Author Topic: Egyptian Composite Bow  (Read 10690 times)

0 Members and 1 Guest are viewing this topic.

Offline ecounter

  • Member
  • Posts: 19
Re: Egyptian Composite Bow
« Reply #15 on: August 21, 2021, 12:07:39 pm »
With all those horn layers and the reflex in the shape didnít think I needed so much sinew but time will tell.  Someone asked about weight #70 at 26 inches or did they mean actual weight of the overall bow?

bownarra

  • Guest
Re: Egyptian Composite Bow
« Reply #16 on: August 22, 2021, 02:24:22 am »
Only the belly layer of horn is doing anything. The more reflex the more strained = the more important the sinew is. Less sinew and you may have run into the core breaking.
Yes I want to know the physical weight. This is a great indicator of potential performance.

Offline ecounter

  • Member
  • Posts: 19
Re: Egyptian Composite Bow
« Reply #17 on: August 25, 2021, 07:25:08 pm »
Total weight is 1lb 8oz

bownarra

  • Guest
Re: Egyptian Composite Bow
« Reply #18 on: August 26, 2021, 04:15:05 am »
Interesting a bow of your draw weight should be around 350 - 400 grammes for best performance.
If you ever made another then use a wood like hard maple for the core and jus use one horn layer.
Horn is around 1.3s.g., osage maybe 0.8 s.g. and maple more like 0.6s.g. if you were to 'swap' the osage and the other horn layers for maple. The bow would be much lighter in physical weight whilst still storging the same energy - this would led to higher efficency. You could likely have used 60 - 70 grammes of sinew to safely back the bow. Again sinew is heavy stuff around 1.3s.g. so you want to use the least amount possible.
Just some pointers for you. I totally dig your bow and think it is something to be very happy with :)

Offline ecounter

  • Member
  • Posts: 19
Re: Egyptian Composite Bow
« Reply #19 on: August 28, 2021, 09:01:15 pm »
Thanks for the pointers!  Next one Iíll try what your suggesting.  This one was more of an experiment following the original cross section from the source article which admittedly seemed overly complex, especially for circa 1000bc

Offline BowEd

  • Member
  • Posts: 9,390
  • BowEd
Re: Egyptian Composite Bow
« Reply #20 on: August 29, 2021, 08:58:52 am »
Yes.Good point by bownarra.I was the one who was wondering about the mass weight.
In retrospect how mass weight can affect a bow I have a black locust self bow [no sinew] that mass weighs 14.25 ounces 63" long stiff handled that pulls 54 pounds @ 28" that is a very efficient bow.Kinda like comparing apples to oranges I know but the relativity is still there putting the mass placement where it is most needed in self bows.
Cool bow you got there though.
I've rummaged through my buffalo and gemsbok horn slat collection and have come up with a pair of gemsbok horn slats that should do the trick for me to make such a style of bow.They are 29" long apiece and 1/8" thick 1" wide midlimb which will give me around 15 to 20 pounds of draw weight.


I've made around a dozen complex bows and will do my calculations to make such an Assyrian type bow in the future using the reflex forms I have here.I have plenty of sinew also.My goal will be to get around 50#'s @ 28".
PS.....A full draw picture of yor bow would be nice.
« Last Edit: August 30, 2021, 08:51:52 am by BowEd »
BowEd
You got to stand for something or you'll fall for anything.
Ed

Offline ecounter

  • Member
  • Posts: 19
Re: Egyptian Composite Bow
« Reply #21 on: September 01, 2021, 03:12:56 pm »
full draw coming promise.  One thing I have no idea on, where can i source the proper maple for these composite bows.  Im guessing a hardwood supply even with the proper grain running in the wood is not the place.  Anybody have suggestions?  Thanks in advance.

Offline BowEd

  • Member
  • Posts: 9,390
  • BowEd
Re: Egyptian Composite Bow
« Reply #22 on: September 02, 2021, 07:24:54 am »
There are other woods out there to use like ironwood [hornbeam or hop hornbeam].They are diffuse pourus also.That's what I'll use this time around.If you use maple make sure it's hard maple.
Made them from very tight ringed hickory a number of times also with very good success.
BowEd
You got to stand for something or you'll fall for anything.
Ed

Offline ecounter

  • Member
  • Posts: 19
Re: Egyptian Composite Bow
« Reply #23 on: September 05, 2021, 07:48:17 pm »
full Draw or at least mine at this poundage

Offline BowEd

  • Member
  • Posts: 9,390
  • BowEd
Re: Egyptian Composite Bow
« Reply #24 on: September 05, 2021, 11:24:12 pm »
Thanks.Looks great I think,and also looks pretty stout for you too.Some pictures of them show a more rounded full draw [out of context comparison] but that is on account of not as much reflex induced in the working limbs on theirs I'm sure.
I was looking at my Ottoman Turkish horn bow book Adam wrote and I had a sheet of paper in the book showing the preperation of an Egyption complex composite put there by me some time ago.It looks to me like an extreme version both ways of deflex and reflex.It's a copy I printed from the atarn.org/islamic/egyption composite files some time ago.Thickness taper is rather extreme in the beginning from the handle then slows down to 1/4 the rate from midlimb to tips.Paralell width to midlimb then tapering to 3/5th's width of handle.

1 reason why bows such as these angular bows need to be braced fairly high to avoid inversion of the limbs after releasing.
« Last Edit: September 07, 2021, 02:12:32 pm by BowEd »
BowEd
You got to stand for something or you'll fall for anything.
Ed