I am wondering about the g-load and its relation to the so called gliding ratio.
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So the g load factor is defined as: g=Lift / Weight
We'll adopt that definition for the purposes of this answer. Note that that is not the entire apparent g-load felt by the aircraft and pilot. It is just the component that is acting in what we might loosely call the "upward" direction in the aircraft's reference frame. More precisely, it is the component acting perpendicular to the flight path. Which is approximately the same as the component that would be registered by a conventional (mechanical) panel-mounted g-meter. No need to get too caught up in semantics here, as long as we clearly define what we are talking about.
(Another minor point would be to suggest that you settle on "g-load" or "load factor", rather than combining the terms into "g-load factor". Even though the two terms arguably have the same meaning.)
and the gliding ratio= L/D
Yes, that's certainly true
- In a descend flight: what does a g-load factor of 0.5 have for a meaning
If L/W is 0.5, the glide angle is (arccos) 0.5, or 60 degrees below horizontal. For more, see the related ASE answer What produces thrust along the line of flight in a glider?
L=Lift ; D=Drag ; W=Weight ; gamma=gliding angle
When gliding, the vertical force components (_v) have to balance the Weight, so:
L_v + D_v = W
with
L_v=Lcos(gamma)
and
D_v=Dsin(gamma)
So:
Lcos(gamma)+Dsin(gamma) = G (1)
All true except the last-- it should be W, not G.
AND
g=L / G = 0.5 (2)
Same-- change "G" to "W" and it's correct
Insert (2) in(1) it comes to:
L/D=sin(gamma)/(2-cos(gamma))
a) Is this correct ?
I don't understand how you did this substitution. Can you edit the question to explain better? Anyway, it is not correct. In our example above where gamma is 60 degrees, when I plug that into your equation, I get an L/D of 0.57778, when it should be 0.5.
b) When I want to have a gamma=10° this would mean that L/D=0.17
From What produces thrust along the line of flight in a glider? we can see that D/L = tan (gamma), where gamma is the glide angle, so L/D = 1 / tan (gamma). If gamma is 10 degrees, L/D is 1 / tan (gamma) = 1 /.1763 = 5.672. The inverse of what you said.
and for gamma=40° L/D=0.52087.
No, the tangent of 40 degrees is 0.8391, and 1/.8391 = 1.1918. So that's the L/D associated with a 40-degree glide angle.
But on the other hand gamma has a relation ship L/D=1/tan(gamma) . So for gamma=40° it comes to L/D=1.19
Yes
I am really confused about that. Can someone help me?
I'm not sure I follow exactly where the confusion arises, but I hope that helps.
