Main Discussion Area > English Warbow
what lbs makes it a warbow insted of a longbow
alanesq:
BTW - Don't forget that shooting an arrow at 45 degrees will result in the arrow having much more speed at its target than a more flat shot will have, so it is preferable for that reason
ChrisD:
--- Quote from: alanesq on July 08, 2009, 06:10:44 pm ---BTW - Don't forget that shooting an arrow at 45 degrees will result in the arrow having much more speed at its target than a more flat shot will have, so it is preferable for that reason
--- End quote ---
I very much doubt that this is the case Alan. I'm no physicist and maths is not my strong point but my logic goes thus. An arrow has most energy when it leaves a bow, converts kinetic energy into mostly potential energy at the apex of its flight and converts that potential energy back into kinetic energy when it comes back down again aided by gravity. No system is completely efficient however and the arrow loses energy to friction with the air when it flies. An arrow with a longer flight path therefore has more opportunity to lose energy to friction than an arrow with a shorter one and therefore, the flatter shot arrow will maintain a bigger proportion of its kinetic energy when leaving the bow than the high shot one.
A flatter shot, is therefore probably a 'stronger' shot - in fact this might be the basis of the idea of 'strong shooting' in which we are all interested. Having said all of that, the longest shot is the one at 45 degrees on flat land and its still likely that this is what was employed in long distance harrying with lighter arrows and this distance is what archers had to be able to reach with those arrows, which kind of makes it reasonable to suppose that it was in or about 220yds or the minimum distance with prickling arrows.
C
alanesq:
The theory I am going on is that if you shoot a arrow very high it will be doing something close to the speed it left the bow at by the time it comes down again (because its falling from a very great height)
I have tried shooting arrows as high and far as I can and measured the speed of the arrow coming down using my high speed camera and they do come down very fast
so if you shoot say 100 yards as flat as you can the arrow speed will be reducing all the time it travels, if you shoot the same distance very high it will be travelling much faster when it hits ?
BTW - In fact here is the video http://homepage.ntlworld.com/alan.blackham/ewbs/hscam/incoming.avi
not an ideal video I know but it was a proof of concept - I then never got round to doing anything with it
The video is filmed at 420frames per sec, the arrow if 34" total length and it takes about 10 frames to travel its length so its doing 120 feet per second on the way down
the arrow was shot from a 120lb bow around 210 yards at a very high angle
ChrisD:
I understand your theory - its just that I think its wrong for the reasons outlined. What you are arguing is akin to saying that an arrow has somehow become a perpetual motion engine which goes faster the longer its in the air. This is physically impossible. The more time its in flight and going up, the more energy it will lose to friction and there isn't any way to get it back!
Heavier arrows suffer less than light - they carry more momentum, but in general terms I believe what I say to be true. Thinking laterally, the same reasoning makes downhill skiers avoid time in the air when they do jumps - they lose too much speed to friction whereas on the snow, they can glide well and remain aerodynamic by minimising drag by posture etc.
In all these things, friction with the air is the killer.
C
Yewboy:
Mark Stretton did some similar tests regrding penetration at various distance and these were measured at the Defence academy test centre at Shrivenham, the results were that:
0-40 yds maximum penetration
40-80 yds minimal reduction in penetration, 2-4% less
80-100 yds penetration was down by 8-10%
100-180 serious reduction in penetration at its worst at 180 yds, approx 15% less
180 -200 a marked increase in penetration from the 180yds penetration approx 8%
200-240yds again an increase in penetration, this time only approx 6% loss from maximum penetration.
So I'm afraid Chris I do agree with Alan on this one.
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