Berti,
As a beginner myself (barely a month now) I can whole-heartedly recommend one of these:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=3720383709&category=10183
It’s a superb student instrument, although my feeling is it’s far more than that, and at the price, it can’t be beat. I’d love to hear a ‘real’ player on one of these, I’m sure it’d make an excellent ‘session’ flute. It’s practically indestructible, and you don’t have to worry about maintenance or spending a fortune on a wooden flute, especially if you later decide that flute isn’t for you.
Is it harder to play the flute than the whistle? For me, definitely. It’s taken me four weeks to get to the point where I can get into the second octave reliably enough to be able to play tunes. Worth the effort and perseverance though!
There’s no real backpressure with the flute. You have to create your own with your embouchure. It’s apparently quite usual for us beginners to get dizzy in the beginning (hyperventilation)…I know I did until I got the hang of it, and until my embouchure started to improve and become ‘reliable’, but you do use more air on flute than on whistle (or at least I do at the moment). It gets easier as you progress (thank gawd).
The fingering on a keyless flute is the same as on the whistle, so any tunes you learn on the whistle you can play on the flute. I find it’s easier to learn the tunes on a whistle, and then learn 'em on the flute later.
Perhaps the best bit of advice I can give is this: Don’t buy an “Acoustica” student flute! I did, 6 months ago. Still can’t get much of a note out of the bl&^dy thing. Thanks to that particular tool of the devil, I took up whistling (a cunning plan of mine: learn the tunes on the whistle, then all I’d have to do is learn to make the flute ‘work’ because I’d already know the tune…yeah right). It was only after buying a bamboo flute from http://www.bamboozle.org.uk that I finally realised it was the Acoustica that was the problem, not me. Thanks to that Acoustica POS I’ve effectively “lost” 6 months of practice time. If only I’d bought the Calmont back then… the Calmont really is an ‘easy blow’ (compared to the bamboo flutes, the Westport, and the M&E I now have).
I think if you can manage a Low D whistle comfortably, you should be able to manage a D flute. Hopefully your friend allowed you to hold one of his, so you could get an idea of how it feels in your hands? And with any luck, he’ll also be able to help out as a teacher, something I don’t have.
Hope this helps…