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Posted: Sun May 06, 2012 3:32 am
by RJB INDUSTRIES
sure, but there are some limits....
I thought that maybe exist some calculations to do....
RJB INDUSTRIES
Posted: Sun May 06, 2012 4:06 am
by jackssmirkingrevenge
RJB INDUSTRIES wrote:I thought that maybe exist some calculations to do....
Oh there are a lot of calculations you can do
but you need to know what you want to penetrate, how far, what sort of trajectory you want, projectile material, target material - on a more intuitive level, it is also helpful to look at real world examples.
For example, in a pneumatic a heavier projectile will always give you more muzzle energy, but at the expense of velocity.
Let's take a GGDT example.
As you can see, we get the highest energy from a 50 gram projectile, but at such a low velocity hitting a target beyond point blank range would be almost impossible.
The 0.25 gram projectile gives us the highest velocity, but also the lowest energy. Assuming all the projectiles are the same size, it will also lose velocity the fastest due to the lower sectional density.
In general, the two gram projectile in this case seems to offer the best compromise between energy and velocity.
The above assumes consistent shape and size, but obviously these are significant variables too.
Rather than projectile weight independently, what you should be looking at is
ballistic coefficient.
This takes into account weight but also projectile shape and cross sectional area. You then have to measure that against what sort of velocities you're getting from your particular launcher.
Posted: Sun May 06, 2012 5:33 am
by Petitlu
he would cross the sound barrier, then a lot of noise!
Posted: Sun May 06, 2012 6:56 am
by RJB INDUSTRIES
I want install a 12 V battery in a combustion on to fill the fans, i am not founding one on ebay, the one I need mustn´t be to heavy or too big....
RJB INDUSTRIES
Posted: Sun May 06, 2012 9:00 am
by jackssmirkingrevenge
RJB INDUSTRIES wrote:I want install a 12 V battery in a combustion on to fill the fans, i am not founding one on ebay, the one I need mustn´t be to heavy or too big...
Here you go, but it won't last terribly long...
Posted: Sun May 06, 2012 9:05 am
by Petitlu
Posted: Sun May 06, 2012 9:39 am
by RJB INDUSTRIES
Petitlu can I charge it after use...? Is there that possibility?
RJB INDUSTRIES
Posted: Sun May 06, 2012 9:41 am
by Petitlu
Posted: Sun May 06, 2012 9:47 am
by RJB INDUSTRIES
What is the input in this charger?
RJB INDUSTRIES
Posted: Sun May 06, 2012 9:51 am
by Petitlu
sorry, this charger is designed for entry-12v ...
The best :
http://www.ebay.com/itm/3S-iMAX-B6-AC-B ... 273wt_1185
Posted: Sun May 06, 2012 9:54 am
by RJB INDUSTRIES
I need a simple one, may be i am gonna do the circuit....
RJB INDUSTRIES
Posted: Sun May 06, 2012 3:48 pm
by Petitlu
ThorJack look of, it's a start ..
Posted: Sun May 06, 2012 5:04 pm
by wyz2285
Cool, looks exactly like you planned. Your barrel is a .50 rifled barrel right? Where did you got one this long?
Posted: Sun May 06, 2012 5:21 pm
by Petitlu
this gun is a 12 mm smooth copper!
I did not put the rifled barrel of .50 because I can not shoot missiles all I want.
I bought my rifled .50 and 106cm to USA
Posted: Mon May 07, 2012 12:22 am
by jackssmirkingrevenge
Very nice, if I flew a helicopter in your vicinity
I'd be shítting myself right now
