ATTN: F-15 Drivers: Aspect Angle ?

[Ironhand]

Ah. OK. I've been using the meaning of Aspect Angle as in my diagram. The only sources (naval aviation) I've ever read have used that meaning.

 

EDIT: I only had time to give your above response a quick read before replying. I'm still at work but had some additional time and, after re-reading your reply and the source you quote, I stand by my previous statement. That diagram (the one with the circle around the fighter) is incorrect. The L and R reference the side of the bogie that is facing you. It's the fighter's heading that is irrelevant to the AA, not the bogie's. My definition of AA is identical to that of your source. It also supports my above contention that the diagram (again, the one with the circle around the fighter) is incorrect.

 

Rich

Edited September 28, 2008 by Ironhand

[tflash]

It is also modelled in the F-15A in TK's WOE/WOI light sim series. I asked it on the forum there and moonjumper gave the following explanation:

 

It is Aspect Angle, i.e how the target is oriented in reference to you.

The readout is Angle to Tail, i.e Target Aspect Angle 0 (T) = the targets rear is pointing towards you.

90L = left side of the target points towards you

130R = the targets 2'clock points towards you

and so on.

The readout on the real thing is usually in steps of tens, e.g. 2R = 20° Right, 16L = 160° Left

 

http://bbs.thirdwire.com/phpBB/viewtopic.php?f=5&t=5735#p35130

 

That is indeed how it reads in that sim.

[A.S]

yupp ..good add :thumbup: that´s why you turn OPPOSITE of L or R in order not to end up on his nose as mentioned in posts before.

[Ironhand]

It is also modelled in the F-15A in TK's WOE/WOI light sim series. I asked it on the forum there and moonjumper gave the following explanation:

 

It is Aspect Angle, i.e how the target is oriented in reference to you.

The readout is Angle to Tail, i.e Target Aspect Angle 0 (T) = the targets rear is pointing towards you.

90L = left side of the target points towards you

130R = the targets 2'clock points towards you

and so on.

The readout on the real thing is usually in steps of tens, e.g. 2R = 20° Right, 16L = 160° Left

 

http://bbs.thirdwire.com/phpBB/viewtopic.php?f=5&t=5735#p35130

Yes. That's correct and in agreement with

 

That is indeed how it reads in that sim.

Thanks. That's how I interpret the meaning as well.

 

EDIT:

 

AS,

 

:poster_oops: Just recognized my confusion on that diagram. I've been thinking the grey fighter(s) were the bogie. It's the red fighter that's the bogie. Senility. Got to love it.

 

Rich

Edited September 28, 2008 by Ironhand

[A.S]

 

 

:poster_oops: Senility. Got to love it.

 

 

Tell me about :helpsmilie: :megalol: ...no worry man ...you do AWESOME JOB for Simmers :thumbup::thumbup::thumbup:

[RvEYoda]

that's what i was trying to say ;)

[Ironhand]

that's what i was trying to say ;)

Yes, I never saw this part: "You are the black plane. The bogey is the red plane." Usually I read posts far more carefully than I did yesterday. My 'excuse' is that I've been at work for most of this "conversation" and the interruptions and distractions were constant. And I completely missed that. Thanks for pointing it out. If I had actually read it, it would have saved me a great deal of angst. :)

 

If nothing else, we now know where ED's formula for calculating the AA went wrong. Instead of using the bearing line (LOS) heading between your a/c and the bogie to calculate the angle, they used the player a/c bearing (heading). After all, the values for DTG and AA are identical when your nose is pointing directly at the bogie:

 

 

While DTG and AA measure two completely different angles, their values are identical with your nose pointing directly at the bogie. So whoever programmed it, simply plugged the wrong bearing (heading) into the formula.

 

Rich

[3Sqn_Sven]

Maths...the bane of the laymans existence...

[Ironhand]

Maths...the bane of the laymans existence...

I hear you. But this is simple geometry. :) The most you or I have to do is add and/or subtract.

 

Rich

[RvEYoda]

I'm just kidding with you Ironhand, you are doing an awesome job

with the tutorials :)

[Ironhand]

I'm just kidding with you Ironhand, you are doing an awesome job with the tutorials :)

Thank you.

 

I apologize, however, that I overlooked your effort to point out where I was making my mistake. Especially since it would have saved me about 30 minutes of drawing and measuring angles before the great "Ah-hah!". :)

 

Rich

[A.S]

 

 

Aspect Angle (AA):

 

The angle between the longitudinal axis of the target (projected rearward) and the

line-of-sight to the fighter, measured from the tail of the target. The fighter's heading is not a

consideration.

 

 

 

Antenna Train Angle (ATA):

 

 

This is the angle between the nose of the fighter and the radar line-ofsight

to the target. ATA is referenced in degrees left or right of 0° azimuth on the MFD.

 

 

Collision Antenna Train Angle (CATA):

 

CATA is the azimuth of the radar antenna when tracking a

target that is on a collision course with the fighter. This is the fighter's quickest route to an

intercept/collision/tally with the target. A target on a collision course drifts straight down the MFD. Its

 

azimuth never changes. An easy way to determine CATA for a cospeed target is to subtract aspect angle

 

from 180°. For example, the CATA for a target with a 150° aspect angle is 30° (180 - 150). Figure 4.65

 

shows these angular relationships.

