Bug in AKAN gunsight?

[Snappy]

Dear Heatblur development team,

 

 

could you kindly take a look at this issue. I'm not entirely sure, but I think the wingspan mode gunsight of the AKAN gunpod is wrongly aligned in the air to air mode.

 

 

I tried to verify it in your manual as well as in the swedish original Viggen system manual, however unfortunately both are very sparse in details details regarding the finer points of the gunsight projection.

 

 

 

 

I made a couple of pictures to better illustrate the issue.

 

The first picture in straight and level flight behind a bandit I painted into it in red colour (excuse my bad painting skills:)

 

Provided you use the correct wingspan selection everything is fine.

 

 

 

In the second picture we are maneuvering for a tracking gun shot on the enemy, which requires that we align our plane-of-motion with the enemy aircraft's.

 

Now the problem becomes visible:

 

I try to describe it at best as I can:

The gunsight is still aligned to the horizon (marked in turqoise colour) instead of being aligned to the viggen's own wingline, which as you can see , renders it useless for correct gun range assessment.

 

 

Even though you matched the enemy aircraft plane of motion, the wingspan markers are

miss-aligned

 

 

 

In the third picture I super-imposed a new gun sight aligned with the Viggens own wingline in bright green.:

Now (as long as you are correctly tracking the enemy aircraft plane-of-motion)

you can use the wing span sight markers to assess correct gun range as intended.

 

You still have to apply lead of course but that is not relevant for this issue.

 

 

The green line of the bottom of the HUD is only to illustrate the viggens wingline at the moment of the picture,

as it is a bit hard to see on the attitude indicator, it s not meant to be a part of the gunsight I drew in.

 

 

 

 

As I wrote I can't prove it with absolute certainty from the manuals,

but simply from a logical standpoint it would make a lot of sense if the wingspan gunsight

was aligned to the Viggen wingline and not to the horizon.

 

Otherwise it could only be used in level flight and normally enemy aircraft can't be expected to cooperate so easily.

 

 

It would be very kind, if you could at least take a look at it, or ask one of your SME.

I'm happy to stand corrected, I know the AJ-Variant is not primarily oriented towards

air2air but the swedish are pretty smart and I would think they would have implemented

the most practical gunsight for the purpose.

 

Thank you very much,

 

 

 

 

Kind regards,

 

 

Snappy

 

 

P.S: Sorry for the small picture size of the last 2 pictures, something went wrong during resizing.

If you can't make out what I mean I can do new ones in larger format.

Edited November 5, 2018 by Snappy

[RagnarDa]

Thanks for the descriptive pictures but that's not the visual range gun sight. You are probably in the wrong mode. The visual ranging mode looks like this:

 

You have to lower you seat a little from the default one (RCtrl+S) to see the symbology. The J/A selector needs to be in this setting:

 

and master mode ANF. You select wing-span with the selector just right of the J/A selector. While in AKAN-LUFT mode you can though change the symbology so it appears like in your picture by initiating a radar-lock (T1). You then dont have to visually tell the range but the time-line indicates instead if you are within range to fire. Hope this helps!

[Snappy]

Hello Ragnar,

 

 

sorry, you are right. I must have acidentally pressed T1 trigger stage so it went into radar ranging mode.

 

However I did it again in pure wingspan mode and the problem is present there as well.

I made a new set of screenshots. The bars are only so far apart because I selected the 50m wingspan value for IL-76 targets:

 

 

Picture 1 gunsight in wingspan mode, aligned to horizon ( marked in yellow ):

 

 

 

 

Picture 2 : inserted bandit aircraft in turn, viggen plane-of-motion aligned with bandits plane-of-motion for a tracking gunshot. The gunsight wingspan markers can't be used due to the alignment to horizon.

 

 

 

 

 

 

Picture 3 : Superimposed a wingspan gunsight with wingspan markers aligned to Viggens own wingline(marked in green across screen).

When flying in same plane-of-motion with bandit, the wingspan markes are usable

again for ranging.

 

 

 

 

 

 

 

Hope this helps.

 

 

 

 

 

 

Kind regards,

 

Oliver

Edited November 8, 2018 by Snappy

[corvinus]

However I did it again in pure wingspan mode and the problem is present there as well.

I think I understand your reasoning and you bring up an interesting point. I would like to add that the Viggen does not know the orientation of your opponent, i.e. it does not know how that plane is pointing in space. So there is no way for the Viggen to orient the wingspan indicator to match the orientation of the wings of your opponent.

 

The Viggen engineers thus had to make a default choice for the orientation of the wings. They chose a level flight for the opponent, which is what you observed: the wingspan indicator is always horizontal.

 

Now for a turning dogfight against a fighter that is probably not the best choice, but for engaging a slowly turning transport aircraft it probably is. I wonder what rationale the Viggen engineers used when designing the indicator. Does anyone know this?

 

P.S.:The wingspan indicator method is not very precise (the wingspan indicator itself can not be set very precisely and the target aspect leads to foreshortening of the observed size of the target), therefore you can get away with mentally comparing the wingspan indicator size with the observed target size.

[Snappy]

Corvinus,

 

 

I think you misunderstood me. I did not mean or propose that the gunsight should somehow "know" the orientation of the bandit. That would require avionics that the viggen does not have.

What I meant is, the gunsight should be aligned to the Viggens own wingline, not the horizon.

