Two stroke Thursday (weird aero edition)

Kinja'd!!! "Cé hé sin" (michael-m-mouse)
06/11/2015 at 18:35 • Filed to: Napier Nomad, Two stroke

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Have a diagram showing the operation of two iterations of the Napier Nomad, a two stroke diesel aero engine with added turbo compounding.

Nomad 1 is the most incomprehensible thing that anyone has ever thought about putting in a plane.

It didn’t work out.

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Picture by

“NomadSchematic 185kBpng360kB” by System of Nomad1 and Nomad2.jpg: User:Tataroko-commonderivative work: Aaa3-other (talk) - System of Nomad1 and Nomad2.jpg. Licensed under Public Domain via Wikimedia Commons -


DISCUSSION (6)


Kinja'd!!! HammerheadFistpunch > Cé hé sin
06/11/2015 at 18:41

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Napier makes the nuttiest stuff. The deltic is by far my favorite type of crazy piston engine.

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Kinja'd!!! Cé hé sin > HammerheadFistpunch
06/11/2015 at 18:44

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Note how one of the cranks contra rotates for added interest.

Sadly, Napier (or their successor company) just makes plain old turbos nowadays.


Kinja'd!!! tromoly > Cé hé sin
06/11/2015 at 19:06

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That first image is hurting my head. Something about trying to combine a Supercharged and a Turbocharger with the same Compressor/Turbine doesn’t make sense.


Kinja'd!!! Cé hé sin > tromoly
06/11/2015 at 19:15

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What they were trying to do was use the diesel engine as the combustion chamber for the jet engine attached to it, the thinking being that the diesel could run at higher temperatures and thus increase the thermal efficiency. It worked in the sense that it used less fuel per hour than a jet but a pure jet engine was so much faster that it used less fuel per mile travelled and was lighter and simpler as well.


Kinja'd!!! tromoly > Cé hé sin
06/11/2015 at 19:59

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That makes so much more sense. Reminds me that back in my Thermo class I realized a Turbocharged engine is similar to a Brayton Cycle system except that the work output comes from the combustion chamber section rather than from the turbine.

I’m curious on the thermal efficiency part, IIRC Brayton Cycle engines can run a higher temperature into the turbine than a Diesel Cycle engine puts out through its exhaust (I may have that wrong, been 3 years since taking Thermo). Something about this is design is making me think that they were banking on the power generated by the Diesel engine would more than make up for a lower exhaust temperature into the turbine.

Really interesting to see these, thanks for sharing them.


Kinja'd!!! Axial > Cé hé sin
06/11/2015 at 22:09

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NOMAD

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