Damage Modelling, Firepower B-17f

[Daiwilletti]

I flew some QC missions with the Firepower Me410 vs the B-17f. Can't remember what I was testing for. The first thing I noticed was how fast and manoeuverable the B-17f was! The Me410 was hard pressed to turn onto this big bomber twisting and pirouetting in the sky.

However what I am interested in feedback about is the damage modelling. The 410 has twin 30mm cannon on top of other firepower, and the B-17 seemed to take an enormous number of hits. When I look at images of the damage that a 30mm cannon shell makes to a B-17 tailplane or vertical, a single hit makes a very big hole.

So what's the story, should the 30mm cannon shell have an uprated damage profile, or should the B-17 have reduced damage points for some parts? Interested in all views. I note the AvHistory 30mm round appears to have higher damage points than the stock rounds. I deliberately have not mentioned Mk103 v. Mk108, because I don't know the difference!

[greycap.raf]

The damage models as a whole are all over the place. Some of them make absolutely no sense, let's have some examples.

AvHistory 4.00 series B-26G:

<Box ID="damagebox_l_wing" Parent="damagebox_fuselage">
<BoxMap SystemID="left_wing" Probability="67" Points="1230"/>
<BoxMap SystemID="left_flap" Probability="9" Points="163"/>
<BoxMap SystemID="left_fuel_tank" Probability="24" Points="446"/>

This is a sensible wing damage model. When hitting the wing damage box the probability of damaging the actual wing structure is 67% and it takes 1230 points to break completely. Half a dozen AvH MK108 rounds take the wing off as they should.

AvHistory 4.00 series P-47D:

<Box ID="damagebox_r_wing" Parent="damagebox_fuselage">
<BoxMap SystemID="right_wing" Probability="3" Points="228"/>
<BoxMap SystemID="machine_guns" Probability="23" Points="81"/>
<BoxMap SystemID="right_cannon" Probability="22" Points="81"/>
<BoxMap SystemID="right_guns" Probability="22" Points="81"/>
<BoxMap SystemID="right_cheek_gun" Probability="22" Points="81"/>
<BoxMap SystemID="right_gear" Probability="5" Points="187"/>
<BoxMap SystemID="right_flap" Probability="1" Points="20"/>
<BoxMap SystemID="bomb_release" Probability="2" Points="74"/>
</Box>

This is anything but a sensible one. The damage points are right in the ballpark but the hit probabilities aren't, hit the wing and the chance of damaging the actual wing is a whopping 3% while the machine guns take damage with a 87% probability. In other words, you won't be shooting the wing off one of these even if the wing itself isn't all that tough.

AvHistory 4.00 series P-51D:

<Box ID="damagebox_r_wing" Parent="damagebox_fuselage">
<BoxMap SystemID="right_wing" Probability="3" Points="168"/>
<BoxMap SystemID="right_guns" Probability="55" Points="162"/>
<BoxMap SystemID="right_cheek_gun" Probability="28" Points="81"/>
<BoxMap SystemID="right_gear" Probability="5" Points="143"/>
<BoxMap SystemID="right_flap" Probability="1" Points="20"/>
<BoxMap SystemID="right_fuel_tank" Probability="5" Points="134"/>
<BoxMap SystemID="bomb_release" Probability="3" Points="83"/>
</Box>

In the same category as the P-47D. And the same conclusion.

The freeware TK B-24 series:

<Box ID="damagebox_r_wing" Parent="damagebox_fuselage">
<BoxMap SystemID="right_wing" Probability="60" Points="19110"/>
<BoxMap SystemID="right_flap" Probability="15" Points="892"/>
<BoxMap SystemID="right_fuel_tank" Probability="12" Points="160"/>
<Boxmap SystemID="right_gear" Probability="13" Points="1000"/>
</Box>

Saved the best one for last. Not trying to shame anyone but it's an excellent example of how much the damage models vary - the wing needs 15 times more damage to break than the AvH B-26, not taking into account the lower chance of damaging the actual wing, and while the Liberator undoubtedly is tougher than the Marauder, it definitely isn't it by such a margin.


This was meant to be a bit of a heads up for everyone. Damage models probably aren't well known to most people but they make a huge difference to how the combat situations turn out.

[NachtPiloten]

I have only used the av specs for years. The original and firepower specs are too weak. Now B17's B24's and lancasters could take a few hits as you see in gun camera footage. BUT the real issue is not the gun specs but the damage models the xdp files. Many of these have been designed to have little damage done and they needed to since in 2003 computers could not process very complex models. WOFF and those folks have some pretty complex models now that seem to work well. SO in lieu of redoing the damage boxes (need mesh for that) recoding the xdp can be the next best thing.

IL2 seems at times a little too easy but again 3-5 30mm shells should rip off a wing (fighter) or set fuel tanks into flames (bombers) -easily especially explosive rounds. I have an entire set of German cannon rounds for AP, HE, and incendiary by coding the damage per round or the likelihood of fire. These seem to work ok. Don't tear off wings easily but fuel tanks and engines do burn nicely.

I have tinkered around with complex damagebox designs and they are pretty cool. Separate boxed for flaps, ailerons, fuel tanks etc. There is a limit but imagination really helps. As long as the boxes are rectangles they work well enough. But seriously who is going to redo all the models, we just don't have the models or the time (speaking for myself).

So in short, I suggest we use the AV specs for uniformity and tinker with the xdp files and model damagepoints to get the planes to behave as we THINK they did......

But since I lurk around here in a very limited way now, these are only my thoughts.

