MIMF

Here it's called Caval and is made out of plum wood or other fruit tree wood. I made it from a PP-R pipe (water pipe) because i couldn't drill such a long piece of wood.
I sounds like a Caval, but it isn't in tune.

What are the formulas for calculating the length of the tube for a given scale (A or B in my case, the most common caval scales), and the placement of the holes? I couldn't find anything that a beginner could understand.

Thank you in advance,
and a Caval song to help you make an ideea about how it sounds (in the second half of the video he plays a Fluier (whistle)):
http://www.youtube.com/watch?v=hwINglPdZRI

In the Links section, under woodwinds and brass, you will find "How to Build a CPVC Bulgarian or Macedonian End-blown Flute (Kaval)", which includes dimensions and hole positions. The general rule for tone holes is to start a bit small, so that they play flat. Then, starting at the bottom hole, enlarge it gradually until it produces the correct pitch, then the next hole, and so on. Each open hole influences the others, so it is a good idea to still leave them a bit flat, and repeat the process.

Thanks, but i didn't found anything about calculating the length for a specific base note (pitch). My Caval has 5 holes and a fipple.

Since no-one else seems to be forthcoming, here's my 5 cent's worth.
I don't know anything about the Romanian kaval. (Good recommendation, isn't it?) But I know a bit about the Hungarian "hosszufurulya" , which is essentially the same. The idea seems to be very similar to the better-known tabor pipes of Western Europe. That is, it is an overblowing flute, with the fingerholes only designed to shape the first three notes of any one octave. I'd say, the first two fingerholes are supposed to play a tone, then another tone step up. The three fingerholes left give the choice of playing a semitone or a tone further up, with the possibility added of various gracenotes introduced. (as on the video, if you look closely.)
As a practical advice, what I'd recommend, is our old friend, Google images. Go there, and tap in "hosszufurulya" (It's because "kaval" mostly gives you the Bulgarian type, that is different.) Now, sort out the 5-fingerhole variety from the 3-fingerhole one. Take a ruler to the screen, and note the relative distances from the mouthpiece to the 1.bottom,2. first fingerhole, 3 second one, and so on and so forth. It's about percentages. Transfer these to the pipe you are making. Make the holes undersize, as noted above by someone else. Keep on enlarging until you are satisfied by the result. You can be absolutely certain that is exactly how those old-timer peasants did make the originals. They didn't have a blueprint exact to the last fraction of millimetre, but only a stick of elder and a pocketknife. And an original model, here substituted by a Google image.

What Yuri said. That's how I've done it for whistles, cornetti, and a couple other oddball things. There are formulas for calculating lengths for a specific pitch, but the open ends and fingerholes introduce an inconvenient number of variables, and you'll still have to trim it by hand and ear (or tuner). The simplest way is to make it long enough to play a bit flat (again), cut off bits until it produces the pitch you want, and use the distance from the fipple block to the end as the base for the percentages that Yuri mentioned.

Is this what you're looking for?

http://forums.chiffandfipple.com/viewto ... 20&t=82135

Thank you all, i will try this.