How to play a trun in Haydn Sonata

There is a Haydn Sonata in C major in the Kohler Sonatina Album, there is no opus number. There are triplets in the left hand with quarter notes and sometimes dotted eigth notes in the right hand. The turn symbol is right above the quarter notes and dotted eighth notes. The book doesn't show how to play them, except for a few times over the quarter notes in which the fingering is printed (3,4,3,2,1) suggesting to play the main note, the one above, main note, one below, main note. I thought it should be : note above, main note, one below, main note. Does anybody know which is right and should the quarter and dotted eights be played essentially the same? How would they fit in with the triplets?

Hope I explained this right. Thanks for your help,

Esweter, the solution you have to the turn is just as valid as the one suggested by the editor, and in fact is the one I teach when I teach this piece. In general, ornaments of the classical period start on the note above the principal, unless marked differently with an extra grace note or whatever. Turns are a special case, and probably the beginning notes were left more to the momentary inspiration of the performer, but the 'idea' behind them - even the name - suggest that the ornament circles around the main note before ending upon it. Incidentally, I teach the turns over the quarter notes in this pice to begin on the beat and so they are essentially performed 4 16ths against the three triplet notes in the left hand. But the turns over the dotted 8ths I teach before the beat, so that the turn finishes on the dotted eighth. These pre-dotted turns are not 4 even sixteenths, but some sort of quick 16th triplet, the first note of which would match up with the 3rd triplet eighth of the 3rd beat of the measure. Whenever I have tried other solutions, the students are unable to correctly place the remaining 16th note at the end of the measure. Besides, the rhythmic pattern of many of the 4th beats of the piece is dotted eighth, sixteenth, (for example, the very first bar of the music begins this way) and that motivic rhythmic pattern is completely obscured when a turn is inserted into the midst of it.

Thank you very much for your detailed reply. I had a much easier time with the way as you suggested, playing the turn as 4- 16th notes over the triplet. Thanks again.

You're welcome.....