Name doesn't exist in English? Au contraire.

Read it and weep, as they say:
http://www.scribd.com/doc/15640992/Bass-Slapophone-Building-...

This appears to be an existing type of instrument known as a slap-o-phone or perhaps slap-o-fone, made from various lengths of PVC or even cardboard pipes/tubes with one open end slapped with a paddle or the bare hand to produce its sound.

Try this search link:
http://www.google.com/search?client=safari&rls=en&q=slap-o-p...

You can click on the image version to see various examples, sometimes spelled without the hyphens.

You can even see an example of the slightly rarer bass slap-o-phone here:
https://sites.google.com/site/blscohen/home/bass-slapophone

Although it seems as though technically a bass slap-o-phone should have one end of the pipes closed to product the lower pitches:
http://www.scribd.com/doc/15640992/Bass-Slapophone-Building-...

Sorry Charles and Phil, but the asker's contratubófono ain't nothin' but a good ol' slap-o-phone. BTW, no, I hadn't already heard of this. I had a hunch and tried a search for pipe-o-phone...

I also included "plosive aerophone" just to cover my bases, since apparently this is sort of the more general technical term for this type of instrument.
See: https://windworld.com/products-page/books-cds/slap-tubes-and...




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Note added at 1 hr (2015-06-19 17:21:29 GMT)
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I just found this video too, and since in this case the name "slap tubes" is applied, I guess I better officially add that term just to cover all my bases (again). If anyone thinks this instrument is a joke, they should watch the video at this link. Notice the convoluted pipework below the "keyboard".
http://makezine.com/2010/12/01/theyre-called-slap-tubes/

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Note added at 6 hrs (2015-06-19 22:06:09 GMT)
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By the way, in retrospect I realize that the way I wrote this answer was a bit cheeky, as the British might say, but it seemed like kind of a whimsical subject and it came along at the end of a long day/week. However, I wasn't trying to offend any of the previous answerers. To me, the fact that I went so far as to use the phrase "au contraire" sort of indicates a tongue-in-cheek tone from the beginning, but that may be my own cultural bias.