I'll be building several new hank drums in the coming weeks. I plan to photograph and videotape the whole process in greater detail this time. In the meantime, I am considering several improvements to the next build. Below are some of my ideas. Feel free to comment if you have anything to contribute to the discussion.
Idea 1 - Move both of the high A and high C tongues further out towards the perimeter of the drum surface. If you've attempted to build the Hank Drum by religiously following Dennis Havlena's plans, (link: http://www.ehhs.cmich.edu/~dhavlena/for-webpage-lp-hang.htm) then you'll find that these two tongue end up in the metal between the low D and the low F and low G tongues. They're darn hard to tune and they don't ring too long. Thus, the experiment to move them closer to the perimeter of the drum.
Idea 2 - Replace the high A and high C tongues with other notes within the D pentatonic scale. The idea here is that if these notes are too short to make a nice note, replace them with a longer tongue and a note that will sound better.
If you not familiar, the basic D minor pentatonic scale is made up of the following six note (in order lowest to highest):
D F G A C D* *octave
The notes currently in Dennis's plans (for the eight tongues) are (in order lowest to highest):
D A C D* F G A* C* *octave
One proposal is to replace the high A and C with the following configurations:
D F G A C D* F *G * *octave
Idea 3 - Of course there are other scales which can be made from eight notes. The easiest extension is to create the D minor scale which would use all eight tongues to create an full octave of notes:
D E F G A A# C D
Idea 4 - One of my favorite scales is called the Spanish Gypsy or "Abba Rabba" scale. In the key of D, this would be:
D D# F# G A A# C D