My Wish:
The ballistics for the nose mounted cannons fireing through the propeller spinners of the P39D, P39Q, Bf109F-K, Ta152 and Yak9T/U are incorrect the moment the round leaves the barrel. The cannons in question in the real aircraft were fixed mounted in the engine center line or fixed parallel to the engine line through the propellor hub line like the P39. No positive angle adjustment to the ballistic trajectory was possible other than by pilot stick input in flight.
Please level these cannons in thier associated mountings to fire from 0 degrees when the aircraft are level.
-------------------------------------------
HUB Cannon/Autocannon/Motorkanone in affected aircraft.
Slowest to fastest cannon by (V0)M/sec. (V0)=Initial Velocity
(MK108/30 - 500-540m/s)**(M4/37mm - 610m/s)**(MG151/20 - 720m/s)
(ShVAK/20 - 750-790m/s)**(HS404/20 - 840-880m/s)**(NV-37/37 - 880-900m/s)
------------------------------------------
Game in Offline Mode Data Collection.
Data Collection - Convergence at 150. Aircraft auto leveled. Only the nose cannon was fired to create patterning at each distance. (.Target xxxx) was set to 50, 100, 150, 200, 300, 400, 500 and 600 yards. On full zoom the impact point from graticul center was recorded in Mil. (2-pixel = 1-mil)
Graticule Center = 0.00mil. All values should be in increasing negative values below 0.00mil if the cannon is mounted level with the engine line.
------------------------------------------
Testing Results in Offline Mode.
Cannon*50*100*150*200*300*400*500*600 - Yards
MK108/Bf*(-6.50)*(-1.62)*(0.00)*(-1.62)*(-3.25)*(-4.87)*(-9.75)*(-14.62)--540m/s
MK108/Ta*(-8.58)*(-4.29)*(0.00)*(-4.29)*(-6.50)*(-6.50)*(-9.75)*(-13.00)--540m/s
M4//37mm*(-8.60)*(-0.81)*(0.00)*(0.00)*(0.00)*(-1.60)*(-3.25)*(-6.50)-----610m/s
MG151/20*(-6.66)*(-1.62)*(0.00)*(0.00)*(0.00)*(-1.62)*(-3.25)*(-6.50)-----720m/s
ShVAK/20*(-6.50)*(-1.62)*(0.00)*(0.00)*(0.00)*(-1.62)*(-4.33)*(-4.87)-----790m/s
HS404/20*(-8.60)*(-3.25)*(0.00)*(0.00)*(0.00)*(0.00)*(-1.62)*(-3.25)------880m/s
NV-37/37*(-6.50)*(-1.62)*(0.00)*(0.00)*(0.00)*(-1.62)*(-1.62)*(-4.33)-----900m/s
Values at 0.00mil show cannon is angled firing upward.
------------------------------------------
Real World Cannon Ballistics Example Firing from Level.
Bf109G-6/U4 MK108/30 to 500 meters in centimeters of bullet drop.
Revi center line 74.5cm above engine center line.
Revi adjusted center look down line of sight = -29cm of engine level at 100m.
Cannon*50*100*200*300*400*500 - Meters
MK108/30*(-6.0cm)*(-19.0cm)*(-74.0cm)*(-189.0cm)*(-338.0cm)*(-553.0cm)--500m/s
Trajectory Calculation (BC Vloss) not included.
V0= 540m/sec Dist=400m time=.74sec Vert.drop= 270cm.
V0= 505m/sec Dist=400m time=.79sec Vert.drop= 305cm.
V0= 500m/sec Dist=400m time=.80sec Vert.drop= 313cm.
(BC Vloss) included.
V0= 500m/sec (-338cm) Vert.drop at 400m.
V0= 505m/sec (-330cm) Vert.drop at 400m.
V0= 540m/sec (-295cm) Vert.drop at 400m.
(BC Vloss) = % velocity lost per 100m based on bullet's ballistic coefficient.
MK108/30 Vloss = 25M/sec+- per 100m.
(V0) = 500m/s. Vloss at 400m = 408m/s
------------------------------------------
Projected Possible Results in Game MK108.
Proportionally adjusted Mil value trajectory for MK108 with cannon line at engine level.
Revi center Bf109 10mil above engine center line before sight line adjustment.
Revi center Ta152 13mil above engine center line before sight line adjustment.
Revi adjusted center = +26mil up to use stadia marks to 400yds. Game default only 300yds.
Cannon*50*100*200*300*400*500 - Yards
MK108/30*(-1.62)*(-4.80)*(-18.24)*(-45.60)*(-77.52)*(-124.00)--500m/s
-----------------------------------------
Sources for MK108 ballistics and values:
General Ballistics Trajectory program from Georgia State University Dept. of Physics and Astronomy.
http://hyperphysics.phy-astr.gsu.edu/hbase/traj.htmlRef. Bf109G-6/U4 1944 appendix 13, armerors ballistics table for MK108 Motorlafette.
L.Dv.T.2109 G-6/U4/Wa - 2 MK 108 in Flugelgondel
Ref.
http://www.luft46.com/armament/mk108.html - for MK108 Minengeschoss at 540m/s.
Ref. Tony Williams(
http://www.quarry.nildram.co.uk/WW2guneffect.htm ) MK108 Minengeschoss at 505m/s.
Ref. Handbuch der Flugzeug Bordwaffenmunition 1936-45 page35 for MK108 Minengeschoss at 500m/s
Vloss = 25m/sec per 100m.