Aspect angle and angle off- confused again!

@imacken,

So is it cleared up now?

The fact that the Navy and Air Force (and French AF in this case) literally do aspect 180 degrees opposite from each other doesn't help either, but the way I like to look at it is that Aspect means more to you pre-merge and Angle Off means more post-merge.

Yes, they're both important, but Aspect is something that your opponent has the most control over, and this is the information that will help you get into the merge in optimal parameters.

Angle Off is something you can control with your pursuit course once you're in a turn fight.

Angle Off is also referred to as Heading-Crossing Angle (HCA), and I actually like this term a lot better because it better describes what is going on post-merge. When you're in a dogfight, youre not only trying to get your nose on the bandit, but you're also trying to get your nose on the bandit's tail (i.e. being on the same approximate vector as the bandit). A low HCA means a better firing solution and less likelihood of overshoot.

EDIT: I saw that someone posted Art of the Kill diagrams earlier. That is a great book that does a good job illustrating the difference between Aspect and Angle-Off in the first chapter. The other thing I recommend is setting up a dogfight with something like a Su-25 (maneuvering, but not a fighter), then practice different pursuit courses and watch how your Angle-Off changes based on how you turn with the bandit.

If I understand correctly

035 (VTH) is the Aspect Angle (AA) relative to the bandit's tail as 0 deg.

142 (VTB) is the Target Aspect Angle (TAA) relative to bandit nose as 0 deg.

I would then flush the paragraph about Angle off tail.

I will also specify that:

"TAA and AA basically refer to the same information (where you are in relationship to the bandit's nose) but use different conventions of zero reference. Aspect Angle (VTH) is useful when pursuing a target since the AA value can be read as a "you will see the bandit at YOUR 035". Target Aspect Angle (VTB) is simply 180 substracted with the Aspect Angle.

Is that explanation clearer?

Is there any particular use for the Target Aspect Angle instead of using Aspect Angle?

If I understand correctly

 

035 (VTH) is the Aspect Angle (AA) relative to the bandit's tail as 0 deg.

 

142 (VTB) is the Target Aspect Angle (TAA) relative to bandit nose as 0 deg.

 

I would then flush the paragraph about Angle off tail.

I would agree with all that.

I will also specify that:

"TAA and AA basically refer to the same information (where you are in relationship to the bandit's nose) but use different conventions of zero reference. Aspect Angle (VTH) is useful when pursuing a target since the AA value can be read as a "you will see the bandit at YOUR 035". Target Aspect Angle (VTB) is simply 180 substracted with the Aspect Angle.

 

Is that explanation clearer?

Personally, I would phrase the first part as:

'TAA and AA refer to your position relative to a line from the bandit's tail to nose. The only difference between the two is that TAA (VTB) uses the nose as zero degrees reference, and AA (VTH) uses the tail as zero degrees reference. TAA is simply 180 minus the AA value.'

I'm not sure I get the bit about 'YOUR 035'.

If I say "target is at your 3 o'clock"... it's similar to "target is at your 090".

If I say "target is at your 3 o'clock"... it's similar to "target is at your 090".

Sure, but this isn't the same. Aspect angle has nothing to do with your heading, so you can't relate it to your '3 o'clock' or your '90'.

AA value can be read as a "you will see the bandit at YOUR 035".

Aspect is a position angle because it describes where you are. Example: you are positioned at the target's 6 o'clock (aspect: behind). Which direction do you look toward the target? Well that all depends on which direction you're facing. You could be pointed toward, away or anywhere in between.

Is there any particular use for the Target Aspect Angle instead of using Aspect Angle?

It's a good question. AA seems to come in for visual tail chase air combat often when the end goal is low aspect while TAA is more often used discussing radars or missiles, long range intercepts, and intercepts from the front (sine 10° is easier to imagine than sine 170°). TAA has the benefit of being able to talk about the target's nose-track-course-heading instead of the more contrived direction projected opposite of that. If AWACSs says there's a target 100 miles direction 045 of you going 360 you can imagine oh I'm TAA 135 left so my lead angle needs to be ____. This same mental exercise working with his tail vector is a little weirder.

Guys, we are not talking about the definitions. Pretty sure that is clear. The issue was/is how they are presented in Chuck's Guide, and I think we have established that there is a mistake there which led to my original confusion.

Dunno about that. From reading many of the previous posts, there was still a lot of confusion about basic definitions.

I'm sorry but why is the blue arc showing 135° while it is called 142°?

And why is blue + green = 180°?

I don't quite get it, sorry.

Edit: Better?

 

Sorry Chuck, but no, I don’t think your diagram is right, nor the first bullet point. It’s a bit late tonight, but I’ll think about it more in the morning!

