This is a really interesting video from a craftsmanship and engineering point of view. I have been tempted to try to build a crossbow for decades now. I will probably never do it, because of time, but it is a challenge I would like to take on.
Crossbows are, of course, weapons, and as such, they are subject to some regulation in most civilized countries.
In CZ, any crossbow can be bought, built, and owned by anyone over the age of 18. Crossbows with a spanning force under 150 N can be legally openly carried and fired anywhere without any regulations. They are still considered a weapon, though, and if someone gets hurt, there are appropriate consequences. Crossbows with higher spanning force, such as this one, can be owned by anyone, but they can be transported only unloaded, in an enclosed container, and they can only be fired at a range or a fenced-off area inaccessible to the public and in a way that there is no danger to the public.
Open thread, talk whatevah, just don’t be an *hole.
But can we mount this fully automated crossbow onto a Ukrainian combat drone?
Silent running!
Bruce @1: 8-)
I would oppose such a thing that targets Trump’s birthday parade, although a non-lethal drone that just scares everybody would be fun.
Charly if you do ever make a crossbow I’m sure it will be a lot more elegant than that one.
@1 Bruce: Recoil would make it very difficult. The Ukrainians prefer to drop grenades, less recoil and they don’t need very precise aiming.
Interesting looking thing. One of the features I always appreciated about the classical crossbow design was that the wielder had a chance of surviving intact in the string broke. That did happen but obviously the operators were pretty cautious about the condition of the string (more like a hawser!) This design inverts that principle and he’s using a modern kevlar string. I hope he remembers not to leave that out in the sun, etc., kevlar care, etc.
I find the sideburns in the thumbnail quite convincing.
@Marcus, there is a commercial crossbow with the same arm position on the market. And on this specific one, the string actually did break during testing (he shows it in the video, right at the start around the 0:19 mark), and not much happened. With a circa 230 N spanning force, it is not exceptionally powerful. And due to the cams, the actual displacement of the bow tips is very small. So even when the string breaks, it is not that dangerous. Probably less dangerous than an angle-grinder and definitely less dangerous than a wood lathe.
On a classical crossbow, I’d be personally more worried if the bow broke on one side and whipped me around the ear with the broken-off piece. I think Tod Todeschini mentioned in one video that this might be one of the reasons medieval crossbows had huge spanning forces but fairly short strokes, and thus were actually not as powerful as the force-reading might imply.
I haven’t watched the full video, but I did see the guy drilling titanium and getting the workpiece stuck on the drill bit.
How is titanium to drill? I find aluminium to be fairly easy to drill, (mild) steel is kind of ok, but I hate drilling copper. While copper is soft, it is also tough and sticky. The only way I’ve found for copper to work is using low revs, drilling with increasing diameter drill bits and using slow feeding speeds.
Update to my previous comment, buried at the end of previous thread.
I saw the ISS again last night, passing moderately close to the nearly full Moon, which was in due south but relatively low at the time (about 15-25 minutes past 11 PM). Since it was evening twilight, the ISS was illuminated as it rose from the southwest, and flew well past due south to the left before disappearing into Earth’s shadow.
I also went out to see the next round, an hour and half later. This time, however, the ISS apparently went dark shortly after rising above horizon, and I couldn’t see it due to some low hanging clouds. The prime observation window is now rapidly shifting from near midnight to earlier in the evening, and the optimal viewpoint for observation is moving from high northern latitude to lower latitudes where the twilight is earlier at this time of year.
Another update: Last night, one ISS flyby was at ca. half past ten. I went out to see if it’s visible in early twilight, when the Sun is stil only a few degrees below horizon. It was, though relatively faint and not too easy to spot. But it also flared briefly at one point, looking much brighter. Now I want to see an ISS flare in darker conditions -- it could be quite impressive.
(see my post on previous page and the Wikipedia link on satellite flares)