 

 

Only to illustrate what I mean, here's a picture of the HUD in nav mode (I know it is something totally different. It is just to explain what I mean by "wingline")

 

 

Take a look at the small wings extending from the flight path vector. I 've marked them in red. These for example are aligned to the Viggens wingsline:

 

 

 

 

I think the wingspan markers of the gunsight should be aligned the same way.

 

To put it in other words, if you fly a turn, the gunsight should be banked as well, not stay fixed to the horizon line.It doesn't make any sense to have it aligned to the horizon.

 

It is the pilots job to get his aircraft into the same plane-of-motion as the bandits aircraft plane-of-motion for a tracking gunshot. Then you can use it to assess range.

 

 

(high aspect snapshots are a different matter, but for those you don't use the wingspan anyway)

 

 

 

Hope that makes my thinking a bit clearer.

 

 

KInd regards,

 

Snappy

Edited November 9, 2018 by Snappy

[corvinus]

I think you misunderstood me. I did not mean or propose that the gunsight should somehow "know" the orientation of the bandit. That would require avionics that the viggen does not have.

What I meant is, the gunsight should be aligned to the Viggens own wingline, not the horizon.

The latter statement is an assumption on your part on how the Viggen should work. I tried to show that you can follow a different reasoning just as well. I am not saying you are wrong, I was only suggesting that the Viggen engineers could have made a different choice.

 

It is the pilots job to get his aircraft into the same plane-of-motion as the bandits aircraft plane-of-motion for a tracking gunshot. Then you can use it to assess range.

Like I said, the wingspan method is a rough method, even with an orientation mismatch you can use it. Of course, for more precision use the radar, especially in a turning dogfight.

 

Anyway if the wingspan is not supposed to be horizontal all the time, then I am sure Heatblur will fix it. They probably have access to documentation explaining the functionality.

[Snappy]

Corvinus,

 

 

yes it is only an assumption on my part, that is correct. As I wrote in my initial post unfortunately the Manuals (both for DCS and the public swedish original) are sparse

on details regarding the finer points of the gunsight projection.

As I said, I think the swedish are pretty smart and I would think they would try to make

it the most useful for the pilot.

 

But as you say, lets wait for Heatblur. Maybe they have more data or details on this

Thank you for your inputs.

 

Kind regards,

Snappy

[Holton181]

Just my two cents here, without having any official information what so ever. But for what I know, this AJS wasn't really build for dogfights in mind making Corvinus theory of using the sight as a rough estimation most plausible in my opinion. It's not very often I believe your would find yourself aligned with the same bank angle as your target during a dogfight either. The JA model might be a different thing, but I have no clue how the sight work on that either.

But with practice our brains are quite remarkable in using imperfect information. A little bit like the graphic scale located somewhere on a regular paper map, or the square grid, when geting used to it you can quite rapidly estimate distances just with a quick glance on the map, without the use of any tools. I think it's the same thing with this sight. Of course the sight could have been aligned with the wings and the pilots brain would have adopted to that, but by having the sight aligned with the horizon the pilot also get distinct orientation information without the need to look at other instruments (I get the feeling it's quite easy to get disoriented while in a dogfight).

Again, this is basically only guessing, would be nice to have some official information.

[Snappy]

Holton,

 

 

no question, air combat was not the primary intended function of the AJ version of the Viggen.

But then again you argue, that the alignment to horizon could have been chosen to help the pilot with orientation during dogfight maneuvering which is a bit contradictory to your first argument, where you say the Viggen is not designed for Air combat maneuvering.

 

 

I also agree that the wingspan sight is made for rough guess when in range for gunshot.

But even if the goal was to provide a simple rough tool for aiming ,it would have been even easier (and probably cheaper too) to project a simply fixed non-moving aiming sight , (already used on WWII aircraft ) and even that would be automatically aligned to the own aircrafts wingline, simply because it would be fixed in its orientation.

 

 

For example see this old spitfire gunsight:

 

 

 

 

 

 

Regarding the maneuvering.Well as I wrote earlier it depends. For a tracking gunshot you would try to match the enemy plane-of-motion by maneuvering as good as you can into it.

 

 

But as you said, we have to wait for more information or a SME.

 

 

I simply wanted to point this out as a possible issue from a logical standpoint. I tried finding more info about it online, but unfortunately no luck so far. :-/

 

Snappy

[Holton181]

Well, I just figured that if dogfights was a major thing for this aircraft, an even more sophisticated solution would be likely (not looking at the radar ranging). A fixed sight would probably be simpler to implement I agree, but then that extra orientation information at a convenient place would be "lost".

Let's hope for some of the devs get in here and share what they know, maybe it's not more than you have found, forcing them to guess.

[Snappy]

Hello,

 

 

has there been any update or official HB position on this issue ?

I noticed the latest open beta changelog includes the following line for the AJS Viggen:

 

 

"The dumping of the sight for sidewinder carried on wingtips should now be relative to the plane and not the horizon."

 

 

Not sure what to make of this. For one the Viggen cannot carry weapons on the wingtips, but even if that referred to the outer most pylons, I loaded it up with RJ-24/sidewinders on those outer pylons and there is no apparent change in the sidewinder sight orientation after the latest update.

 

 

Besides I don't quite understand why the sidewinder sight would get changed but the AKAN a2a gunsight not.

 

 

Would be thankful to hear some developers statement on this.

 

Thank you for your continued work.

 

Kind regards

 

 

Snappy.

[Holton181]

I noticed it as well. But according to several other threads it seems many of the announced changes reached ED to late for them to be included in the patch.