gavagai Posted November 3, 2021 Share Posted November 3, 2021 Both of these pics are ~400 knots and 4g. In both pics I hold the trigger long enough for the tracers to disappear. I thought these two aircraft had the same gun, or am I seeing things? With the F-16 the tracers are noticeably more spaced out and fall below the HUD. Are the tracer types different, one with longer burn? Different ratio of tracers? I thought these two aircraft had the same gun but my subjective impression was that I don't have to pull nearly as much lead with the F-18, which made me wonder... If I knew nothing about these aircraft I would have assumed the F-16 cannon had a lower muzzle velocity, or fired a different type of shell with different ballistic properties. Appreciate it if someone can explain. 1 P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria Link to comment Share on other sites More sharing options...
TLTeo Posted November 3, 2021 Share Posted November 3, 2021 Lots of things could be different - tracer composition as you said, but also seating position and viewing angle for instance. On top of that, the ADL is not necessarily the same. For example, the guns on the F5 are (very) slightly canted upwards, while that would not have been the case e.g. with the F-100 or F-101 (which carried the same guns, but under rather than above the nose). Link to comment Share on other sites More sharing options...
darkman222 Posted November 3, 2021 Share Posted November 3, 2021 I think you cant compare it if you consider speed and Gs. Flying a 4G turn at 400 kts in the F16 and the F18 will result in different turn rates. That might cause the difference in spacing between the tracers. Try to compare this under the same turn rate between the jets. But I am just guessing here. Link to comment Share on other sites More sharing options...
gavagai Posted November 3, 2021 Author Share Posted November 3, 2021 19 minutes ago, darkman222 said: I think you cant compare it if you consider speed and Gs. Flying a 4G turn at 400 kts in the F16 and the F18 will result in different turn rates. That might cause the difference in spacing between the tracers. Try to compare this under the same turn rate between the jets. But I am just guessing here. No, the turn rates are identical. radial acceleration = v^2 / r P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria Link to comment Share on other sites More sharing options...
TLTeo Posted November 3, 2021 Share Posted November 3, 2021 ^ that. For fixed G and airspeed, (instantaneous) turn rates are the same. What may differ is a) the AoA each jet requires to obtain a given G (which depends on airframe, especially wing, design) and b) whether each jet has enough power to sustain those turns or not (which is a function of available power, and required AoA to reach a desired G). This should be obvious if you look at an EM diagram comparing two aircraft for instance. Link to comment Share on other sites More sharing options...
Mover Posted November 3, 2021 Share Posted November 3, 2021 F/A-18 gun is canted up. F-16 gun is boresighted. It affects strafe also. 2 Link to comment Share on other sites More sharing options...
gavagai Posted November 3, 2021 Author Share Posted November 3, 2021 28 minutes ago, Mover said: F/A-18 gun is canted up. F-16 gun is boresighted. It affects strafe also. That is fascinating. I can't find any mention of it. Do you know by how many degrees it is canted upward compared to the F-16? P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria Link to comment Share on other sites More sharing options...
Mover Posted November 3, 2021 Share Posted November 3, 2021 2 minutes ago, gavagai said: That is fascinating. I can't find any mention of it. Do you know by how many degrees it is canted upward compared to the F-16? IIRC 2 degrees. 1 Link to comment Share on other sites More sharing options...
gavagai Posted November 3, 2021 Author Share Posted November 3, 2021 That sounds reasonable. The screenshots make it look more like 10 degrees difference! P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria Link to comment Share on other sites More sharing options...
Mover Posted November 3, 2021 Share Posted November 3, 2021 15 minutes ago, gavagai said: That sounds reasonable. The screenshots make it look more like 10 degrees difference! There are other factors, obviously. What was the range? Heading crossing angle? Aspect angle? What's the energy state of the other aircraft? Link to comment Share on other sites More sharing options...
gavagai Posted November 3, 2021 Author Share Posted November 3, 2021 (edited) 1 hour ago, Mover said: There are other factors, obviously. What was the range? Heading crossing angle? Aspect angle? What's the energy state of the other aircraft? Too many variables there to give a coherent answer. I can show you this pic though. Both aircraft confirmed to have 1.2 degrees aoa when shooting, both with altitude hold. It looks like the F-18 upward cant is as much as 5 degrees after subtracting aoa. Edited November 4, 2021 by gavagai attached protractor P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria Link to comment Share on other sites More sharing options...
Machalot Posted November 4, 2021 Share Posted November 4, 2021 You also are at different altitudes, which causes different drag on the bullets. "Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot." Link to comment Share on other sites More sharing options...
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