chapter I "the beginning" first of all, there are two principles: 1)DM must be stable, no random calculations except fortunity of hitting target. 2)DM must be tactically realistic, even though IRL hit ratio is 2% and FH hit ratio is 10%. therefore not physically realistic. ok, here we go. irl usual shell composition: AP-HE-AP-HE-IncendiaryTracer it may vary somehow, but i supposed it's as a standard for 20mm. for example ShVAK (let's consider wing type, not moto or syncronised) has: HE: 67.6g shell, 6.7g explosives, 0g incendiary, 790m/s APHV: 96g shell, 0g explosives, 2.5g incendiary, 750m/s HE&In&Tr: 75.8g shell, 2.8g explosives, 3.3g incendiary, 770m/s i supposed for: HE: 40 HE points, 3 AP points, 1 incendiary points (for explosive) APHV: 0 HE points, 40 AP points, 0 incendiary points HE&In&Tr: 20 HE points, 3 AP points, 3 incendiary points So, in burst of 10 shells, ShVAK delivers: 4*HE+4*AP+2*HE&In&Tr that gives 200 HE points, 178 AP points, 10 incendiary points to remove randomisation, each shell in the game should be equal. so, each of 10 shells has an average values of 20HE, 18AP, 1In per shell. you ask me, why shell can be HE to explode immediately and AP to pierce several parts at the same time? sorry. it is hypothesis of TH DM. i hate single 7.62PK and 37mm dud (because it happened to be an AP shell, not HE from your belt). in reality 37mm AP shell will make a little hole in the wing (with few changes to destroy a longeron or control wire). in the game 37mm will always break wing of single engine fighter. that's why shells are HE, AP and In simultaneously. ok? btw, these 18AP points are developed at 300m (approx d3). having analysed change of real penetration power with distance for several real guns, i set 21AP for d0-d1, 20AP for d1-d2, ..., 12AP for d9-d10 why so? what for are these AP and In? couldn't it be made by just HE? no: 1.most of shooting is made from 6'o-clock and most hit elements are stabs and controls. how will you complain about DM when first of all you will loose stabs and controls? yup... 2.WB calculates wether player hit the displayed target, and sends to server hit requests that report gun type, target nick, up to four parts that are geometrically pierced ("the neddle"). the needle gives a nice opportunity to save stabs from genocide, and we must use it. resume of chapter I: each ShVAK shell of TabaHost has 20HE, 18AP, 1In points, 21AP@d0 with -1AP/d1 all 8mm have equal charateristics, 13mm guns have individual, 20mm individual, 37mm equal. other individuals: 15mm MG 151/20, 23mm VYa, 30mm MK 108, 75mm T13E1, rockets. 500lb bomb is the same as 250kg, 100lb=50kg etc. chapter II "ingnition" having studied IEN DM elements, i understood that the only part that can burn is fuel tank. IEN elements are very primitive, and making "text chat DM" without appropriate graphic effects is quite silly for me. but the fuel fires can be done very simply in terms of IEN elements: when it fires, it explodes immediatedly. usual protected fuel tank has 100 structure points, unprotected - 50STR. when fuel "strength" is between 0 and 25 the fuel tank begins leaking, and every single shell that hit leaking tank (i hope you remember that every single shell has 1In point) will explode it with breaking away the element that contains this fuel tank. since every shell has 1 incendiary point and only fuel will burn, incendiary effect of shells are ignored. incendiary effect is considered only when fuel tank is hit. we remove incendiaries from our picture for simplicity. we will recall that 1 point only for fuel tank calculations. resume of chapter II: when fuel is leaking and is hit again, it will explode with the wing or rearfus that contain the tank. other parts won?t burn ever. chapter III "others" actually first calculations in creating TH DM were made with MG 151/20 against Yak-9. MG 151/20 was taken because it's characteristics lays in the middle of field of characteristics of other 20mm guns. well, when i created DM model of MG 151/20:Yak-9, the corner stone was put. the further work is described as search for TH coefficients for principal classes of planes DM and guns DM. these are: 20mm, 13mm, 8mm, 37mm, bombs, rockets, big guns, and, finally, the torpedo. as well as: tiny fighters, fighters, heavy fighters, scouts (single engine attackers, light bombers, torpedo bombers, dive bombers etc...), il-2 prod.1942, destroyers (two engine light bombers, dive bombers, heavy fighters etc...), medium bombers (2-3 engines), heavy bombers (4 engines). then i classified game aircrafts and weapons according to these classes and voila! i touched some planes, such as Ki-43, Il-2, G4M, B-24, Fw 190A-8/R8. other planes remained in their classes. then i began to make differences in 20mm and 13mm guns. you know, hispano?s rate is lower, but shell are more harmful, shvak?s rate is higher, but shells are less harmful, etc. all 8mm and 37mm shells are exactly equal with other 8mm and 37mm of any weapon. resume of chapter III: F6F has the same DM strength as Fw 190 and N1K1-J. B-25 has the same DM as Il-4 and Ju 88A, Ki-27 = I-153 = I-16 etc. B-24 has weaker wings and stronger fuselage than B-17. Sturmbock is more durable than basic Fw 190A-8. G4M has no self-sealing tanks and pilot armour before 1942, as well as Ki-43 before 1943. Il-2 prod 1941 has different DM for 1941 and 1942. Il-2 prod 1943 has different DM for 1943 and 1944. chapter IV "they meet" each part of airplanes is described with 4 numbers: A)structure strength. obvious? B)AP stopping capability. rear fus and engine with the same stength can stop AP shells with different effect. right? engine is approx 600kg of metal, while rfus is almost hollow. C)immunity. what? try to stick you finger into metal aileron. huh. your finger can inflict too few damage (though it can). metal aileron is immune from your fingers. if shell brings damage below certain level, it is ignored. mg shell that penetrated vstab, rfus, cfuel probably won't be able to make any harm to armour seat back. that's it. D)parent part number. aileron is attached to wing, rudder to fin. it's simple. if an element is overkilled, excessive damage is transferred to parent element. that?s why 37mm that his the rudder will kill entire rear fuselage. so what happens when MG 151/20 shell hits right wing of Yak-9 at d4? let's see. suppose the needle is "raileron-rwing-atmosphere". two parts. MG 151 shell has 25HE points and 17AP points at d4. aileron Structure=80, APstopping=5, Immunity=4, parent=right wing. so it receives 25 damage points from HE effect. also, it takes 5AP points from 17AP points, because it stops the shell a little. aileron doesn't burn, so we ignore incendiary effect. totally, aileron receives 25+5 damage points and now structure stength is 80-30=50. when the shell penetrates the aileron, it exits with 0HE and 17-5=12 AP points. now it enters the wing. wing structure=190, APstopping=5, Immunity=4, parent=central fuselage. wing will take only that it can stop from AP effect, i.e. 5AP damage points, and let the shell leave to atmoshpere with 0HE and 12-5=7AP points. after the penetration, the wing will have 185 structure points. don't ask me wether we need 190/5=38 hits into the same right wing of Yak-9. with several hits, you will destroy right aileron, and wing will begin to absorb 30 points itself. it will stand approximately 6-7 hits of MG 151/20, and then it will fall away. resume of chapter IV: you must aim well to destroy one vital part instead of spreading all over the plane. you can put two 30mm shells into central fuselage of Yak-9, 2 into left wing, 2 into right wing, 1 into each controls, 2 into rear fuselage, and Yak will fly away with no visual damage after 13x30mm hits. or you can put 3*30mm into the same left wing to shot Yak down. you decide.