SpudFiles

Oops, DYI, I missed the fact that you were talking to Zeus -- and ramses I'm not sure who you are talking about in the beginning of your last post. Anyway...

The centrifuge would work if there is a significant difference in the density of the two propellent types. You could customize the gradient ...

DYI, ramses wasn't talking about a ram cannon. He was talking about a pellet configuration for a chemical gun that was made of two different types of propellant, one slow-burning and one fast-burning, such that the slow-burning section was ignited first and, as it burned, the concentration of the ...

Such a cartridge will provide constant pressure, at the breech,
not the muzzle.

For sub mach 2 projectiles, a "shaped charge" would help, but past that,
it's hard to keep the gases at the base of the projectile for the whole
length of the barrel.

I understand what you are saying about the ...

The point, ramses, is that they do not change at the same rate, which they should to maintain the maximum pressure.

ramses,

I see that you posted a picture of an ETG. I was referring to chemical propellants.

A problem, however, with that design is that the rate of the release of gas increases linearly, while the volume behind the projectile increases exponentially.

My quest was to find a method of using ...

I'm on the fence about an ETG or a railgun because the latter can maintain a constant acceleration for the entire length of the barrel, regardless of the acceleration or speed of the projectile with much less difficulty than with a conventionally propelled projectile or ETG, which I believe would ...

When we look to achieve ultrasonic muzzle speeds, we will need propellants that can burn at a rate such that they can fill the void created by the traveling projectile much faster than it creates it, otherwise they will not continue to apply pressure to the projectile as it travels down the barrel ...

Even with extremely high pressures it does take some time to push the projectile up to speed such that a lower pressure over a longer time will be better , this was the problem when nitrocellulose was first used until ways were found to slow it down. [...]

So its not just more pressure and ...

But I assume thats the problem with ETG's in general, slowing down the energy release to propel rather then explode.

If the objective of any propulsive system is to attain maximum speed, an explosion, assuming it is confined within the chamber and is only allowed to escape via displacing the ...

I was VERY wrong on my theoretical speed calculations. Somehow the weight of the polypropylene ball was very much miscalculated -- I knew that 0.4 grams seemed heavy for one of the lightest plastics available. It was actually off by an order of magnitude!

Since these numbers are so staggering, I'm ...

I was undecided as to whether to make the chamber part of the circuit or insulated. Being that this system would only be a prototype and not an actual field-use unit, I believe I'm going to use the chamber as part of the circuit in my actual build in an attempt to concentrate resources on ...

You should wander around McMaster.com and you'd find a plethora of exotic materials and parts that can find great use in such an undertaking as this.

"Very High Temperature Nonporous High-Alumina Ceramics"
Tube shape - 1/8" ID 1/4" OD 12" Length
for $13.48, and the tolerances are relatively tight ...

To prevent structural deformation, I'm going to use a very thick chamber made from hardened 440C, which is extremely hard and strong.

To prevent barrel erosion, I'm hoping to install a barrel liner made of a high-alumina ceramic.

Also, for any given CT ID, however small, I can shorten the CT such ...

DYI,

I'm sorry for being so persistent on the size vs. pressure debate, perhaps I have falsely recalled one of your designs. It seems that I remember seeing you having a design that had a CT, a chamber larger than either the CT and the barrel, and then the barrel. Regardless, the debate was still ...

I performed a preliminary test using a ratio of 5 cubic centimeters of SAP and 2 ounces of water.

The water had a weight of 60 grams for a 1/4-cup volume.

The saturated SAP had a weight of 19 grams for the same volume.

It is looking like the S-SAP could be an ideal ablation material for an ETG.