Afternoon All,
I've been in hibernation working through exams and sitting finally the last one of seven, Ops this week and hoping I can get clarification on an answer to this question.
For powered flight in a helicopter, the never exceeded speed VNE is an indicated airspeed limitation which?
A. May vary with changing conditions of weight, RRPM, altitude or temperature.
B. Remains constant for all conditions of weight and RRPM but may vary with changing altitude or temperature.
C. Remains constant for all conditions of altitude and temperature but may vary with changing weight or RRPM.
D. Remains constant for all conditions of weight, RRPM, altitude and temperature.
My answer was A however in conversation with others there is a leaning towards B. I assumed that as we increase our height into the atmosphere everything is subject to change. Altitude changes as we climb, weight as fuel is burned off, temperature with height and RRPM to due to decreased air density.
Look forward to some clarification and Thanks in advance.
Dobbo.
First, while I have some engineering background with helos, I don't consider myself to be an expert in any shape or form ....
However, you might like to have a look at a relevant thread on PPRuNe ( https://www.pprune.org/rotorheads/477083-vne-light-helicopter-altitude-reduction.html) which speaks to the topic. I would be very attentive to the posts by Shawn Coyle and Nick Lappos (these guys are real helo experts). Some of the others may, likewise, be experts but I don't know their individual stories so I am not able to comment.
The options in your cited question look to be a bit simplistic so perhaps it is a case of knowing what the particular examiner is looking for in the answer ?
Following the time-honoured "check each option before selecting your answer" ...
(a) option A - sounds OK to me
(b) option B - blade aerodynamics are pretty critical for helos. Weight and RRPM relate to lift which affects blade airflow. Don't like this one ..
(c) option C - show me a helo which doesn't have Vne varying as you climb ... don't like this one, either
(d) option D - I don't think do .. bin this one without any further thought
I think I might go with you .. option A sounds the best of the bunch.
Engineering specialist in aircraft performance and weight control.
Cheers John, I'll check out the threads.
