SlowMotion Posted March 2, 2019 Share Posted March 2, 2019 Here is a video showing how a 76mm tank shell flies to target. Captured with a high speed camera. The movement of the shell is not exactly what you might expect.https://youtu.be/xpJ8EoGmLuE?t=348 Later after this experment they shoot water melons with a 152mm gun. 1 Quote Link to comment Share on other sites More sharing options...
Zaba Posted March 2, 2019 Share Posted March 2, 2019 I´m amazed to see these watermelons deflecting a 152mm proyectil at that distance... 0 Quote Link to comment Share on other sites More sharing options...
Erwin Posted March 2, 2019 Share Posted March 2, 2019 (edited) With benefit of hindsight... my theory is that since melons are basically water, it's like shooting thru several feet of water. And that would deflect a projectile - it effectively skipped upwards. Edited March 2, 2019 by Erwin 0 Quote Link to comment Share on other sites More sharing options...
Sgt.Squarehead Posted March 2, 2019 Share Posted March 2, 2019 Dammit, so my proposal for defensive Melon Modules will probably fall on deaf ears at DARPA. 1 Quote Link to comment Share on other sites More sharing options...
SlowMotion Posted March 2, 2019 Author Share Posted March 2, 2019 2 hours ago, Zaba said: I´m amazed to see these watermelons deflecting a 152mm proyectil at that distance... If melons were cube-shaped maybe this deflection would not happen. I was amazed about how much the Sherman shell moved up and down during the flight. Yaw? 0 Quote Link to comment Share on other sites More sharing options...
Erwin Posted March 2, 2019 Share Posted March 2, 2019 2 hours ago, Sgt.Squarehead said: Dammit, so my proposal for defensive Melon Modules will probably fall on deaf ears at DARPA. Not necessarily. You simply need to get a DC sponsor. 2 hours ago, SlowMotion said: If melons were cube-shaped maybe this deflection would not happen. Definitely a DARPA research grant coming together nicely here. 0 Quote Link to comment Share on other sites More sharing options...
StieliAlpha Posted March 2, 2019 Share Posted March 2, 2019 5 hours ago, Sgt.Squarehead said: Dammit, so my proposal for defensive Melon Modules will probably fall on deaf ears at DARPA. Be careful with the design. Since water is incompressible, you will need a soft cushion between melon and armor plate. Say,, a layer of bananas. 2 Quote Link to comment Share on other sites More sharing options...
Sgt.Squarehead Posted March 4, 2019 Share Posted March 4, 2019 Sounds like a waste of perfectly good 'nanas to me! 0 Quote Link to comment Share on other sites More sharing options...
Michael Emrys Posted March 4, 2019 Share Posted March 4, 2019 On 3/2/2019 at 5:20 AM, SlowMotion said: Here is a video showing how a 76mm tank shell flies to target. Captured with a high speed camera. The movement of the shell is not exactly what you might expect. Quite a few years ago I was watching a documentary on slo-mo technology when they showed something that really got my attention. It was a film of a 17pdr shot in flight and the way they went about filming it was rather ingenious. Instead of trying to film it with a single high speed cine camera, they used a series of still cameras set up along the trajectory of the shot and then edited all those photos into one continuous movie lasting several seconds. The thing that struck me was how dramatically the shot wobbled in flight. It was well known that the APDS round had poor accuracy, and here was the reason before my very eyes. Eventually the discarding sabot separation problem was solved yielding today's DS rounds tack driving accuracy. I notice that the 76mm round in the linked film wobbles a little too, but nothing like as much as the 17pdr I saw. Michael 1 Quote Link to comment Share on other sites More sharing options...
