Looking at some numbers in the formula I gave in post 14, they have nothing to do with the numbers Brad gave in post #4.

 

Let's consider the high-ship maximum visual range of about 180 nm given in the manual. In this case, the height of the ship has little effect on the range, so we use the one-term formula SQRT (2Rh) = SQRT (7000 x 4.5) nm ~ 180 nm. I have used a height of 4.5 nm somewhere in the middle of the high band. This number checks out OK.

 

Consider the low-low range given as about 60 nm in the manual. Here we use the symmetrical two-term formula 2*SQRT (7000 x .14) nm = about 60 nm. I have used a height of 250 m, somewhere in the middle of the low band.

 

So my formula corresponds to the numbers in the manual, although there are huge approximations, but the actual visual detection rules and in-game results show little correspondence to the geometrical maximums.

Looking at some numbers in the formula I gave in post 14, they have nothing to do with the numbers Brad gave in post #4.

 

Let's consider the high-ship maximum visual range of about 180 nm given in the manual. In this case, the height of the ship has little effect on the range, so we use the one-term formula SQRT (2Rh) = SQRT (7000 x 4.5) nm ~ 180 nm. I have used a height of 4.5 nm somewhere in the middle of the high band. This number checks out OK.

 

Consider the low-low range given as about 60 nm in the manual. Here we use the symmetrical two-term formula 2*SQRT (7000 x .14) nm = about 60 nm. I have used a height of 250 m, somewhere in the middle of the low band.

 

So my formula corresponds to the numbers in the manual, although there are huge approximations, but the actual visual detection rules and in-game results show little correspondence to the geometrical maximums.

Have I missed something, do we have the game rules for visual detection of ships (Brad's post #4 is only air to air isn't it?)?

RE visual of ships from the air, it seems that in the game tests I did (flying low and medium with all sized ships) I was getting consistent visuals at a factor of 5 to 10 times less than indicated in the manual. These were in daylight fine weather. I guess we also need to know how the probabilities are worked out?

I'll try some air to air runs to.

Don

Have I missed something, do we have the game rules for visual detection of ships (Brad's post #4 is only air to air isn't it?)?

 

Yes, I was only talking about how the code handles air to air visuals, as that was the source of the reported difficulty in gameplay.

The visual detection and line of sight rules are also governed - at least to some extent - by H3 paper (as with the radar LOS).

 

The air to air visual LOS is related to the 'size' of the target, except at High altitude, where it is 50 nm.

 

Otherwise, at Low altitudes:

 

Vsmall - 0 nm

Small - 3 nm

Large - 6 nm

 

Recall that the 'size' of the target is determined by the Size Field in the Aircraft Annex of the PE.

 

The time of day will also affect chance of visual detection, i.e. 100% in daytime, 66% in twilight, 33% at night

...................

Anyone know where the rules came from originally?

From my house (on a small ridge at the edge of a shallow valley full of farm land) I can see a gyrocopter that often flies overhead from between about 1 and 2 mile away. I usually hear it a bit before I can see it and it comes form a near neighbour about 2 mile away but I see it near the edge of our property about 1 mile away. Also I can see small fixed wing planes (and before when they used helicopters) that inspect a power grid line that runs along the valley opposite me about 2 mile away but sometimes loose sight when it nears the ridge at the other end about 4 mile away. These are all very low flying silhouetted against hills. I think this doesn't tie in very well with the 0 nm visibility of vsmall aircraft.

The trouble I keep thinking of though is how to compare say a single seat fighter flying very low minutes away from weapon release and a reconnaissance plane cruising, their respective abilities to ID visually must be incredibly different.

Don Thomas

Don, for those planes you are watching, how are they painted? It seems to me that the typical commercial paint job would be rather significantly more visible than that of a combat aircraft which is deliberately painted to blend in with its environment.

Most Vsmall types in the database (the HCDB, at least) are of the stealth variety, UAVs or aircraft types that might spend a lot of time in the weeds staying out of sight (e.g. attack helicopters). From a quick review, there are some that probably need adjustment up to the Small size, but for the most part, they are Vsmall for good reason.

