Really it's started out a recorder with a clarinet mouthpiece, but it sounds a lot like a B-flat clarinet. In fact, I was going to make a recorder, but by using the clarinet mouthpiece I saved a lot of trouble getting the fipple (whistle mouthpiece) right. The clarinet mouthpiece and reeds bumped the construction cost from about $5 to $40.
Then it sort of went from being a modified recorder back to being a (keyless) clarinet, as I took a heat gun to a section of pipe to make a bell and added it to the body. Since the body itself is nothing more than a straight piece of CPVC and the mouthpiece and bell are easily transferred, I'm experimenting with different fingering arrangements.
Well... really they're pretty much just a CPVC plumbing pipe cut to lengths, with finger holes drilled in them, but they sound OK. In fact, they sound a lot better than I thought they would.
After making it, I discovered that the clarinet reed/recorder fingering combination is sometimes called a saxinet.
In making the instrument I made some reference to The Physics of Music and Musical Instruments, by David Lapp to get the tuning right.