To the believers of the downwind turn I offer the following experience. Where I flew 60-70 knots of wind was not uncommon. Taking off from a platform and climbing out at BROC (74 knots) turning downwind had absolutly no impact on aircraft performance. However there is an extremely strong and powerful VISUAL impact as the groundspeed goes from 14 knots to 134 knots. This is where pilots (my opinion only) run into trouble as they perceive the reduced climb gradient on the downwind as a loss of climb performance and naturally pull back on the stick to restore the perceived performance required. More attention to what the dials are saying negates the very powerful visual influence. As helo pilots we are a very visual lot in that we take our cues from what the terrain about us is doing rather than what the gauges may be saying (VSI, airspeed). What helo pilot has not been caught out and finding him/her self landing with the wind, however slight, up the tail.
The accident reports are replete with people who on turning downwind find the collective up under the arm pit and the aircraft still descending. Why? Because they've allowed the airspeed to zero out at some point during the turn due to them taking their cues from ground motion.
Used to see new guys occasionaly fall afoul of this powerful visual stimuli in another way as well. Enter the downwind with 60 knots of wind and decelerate the aircraft to zero airspeed prior to commencing the turn to base/final because they are taking their cues from outside the cockpit. On one occassion I unfortunately let the situation in a 76 deteriorate to the point where we just had enough height to make a recovery.