 

Keep in mind as well that HCE does not model clutter, terrain, foliage or flocks of birds, or smoke, haze, clouds, or diving out of the sun.

An excerpt from the April 2004 issue of Air Forces Monthly that some folks might find interesting:

 

For the entire duration of the war, almost all air combat over the North was visual. In the vodka clear skies over the Mojave Desert, this would have posed few problems. But Southeast Asia was different. For much of the year, the monsoon produced a solid undercast, with huge electrical storms. Even on good days, haze restricted visibility below about 4500 m. Nor was radar much use in searching for targets at a lower level. The problems of ground clutter had yet to be overcome. This was the situation through much of the war. Overall, the US kill/loss ratio was on the right side, but only just. At times, however, it was distinctly adverse.

 

What exactly was the MiG-21F-13 worth ? It was small. To maximize performance, designer Artem Mikoyan had wrapped the smallest possible airframe around a powerful engine. Its dimunitive size made it difficult to see at any distance: from head-on or tail-on it was all but invisible at 5 km. In planform, 8 km was about the max. Positive visual identification generally could only be made at one third of these distances. To make matters worse, its Tumansky turbojet was smokeless, unlike those of the US fighters, which left sooty black trails across the sky, visible from 16 km away.

An excerpt from the April 2004 issue of Air Forces Monthly that some folks might find interesting:

 

For the entire duration of the war, almost all air combat over the North was visual. In the vodka clear skies over the Mojave Desert, this would have posed few problems. But Southeast Asia was different. For much of the year, the monsoon produced a solid undercast, with huge electrical storms. Even on good days, haze restricted visibility below about 4500 m. Nor was radar much use in searching for targets at a lower level. The problems of ground clutter had yet to be overcome. This was the situation through much of the war. Overall, the US kill/loss ratio was on the right side, but only just. At times, however, it was distinctly adverse.

 

What exactly was the MiG-21F-13 worth ? It was small. To maximize performance, designer Artem Mikoyan had wrapped the smallest possible airframe around a powerful engine. Its dimunitive size made it difficult to see at any distance: from head-on or tail-on it was all but invisible at 5 km. In planform, 8 km was about the max. Positive visual identification generally could only be made at one third of these distances. To make matters worse, its Tumansky turbojet was smokeless, unlike those of the US fighters, which left sooty black trails across the sky, visible from 16 km away.

 

In the same vein, I've read that in the Battle of the Philippine Sea (i.e. the Turkey Shoot), contrails made the Japanese planes easy to see from miles away. At least that's what I read in The Big E. So that's not something you can model reliably, either.

Don, for those planes you are watching, how are they painted? It seems to me that the typical commercial paint job would be rather significantly more visible than that of a combat aircraft which is deliberately painted to blend in with its environment.

Very good point.

I read the air to air detection for vsmall aircraft being 0 nm as meaning that at 0 nm range detection is possible, but when I try this it seems that no visual detection occurs, ie vsmall sized aircraft are invisible.

I've attached a zipped save where 6 Tiger ARH helicopters are hovering over Amberley air base which in turn has a long range patroling MRH-90 helo also hovering directly above. All show up as at 0nm distance apart. no matter how long this is allowed neither the bse nor the HRH-90 make a visual on the 6 Tigers. There is also a Red MRH-90 hovering at 0nm distance from a loitering starlifter, AMberley has ESM on the MRN-90 but no visual is ever made.

It seems to me that there is some problem with the 0 nm range.

Even if the helos are hard to spot in this situation they would be heard, and then spotted, surely?

Also if we do something simiilar with a stealth jet flying overhead vlow, Iaccept it probably won't be seen approaching but it will be heard as it overpasses, and a visual for a short time on its departure, surely?

Amberley radar is off, 'see all' mode has been utilised, I used GE 2009.53, HCDB-110225, westpac BS.