I quoted almost verbatim the explanation you sent me, mate. You will have to provide me with a better one.

Sorry Chuck, but no, I don’t think your diagram is right, nor the first bullet point. It’s a bit late tonight, but I’ll think about it more in the morning!

The first bullet point (aspect angle definition) is in fact correct, just uses slightly different wording, while the diagram is wrong, the blue and green angle arcs should be around the target instead of own aircraft.

I quoted almost verbatim the explanation you sent me, mate. You will have to provide me with a better one.

Not sure why there is a bit of aggression creeping in there.

I mentioned the first bullet point, and that is not what I sent you at all. (That was your last point, and that looks fine to me). It’s the ‘extending from your nose’ that I don’t feel is correct in the first bullet.

Regarding the diagram, the angles should be drawn from the bandit, not your plane.

In addition, although we can say TAA is 180 minus the AA, it should be shown as 0 degrees at the nose on a diagram. So, maybe you should have from 0 to 180 (from tail) in one colour representing AA, and 180 to 0 (from tail) for TAA.

We’re all just trying to get this right!

No agression from my part.

Let's make this more simple: please send a picture of the diagram with what you have in mind.

Well, excuse my appalling curves, but this is how I see it.

Oh, I get it now.

Thank you for taking the time to do it. I'll try to update it tonight.

Last attempt. Hope it's accurate, this time.

Excellent, accurate and much clearer.

Last attempt. Hope it's accurate, this time.

 

Yep, looks good to me!

I realize this is an old post, but I wanted to point out some inaccuracies that I found in the graphic and some of the statements on the page above from Chuck’s Guide. On the page above from Chuck’s Guide, it says: “TAA is simply 180 minus the AA value.” But in the graphic shown on the page, it says that TAA is 142 and AA is 035.  Obviously 180 minus 35 is 145, not 142. I understand where the 3 degree difference is coming from because it’s eluded to on this page from Chuck’s guide, but the statement that “TAA is simply 180 minus the AA value” is not correct. 

Elsewhere on the page from Chuck’s guide it says “TAA and AA refer to your position relative to a line from the bandit’s tail to nose. The only difference between the two is that TAA (VTB) uses the nose as zero degrees reference, and AA (VTH) uses the tail as zero degrees reference. TAA is simply 180 minus the AA value.”  It’s partially accurate, but I don’t think it’s worded correctly. The statement leaves out an important point and this is also evident in the graphic shown at the bottom middle of the page from Chuck’s guide shows that TAA and AA are essentially opposite halves of the 180 degree pie and the graphic shows the line from the attacker intersecting the center of the bandit. But that’s not accurate.

For AA, the line from the attacker should intersect at the tail of the bandit, not the center of the bandit and then another line should come straight out the back of the tail of the bandit. And the degrees difference between those two lines is the AA.

And for TAA, the line from the attacker should intersect the bandit at it’s nose, not the center of the bandit, as the graphic shows and then another line should come straight forward out of the nose of the bandit. And the degree difference between those two lines is the TAA. 

The graphic from Chuck’s Guide, shows for both TAA and AA, the line from the attacker to the bandit intersecting the center of the bandit.  I understand what he was trying to demonstrate in the graphic with the circle and showing the 360 degrees. He was trying have a simple way to show that AA and TAA are basically opposite sides of the 180 degrees of the circle on the side of the attacking airplane, but it’s not an accurate way to depict AA and TAA because they intersect the bandit at different parts of the bandit aircraft, not at it’s center. 

On the Chuck’s Guide page it says that AA is relative to the bandits tail as 0 deg and TAA is relative to the nose as 0 deg. That’s accurate, but the graphic at the bottom center the page doesn’t depict this. The graphic depicts both TAA and AA inspecting the center the bandit.  That’s where the statement  “TAA is simply 180 minus the AA value” came from, but this statement isn’t correct because TAA and AA don’t insect at the same location on the bandit. 

For AA,  the line coming straight back out of the bandit’s tail and the line coming from the attacker to the bandit, should converge at the bandits tail, not the bandit’s center and for TAA, the line coming out straight forward out of the nose of the bandit and going from the attacker to the bandit, should meet at the nose of the bandit, not the bandit’s center.
 

In the example used in Chuck’s Guide, TAA is 142 degrees and AA is 35 degrees according to the VTB and VTH (HUD). As we’ve already determined, 180 degrees minus 35 degrees (TAA) is 145 degrees not 142.  It’s 3 degrees off. The degree difference between the nose and tail relative to the attacker is the 3 degrees that the statement “TAA is simply 180 minus the AA value” is off by.