load factor:stall
 

If I am on the wrong forum I apologize.:ugh:
can someone explain load factor, and what does it mean when they say a/c stalls at a load factor of 0.98? And how is it different from wing loading?.or is it the same ?
if am on the wrong page could someone vector me ?:)

I guess tech log or questions might be more appropriate but to answer your questions then;
Load factor is simply the ratio of the magnitude of the lift vector to the magnitude of the weight vector & gives a dimensionless quantity, hence in steady, level flight it has a value of one.
Wing loading is the ratio of weight to wing reference area, so a heavy aircraft with a small wing area would have a high wing loading.
As for stalling at a load factor of 0.98 then I would guess someone was referring to the stall speed at a load factor of 0.98? It just means the speed the aircraft stalls at when the load factor is 0.98. Both the load factor & wing loading affect stall speed. For each case the stall speed varies with the square root of said quantity, so doubling either the wing loading or the load factor would increase the stall speed by about 41%.
Hope this helps

Load factor is the number of "g" the aircraft is experiencing. Standard rate of g is 9.81m/s^2.

0.98g is almost 1g, ie normal conditions. When aircraft are carrying out flight testing, the pilot tries to keep the aircraft at 1g through the deceleration phase, to reach the stall. In normal circumstances, human error is such that just before the stall, the pilot might pull back ever so slightly on the stick, increasing the load factor slightly, so it is infact interpolated.

At the stall, the aircraft reaches CLmax (fnnar fnnar), and with a load factor, this will increase the stall speed.

Wing loading is different. In wing designer terms, it is W/S or weight per unit area of wing (includes the wing area sheilded by the fuselage). In pilot terms, loading and ng (n being the number of g) are the same thing.

Dont shoot me down in flames guys, its been a while :}

Here are my 2 Ps.

First small correction, 1g is 1g therefore NOT 0.98.

What I mean is that acceleration of 9.81 m/s^2 is 1g. Now each maneuver can cause much higher acceleration in any of the 3 mutually orthogonal direction (X, Y or Z), every of them expressed in terms of how many Gs.

For example 5g down means 5*1g in vertical (z) direction.

Whatever is the load that goes onto the wing, stemming from the specific maneuver it can be "spread" over the whole "washed" area of the wing ("Washed" = exposed to the air current) giving you the wing load.


Maybe someone like for example MFS can get you a cleaner answer. I am usually on the receiving side of these loads but rarely) I have to generate them, not without pain, I have to say!

Regards,

roger that
 

thank you all; that has kind of cleared things up:)

To keep it simple; the Load Factor is the ratio between aircraft weight and wing lift.

The other way around; wing loading can be determined as a function of load factor and weight.

In normal straight-and-level, unaccelerated flight, load factor is 1, i.e. lift equals weight. Vertical acceleration, as experienced when changing rate of climb/descent, or in level turns, would change the load factor. The LF can also be measured with an accelerometer parallell to the aircrafts vertical axis.

ok to rephrase my qest, when one talks of 1G concept on an Airbus is the a/c incapable of exceeding 1G? if so are they talking about load factor or wing loading:\

From your original post, you're talking about stalling.

There are two ways to define stall speed - one is the traditional "Vmin" approach, where basically you just read the minimum speed achieved in a stalling manoeuvre, the other is "Vs1g" where you determine the maximum lift coefficient during the manoeuvre and then define the stall speed for stable 1'g' level flight.

The 'Vmin' method generally gives lower speeds, because often the aircraft is at less than 1'g' at the point of minimum speed; consequently, aircraft using the 'Vs1g' method often are permitted to use lower speed factors when determining operational speeds (V2, Vref) as a function of stall speed.

Therefore, I'd say that then its a discussion of the use of the 'Vs1g' methodology to define the reference stall speed, Vsr, and there is no implication that 1'g' is any kind of capability limit.

Hopefully that's the correct interpretation of your original post.