Inspired by a recent thread on whether or not a crossbow can penetrate a Kevlar vest, I wondered whether or not it was possible for an arrow to exceed the sound barrier in flight. Is it, or is it not possible, and if it is, what sort of bow would be able to fire a supersonic arrow? I assume a crossbow; those things are pretty powerful, from what I hear, but maybe a nice composite, with sufficient tension and a sufficiently strong shooter could do it…
No, not really. The speed of sound is approximately 1129ft/sec or 771mph. A reasonably powerful hunting crossbow boasts of a “blazing 330 ft/sec”.
You’d need to more than triple existing high-powered crossbows to even get near the speed of sound.
“Peak velocity for hunting crossbow/bolt combinations is usually under 250 fps…” My source
250 fps = 76,2 meters/second = 274,32 km/h
Mach 1 at sea level is about 1225 km/h
Mach 1 at 10 km is about 1080 km/h
So at least to me it seems that the answer is no. Someone who knows a little more about physics could prove me wrong, though.
I would think the answer is that of course it’s possible, but not within current technological limitations. I can’t think of any physical reason that an arrow couldn’t in principle go that fast if you could somehow find a means of giving it enough energy, after all.
Like everyone else has mentioned I seriously doubt it. In addition, I doubt anyone would want one either. As you approach the speed of sound a pretty strong pressure wave builds up in front of the object. In the early attempts to break the sound barrier this pressure wave destroyed the aircraft(s) trying to punch through it. Granted, an arrow or bolt isn’t a plane but the pressure wave would undoubtedly make the arrow extremely inaccurate as it got buffeted around. Finally, to go that fast would take more than three times the energy mentioned in previous posts. Each MPH faster requires more energy than it took to push the arrow the previous MPH faster. You’d need one helluva bow to make such a thing happen and such a bow would probably be unusable by a human (unless we get to machinery which makes the thing not very portable or easy to use).
>> I can’t think of any physical reason that an arrow couldn’t in principle go that fast if you could somehow find a means of giving it enough energy
Like shooting it out of a gun… then it’s called a bullet and it can exceed mach1.
On the other hand, the tip of a whip can exceed mach1. That is what the crack of the whip is: a sonic boom. (I read that somewhere, I’ll let others prove it or disprove it).
It is possible for an arrow to exceed Mach 1 with today’s technology.
Step one: Get an arrow
Step two: Buy it a seat on the Concorde
I think it could be done if you could somehow use an effect like siege catapults used (the projectile is ‘flicked’ like the tip of a whip, rather than simply propelled)
Fortunately for your suggestion, the Concorde is flying again. A couple of months ago, that would not have been the case.
Any bow that could push a standard sized arrow up to the speed of sound is going to need some sort of very hefty mechanism for pulling the string. A two hundred pound crossbow will not get you any where near the speed of sound, but this is already getting into an area where you need a small winch built into the bow in order to cock it. The problem as I see it, though, is not the arrow. You also have to get the arms of the bow up to the speed of sound. Bow design is complicated enough without having to mix in supersonic aerodynamics. Imagine the sound - two small sonic booms as the arms break the sound barrier followed by a third as the arrow goes through. Brrrraaaakkkaaakkk - Bammm! It’d be cool, but I don’t see it happening any time soon.
Actually, there are arrows that exceed Mach 1. They are called ‘Flechettes’ and are fired like a bullet. There’s also the SABOT round, which is basically a bullet that sheds its skin and becomes a slim, arrow-like projectile. they are used for piercing armor.
Just try getting that bow past airport security.
A nessessary part of a supersonic arrow would be a hypersonic bow cord (if fired dry (unloaded). I would say that the bow cord is not strong enough to travel past the S.o.S. nor the bow/crossbow not stiff enough.
An arrow (or at least the shaft) should be able to exceed the speed of sound when fired from a rail gun.
Of course the shaft would have to be metallic. Wood definitely wouldn’t work.
Certainly!
You just need enough energy to push the arrow. Just take a look at the long-in-tooth F-4 Phantom; that thing is certainly no “arrow” and didn’t have much problem attaining Mach1(+).
Brick bats and pigs fall in the same aerodynamic category: anything will fly with the right amount of power.
Cecil mentions something about a bullwhip exceeding the speed of sound.
I forget the movie (Top Gun?) but they were talking about the Phantom and said something to the effect of, “Just goes to show if you give something a big enough engine even bricks can fly.”
When I was in the Air Force, we referred to this as the McDonnell-Douglas barn door theory. Even a barn door will fly if you strap a big enough motor on it.
Does anyone have any speed statistics for unlimited-class flight bows? Flight shooting is purely for distance, and the unlimited class means there is no upper limit on the draw weight of the bow - the more powerful ones are shot, IIRC, by lying on your back, pushing the bow with both feet while pulling back on the bowstring with both hands…
…and I’ve always had a conceptual problem with this; like many beginning archers, I had the flesh of the inside of my left forearm battered to hamburger, even with a bracer, until I learned the proper way to hold a conventional bow. When I consider the forces involved with a flight bow, and the, errrm, more sensitive regions that would be exposed, I get a distinctly creepy feeling. ([Bluebottle]“Looking down I see my knees are gone and other vital things”[/Bluebottle]). Can this be avoided? Or is flight shooting practice invariably accompanied by a chorus of falsetto screams?
Anyway. My WAG is that the more powerful flight bows would at least compare with, possibly exceed, the performance of a crossbow - but that they still wouldn’t shoot at anything near the speed of sound. Or, if they can, somebody else can demonstrate… I do not want a bowstring travelling at transsonic speeds half an inch over my crotch… parts of my body are trying to retract themselves just at the thought…
Reading the replies, I assume the only ways I can launch a supersonic arrow are by employing a ballista, buying a seat on any old SST (there’s only one type in service, but there was a Soviet SST at one time, too, IIRC), or by encasing it in a sabot and launching it out of a firearm, either explosive or railgun…
Okay. As Mangetout suggested, what about flicking it from a catapult-type mechanism? I’m thinking of something akin to the steam catapults used on aircraft carriers, not the sort used to hurtle cows at seekers of holy relics. Any elaboration to give?
This guy got one to 507 mph.
That’s 507 FPS not MPH.
Sorry.