SpudFiles

Actually, a scramjet would be better, they are capable of higher speeds

But they require much higher speeds initially i am currently playing with ideas in Autocad CDF i will post results shortly

Edit:
After several different destines this is the one that did the best

Hm, thank you!

It kinda makes sense that shape, because the "pressure point" is so far forward, by the time the gas ignites it has a lot of surface area to push on, unless I'm thinking of it the wrong way.

I'm still hoping those guides can double as fins

idk i will do some free flow sims today

Hey is that projectile above a ramjet or scramjet? I forgot to ask earlier...

It has charastics of both but more similar to scramjet

Edit: It looks like it ill flw well with the fins

But it will make an epic shockwave

Shockwave

Though with a projectile like that you'd need a sabot, or else it'll be really not airtight (for the injector) and inefficient...

Now if only I had a Hawaiian island so this could be like a 70-stage accelerator

How small will these projectiles be? I should be done with a .22 caliber 40x hybrid sometime after Christmas, which could be an injector for the accelerator.

This is what happens when it moves too fast (it ignites the gas in front of it) blow back seems like it would be bad...

Well as long as the injector seals against the accelerator, blowback should be TOO much of an issue, as long as the injector can take the pressures.

Also, I recently edited my above post, not sure if you noticed.

Edit: looks like I misunderstood your post

That does seem like an issue, like a jet firing it's engine backwards... Though if it's going supersonic, I don't quite understand why that would happen

The projectiles are 2in in diameter and by blow back i mean it would ignite the gas in-front of it blowing the projectile back into the gun

How do professional accelerators avoid blowback? I'm gonna research a bunch and see if I can comeup with anything...

I would love to see this built and played with I think it could be a new era for spud guns (that of the ridiculously expensive projectiles shot at extremely high speeds just because you can)

Edit: After duble checking my math you would need pressures in the 190,000psi to get the oxygen/hydrogen gas to get it up to the 1095deg F required for ignition. I was looking at butane due to its much lower spontaneous ignition temperature (However I a assuming that just the pressure increase is creating the change in temperature not anything additional so this could be inaccurate)

Hm, 200k psi is a little high for any commercially available tubing... Though I have seen 100k psi rated.

That's not the only thing igniting it however, because the flame front from the injector should help light the gas. Once the cycle is started, I believe the flame front behind the projectile should help light it.

Also, though it doesn't have to be mini, or just petit, I think a small caliber than 2" would probably be more fun.(not so much huge heavy stuff to store/transport) also, it's very hard to find stuff (or make it) that's safe with extreme pressures at so large a size.

Well I did a little digging and Autodesk CDF cannot simulate the shock wave in sutch a small space as the tube, so the shock wave would impart enough energy on the gas to ignite it, at least according to what I read. I will have to brush up on my, well everything.

Edit: here is one of the papers that I thought was the best
https://people.mcgill.ca/files/andrew.h ... 09-632.pdf

As I remember, Autodesk CFD doesn't simulate compressible fluids.