It's not a cuica but in the same family, Membranophone

Finally, the device is complete.

Scratchy, scrape-y, springy, insect-like, not all all what I had in mind when I started, but then it got away from me and went its own way.  Of course this means I have the pleasure of trying for the rain sound again on another device.

In the meantime, I would classify this device as a Hornbostel-Sachs 211.211.1 instrument in which the membrane is struck directly, the body is tubular, of equal diameter at the middle and end, with one usable membrane and in which the end without the membrane is open. Membranophones are one of the five different categories of musical instruments used by ethnomusicologists (hah, first time I've used that word in a sentence!). Just to be clear, a cuica is also a membranophone, but classified instead as 231.11 a friction drum with stick in which the membrane is vibrated from the stick that is rubbed or used to rub the membrane and in which the stick can not be moved.

The first time I saw or heard a cuica was in a performance by Airto Moreia and Flora Purim at a nightclub in Chicago in the 80's - it sounded like a squeaky dog-toy, but Airto played it rhythmically.

The development of this device: PVC waste water pipe, 200 diam x 600 long (will just fit in my suitcase); goatskin scraped clean of all hair;

the skin soaking in hot water to soften and stretch over the top of the pipe;

now stretched and drying over the top of the pipe and secured with bespoke 700mm long Jubilee clip,

with end trimmed off to length. Note how close the skin edge is to the clip and without any positive locating mechanism of the clip to the pipe.

Just a few taps on the drum with my fingers and the clip lost its grip on the skin. While it sounded very nice, and even better when the body was up off the floor as a proper open-ended resonating chamber, I had to start over.

LOTS of extra skin now so the clip will stay tight as it's now locked into position, trapped between the joint flange and the excess skin.

 Detail of the pipe joint flange.

Here is where Sertaç worked with the spring maker and we agreed on how to make it unstable and wobbly. Plus the very clever sleeve through which the crank handle turns the main spring!

And two extra curlicue loops on the long straight leg through which I secured the spring to the pipe:

A visit to a charming Armenian selling woven stainless steel cable, both with and without plastic encapsulation, here 1.5mm diam short lengths pinched between the coils of the spring;

Played first very slowly, then clockwise and finally anti-clockwise, with a wobble rhythm all its own (turn your volume down  - it's not a soothing sound!):

'...the usefulness of the useless and the uselessness of the useful...' Ionesco