Onboard pumps

[inonickname]

Des-2 was originally designed to use an onboard pump. For those with experience; what is the practicality of this? The pump I have made so far is 1.9cmx35cm, and I'm hoping to use around 300-400 psi. The total pumping volume is just under 35 cc, or around 2 cubic inches.

The way the pump/check valve is made, there is around a 2x1mm dead space before the check valve. Damn right, the efficiency nazis are afoot. So, reaching these pressures shouldn't be *too hard.

The pump volume is around 100cc. I remember thinking I'd get 1 bar/pump, but hell, it was nowhere near that. (with my last pump).

So, am I correct in thinking that this is a good and working idea, or am I going to fall short on pressure and practicality?

[Gippeto]

73 looky lous and not a single reply.

Sounds adequate, but whether you can apply the necessary force to reach your pressure goals will depend on the layout of the pump/launcher.(Simple straight pump, double linkage pump(like that used on the crosman 13xx series), etc.)

ie. 1.9cm bore will require 179 lb force at 400psi or 134 lb force at 300psi

Have a picture??