toc1955's video: Traveling wave thermoacoustic engine

(Adolf Cortel, June 2020). This thermoacoustic engine is based on the design shown in https://www.youtube.com/watch?v=DiQRYrC1rWY in the chanel of Mightydynamo. I have described in some details the building of the part containing the membranes which seems to be the critical one. This engine works very well: it starts running after only 10 seconds of heating with a small alcohol burner and also works (though slowly) at sunlight (with a concave mirror or Fresnel lens). With a coil as alternator it is able to give a voltage (open circuit) between 5 and 7 V (peak) at 20 Hz; when loaded the voltage drops a lot and the maximum current I have got is around 10 mA, but this is enough for LEDs or piezo buzzers. At 270ºC it runs very energetically and it seems that only needs 170ºC to run smoothly, which is very good for a thermoacustic engine. Some strange movements seen it the video arise from a stroboscopic effect between the freqüency of vibration of the engine and the frequency of frames of the video recorded. I have used a fragment of the extraordinary version of “Si tu vois ma mère” (Sidney Bechet) by The Man Overboard (clarinetist Ewan Bleach) without having rights on it, only for the educational purposes to which this video is aimed.