220

191.2

24.29

1.79

0.877

230

199.9

26.60

1.96

0.961

240

208.6

29.03

2.13

1.048

250

217.2

31.56

2.32

1.140

260

225.9

34.21

2.52

1.236

270

234.6

36.98

2.72

1.335

280

243.3

39.86

2.93

1.440

290

252.0

42.87

3.15

1.548

300

260.7

45.99

3.38

1.661

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