I recently got a Venova and have been enjoying learning how to play it:

It combines a saxophone mouthpiece with recorder fingering and a little nose to overblow an octave instead of a twelfth.

It's somewhere between a real instrument and a toy, and one of its bigger problems is that while it's great in C it gets harder to play the more sharps or flats you want. Since I mostly play contra music, typically in 2-3 sharps, this isn't ideal.

A Venova in D (two sharps) would be great, but I don't see this coming. If we're going to put in a bunch more work somehow, what if we went all the way to a double bore?

Imagine two parallel bores with the tone holes lined up exactly, so that when you put your finger down it covers both. The holes would look a bit like the double holes on a recorder, but they could be closer together because you never need to cover just one of them:

The obvious way to do it, and the equivalent of a B/C melodeon, is a C tube for the "white keys" and a B tube for the "black keys": between them you can play every note. The venova already uses a "meandering bore" to bring the holes closer together: to keep them in tune you put slightly larger meanders all along the B bore so the wavelength is consistently a half step longer.

Then you need some way to choose which bore the air flows through, so only one is active at once. We could borrow from the solutions brass instruments have come up with. Since those are solving a much harder problem (routing air through a loop) we can do something simpler. I think a flapper valve would be a better fit: much cheaper to make, and more moisture resistant.

When you think about B/C fingering, though, you'll notice that we're using one bore for 7 notes, and the other for 5. Let's take inspiration from a Janko keyboard and do 6 and 6: two sets of whole steps, a half step apart. One bore would be C, D, E, F#, G#, Bb while the other would be C#, D#, F, G, A, B. This lets you use your left thumb for the valve, left forefinger for the octave key, and then your remaining five non-pinky fingers for the notes. No keywork, and the only bit that's tricky to manufacture is the valve.

I especially like that the fingering is partly isomorphic: lifting a finger always moves you up a whole step, engaging the valve always moves you up a half step. And if you prefer flutes (or pennywhistle) to reeds this should work there too.

Note, however, that we now have a bunch of free fingers. If we do stick with the reed, what if we do away with the 'nose', and accept that we'll now overblow a twelfth like a clarinet? Can we build a keyless three-octave dual bore meandering pipe woodwind with no fork fingerings?

Unfortunately not: after allocating a finger to the bore selection valve and another to the register jump most people are down to 8 fingers. To play chromatically across a full register we need 19 notes, which means one bore needs to be responsible for 10. With simple fingering, the most you can do with eight fingers is nine notes: all open gives you the highest note, and then each additional finger gives you another note. This gives us 18 notes (9 + 9) across the two bores, which is so painfully close to the 19 we need. And even if this worked (perhaps we're willing to give up D#) it would be awkward to use all the fingers (and thumbs) this way.

If we compromise slightly, though, and add two keys, very similar to the keys the Venova already uses, we should be able to get all ten notes and also free up the right thumb to steady the instrument. I should probably put an image here demonstrating, but drawing is hard and this is way beyond what current AI models can do. [1][2]

This would be cheap to manufacture, since while a meandering tube is a pain with traditional tooling it's no issue with molded ABS resin. I think this would solve most of the Venova's flaws (missing notes, fork fingerings, limited range), while avoiding almost all the keywork of the clarinet or sax.

[1] Gemini 3.1 Pro, completely missing the point with two mouthpieces, straight bore, lots of keywork, no ligature, useless acrylic, bad hole spacing, and levitation:

[2] ChatGPT 5.5 Pro, doing somewhat better, but with no reed, lots of keywork, a third bore at the bottom, and an insufficiently meandering bore: