Hi, Recently, I was reading through

[Jnnal]

Hi, Recently, I was reading through AC23-13A. The exceedance curves are normalized with Incremental Design Limit Maneuver Load Factor at Maximum Gross Weight (anLff) to get Incremental Maneuver Load Factor at Operating Weight (an). What is the meaning here of the word incremental in anlff? Is for particular aircraft anlff computed given in the formula comes around 3.5 (What it really means, incremental), is (an)computed is deltag. is the total acceleration at CG is 1+deltag? Really confusing. Please anybody may give little thoughts on that front.Is any references to read about it? please. Thank you.

 

[rb1957]

I'm sorry I can't add anything meaningful, but maybe "aniff" is "enough" ... please, it sounds like it (no more dad jokes)

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[Sparweb]

You mean Acceleration Fraction, a_n / a_nLLF

LLF = Limit Load Factor
n = normal (in other words perpendicular to the plane of the aircraft, or in other words "up and down")
a = acceleration, ft/sec^2 (it's all in US customary units)

If you are looking at Appendix 1, page A1-3 or section A1-2(b) the "incremental" is the change relative to whatever load factor the aircraft was experiencing at the time of encountering the gust. If flying straight and level in still air up to that moment, then yes, it was at 1g, to which you add the gust load factor. If the incremental you calculate is +3.5g then yes, you add 1 to find the total load factor to be +4.5g which is positive, and a fairly typical value for a sharp-edge gust.

Normalization has more to do with comparing any momentary acceleration with the limit load factor at gross weight. That is the standard against which to compare all the other possibilities. The exceedance curves are for generic aircraft types, so a specific load factor in "g" doesn't apply.