Chris LaPanse

Oh, and I’m up for a 4 inch Smoke drag race anytime 😀

The general trends should hold, though you’re right that the pressures used were sea level standard. I would think the same idea would be fine for our site though, since that’s only a pressure difference of 20% or so.(I’d still…   Read more»

Since this is an interesting problem, and I had a bit of free time, I ran some rough CFD sims on a Nike (this one is 1/4 scale, but the general trends should be valid for any of them that…   Read more»

Personally, I wouldn’t. It would make it very challenging to get the sleeve on after soaking the tube in resin. What I would do is use a fairly thin, slow-cure epoxy, and really work it into the weave. Spend some…   Read more»

I’ll be there :DMy Nike has a date with a K2045…

There’s always Tripoli Colorado next weekend…

I’ll gladly help with button pushing whenever I’m not launching. If the weather’s remotely decent, I’ll have an apogee deploy at 4k+ though, so I don’t know how long I’ll be out hiking. Whenever I do get back though, I’ll…   Read more»

My guess is that when a large chunk of fuel hits the ground, it cracks or fragments, substantially increasing the burn surface area and dispersing burning chunks.

Hard to say, honestly (especially since I don’t remember the event). I’d be surprised if it were mach-related, but it’s not impossible.

You can figure out the appropriate temperature and pressure fairly easily from the phase diagram of water. The numbers I used before (1000 PSI at 550F) are actually attainable using the heating-only method. Also, given my calculations, you’ll likely need…   Read more»

OK, here are the equations, with somewhat of an explanation. For a nozzle flow, the key defining factor is known as choked flow. When you have choked flow through a nozzle, the flow in the nozzle throat is at mach…   Read more»

Why would you need to pressurize the tank? When you heat the tank, it will pressurize itself.(By the way, just out of curiosity, which school are you going to?)

What equations are you using for those numbers? I cant even start to understand the dynamics books I looked at.Well the equations are fairly complicated, so the easy way is to use tables (which is what I did). However, I…   Read more»

So basically that idea would mean you fill the tank partially of water and heat it till its all vapor? Then release it throught the valve and nozzle? Wouldnt that limit the amount of vapor you could produce? If you…   Read more»

Darn. Double post and I can’t find the delete button…

I just ran some numbers with a chamber pressure of 1000PSI, a chamber temperature of 550F, and an exhaust pressure of 25 PSI (slightly underexpanded), here’s what I get (assuming that the stuff entering the nozzle is 100% pure water…   Read more»

The benoulli relation will be relatively useless in this case, since the flow in a rocket motor is definitely compressible (and bernoulli basically assumes incompressible flow). The phase diagram of water is useful though.Oh, and Ken’s suggestion does bring to…   Read more»

So if there might be a problem of the water transfering to steam before exiting the nozzle, how can we fix that? should we make the distance between the tank longer so it has more time to change into steam?It’s…   Read more»

Chris,I think what Shredder is getting at, is assuming that all water in the tank has been heated to the gas phase, no liquid in the tank.If that’s the case, the pressure in the tank will be absolutely absurd, as…   Read more»

Even if the system was laying on its side it shouldnt matter if the nozzle is above or below the container. There should be no air in the system and as soon as the water hits the atmospheric pressure its…   Read more»