A good set of questions.
The H/V Diagram does not apply for approch and landing, [Ive rephrased this from only applies for take off to make it clearer].
The laws of Physics apply all the time.
We had a test pilot come and talk about how the H/V Curve is constructed at the last Redhill safety evening to try and dispel this myth that you need to stay out of the H/V curve on approach. I am not going to try and quote him here but the fact that the test flights for the curve are carried from level flight at various speeds and altitudes with a delay in the intervention time means that the flight conditions are completely different for those experienced in the descent. He pointed out that most constant angle approaches are in fact made through the curve but under different conditions.
It would be possible to construct a curve for the approach but no manufacturer I know of does it (or publishes the results).
I am with Arm Out The Window, the technique that gets used depends on the area you are approaching.
Rotorfossil gives a good description of how things are in the R22.
Remember your instructors have to hang their hats somewhere and teach you something, personally I hold some speed until later in the approach in an R22 (caveat not current on R22 or R44 but haven't forgotten) , but it can be too much for some students early on to be flaring a bit tighter and feeding in power more quickly at the bottom of an approach.
Assuming you are training on an airfield ask you instructor(s) to demo an engine failure on the approach from a point of your choosing (verbally only) and see where you end up and how you get there. Perhaps get them too talk to one another and set some kind of standard for your training.
Remember the slower you are going the shorter you will fall on the approach (from the same altitude) so losing speed too early in the unlikely event of an engine failure means you might not make the spot.
The link Vital Actions posted has a furher link to some approach photos and for me I cant help wondering why you would teach someone to be where they were taken from over that lake, there is only one place they'd be going IF the engine stopped, so my vote says sight picture good for flat ground beneath, ground track bad for that altitude (with the view seen out of the window).
Don't be too concerned about Vortex Ring, the figures that get taught are quite conservative , don't let the rate of descent develop into something you don't have the performance to arrest, that causes a lot of accidents and the VRS brush comes out to tar them with. The lighter the aircraft is the easier it is to get it into VRS and the easier it is to get it out !
Last edited by VeeAny; 9th February 2010 at 17:32.