Don

a2a_vis.zip

I read the air to air detection for vsmall aircraft being 0 nm as meaning that at 0 nm range detection is possible, but when I try this it seems that no visual detection occurs, ie vsmall sized aircraft are invisible. I've attached a zipped save where 6 Tiger ARH helicopters are hovering over Amberley air base which in turn has a long range patroling MRH-90 helo also hovering directly above. All show up as at 0nm distance apart. no matter how long this is allowed neither the bse nor the HRH-90 make a visual on the 6 Tigers. There is also a Red MRH-90 hovering at 0nm distance from a loitering starlifter, AMberley has ESM on the MRN-90 but no visual is ever made. It seems to me that there is some problem with the 0 nm range.

Even if the helos are hard to spot in this situation they would be heard, and then spotted, surely? Also if we do something simiilar with a stealth jet flying overhead vlow, Iaccept it probably won't be seen approaching but it will be heard as it overpasses, and a visual for a short time on its departure, surely? Amberley radar is off, 'see all' mode has been utilised, I used GE 2009.53, HCDB-110225, westpac BS.

 

I am not surprised that '0 nm' actually means '0 nm', as far as the code is concerned. The question arises, then, whether it should be actually be zero, or some other number, say 1 nm. Or, if there should be any Vsmall aircraft. Personally, I find it useful to have Vsmall aircraft (like UAVs) in play.

 

Keep in mind that there is no model for being able to 'hear' aircraft overhead or nearby.

 

The MRH-90, btw, (and some others) has since been changed to Small, because as I said earlier in the thread, I intended to make some adjustments as to which aircraft were actually Vsmall.

I am not surprised that '0 nm' actually means '0 nm', as far as the code is concerned. The question arises, then, whether it should be actually be zero, or some other number, say 1 nm. Or, if there should be any Vsmall aircraft. Personally, I find it useful to have Vsmall aircraft (like UAVs) in play.

When I think about this I assume that there is a typical periodic test (1 per second, 1 per minute, what ever) with a probability of detection. On that basis I'd think that a 1 nm range (and possibly need to fiddle of the probability) so that a fast incoming fixed wing has little chance of detection (as should be the case) but a slower chopper or sluggish fixed wing is likely to get picked up overhead.

 

Keep in mind that there is no model for being able to 'hear' aircraft overhead or nearby.

It's in view of no sound model that I think some adjustment would be good so that slower air craft will be likely to be seen at soome stage. With vlow attacking aircraft I'd expect you hear first then that tells you where to look, so to 'cheat' on this I think a slightly more lenient visual detection would be an improvement.

 

The MRH-90, btw, (and some others) has since been changed to Small, because as I said earlier in the thread, I intended to make some adjustments as to which aircraft were actually Vsmall.

Which needs least work, revising code or going through all the databases? Probably wouldn't need both.

Don

Which needs least work, revising code or going through all the databases? Probably wouldn't need both.

 

I've already made the changes to the database (which would have been easiest, in any event), but haven't uploaded the new version yet. Keep in mind that the stealthy types, attack helos and UAVs will still have the Vsmall rating, at least for now.

Other adjustments beside (for stealth, attack helicopters and perhaps small UAVs) I use this formula:

Aircraft Height (in meters) X Aircraft Lenght (in meters) X Aircraft Wing Area (in meters, in helicopters Rotor Area/10)= Y

If Y <= 45 (if Y equal or smaller than 45), signature Very Small.

If Y between 45 and 70, signature Small.

If Y > 70 (if Y greater than 70), signature Large.

I read the air to air detection for vsmall aircraft being 0 nm as meaning that at 0 nm range detection is possible, but when I try this it seems that no visual detection occurs, ie vsmall sized aircraft are invisible.

...

Hmmm... I wonder if this is the explanation for the occasional "self destruction" of pairs of my F-14s, etc. when none of my units ever detect anything in the area to account for it? In at least one of these instances, there were Eurofighters in the scenario, which could have been the culprits. Even so, I am still puzzled about how the Eurofighters (or whoever) even knew to look for the F-14s that were way out there in the ether... not to mention wondering how they had enough gas to get way out there to knock 'em off.