Erwin Posted March 4, 2019 Share Posted March 4, 2019 7 hours ago, Michael Emrys said: I notice that the 76mm round in the linked film wobbles a little too, but nothing like as much as the 17pdr I saw. Very interesting to watch. One can't help but wonder how effective those rounds would have been as it seems quite likely that many would not have hit the target with the correct angle for effective penetration. "...the way they went about filming it was rather ingenious. Instead of trying to film it with a single high speed cine camera, they used a series of still cameras set up along the trajectory of the shot and then edited all those photos into one continuous movie lasting several seconds." I wonder if they didn't have the technology back then to shoot enuff film at fast enuff speed with one camera. 0 Quote Link to comment Share on other sites More sharing options...
Michael Emrys Posted March 5, 2019 Share Posted March 5, 2019 14 hours ago, Erwin said: I wonder if they didn't have the technology back then to shoot enuff film at fast enuff speed with one camera. They may have had the cameras (my impression was that this was done early postwar), but you would have a problem of moving the camera to track the shot. You would have to blast it alongside the trajectory of the shot to get the film that I saw, and I doubt that that was possible with the equipment on hand at the time. Michael 0 Quote Link to comment Share on other sites More sharing options...
benpark Posted March 5, 2019 Share Posted March 5, 2019 (edited) "...the way they went about filming it was rather ingenious. Instead of trying to film it with a single high speed cine camera, they used a series of still cameras set up along the trajectory of the shot and then edited all those photos into one continuous movie lasting several seconds." Eadweard Muybridge was doing a version of this exact thing, starting in 1872. It would not have been fast enough for a shell in flight of course (there are birds!), but it is what got us there, by doing exactly the aforementioned method. That film was slow in terms of relative sensitivity to light versus what was even available in the 1940's. This resulting set of consecutively made still images would later be able to be viewed with a zoopraxiscope- which is in essence a flip-book method of pre-cinema motion. Edited March 5, 2019 by benpark 1 Quote Link to comment Share on other sites More sharing options...
Michael Emrys Posted March 6, 2019 Share Posted March 6, 2019 16 hours ago, benpark said: This resulting set of consecutively made still images would later be able to be viewed with a zoopraxiscope- which is in essence a flip-book method of pre-cinema motion. Was this the famous one of a horse and rider galloping? Michael 0 Quote Link to comment Share on other sites More sharing options...
benpark Posted March 6, 2019 Share Posted March 6, 2019 (edited) Yes- all to solve a bet to see if all of the horse's feet were off the ground (or not) during that one fraction of an instant that was too fast for precise visual perception: https://en.wikipedia.org/wiki/Sallie_Gardner_at_a_Gallop Edited March 6, 2019 by benpark 0 Quote Link to comment Share on other sites More sharing options...
Michael Emrys Posted March 9, 2019 Share Posted March 9, 2019 By coincidence I came across this last night. This is not the process I had reference to in my earlier post, but I still found it interesting and informative and relevant to this thread. Michael 2 Quote Link to comment Share on other sites More sharing options...
benpark Posted March 9, 2019 Share Posted March 9, 2019 (edited) Oh, that video is all kinds of interesting. Just found this, to keep the tangent going... https://apps.dtic.mil/dtic/tr/fulltext/u2/a474188.pdf I have about half the parts, but none of the time! Edited March 9, 2019 by benpark 0 Quote Link to comment Share on other sites More sharing options...
Erwin Posted March 9, 2019 Share Posted March 9, 2019 Very interesting video. And good to see Uncle Fester got a new job: 1 Quote Link to comment Share on other sites More sharing options...
John Kettler Posted March 15, 2019 Share Posted March 15, 2019 SlowMotion and Michael Emrys, Wonderful videos. Have shared the first one with the CoC group on FB. Ref watermelon bounced 152 projectile, recall the Russian show where a live shell from a Msta-S was supposed to destroy Russian Fiat sedan clone in DF, but shell hit roof at shallow angle and richocheted, leaving only a dent, before entering a gully not far behind it and detonating. Guys, Great thread! Regards, John Kettler 0 Quote Link to comment Share on other sites More sharing options...
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