Need a 300lb@20" wood bow for my crossbow

[bowman123]

Hi Everyone,
I'm looking for dimensions for a 300lb@20" self or sinew backed wood bow (no fiberglass)

I am working on my Han Dynasty Chinese crossbow (https://www.youtube.com/watch?v=uZVbwZbg9Oc)
and so far I have only used fiberglass laminated bows for this crossbow.
This 95lb@31" korean bow mounted on the crossbow shot around the same speed with equivalent bolt weight compared to a 960lb steel crossbow.
Of course, powerstroke and limb mass efficiency places a big role here.

The prod itself is a modern prod, so I'm ready to use a historical prod now, starting with wood.

Although the Chinese did use horn composite prods, wood and bamboo prods were the most common choice (according to Mr.Selby).

So im interested to make/order a self wood crossbow prod, around 300lb@20".
see this link for chinese self bows to get an idea of the selfbow design (http://www.primitivearcher.com/smf/index.php?topic=46691.0)

im unsure about dimensions to achieve 300lb@20" (length, width, backing, and wood)

[Digital Caveman]

How are you going to cock the thing and carry it around?  While you're at it why not just build a ballista?

[stuckinthemud]

This was a build that might be interest http://www.primitivearcher.com/smf/index.php/topic,68057.0.html

[eastcreekarchery]

Ive seen some medieval crossbows made from yew and sinew and sometimes horn too. I do t recall where i saw it however, maybe on PA. Might be worth searching thru old posts in here.

[stuckinthemud]

European crossbows and Asian crossbows operate on completely different principles,  you won't be able to easily adapt bows designed for short throw, high power to your needs.  European wood based crossbows worked on a 25% length to draw length: 4ft long bows had 1ft draw length. I would suggest bamboo based technologies are the way forward. Even in the archery world a 20 inch draw would need a wood/sinew bow of at least 40 inches length

[stuckinthemud]

Are you aware of this discussion?

https://historum.com/threads/han-dynasty-crossbow-iii.179336/page-1

[stuckinthemud]

Sorry, that post gives lots of details, they did use wood bows, also wood sinew and wood sinew horn.  Dimensions are given at 1.6m to 1.9m. Very interesting that wood is given as 1 stone (65lb) adding sinew adds 1 stone, adding horn increases it by the same amount again .  I'm guessing a 1.6m 130lb 2 stone bow with horn and sinew will give you what you need or eise a 1.9m bow of 380lb.  Myself, I'd strip the sapwood off a 5ft yew stave and heavily sinew it but all the usual bow woods would be good. Would mulberry be traditional? Maybe start with a 2x2inch stave and see how you go.

[willie]

for wood, your bow length should be 2 - 2.5 times the drawlength. To get 300# it would have to be quite wide. Maybe a keyhole type arrow "pass". what kind of wood do your want to use?

[stuckinthemud]

No, sorry, archery rules do not apply to crossbows which are drawn for prolonged periods, do not go below 50 inches, 60 inches should really be looked on as minimum for a wood only crossbow.  Sinew is a massive game changer

[bownarra]

I made one of these longdraw crossbows and it is sweet! Just got to get round to making a hornbow prod for it. Mine is about 100#, boo backed ipe and can be drawn 26" from memory. Will have to dig it out again as it really is fun with the long draw and energy storage.

[scp]

60 inch crossbow prod? It would be rather unwieldy. Isn't the draw length of most crossbows rather short, like less than 20 inches?

[stuckinthemud]

Yes, unwieldy,  but historically accurate, Europeans might have callled them 2-foot crossbow,  drawn by sitting down, legs bent, string held to tummy, bow pushed away. Efficient power stroke, devastating power

[lonbow]

An all wooden prod should be at least three times as long as the draw length, because the prod is drawn for a longer period and also stronger then a normal bow.

have a look at this skandinavian whale hunting crossbow on :
http://www.vikingsword.com/vb/showpost.php?p=140734&postcount=168

This kind of mechanism (Zapfenschloss) was already used in medival times!

[stuckinthemud]

Its different horses for different courses, if you skirmish in woodland and from horseback, you neec a different weapeon from a set battle in wide open country