Pauke Pauke

[greycap.raf]

One thing that would be great to have would be for the damaged wing to "stop flying" after a couple of big enough hits. When the wing has taken three or four 30 mm Minengeschoss rounds its surface is so torn up with sheetmetal blown up into jagged shapes that the drag is huge (something we can't model) and the lift is very severely compromised. This could perhaps be simulated by a higher probability of damage to the ailerons and control cables, destroying the controllability on that side.

[NachtPiloten]

The probability of damage in my opinion was a representation of the chance that part would be hit if the wing structure was. If you want to model a faster damage profile, then you are correct increase the probability of a part being hit and that would disable it or limit its function more quickly. Now how quickly do you want this to happen, with large wings is hitting the aileron or flap is proportional to that of a small surface area? If so, then just recode the file. You could bring in Effect = "Break" sooner and see what happens. Not sure that signals for the wing to separate - would think so.

Oh, points - I use the AV History points calculator spread sheet. Really cool little excel spread sheet that lets you determine the points for the parts based on certain parameters like weight, number and type of engines, fuel, and I think one or two other parameters. These data are consistent with the damage generated by the AV history guns. I use this as a start and tinker to get what I want.....usually I am satisfied by what the spread sheet suggests.

My little WW1 planes the SSW III and IV have damage boxes similar to WOFF - you can see these when you use model view. Not as complete but I did not go as far as I could have.

Maybe I will model one of those brit bombers to have a more complex damagebox model and xdp and see what happens - all I can do is crash the 'puter....

If you want any of the stuff I mentioned let me know I did them up for those interested. Oh to see what you can model you can open the cfs3 exporter in gmax with notepad and see the parameters and options you have. Most of what is in there is coded - not all the engine stuff but most.

[Daiwilletti]

Thanks guys this pretty much covers what I hoped it would. I definitely wasn't suggesting re-doing damage boxes! Very much just wondering whether to change probablities and points in the aircraft xdp, or beef up the hit points in the cannon shell's .xdp file.

Given that there is some inconsistency in damage profiling between aircraft, ideally modifying damage-box probabilities would be the way to go. At the moment I notice that I can put one or two shells into the tail of a Friederich, and it is disabled, whereas the dreaded Spitfires can end up looking like a collander and still sneak up behind me and blast me from the sky

[NachtPiloten]

I am going to remodel one of my older models to have a much more complex damagebox design. When you open up the export plugin for gmax in word you see about 30 or so damagebox options. We usually only use a small handful. Wings can be easily split into three sections damagebox_l_wing, damagebox_l_wing1, and damagebox_l_wing2. Wingtips and horizontals too. The game does not care what you use the damagebox for, that is damagebox_canopy1 could be nose gunner, pilot, waits, tail, or ventral gunners. So I was thinking that I could take some of these canopy or extra horizontal boxes and use them to better model say fuel tanks, and such. On smaller aircraft you could use the wingx to model flaps or ailerons only and not have to guess at the probability of a hit to wing to damage the various parts. Years ago the computer power limited the creativity we could have but now not so much. The more complex bombers with larger wing areas etc and gunner positions will be constrained a bit, but maybe some more options could be had.

I was thinking of this thought hey why not, what could possibly go wrong?! Will do this and report back. Think I'll screw around with the Queen of the Skies and see if we can get her to behave. Oh, read that 2-5 30mm would easily take down an allied bomber and 8-12 20mm (wing shots). I was always frustrated sallying up under a Lancaster. Fire a one-two second burst into the wing root with 20 mm cannon (with 600 rpm, 10 rounds a second we are talking about 20-40 rounds) and well a little smoke, some debris and maybe a small fire. It should burst into flames and another one down, but not so much.

Off to see what happens.....

[Daiwilletti]

Can't wait to see what you come up with, Nachtpiloten! Hadn't thought about the compromises required because of lower computer power. That's why we are able to get so much from an old game engine, I guess.

I'm still wondering if the hitting power of the cannon rounds is too low? I tweaked the stock 30mm rounds to be more in line with the Av_History versions. It was noticeable when flying a 109 G10 last night, and took a wing off a normally indestructible P47D_25. Very satisfying and helps to level the playing field.

Stay frosty up there!

[greycap.raf]

I'm still wondering if the hitting power of the cannon rounds is too low? I tweaked the stock 30mm rounds to be more in line with the Av_History versions. It was noticeable when flying a 109 G10 last night, and took a wing off a normally indestructible P47D_25. Very satisfying and helps to level the playing field.

It's a bit of both, the weapons being weak and some aircraft being far too tough. Changing all guns on all aircraft to AvHistory (an insane job but ultimately worth it, a good alternative is to only fly AvHistory aircraft or other modern add-ons) is a good start but it still won't fix the problem when the aircraft are built to be nearly impossible to shoot down.

See my examples in the earlier post, the B-26 is the only one out of them with a sensible wing damage profile. In the P-47D and P-51D only every 33rd hit does damage to the actual wing - you can do the math why they're hard to shoot down, and increasing the weapon power alone isn't going to be enough. On the other hand in the B-24 the wing needs several dozen 30 mm hits simply because the amount of damage points is so high - 15 times higher than in the B-26 which goes down after around ten hits.

[NachtPiloten]

That is a typo mistake in the xdp. I will run the av history damage file spread sheet and have new numbers - which is 1800 points my bad all those years ago...must have been the bourbon...

[Daiwilletti]

@ nachtpiloten - well the bourbon excuses a lot of things, IMHO!

@ Greycap.raf - yes, converting all to AvHistory weapons would be a hell of a job. However so would achieving agreement as to consistent damage profiles! After all, modellers will all have their own opinions... And there are a few things I don't agree with in the AvHistory weapons set. Like the blast radius in the Spitfire 500lb bomb .....