I think you'll find it was down to the Lift Pixies explained here very well from an old thread.
Originally Posted by BluntM8
An aeroplane can only fly due to the presence of Lift Pixies. Lift Pixies eat Bernoullies and this gives them the strength to keep the areoplane in the air. The Bernoullies are cut into manageable chunks by the knife like shape of the wing - at high alpha the wing is too blunt and the Bernoullies get too big for the Lift Pixies to eat. This causes the Bernoullies to pile up on the wings and weigh the aeroplane down. Furthermore, at slow speed, the Bernoullies don't get cut up so well either, so you have to get more Lift Pixies to eat them. This may be achieved by lowering the flaps, which is where the Lift Pixies live. If you put the flaps down they will come out and help eat the Bernoullies.
As yet, attempts to colonise Lift Pixies on helicopters have failed due to the lack of suitable habitats (flaps). Therefore, helicopter flight may only be explained by the "Wind Submission by Battery" theorum, which is dicussed elsewhere.
Cheers
Whirls