You could tape over hole 1 and 3 (L1 and R1) and play pentatonic on the remaining holes with one hand.
True. Or tape over holes 1, 2 and 3 and play it as a tabor pipe from hell. 
The thing with normal pea whistles is that they seem impossible to overblow*. Normal whistles have a volume level to play music, not direct traffic around road construction, although I bet that a G whistle played in the second and third octaves would produce the needed volume. Makes me want to take a whistle head, buy some copper tubing, bend the body like a bugle’s and drill holes at the correct tabor intervals. Even an overtone flute constructed properly could probably hit the correct volume, add a “drone” a few cents off would produce an uncomfortable vibrato.
*which seems odd considering I can get 3 notes from a glass bottle.
supposedly helmholtz resonators [which is what any closed-end flute or ocarina is] are impossible to overblow
apparently that ability comes from an open air column
you can alter the pitch somewhat by blowing differently, but not an octave
my police-whistle measurements indicate 2-3 semitones range from that
but of course blowing harder [for sharper] also makes it way louder, and vice versa
and regular whistles do that too, there is only one correct volume for exact in-tune pitch
i have a generation G whistle
they are certainly loud
a key [like a flute] might be a good idea
i think though that a slide covering the hole might give more controllable pitch
also a key is a lot like a finger
though it could operate in reverse
the unpressed key would be the lowest note
as opposed to the uncovered finger hole, which would be the highest
wle
i think
the whistle ideas are good [ i like the ‘whistle with a pea chamber’ ideas]
but i think it should be lighter and smaller than even a G whistle
the flute-key is a good idea
what i like about that is that the key could open a hole with ‘correction’
that is, if you wanted to or had to, you could have the ‘hole open area’ vary with key operation, arbitrarily
maybe you want the first 10% of the key distance to open 25% of the area, for instance, or 35%, instead of the simpler 10%]
just examples
might make it easier to play
also a key could be either ‘normally open’ or ‘normally closed’
so if you just grab it and don;t hit the key, it could be either the highest note [open] or the lowest note [closed]
it needs to hang from a string and be grabbable and playable without looking at it
like maybe the key is just some kind of squeezer thing that you can manipulate very simply
or you can feel it without looking
wle
I would think it would be easier to make a spring loaded slide in a body than a key. Set up a traverse body with a pea in it,and pinch to raise the pitch, release to lower. Play like a mini trombone.**
Never understood this. I would think that the bottle below would qualify as a helmholtz resonator, but I can get at least 3 notes from it (sorry the lowest note is barley audible). I would have thought it should be just a closed end harmonic series.
3 Notes from empty bottle
Edit: Just read up on it, closed end cannot overblow the second or even harmonics, third, fifth, etc. should be fine.
** On the slide idea I popped the head off of my whistle and cupped it with my hand. Fipple on the outside held with my thumb against my hand. makes a convincing slide sound just opening and closing the thing. Haven’t tried overblowing it. One had, multi-pitch, no moving parts, easy to make…
Just found this eBay listing (nothing to do with me!) and instantly thought of this thread:
http://www.ebay.co.uk/itm/Collectable-ACME-Double-Whistle-/150681840350
look at that!
thanks
i;ve asked the seller some questions, can post reply if anyone cares besides me
wle