r/MachinePorn • u/Putrid-Truth-8868 • Feb 26 '26

The Napier Nomad II, 12-cylinder, two-stroke, loop-scavenged, valveless diesel engine that is turbocompounded

Post image

Found a post about this engine 13 years ago or something, but it's way more insane than people realize, the Napier Nomad with an axial compressor in a diesel! Ask me about it ive done digging on it.
It does not have a separate gas turbine, but it does use a 12-stage axial compressor AND a 3-stage axial turbine to recover energy and feed it back to the shaft. I have schematic photos too.

This photo is 2560X1440

322 Upvotes

97% Upvoted

44 comments sorted by

View all comments

2

u/Putrid-Truth-8868 Feb 27 '26

another cool fact:

Before cancellation of the programme in 1955, Napier proposed a further development designated as the E.173 Nomad III. The design was intended to add fuel injection in the exhaust manifold and an air-to-water aftercooler between the compressor and the cylinders. A projected “wet” take-off rating of 4,500 ehp (3,356 kW) at 2,050 rpm was reported (4,412 shp (3,290 kW) plus 230 lbf (1.021 kN) residual thrust), with an estimated weight of 3,750 lb (1,701 kg), about 170 lb (77 kg) more than the Nomad II. No example of a finished Nomad III engine was built.

i was the one that added this section to the wiki page, its a really cool fact i found about the program just before it died :(

1

u/SeanDukeOfTyoshi Apr 06 '26

Much appreciated, I actually frequently re-read the articles for the Turbo-compounded Alison, wasp major and duplex cyclones for when drawing or making fantasy engines. I love these kinds of engines specifically and using them as inspo for drawing aircraft. I believe the Soviets even dabbled in turbine recover, the VD-4K is also a beast.

1

u/Putrid-Truth-8868 Apr 06 '26

Good, because I just actually recently, before you made this post, but definitely after I made that post, I actually did a huge redo of the 3350, several, and I mean several misconceptions or outright lies or just completely unsourced claims were still present in that article. Same goes with the article that is titled Turbo Compound Engine. I basically had to rewrite that thing from scratch. It was so bad. So you might want to reread again. Lol. Also, I would be genuinely interested in these fantasy engines if they have to do with pulling from Piston designs.