Hi all, We had another great day this weekend launching rockets at the NSWRA launch meet. There was a unique opportunity to launch during fog to see if we...
I think the problem with the last flight was a basic stability issue. We reviewed the video frame by frame, and it looked like the most plausible explanation....
Well done George – Some height you got. Damn good footage of the flights and what a pit about that rocket crashing. All that work gone up in a heap. I am ...
Looking through the archives, I saw several members mention using RockSim to calculat CP and/or CG. RockSim is my simulator of choice for pyro rockets. It has...
Hi Daniel, That would be very cool to try with RockSim. It would be worth trialing to see how well RockSim can predict altitude compared to actual flight. I...
The thrust curve is phenomenally complicated, but if you figure several factors you should be able to get a good approximation. First up, the total energy in...
<snip> There's a point during the thrust of every good WR where the exhaust water is stationary - before that it's moving downward, later it's departing...
I have used RockSim, but only to figure out the drag coefficient (Cd) of different bottle shapes/combinations so that info fed into WR sims like Clifford's are...
... For optimum efficiency, the available energy is converted to the maximum amount of kinetic energy in the rocket (obvious). That means that anything else so...
... I guess the only two options here would be to either decrease the volume of the pressure chamber as the rocket accelerates in order to increase the...
The volume of the chamber does decrease, at least a little. The soda bottle is elastic and stores some energy there returning it as the pressure starts to...
... Maybe I should cross-post this to the microhybrids group: http://groups.yahoo.com/group/microhybrids/ They fly pyro rockets with solid fuels and liquid N2O...
... Water rocket motors have different thrust curves when run stationary vs flying, due to the effect on nozzle pressure of lifting the water. It would still...
If someone wants to quantify it... The extension of the bottle is going to be pretty much the same regardless of whether there is water or air (or both) in it...
Cliff, as you mentioned that varying the nozzle size in flight would not help, and since increasing the air pressure in flight is a also little more difficult,...
Dear Water Rocket Enthusiasts and Experts, Production has begun on a major new series for the Children's BBC – `Richard Hammond's Lab Rats'. Every show will...
This is a legit request. I corresponded with Any myself. Please respond directly to Andy and then let the rest of us know if you'll participate. Mike...
If you change the density of the fluid I suspect that it will be a case of "what you gain on the swings you lose on the roundabout". You will still have to...
Hi Gazza/George Let me get this straight – Are we looking for a thrust that is constant whether it be air or water. Trying to hold a longer thrust time yet...
There is a mass flow controller that also regulates flow independant of the pressure or temperature variations. I don't know what kind of valve it uses, but...
My rocket was launching fine, but as soon as the water ran out, it would go unstable, tumble wildly, and decelerate abruptly. I needed to add nose weight for...
Great to hear you had some success there Daniel! :) Well done. Using the water as nose weight is a good idea too. We've used the technique a few times and...
So what do you guys put on your checklist when going out launching? I'll start the ball rolling with ours: Always Bring * Silicone Grease (for nozzles and...
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