The reason for a tight turn would be a hill in the way.
Example include Elba, Albenga, Calvi, Oban. Or even Shoreham if turning onto 20 before the hill (which most don’t do).
It seems that a good safe way to do a tight turn is to unload the wings, by trading height for a reduced G. This lowers Vs. So accelerate downwards (a constant VS is not enough) through the turn.
Also the lowest speed gives the tightest turn radius, for a given G, but one might get turbulence due to the hill…
Unloading the wing is good, or flying faster works, too. That and avoiding skidding in the turn. In doubt train youself to slip the aircraft. That way even in a stall you won’t stall into the turn but rather roll over the opposite direction and have ample time just to reduce back pressure and end the stall with only minor altitude loss. Some aircraft would drop into the turn even if stalled coordinated but no normal certified aircraft (that I have heard from) would fall into the turn if slipped and stalled in a turn.
What most pilots who haven’t benefited of flying instruction in mountainous environments are afraid of is flying close to terrain. It is often the best or only solution to finding a safe trajectory that gives you the space and the track miles for a stable approach. If you take into account issues like obstacles and winds.
Thinking for example of Barcelonnette, which is a cemetery of small plane wrecks.
Barcelonette, which is a cemetery of small plane wrecks.
Ouch! And that field is high on my list of possible routes into Italy, with my very low-performance plane. What is so bad about it?
To answer the opening question: keep the speed up at all costs is what I was taught – and trading height for speed is the evident way. That is another reason I approach too high rather than too low. Risk of engine failure being the first.
Jan_Olieslagers wrote:
What is so bad about it?
As far as I understand it, it’s dangerous in high (or medium) wind conditions, and since the circuit is deep inside the valley, you must not give in to the urge of cutting short the circuit. On departure, you must also consider winds and the climb performance of your plane. Though I tend to think that it’s not about how many BHP your engine has, but how you use them (always keep an “out”). 
Otherwise it’s very nice there. 
It seems that a good safe way to do a tight turn is to unload the wings, by trading height for a reduced G..
That is how I turn in valleys. I posted a video in a thread long ago, but I think my explanation was poor.
If you don’t lose control at altitude, why should you do so at low level?
because at altitude one is less concerned by the proximity of ground, leaving more attention for other subtleties?
In the way you suggest, but continuous radius to roll out on very short final. It is the only way into many strips. Box circuits and long finals use up huge amounts of room. At Shoreham you should be in the radius inside the river which would make a landing entirely possible with the hill a great deal closer.
If you don’t lose control at altitude, why should you do so at low level?
Perhaps because at altitude you are normally doing plenty of speed, whereas at low level, in this case, you are trying to land?
but continuous radius to roll out on very short final. It is the only way into many strips. Box circuits and long finals use up huge amounts of room
There is a subtle thing I had in mind. If you do a continuous turn onto final, and misjudge it and need to tighten it up to (a) avoid the hill and maybe even (b) line up with the runway, then you are in a sticky situation. Whereas if you fly more or less straight towards a point next to the hill and only then turn onto final, you have only half the job to do.
Not that I know anything about aeros, but the same thing is (or should be – Shoreham 2015 was a bad example) done in displays where one does a loop, except in the vertical plane (no pun intended). The bottom part of the loop has a lot gentler radius, enabling the ground clearance to be more easily controlled, and the public can’t tell the difference anyway.
Indeed some of these are more suited to an RAF curved turn onto final. You don’t have to fly a rectangle.
