What is "Level Lugs Line"?

[Lazerhawk]

Hello,

I'm reading "Air Forces Manual No.64 - Fighter Gunnery Firing Rockets Dive Bombing 1May1945.pdf" about wing lines and dive bombing in the P-51.

On p. 78 I read the term "6 deg from level lugs line":

As I'm not a native English speaker I'm having trouble to understand what is meant by this (my dictionary also didn't help).

On p. 75 I also found this picture, where they talk about "leave lugs" which I understand even less

And finally on p. 74 there is a section that gives additional explanations (for P-47, but I think it's also true for P-51):

Where are the 6 deg being measured from exactly?
From p. 74 I would assume it's measured 6 deg down from the plane's nose (?).

I also found something that looks similar in Chuck's Guide on p. 123:

(107 mils is the same as 6 deg)

Here the 6 deg are measured from the center of the gun sight. Does this correspond to the Air Forces manual?

 

Sorry for asking such pedantic questions, I just find it interesting and like to understand as much as possible

Thanks!

 

 

Edited April 27, 2023 by Lazerhawk

[=475FG= Dawger]

Leveling lugs are devices attached to the aircraft that allow the maintenance crew to use a spirit level to adjust the aircraft to level. 
 

Useful for various procedures.

Looks like sight adjustment uses the line created by those lugs as a reference.

[Lazerhawk]

3 hours ago, =475FG= Dawger said:

Leveling lugs are devices attached to the aircraft that allow the maintenance crew to use a spirit level to adjust the aircraft to level. 
 

Useful for various procedures.

Looks like sight adjustment uses the line created by those lugs as a reference.

@=475FG= DawgerThank you!

[Nodak]

On some modern aircraft the jack lugs, what you bolt onto the aircraft as a jack point often double as a level attachment point.  The C-141 had to be jacked and leveled to load an 80,000# minuteman III or you risk cracking it in half if it were to settle during loading/ unloading.  For weight and balancing an F-16A I remember the intake scoop itself had a designated spot to lay the level, the jacks were the weight scale, to be accurate it had to be level.