some1 Posted February 19, 2016 Posted February 19, 2016 The gun in ZA is mounted below the fuselage and wings, so why the aircraft pitches up when firing? The gun is angled downwards, or is that a bug? Hardware: VPForce Rhino, FSSB R3 Ultra, Virpil WarBRD, Hotas Warthog, Winwing F15EX, Slaw Rudder, GVL224 Trio Throttle, Thrustmaster MFDs, Saitek Trim wheel, Trackir 5, Quest Pro
Badger1-1 Posted February 20, 2016 Posted February 20, 2016 if the gun is angled downward, why wouldnt there be an upward pitch? ;)
Anatoli-Kagari9 Posted February 20, 2016 Posted February 20, 2016 And, since it's placed bellow the Center of Rotation / CoG, it'll create a pitching up moment ! Flight Simulation is the Virtual Materialization of a Dream...
mr_mojo97 Posted February 20, 2016 Posted February 20, 2016 Remember Newton's third law - Every action has an equal and opposite reaction so when the cannons are fired the slight downward projection of shells it will indeed cause the nose to pitch up MSI M5 z270 | Intel i5 7600k (OC) 4.8GHz | MSI GTX1080ti Gaming X 11Gb | 500gb Samsung 970 Evo NVME M.2 (DCS World) | 500gb Samsung 850 Evo SSD (OS and Apps) | 32Gb 2400MHz DDR4 - Crucial Ballistix | Be Quiet Silent Loop 240mm | NZXT H440 case | Thrustmaster Warthog - 47608 with Virpil Mongoose joystick base | MFG Crosswinds - 1241 | Westland Lynx collective with Bodnar X board | Pilot's seat from ZH832 Merlin | JetSeat | Oculus Rift S | Windows 10 | VA |
Blooddawn1942 Posted February 20, 2016 Posted February 20, 2016 What is even more strange, is the fact that in my case, when firing the gun, my Engine RPM decreases!!!! Outgunned, outnumbered, though never outclassed!!!
ED Team Mr.Pitt Posted February 20, 2016 ED Team Posted February 20, 2016 What is even more strange, is the fact that in my case, when firing the gun, my Engine RPM decreases!!!! The РТ-12 system for the L-39ZA has an additional function designed for decreasing fuel supply from the main fuel system while firing the gun. This precaution is made to prevent the gunpowder gases from getting into the inlet. The РТ-12 system starts operation when the gun firing mode is selected and the trigger button is pressed. Fuel supply decrease occurs the whole time when the trigger button is pressed; the engine speed can be decreased down to idle. After the trigger button is released, the speed returns to its previous value. Amat Victoria Curam.
NeilWillis Posted February 20, 2016 Posted February 20, 2016 So it functions exactly as advertised, which is a good thing where I come from!
some1 Posted February 20, 2016 Author Posted February 20, 2016 if the gun is angled downward, why wouldnt there be an upward pitch? ;) Maybe I worded it incorrectly, but that's my original question. Is the gun angled downwards? Hardware: VPForce Rhino, FSSB R3 Ultra, Virpil WarBRD, Hotas Warthog, Winwing F15EX, Slaw Rudder, GVL224 Trio Throttle, Thrustmaster MFDs, Saitek Trim wheel, Trackir 5, Quest Pro
Retu81 Posted February 20, 2016 Posted February 20, 2016 Maybe I worded it incorrectly, but that's my original question. Is the gun angled downwards? Muzzle blast is directed downwards:
some1 Posted February 20, 2016 Author Posted February 20, 2016 Muzzle blast is directed downwards: Well, maybe you're right, but so it is in the Su-25, yet the Su-25 has a strong pitch-down tendency when firing gun. Here's a video of a real L-39 on a shooting range, though it's hard to tell if the gun pushes the nose or not: [ame] [/ame] Hardware: VPForce Rhino, FSSB R3 Ultra, Virpil WarBRD, Hotas Warthog, Winwing F15EX, Slaw Rudder, GVL224 Trio Throttle, Thrustmaster MFDs, Saitek Trim wheel, Trackir 5, Quest Pro
Dr_Arrow Posted February 20, 2016 Posted February 20, 2016 (edited) The muzzle is oriented downwards to compensate for pitch-down moment when firing the gun. The whole front part is called compensator and is designed to create upward rotational moment and it is possible to adjust it. I don't know however how well it works in real life. Edited February 20, 2016 by Dr_Arrow
Holbeach Posted February 21, 2016 Posted February 21, 2016 The muzzle is oriented downwards to compensate for pitch-down moment when firing the gun. The whole front part is called compensator and is designed to create upward rotational moment and it is possible to adjust it. I don't know however how well it works in real life. This is how I would expect it to work. An underslung gun recoil should cause a downward pitch. The compensator should reduce that pitch down. It would be pointless if it replaced downward with upward pitch. I don't have the L-39, but it will be interesting to find out how the Hawk deals with the same situation when it gets its EFM. .. ASUS 2600K 3.8. P8Z68-V. ASUS ROG Strix RTX 2080Ti, RAM 16gb Corsair. M2 NVME 2gb. 2 SSD. 3 HDD. 1 kW ps. X-52. Saitek pedals. ..
Flamin_Squirrel Posted February 21, 2016 Posted February 21, 2016 if the gun is angled downward, why wouldnt there be an upward pitch? ;) Because the gun isn't angled down far enough. The point of rotation is the centre of gravity about which the turning moment acts, and the force is created by the gun's recoil acting backwards along the axis of the gun's barrel. The axis of gun's barrel would have to pass ABOVE the centre of gravity in order to create a nose up pitch. You can see just by looking at photos of the ZA that this isn't the case. This is by no means saying that the nose up pitch we experience is wrong, it just isn't caused by recoil.
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