What are the construction guidelines to geometrically build a NACA intake (submerged intake) for aircrafts?

The relationships between the aerodynamic performance parameters (ram recovery, drag, and mass flow rate) with the geometric parameters (width of the intake, height, length of ramp, ramp angle, inlet radius and angle, divergent wall angles, divergent wall curve radius, etc...) would provide a guide to begin the construction process for a base model, which could then be refined with further investigation for a specific aircraft.

There are even tools to construct the curve of the NACA intakes. However, the background of the tool as its aerodynamic justification isn't available or at least not found.

I would therefore greatly appreciate any material on the correct geometric construction of NACA intakes.


1 Answer 1


NACA itself published quite a few papers on their submerged duct design. As a starter have a look at:

  • Mossman, Emmet A., et al. NACA-RM-A7I30 "An experimental investigation of the design variables for NACA submerged duct entrances", 08. January 1948

  • Frick, Charles W., et al. NACA-ACR-5I20 "An Experimental Investigation of NACA Submerged-Duct Entrances", 01. October 1945

The NASA Technical Reports Server as well as the UK archive of digitised NACA Reports offer a lot more material for further investigation.


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