Home Forums WWII When is extreme range HE direct fire best handled as concentrated HE area fire?

This topic contains 7 replies, has 5 voices, and was last updated by Ivan Sorensen Ivan Sorensen 6 months, 1 week ago.

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  • #81434

    Les Hammond
    Participant

    When firing HE at the extremes of direct fire  range, I imagine the trajectory of the shell to be pretty steep and any direct hits to perhaps benefit landing on thinly armoured AFV top surfaces.

    In old school wargaming rules, there is often a chart for this observed & aimed HE fire by guns & howitzers (typically 1.5-2.5km) but simply a maximum range (in the region of 8-15km) for indirect or map HE fire with an area fire or blast radius effect calculation to be done.

    So what I am getting at is, how far down the direct fire table should HE rounds really be landing on top of objects and not impacting against the sides? Should extreme range HE direct fire blend seemlessly into howsoever the rules handle artillery barrage fire?

    I am thinking it ought to.

    Forgive my lack of proper military terminology here.

    • This topic was modified 6 months, 1 week ago by  Les Hammond. Reason: Terminology corrected

    6mm France 1940

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    #81436
    Grimheart
    Grimheart
    Participant

    I am a bit confused by what you mean tbh, sorry!

    While direct fire by artillery did happen it certainly was not the norm and generally meant something had gone very wrong.

    I doubt very much that any direct fire would be at a steep enough angle to generally hit the top of a tank unless the artillery was on a higher elevation so personally I would always have direct fire as hitting the front or side, never the top. Lack of specific optics etc and generally slow shell speed, etc would also mean it would have a very low chance of a direct hit imo.

    This site has a lot of very good info on how british artillery worked in ww2, well worth a read:

    http://nigelef.tripod.com/

     

    Interest include 6mm WW2, 6mm SciFi, 30mm Old West, DropFleet, Warlords Exterminate and others!

    #81441
    John D Salt
    John D Salt
    Participant

    I have just had a quick pootle with a simple square-law drag program I wrote in Python a while ago, which calculates the angle of fall of a projectile given its initial velocity and drag. Taking one of the most curved-trajectory tank guns I can think of, the 7.5cm KwK L/24, and guessing a drag coefficient based on some curve-fitting to published penetration tables I did earlier for fun, I reckon it would be falling at an angle of about 5 degrees at 2000 metres, and twice that at 3000 metres. Good luck hitting anything at that range; the program gives the time of flight as about ten seconds.

    On the strength of this, I do not think the angles are likely to involve any useful element of top attack for any range at which a target is going to be seen, as long as the shot is fired in the lower register. In the upper register, obviously things are going to have more of a coming-down than going-along component, but I am not aware of any tank main armament that can fire in the upper register.

    Howitzers can, and mortars usually must, fire in the upper register, and the big advantage of this at the target end is that the lethal area — the intersection with the ground plane of the expanding doughnut of steel fragments from the shell burst — can be a good deal larger for the same shell. If wargames rules writers were such obsessive detail freaks about field artillery as they were for AFVs, there would be rules showing how the lethal area varies with range, but as far as I am aware no wargames rules, and indeed no artillery norms in Russian, British and Canadian artillery doctrine that I have seen, do so. Not much point making the game more detailed than real life, is there?

    The dear old 1973 WRG 1925-50 rules I recall used the same areas of effect for both direct and indirect area fire, and this seems quite sensible to me; the problem is that too few rules these days allow for direct area fire. This changes the question to “at what range does point fire become area fire?”, and that is going to depend on the precision with which the targets can be located. At (say) 2000 metres, with binoculars, you may well be able to spot a building or substantial field fortification well enough to engage it with point fire, but for properly-concealed infanteers, forget it. The WRG rules let the firer decide.

