Shooting machine problems

[DC]

Here's a couple of pictures of my shooting machine. The second pic is sighting to the target. The blue pointer is where the arrow is aimed, the red one is where it hits about 8" high. This would be 8" to the left if the bow was vertical. The target is 9' from the back of the bow. I have to use carbon arrows because my wood or bamboo ones break just about every time I shoot one through the machine. Can anyone see any glaring problems that might be causing this?

[Badger]

   My first thought would be too stiff of an arrow.

[DC]

The arrow is definitely too stiff and that was my first thought. I was using a new bow(the Doug maple) but it's 40# so I tried a 44# bamboo arrow. It shot about 3" lower but it broke . If you look at the second picture you can see the ice cream buckets I use for light diffusers. The arrow actually brushes against them.

[willie]

too stiff, as in not hitting the backstop straight on? can you shorten the distance? or shoot into something softer? I have a cardboard box stuffed lightly with throw away plastic grocery store bags

[DC]

Here's a pic of how the arrow hits. The fletch is about 1/2" high and 1/2"to the right. The target is a plywood box filled with plastic bags and covered with heavy duty tarp material.

[willie]

but the stiff ones you are breaking might be hitting at a much more acute angle. some bare shaft tuning recommendations call for very short distances, like less than a meter, to prevent breakage before the arrow gets sideways

[bradsmith2010]

What about the bow being clamped is not letting the arrow paradox...try shooting by hand at that distance

[DC]

I had the saddle for the bow lined with foam so the bow was free to rotate some. I just put that clamp on there today. It didn't seem to make any difference.

[DC]

The really stiff ones are carbon. They are 300's with lightish tips. The only reason they survive is because carbons are so strong. If the rain stops tomorrow I'll shoot a bunch of arrows until I find the one that flies the best. Then I'll sacrifice it. In the 5 or so years I've been doing this I've never broken an arrow other than hitting a rock dead on. Since I started using this machine I've broken close to a dozen. That's why I started using carbons. I'm thinking I'll buy a 600 or 700 carbon and see what it does.

[DC]

.try shooting by hand at that distance

It took a couple of hours for this to click in . I have shot many bamboo arrows by hand into this target. Worked fine. I was a few(maybe 4') further away. I'll try it from the same distance. I can't pull as far as the machine so the draw weight will be down but I can shorten the DL on the machine. Tomorrow. Thanks Brad that shpuld narrow it down.

[Del the cat]

It looks to me as though you aren't actually lining up true.
The string seems to be coming up onto the latch mechanism, a bit like a crossbow with the bow mounted below the track.
If you run a straight edge along the track in line with where the .... hang on I'll draw a pic ... it's easier.
Don't run away!
I'm back....
My sketch shows how it should line up and you can see the arrow would be aiming up (if the bow isn't cut away to centre shot). On your one the latch is too high which makes it look like the arrow should go horizontal. But as soon as the string is off the latch it drops into line pulling the arrow into that point up, nock down alignment.

I made the same mistake on mine at first, I built it with the track lining up but forgot the height of the latch!
Del

[Del the cat]

There are also some differences between a machine and a person too.
When you shoot, as the arrow getting forced left as it goes past the grip, the bow (and archers arm) is also pushed right (action and reaction). The effect is seen in the slo mo on my blog
https://bowyersdiary.blogspot.com/2014/06/slow-mo-hat-cam.html
With a rigid machine you don't get that flexing of the archers arm this makes the arrow actually kick more than expected.
I notice your machine is mounted at the bow end which prevents any flex.
Mine is mounted nearer the back/middle and I've noticed a degree of flex in some of the slo mo.
If there are alignment probs, simply allowing the bow to twist in the "hand" clamp will help. As long as it shoots consistently it doesn't really matter that looks to be high.
Del

[DC]

Thanks Del. Fortunately I haven't glued the bow mount to the frame yet(I almost did yesterday) so I can raise or lower it. Your picture shows that I should raise it. Did you have to make spacers to compensate for different handle widths or is it not that critical? I originally had the bow mounted if foam(wet suit material)with a bungy to hold it down. The clamp was done yesterday as a test.

[Del the cat]

Make spacers?
I have a box under the bandsaw with loads of custom made spacers in it 
Nah, I just have some bits of pipe insulating foam, rubber strapping and other such odds n ends. (this allows a bit of automatic alignment/twist etc)
Your set up is more of a precision job by the look of it. Mine was quick, dirty use it outdoors collapsible version just to get some slo mo vid of flight arrows. Not used it since, but it showed what I needed to know and it may get some use in the future.
I don't think the set up is hyper critical, it's just that you obviously aren't happy with how it's lining up at the moment. I expect you'll soon get a handle on cause and effect once you start playing with it.

Yes it looks like you should raise the bow. This will of course make it look like it will hit where you have seen the arrows are actually going.
You'll need to adjust the chrono position up a tad to match persumably.
Keep us posted
Del

[DC]

I guess I should have said "use spacers".   I don't even have a box under the bandsaw. It just builds up on the floor until it's nice day for burning.