ORIGINAL: essyou35
"A level 45 degree turn has a loading of 1.41 G's, or a level 60 degree turn - 2 G's"
G force is a function of speed and turn radius, not bank angle. I can make a turn banked at 45 degrees and have 1 G or 9 Gs depending speed. A change in direction is an acceleration, and that is then divided by 9.8 to get the factor of normal gravity you feel.
To get turn radius, you need either degrees per second and speed, RPM, or the arc length of the turn.
ok,I was reading this quietly but upon reading this I had to jump in....
you can make a turn at any angle of bank and any speed but if you want to make a sustained LEVELturn, the G will have to be 1 divided by the cosine of the angle of Bank. IE G=1/cos(AoB)
45 degrees angle of bank will require 1.41G and 60 degrees angle of bank will require 2 G for a sustained level turn at the respective angles of bank..
Now the stall speed is a function of the 1 G stall speed multiplied by the Square root of the G
For example, an aircraft stalls at 100 kts at 1 G - in a 4 G turn (or manouver) it will stall at (100 x Square root of 4) IE 200 Kts...
Really quite simple math..
This math is used when determining manouver speed for an aircraft.. Utilsing the structural designed G load of the aircraft in this formula... IE, for an aicraft has a 4 G structural limit..
If it stalls at 100 Kts then you can safely fly it up to 200 kts and it is physically impossible to break the aircraft, because at or below 200Kts it will stall at or below 4 G... so up to this maximum manouver speed you can use full control deflection Eg full up elevator and the wings will not fall off.. the plane will stall prior to reaching the design load limit..
Above 200 knots in the above example you can generate more than 4 G and therefore you can break the wings in flight..
This is a simplification, but essentially sound theory (yes I know rolling G is a factor and Design load limit is not ultimate load limit but I'm keeping it simple....)
As for tip stalling..
The propogation of a stall on a wing depends on a number of things, Aspect ratio, airfoil design, washout, sweepback, wing taper.... In a purely rectangular wing, the stall will propogate from the root and work outwards... a higher aspect ratio wing will generally stall at a lower crticail angle, so a tapered wing effectively makes the tip higher aspect ratio than the root and a tapered wing can stall at the tip before the root..
It one wing stalls before the other, there will be a roll or "snap" effect and this will be far more pronounced if the tip of the wing stalls first, simple leverage explains this.. an imbalance of lift at the tip of the wing will cause a faster roll than an imbalance of lift at the root..
Other factors are any input of aileron (changing angle of attack) and also any yaw present...
If you experience a tip stall (or any stall for that matter, just relax the elevator a few millimeters - yes millimeters and the aircraft wing will unstall and the tip stall (snapping) effect will disappear...
Your elevator stick is really a direct angle of attack control device.. you will only stall if you use too much angle of attack which means too much back elevator.. relaxing elevator in any stall situation will usually be enough to recover instantly...
The greatest design feature in a wing to prevent a stall commencing at the tip is "Washout" where the wing is essentially twisted from root to tip, so that the angle of attack of the tip is always less than the root.. this virtually guarantees the wing root stalls first and the tips (with ailerons) remain at a lower angle of attack and therefore unstalled.
(3500 hours of teaching aerobatics in real aircraft) the theory works just the same in real planes as it does in our models.