    The other aspect to consider is how the shots are sensed and corrected. Most WW2 HE weapons, I believe, would employ bracketing drills in order to correct fire onto a target, somewhat after the fashion of an FOO correcting artillery fire. However with the 75mm M3 in the Sherman (and so analogously the 75mm Mk 5 in Cromwell and Churchill) it was found possible to employ direct laying — as if shooting a tank — up to 2,000 yards. That seems to have remained pretty much the British Army’s doctrinal distance for precise tank HE fire in support of infantry ever since; at least, in my day, Chieftain was supposed to do this with 120mm HESH up to 2000 metres.

    Mr. Picky, while forgiving, would like to remind people that a “barrage” is a linear pattern of fire (as one might expect from the original French). Most artillery fire on the wargames table is fired in simple concentrations. Nigel Evans’ wonderful artillery pages doubtless have more detail.

    All the best,

    John.

    #81444

    Les Hammond
    Participant

    …taking one of the most curved-trajectory tank guns I can think of, the 7.5cm KwK L/24, and guessing a drag coefficient based on some curve-fitting to published penetration tables I did earlier for fun, I reckon it would be falling at an angle of about 5 degrees at 2000 metres, and twice that at 3000 metres…On the strength of this, I do not think the angles are likely to involve any useful element of top attack for any range at which a target is going to be seen, as long as the shot is fired in the lower register…However with the 75mm M3 in the Sherman (and so analogously the 75mm Mk 5 in Cromwell and Churchill) it was found possible to employ direct laying — as if shooting a tank — up to 2,000 yards.

    Which makes me think it wouldn’t be much of a loss of realism if AFVs & AT guns firing HE were unable to engage beyond direct fire range anyway.

    . Howitzers can, and mortars usually must, fire in the upper register…

    So leaving out mortars which pretty much will have to use ‘high trajectory area fire rules’, howitzers (and probably infantry and field guns?) ought to have a grey area toward the end of their direct fire table where such aimed fire might ‘blend’ into ‘direct area fire’ rules.

    Mr. Picky, while forgiving, would like to remind people that a “barrage” is a linear pattern of fire (as one might expect from the original French). Most artillery fire on the wargames table is fired in simple concentrations. Nigel Evans’ wonderful artillery pages doubtless have more detail.

    Ah yes, concentrations, that’s a better word for what I was trying to describe (subject title upgraded) and Nigel’s pages are excellent.

    6mm France 1940

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    #81464
    MartinR
    MartinR
    Participant

    While the vast majority of tank HE was fired direct at ranges up to 2000 yards (commonly rather less!), bear in mind those odd occasions where Shermans etc were parked on the reverse slope of hills and used to fire 75mm indirect concentrations. WRG let you do that too.

    "Mistakes in the initial deployment cannot be rectified" - Helmuth von Moltke

    #81537
    Ivan Sorensen
    Ivan Sorensen
    Moderator

    American tank destroyer battalions fired something like 3 times as many shells indirectly as they did direct fire at vehicle targets, so it is certainly something to consider.

    But… on how many of our gaming tables can your tanks find a target 2 kilometers away?

    Nordic Weasel Games
    https://sites.google.com/site/nordicweaselgames/

    #81667
    MartinR
    MartinR
    Participant

    Depends on the terrain and game scale really. The German AT guns dug in on Bourgebous Ridge didn’t have any great difficulty finding lots of targets to engage at 2km range, and 9th RTR War Diary describes a number of occasions in Holland when they were brassing up villages 3km away with HE. Some bits of Holland are quite flat though with very thin intervening tree lines.

    I would be a tad surprised to see it in a 1:1 type game though.

    "Mistakes in the initial deployment cannot be rectified" - Helmuth von Moltke

    #81710
    Ivan Sorensen
    Ivan Sorensen
    Moderator

    I guess it also depends on whether the detail is important.

    If my company has some supporting fire before they go in, does it matter what guns it’s coming from, other than whether its “Bother Fritz” or “Kill Fritz” weight and duration ?

    Nordic Weasel Games
    https://sites.google.com/site/nordicweaselgames/

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