Page 1 - Combined_115_OCR

INTER COMPANY CORRESPONDENCE
W
FILE
date14 May 1969
CODE
TO - NAME DEPT. DIVISION PLANT/OFFICE
M. L. Bell 4800 Space 7804
FROM - NAME DEPT. DIVISION PLANT/OFFICE
G. F. McCanless 4830 Space 7804

CALIBRATION OF THE NACA SUBMERGED INLET

This memorandum describes test procedures that will determine if a NACA
submerged inlet (described in NACA RM #A7I30) significantly increases the mass
flow of air to an automobile carburetor. The static pressure on one side of the
carburetor should be measured. These tests should be made at a given velocity
(150 mph or greater) and under uniform atmospheric conditions. Runs should in­
clude cases with no inlet, with an inlet of the type previously used that takes in air
just in front of the wind shield, and with the NACA submerged inlet. The static
pressure data can be used in connection with Figure 1 to determine the relative
mass flow of air into the carburetor. Figure 1 is based on a volumetric flow of
950 cfm and on the assumption of no heat transfer to or from the air stream prior
to its entry to the carburetor intake.

Calculations were also made to establish the expected ranges of the carburetor
intake static pressure data. An efficiency of 0.05 was assumed when no inlet is used.
Efficiencies of 0.15 and 0.30 were assumed for the windshield inlet. An efficiency
of 0.87 was assumed for the NACA submerged inlet. In addition, the foliowin
atmospheric and carburetor characteristics were used in the calculations.

Pressure 14.7 psi
Temperature 70 °F
Density 75.03 • IO"3 lbm/ft CO
Carburetor Volumetric Flow 950 cfm
LO
Carburetor Intake Area 0.1365 ft

The results of these calculations are shown in Figure 2.

G. F. McCanless

GFMc:ws

cc:
H. Bader, Jr.
F. W. Deady
H. D. Reeker
J. E. Vaughn
W. P. Wright
E. E. Zimmerman

84- 1 10-7879 REV. 1-63