My ISP will soon be cancelling their consumer website service,
so I decided to document this while I still can upload pictures the easy way.
This is a modernized version of a "primitive" design from several years ago
see the wooden version here:
I found an inexpensive source for suitable fiberglass rod , and wanted to see how this system would work with it.
The bows here are made of 8x11mm flattened hexagonal profile.
80cm piece of this can take 60 Joule load, so very small and powerful bows can be made this way.
First prototype was done couple years ago
- or maybe four I've been a bit lazy at documenting my work.
27 kg 19cm power stroke. Light enough to be cocked without stirrup.
The extra long handle allows elbow room when the butt is braced against hip for spanning.
It also doubles as mount for iron sight with reasonable radius.
Nobody has been willing to sell me a chrony, but at close range this nails a soup tin to a pine board with a blunt 5mm thick 800 milligram bolt. And it shoots flat enough to hit one at 70 meters.
With 25J potential energy and couple hundred gram mass this is like a high power air rifle with 1/10 the weight and 1/100 the cost.
And the somewhat over engineered second version
Peak weight 40kg, powerstroke 178mm (90#7")
with noticeable let-off at end of draw.
Clap lock, apple tree branch frame.
This can still be spanned without stirrup,
which is what this butt-stock is for. It is not a shoulder stock.
The wire is holding the hold-open spring for the lock clap.
It coud look nicer, but I keep losing interest in my projects once I get them to sort of work.
Here is the new "full power" version 140#/12", still in testing.
The bows and trigger have been recycled from earlier projects.
I've been intentionally hitting targets upto 178m distances with 20 gram bolts.
This works too well, so it needs to be rebuilt better.
- someday - maybe