Some thoughts on the articles currently at tuned pipe and expansion chamber and where to from here, stemming originally from Talk:Expansion chamber#rename to tuned pipe, a requested move that seems to have been more of a badly formatted merge request.

It seems likely that both terms will require disambiguation in the long term, but it's possible one or both will not. So here is a scratchpad for working it out.

Tuned pipe

Google websearches:

• "tuned pipe" -wikipedia 963,000 ghits (your results may vary) and the first few all seem to be about engine exhaust systems
• "tuned pipe" -wikipedia -exhaust 539,000 and still all about engines, including the YS 45 FR which appears to be a model aeroplane engine.

Google books does better.

• Search on "tuned pipe"
  • Understanding The Pipe Organ, but only one hit
  • Air Breathing Engines and Aerospace Propulsion: Proceedings of NCABE 2004, three hits in close proximity
  • Popular Science Dec 1970 "Outboard Motors: The Sweet, Elusive Sound of Speed" Now we've replaced the untuned expansion chamber with a straight, tuned pipe. Initiate a sonic disturbance at one end of such a pipe (as when the piston uncovers the exhaust port) and a pressure wave travels from the port along the... ... Interesting, it contrasts an untuned expansion chamber with a straight, tuned pipe.
  • Acoustic experiments with the pin-hole probe and the interferometer u-gage Finally, in figure 223, for the optimum ^=35, the successively tuned pipe is compared with the untuned pipe. ... Thereafter the divergence rapidly increases, the tuned pipe naturally being in excess. From C= 0.8 on, passage of the ...

Expansion chamber

• Google books [1] gives even more variety than with tuned pipe.
  • Popular Science - Vol. 223, No. 3 p26 Energy-saving expansion chamber returns hot water to the tank ... The system consists of an expansion chamber mounted between the cold- water inflow and a home's water heater... (my emphasis)
  • Official gazette of the United States Patent Office: Volume 242 2 hits, one reads a steam separator consisting of an expansion chamber having drip retaining means,... (my emphasis)... no obvious connection to internal combustion engines
  • The Fabrication and Characterization of High Temperature Terahertz Emitters nothing to do with internal combustion engines
  • Pumping Station Design - Page 22-44 Expansion chamber. where S1 and S2 represent the cross-sectional area of the inlet pipe and the expansion chamber, respectively.
  • Aerosol Measurement: Principles, Techniques, and Applications - Page 384 (Section 17.3: Condensation Particle Counters) 17.3.1.1 Expansion-Type CPCs An expansion-type CPC consists of a humidifier, an expansion chamber, and a detector. Water is the working fluid for this type of CPC. The aerosol stream is first humidified to reach the saturation of water... (my emphasis)

Progress

Created:

• Stub at condensation particle counter (partly to provide a third item line for Expansion chamber (disambiguation), but it's a good stub in its own right, otherwise there would be no point)
• Stub at tuned exhaust and talk page talk:tuned exhaust
• DAB at Expansion chamber (disambiguation) and talk page talk:Expansion chamber (disambiguation)
• DAB at Tuned pipe (disambiguation) and talk page talk:Tuned pipe (disambiguation)

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