Ramjet Sabot

[PaperNinja]

I've been thinking about: ramjets in ram accelerators until I realized that a projectile with a ramjet would not be very expendable, and then I'd have a miniboy-like situation. I was just wondering if a ramjet sabot would be feasible, while the sabot is reuseable, but the projectile isn't. The problem I had though, was that the ramjet would be pretty heavy itself, and would go flying along with the projectile. Maybe if I attached some kind of parachute or something with it it could slow down? The problem is it's going so fast (>supersonic) that I don't really have a good way of using it again, which defeats the entire point. Any ideas?

(note that this is just a theory , it's unlikely that I'll be making a ram accelerator anytime soon)

[jackssmirkingrevenge]

For starters, you need a launcher that can fire your ramjet sabot past the speed of sound. This in itself is not such a simple task, but has to be accomplished before your theory can be contemplated.

[PaperNinja]

I know, but that's not the point , that could be done with a powerful hybrid, or medium ETG.

I'm trying to think how to reuse the sabot, when it's going so fast and is so (relatively) heavy.

[Zeus]

Remember, (sc)ramjets are very reliant on geometry, so where do you propose the projectile goes in relation to the ramjet? Not to mention how the ramjet will be fueled.

I think you should focus on a simple ramjet than devising Goldbergian schemes to save money. It's unlikely you'll fire it more than a dozen times, so an economical ramjet is the way to go.

[PaperNinja]

I was thinking the ramjet would go around the back of the projectile, kinda like this:

When I say ramjet, I just mean the pusher-thing in the ram accelerator. It's the same as a ramjet, but doesn't fuel itself, it just uses a premixed fuel in the accelerator.

So there's no way really to re-use the "ramjet"? I don't have a good way to make them, so I would hate to have to wait several days/weeks and spend a lot of money on each shot.

[mobile chernobyl]

Mostly likely - you WILL spend a lot of money on each shot, and you WILL spend a lot of time making them. If you somehow found a way around this you might just become the next Tony Stark.

We've bounced this idea around a lot on the Hybrid side of things - mostly the idea has always been under the assumption that the ramjet engine will be the projectile itself and it will be a consumable.

As JSR said - but even before what he said:
Try making a ramjet engine that produces any substantial thrust on land first before you jump to making one that will provide thrust on a projectile. You can simulate the fast air velocities of a projectile with the right type of pump and nozzle system.
- it will have a split second to fire up and begin producing thrust before it acts as a huge parachute and makes your design decelerate and lose control extremely fast!

[ferret_guy]

I don't think you know that a Ram Accelerator is. Here is a (very cool) link explaining that they are. (I want to make one now)

[PaperNinja]

I'm sorry I was being confusing, I didn't actually mean a ramjet engine, I was only using that as the term for the projectile in ram accelerators. The difference is, the ramjet (projectile) is the same as a ramjet (engine) but it (projectile) DOES NOT have it's own gas tank/flow, and as it moves through a tube it compresses a fuel/air mix, the compression heats the mix, ignites it and spits it out the back making pressure. The ramjet (engine) has its own fuel supply, and doesn't need the tube (accelerator).

I'm not trying to be sarcastic or anything, I'm just trying to clarify

Edit:

ferret_guy, that's a little different than I was thinking, but it very well could work, there'd just have to be near-perfect alignment so the projectile doesn't smash into the rails. As I said above, I thought a ram accelerator just used a ramjet engine, without it's own fuel supply instead of a rail system like that, but that could work.

[ferret_guy]

If the projectile were like this it would be easier

[PaperNinja]

Yeah that could work... Though that's getting more and more into the realm of not-expendable-projectiles...

I could possibly use those buzzer magnets, but then I'd have to find the barrel to fit. Ilikethe idea though, because the guides could also be fins.

[Goats spudz]

Projectile? Seems Possible, Would also make a nice ornament! Ill Machine one when i get chance.

[ferret_guy]

Today i did lots of heavy math with gasses, and autoignition temperatures. Figured everything out will be posting it shortly

[PaperNinja]

Goats, Im thinking that projectile isn't the best model, aren't rounded noses better for supersonic flight?

[sagthegreat]

that projectile looks BAWS

[ferret_guy]

That is not a projectile simply a ram jet and at supersonic velocities pointy is bettor for air flow (on a side note CDF simulations take a long tome to bake)

Edit:
So after reading up on Ramjets (and running some CDF simulations) I found out I was trying to model a scramjet...