New bow, hybrid between molgabet and recurve

[Shadowcleaver]

Hey guys,

I'm have two boards coming in, one ash and one hickory. I would like to make a recurve out of one of them but i don't feel really comfortable trying to heat bent them as I have no idea how long they've been drying. That's why I thought I might make a hybrid between a molgabet and a recurve. I would take the dimensions of boariorbows "Molgabet under 25 $) and attach two hardwood siyahs to the static limbs. My questions to all the very experienced bowyer out here are two fold

-Should i keep the dimensions (static limb same length as the working limb), or should the static be shorter?
-Do i need to thin the static limbs by the same amount as the the thickness of the siyahs? I'm asking because i same boariorbow's "elf lord " bow and it seemed to me that he tillered the back of the bow down towards the tips and the siyahs fit exactly on this (being thin in the direction of the handle and getting thicker near the tips).

Thx in advance :-)

[Shadowcleaver]

I just thought it might be a good idea to include the dimensions I'm aiming for. Sorry for the metric, but I when I draw on wood I only have a metric tape measure.

178 cm length

30 cm stiff limb ==>2 cm width
5 cm fade
36 cm working limb  ==> 5cm width
5 cm fade
13 cm handle ==> 4 cm

89 cm left

13 cm handle ==> 4 cm
5 cm fade
36 cm working limb ==> 5cm width
5 cm fade
30 cm stiff limb 2 cm width

89 cm right

[mikekeswick]

Unfortunatel you have picked two designs that are not compatible to be combined. A recurve needs outer limb width to ensure stability and a narrowed outer limb bow is made that way to minimise outer limb weight and is therefore very narrow which would equal little stability for the lateral forces a recurve can exert during the draw.
Make one or the other is my advice. They are both great designs in their own right. Combining them would mean you wouldn't get the benefits of either. You can of course reflex the outer limbs of a narrowed outer limb bow but there is a limit. The more you push the reflex the heavier they need to be.

[loon]

I have some pictures of "molly curve" bows from old PA threads. They're kind of like the Han dynasty bows or Hun bows but symmetric (non-contact, so maybe not "true recurves"), but with no setback handle.

I wouldn't do a "true recurve" with contact ears/siyahs though, especially not for a first

Just boil it to bend, lol. May take a while to dry back though. Hmm.
Or instead of attaching ears to straight static limbs, you could attach them to the outer fades. Kind of like how Dave Mead does it with his horsebow kit..

Though, someone else was making mollegabet bows with the static limbs bent forward in the middle rather than at the fade. That should work well.. Possibly strain the bow less.

[loon]

Here are some, hope they don't mind me stealing the pictures... you can try to reverse image search them with google. The red one was posted here but the imageshack links died, and also on paleoplanet but it's not loading for me..

Code: [Select]

https://imgur.com/a/XRkMq

[Shadowcleaver]

I looked up a Han Dynasty bow and found one on Alieexpress where you can see the side profile. If I understand correctly it has a somewhat molgebat design layout, but the recurving is done in the working limb, not at the end of the static one? Cause it seems to me that even at full draw the entire bottom part of the limb stay's unmoving.

[loon]

That reflex seems to be spread through the outer limb, fade, and inner levers. Some of the han bows do have some bending where that reflex happens.

[Shadowcleaver]

I might just try the normal molgabet first then. Getting kinda scared now, when I see the actual difficulties involved. Thx for the info guys, i'll keep you updated

[Del the cat]

Just one of my pet peeves for which I oppologise in advance.
Please don't use cm there are an abomination in engineering terms.... use mm.
Some people (my wife and sister mostly  ) argue that they are legititimate units as they are factors of 10 up from mm.
But no one uses decimetres!
For real men it's mm all the way or imperial.
I rest my case.
Del 

[Shadowcleaver]

Seems like a valid point.
I use them mostly because I draw out my designs in rather thick marker, which makes the mm marks a bit obsolete. I understand the engineering point of view though :-)  so +I'll remember for the future.

[PatM]

If the limbs are static the bow wouldn't bend...

[bubby]

Here's one a hybrid i guess it is a modifyed molly with the tips recurved, the molly limbs taper to 1" wide at the top fade , 1" long fade that tapers to 3/4" then straight taper to1/2" rough ot demensionshttp://www.primitivearcher.com/smf/index.php/topic,51951.msg703006.html#msg703006

[PatM]

I don't buy the width equals stability theory. A Mollie is just the first step towards a static recurve.  As you increase the angle you need to extend the working limb length and decrease the static portion perhaps but not the outer limb width.

[Onebowonder]

Unfortunatel you have picked two designs that are not compatible to be combined. A recurve needs outer limb width to ensure stability and a narrowed outer limb bow is made that way to minimise outer limb weight and is therefore very narrow which would equal little stability for the lateral forces a recurve can exert during the draw.
Make one or the other is my advice. They are both great designs in their own right. Combining them would mean you wouldn't get the benefits of either. You can of course reflex the outer limbs of a narrowed outer limb bow but there is a limit. The more you push the reflex the heavier they need to be.

Though I have made two bows that might be kind of considered to be Molly/Recurve Hybrids, Mike is Right here!  I wound up having to add hard wood laminations on either side of the curved Molly ends to regain the lateral stability I lost when narrowing the levers initially.  It looked a little funky and though the hand shock the extra weight created was very minimal, The performance was sluggish compared regular Molly's or a recurve. 

I still plan to make another run at this design, but I'm still not sure how to make it work optimally.  I'm thinking to try really light weight wood for the siyah material and then use a thin flattened piece of cow horn as a single layer lamination sandwiched between two sides of ERC or yew.  IDK - maybe that'll be stiff enough without being too heavy.

OneBow

BTW - If this is a first of early bow for you, please choose to start with a design that would be more likely to produce an effective shooter.  I think you'll be happier with the results.

[bubby]

http://www.primitivearcher.com/smf/index.php/topic,51951.msg703006.html#msg703006

Here is that pic