 

 

 

EDIT: wrong part and lockon examples deleted here

Edited September 29, 2008 by A.S

[Ironhand]

as you can see here in this picture post #16[/left]

 

 

it says suddenly left where the target is on YOUR right.

 

as i said before .....

 

It does DO NOT only describe a full geometrical readout like you would have to understand on paper...... It is an interception guide or/and indicator !!! and as such to understand if shown in VSD

considering this maybe you may find a reasons why the display in LO VSD seems to be odd.

AS,

 

Are you saying that I'm wrong and the aspect angle is properly depicted in the sim?

 

The FC V1.12 VSD does not display any sort of Aspect Angle. (I have never been in LO V1.02's F-15. That could be different.) It displays what naval aviation refers to as the Degrees-To-Go (DTG) and FC's so-called Aspect Angle is exclusively determined by your and the bogie's headings. What is displayed is always the difference between the two.

 

The DTG direction is determined by it's definition: the fewest degrees to have to turn to make the bogie's heading your own. It just so happens that the Aspect Angle's definition--the angle formed by the Bogie Reciprocal longitudinal axis of the target (projected rearward) and the bearing line (line-of-sight) of the fighter measured from the tail of the target--determines the aspect (the side of the fighter facing you). That aspect and the direction of the DTG will always be identical.

 

Of course the aspect in your graphic shows left (L). The bogie's left side is facing you throughout the conversion that's shown. As your source notes, where your nose is pointing has no bearing on the Aspect Angle. That FC's version of Aspect Angle changes as your heading changes alone should be proof that it's not an aspect angle that's being represented in the sim.

 

Like I said to someone in an earlier post. Give me your heading and the bogie's at the time you want to check the VSD, and I'll tell you what number and aspect you'll see without knowing any of the angles involved.

 

Nor is it an interception guide. Set up a mission with your heading as 0. Set up an a/c to cross in front of your nose at 40nm from left-to-right. The Aspect Angle will read 9R for it's entire flight from the left edge of your radar to the right edge. Interception guide? No. That number is simply telling you to turn right 90 degrees to fly the same heading as the target aircraft It's the DTG.

 

I may be on the road for a few days. If I go "silent", that's the reason.

 

Rich

[A.S]

you are right ..Lockon does screw it up BIGTIME

 

i made few tests ingame .....cold/hot beam...head on....notch ..different angles ...all kind of situations

 

BUT:

 

it looks for me :drunk: ..that all is fine ...except L is displayed instead of R and reverse if target is closing and it shows Angle Off instead Aspect Angle :P

 

.....:suspect: :juggle:

 

 

Pic 1 post #37 shows it right ..ASPECT Angle 150 on BANDITS RIGHT ... = 15 R

 

Lockon would show in that same case 15L

 

basically what lockon does is...it shows you the shortest way to turn for bandits heading ...nothing more.

 

and therefore !!!!!!! not usefull as interception guide .. ..( what is actually used for IronHand :smilewink: ) .. well if you drunk it works

Edited September 29, 2008 by A.S

[GGTharos]

Yes. It shows you DTG, as has been mentioned MULTIPLE times here ;)

 

And, IIRC, 180-(DTG+AO)=TA

 

AA = 180-TA.

 

Therefore, AA = DTG+AO ;)

 

basically what lockon does is...it shows you the shortest way to turn for bandits heading ...nothing more.

[Ironhand]

...basically what lockon does is...it shows you the shortest way to turn for bandits heading ...nothing more...

It sounds like we're in agreement then, I think. :) But as GG has saved me from pointing out, it can still be useful. You just have to understand the relationships of the various angles to each other and do the math (3Sqn_Sven?? :) ).

 

EDIT START:

Pic 1 post #37 shows it right ..ASPECT Angle 150 on BANDITS RIGHT ... = 15 R

 

Lockon would show in that same case 15L

Just reread this after my morning coffee and I want to add that, in the case you cite, I think you'd find that LockOn would actually show 12R because you'd have to turn right, 120 degrees to be on the bandit's heading.

 

::EDIT END

 

...as has been mentioned MULTIPLE times here...

I sound like a broken record, don't I?

 

Rich

Edited September 30, 2008 by Ironhand

[A.S]

whatever....hope we could finally help lightening the darkness :pain: ...:ermm:

[Ironhand]

whatever...

Sorry. I can sometimes be obsessive. However, it's been an entertaining and educational discussion. Thank you.

 

Rich

[wuwenyao]

thanks ironhand and A.S,the FC1.12 "VSD aspect angle" confuse me a lot

[shu77]

hahahah I saw this and got all excited that Rich was working on a new tutorial, then realised that it was an old thread :(

[G3]

same here, and hopefully others will too :),

better still someone new might pickup on his work,

Ironhand's stuff is top notch.

[RipKirby]

hahahah I saw this and got all excited that Rich was working on a new tutorial, then realised that it was an old thread :(

 

lol, same here! :doh: