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Posted: Sat Apr 14, 2012 5:50 am
by jackssmirkingrevenge
Petitlu wrote:the round completely through the fin?
No, the length of the fin is 28mm but the hole is 20mm, keeps the centre of gravity a bit more forward

Posted: Sat Apr 14, 2012 6:03 am
by Petitlu
Ok
then exceed 30mm of the fin.
You know the weight of the tungsten rod?
Posted: Sat Apr 14, 2012 6:34 am
by jackssmirkingrevenge
Petitlu wrote:You know the weight of the tungsten rod?
Should be around 22 grams, I definitely would not want to stand in the way of this thing

Posted: Sat Apr 14, 2012 12:23 pm
by Petitlu
That's for sure!
With a 22 g bullet, gives HGTD 1627j to Mix40!
Tungsten vs steel profile, that will win?

Posted: Sat Apr 14, 2012 12:48 pm
by jackssmirkingrevenge
Petitlu wrote:Tungsten vs steel profile, that will win?

Based of the performance of the SP-6 round I mentioned earlier, I'm quite confident you will have full penetration. What velocity does HGDT predict?
Here's what I made so far, a couple of variations because I'm not a CNC machine and making 10 exact copies of the same thing would get boring

Posted: Sat Apr 14, 2012 1:07 pm
by Petitlu
Nice work !
here is the Velocity: 376 m / s barrel of 100cm
With a barrel 120cm: 402m / s and 1782j ...
although it is different, we can compare the results!
it how long you need to make a fin?
Posted: Sat Apr 14, 2012 1:38 pm
by jackssmirkingrevenge
Petitlu wrote:it how long you need to make a fin?
I timed the manufacture of fin N<sup>
o.</sup> 10, it took me 15 minutes from cutting the delrin rod to the finished product.
All that's left now is the pusher plates.
Any other interesting stuff that fits in the barrel you might want to launch?
Posted: Sat Apr 14, 2012 1:58 pm
by Petitlu
More than 2 hours of work anyway ...

thank you
A playmobil!
Yes, an arrow arc carbon, 5mm in diameter!

Posted: Sat Apr 14, 2012 2:51 pm
by jackssmirkingrevenge
Petitlu wrote:More than 2 hours of work anyway ...

thank you
Machining is fun, you don't realise that time is passing
A playmobil!

You need a bigger barrel than that hehe:
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Yes, an arrow arc carbon, 5mm in diameter!
Can you show me a photo of this arrow?
Tomorrow I want to try and shoot some coins

Posted: Sat Apr 14, 2012 2:54 pm
by al-xg
I've shot CF arrows before, make sure they don't hit something too hard, I've had one explode on impact before.
The larger fins, were troublesome to fit into a 14mm barrel, so 12mm may be a little tight.
I used nitrile plugs used for plumbing as the pusher plate.
And foam or even tissue paper rolled up to keep the arrow head centred. If the arrow is longer than the barrel you could use something like this:

Posted: Sat Apr 14, 2012 3:03 pm
by Petitlu
I make a picture ...
it is not useful to have an arrow pen to go right!
I draw no pen to 30m without missing the target ...
Posted: Sat Apr 14, 2012 3:23 pm
by Petitlu
is an arrow of initiation, my first arrows ...
After I do not know if it's worth it to make a shoe for an arrow ...
length: 720mm

Posted: Sat Apr 14, 2012 3:52 pm
by jackssmirkingrevenge
What's the major diameter of the tip of the arrow head? I might have a reasonably easy solution. What about the fins, can they bend to fit the barrel?
In the meantime, tungsten carbide rod fins and pusher plates done

much happier with these than the rough cut first ones I sent you.
Posted: Sat Apr 14, 2012 4:02 pm
by Petitlu
Yes they are very pretty!
Maximum diameter of the head: 6mm
The pens can bend and come within a 12mm barrel
Posted: Sat Apr 14, 2012 4:18 pm
by jackssmirkingrevenge
What about the diameter of the nock? Not sure what the French word is, the green bit of plastic at the end.