Near the end of the NASA video Rocket Engine Testing the NASA Way! there is an image that appears to be archival an possibly quite old. It's a long cylinder densely wrapped with what I assume is cooling liquid piping, hanging inside a test tunnel.

Can anyone recognize this object, what the purpose is or what experiment is being done, and say a little more about how it was used?

screen shot from Rocket Engine Testing the NASA Way!


1 Answer 1


This is a NACA test of a 20-inch diameter ramjet in the Altitude Wind Tunnel (AWT) on February 7, 1946.

20-inch diameter ramjet mounted in AWT

The AWT analyzed the overall performance of ramjets at altitudes up to 47,000 feet. In this test, the ramjet was tested at altitudes ranging from 7000 to 41,500 feet and at ram-pressure ratios equivalent to free-stream Mach numbers as great as 1.84 using preheated 62-octane fuel.

From the report summary:

At an equivalent free-stream Mach number of 1.84 and a gas total-temperature ratio across the engine of 5.7, the equivalent sea-level net thrust was 8135 pounds. For these conditions, the over-all efficiency was 12.6 percent and the combustion efficiency was 70.3 percent. The corresponding net-thrust coefficient was 0.74. The investigation also showed that no change in the performance or operating range of the engine occurred when the fuel was changed from preheated 62-octane to preheated 100-octane gasoline.


  • 2
    $\begingroup$ Very nice find! $\endgroup$ May 7, 2019 at 15:00
  • 3
    $\begingroup$ @OrganicMarble It took a while to track it down. I just started searching for "diameter tube" and "tunnel" and looking through the results until I found something that looked similar. The first thing I found was not it, but it pointed me to the AWT website where I found this picture. $\endgroup$
    – called2voyage
    May 7, 2019 at 15:01
  • $\begingroup$ I'm enjoying the photo, and the links, and their photos very much, thank you! $\endgroup$
    – uhoh
    May 7, 2019 at 17:20

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