Started by 375CT, February 11, 2014, 07:30:08 PM
Quote from: mman on February 13, 2014, 09:19:29 PMMy ballistic calculator estimates vertical drift due to crosswind. But I guess you meant vertical drift from actual vertical wind component. For that you can use the same formula as for crosswind.For exampleWd = Ws * Tlag Wd = vertical wind driftWs = velocity of vertical wind component Tlag = lag timeandTlag = Tf - R/V0R = shooting rangeV0 = muzzle velocityTf = actual time of flight (you can use any ballistic calculator to solve this)
Quote from: 375CT on February 15, 2014, 04:39:31 AMDoes this change your answer or does it remains the same?Thanks!
Quote from: mman on February 15, 2014, 07:10:48 AMQuote from: 375CT on February 15, 2014, 04:39:31 AMDoes this change your answer or does it remains the same?Thanks!Basicly it doesn't. In downhill shooting the easiest approach would be to divide wind into 3 components. Parallel to bullet path (aka. range wind), side component (crosswind) and vertical component. Then you can separately calculate all these components. Most ballistic calculators are capable of calculating range wind and cross wind and there you have it. For example if your downhill shooting angle is 30 deg and you are shooting directly against 10 m/s wind:Range wind component is cos(30) * 10 m/s = 8,7 m/s Vertical component is sin(30) * 10 m/s = 5,0 m/s To be exact bullet path curves along the trajectory so this 30 deg angle is not exactly constant but it is close enough remembering that in practice wind velocity is always only an estimate.And then of course there would be a sideway aerodynamic jump due to vertical wind when bullet aligns against incoming air flow. If vertical wind comes from upwards then aerodynamic jump drifts left (right hand twist).This down/uphill shooting is actually something I could include my ballistics calculator. I haven't thought about it since it's so flat where I live.
Quote from: mman on February 21, 2014, 05:03:51 PMI looked into it and I think it actually doesn't make sense to add vertical wind due to up/downhill shooting. That's because flat fire approximation in bfx doesn't allow shooting angles larger than 15 degrees or so. But I did it anyway. You can play with following input values and see the results for vertical wind on horizontal and vertical plane:Shooting angle [deg] Wind velocity [m/s] Incoming wind direction [deg]
Quote from: 375CT on February 25, 2014, 07:44:04 PMI have a question, if you don't mind. Why did you care about the slope angle? I mean, I assume that a vertical wind is always normal to the LOS.
Quote from: mman on February 25, 2014, 08:10:03 PMQuote from: 375CT on February 25, 2014, 07:44:04 PMI have a question, if you don't mind. Why did you care about the slope angle? I mean, I assume that a vertical wind is always normal to the LOS.I'm not quite sure if I understand your question. Do you mean why I mentioned flat fire approximation in bFX?
Quote from: mman on February 26, 2014, 08:38:18 AMThat's because due to slope angle there is vertical wind component even when wind direction is parallel to ground level. I thought it was something you wanted but now I understand that you would like to input the actual vertical wind component. Okay let's assume that wind direction is so that there is an actual vertical component, how can you measure it in practise?