nater Posted June 8, 2014 Share Posted June 8, 2014 I tested a few motors on the ground and few a few more at a shoot this afternoon. The video didn't turn out very well, these rockets were fast and hard to track. A 1" motor with Dan Thames' "Super Whistle Fuel" pressed on Firesmith 1" Universal spindle generated just shy of 100 pounds of thrust. According to the software on the ACME test stand, this motor will lift a 6" ball shell to 600 ft. This was my goal anyway, although I suspect I could squeak some more thrust out of this spindle if I really try. Dag or Peret, what is the limit on the load cell that was included? I flew a small 2oz lampara on an identical motor. It was high enough up, you saw a small orange dot and you still could hear the motor whistling about 3.5 seconds after it burned out. Link to comment Share on other sites More sharing options...
ddewees Posted June 8, 2014 Share Posted June 8, 2014 Wow, I haven't noticed that fuel to be that hot... That's great. I love how the entire contents were basically consumed in just over a half second. Chinese perc? Did you use 5% 80 mesh, or 3% 36 mesh? Mineral oil or Vaseline... 3%? Link to comment Share on other sites More sharing options...
nater Posted June 8, 2014 Author Share Posted June 8, 2014 (edited) I use Chinese Perc from Uncle Buck. The charcoal was 4% 36 mesh. 3% mineral oil dissolved in acetone. As I have posted before, typically I get the Na Benzoate as fine as I can and screen the catalyst with it until it is uniform in color. Then I disperse the mineral oil in a small amount of acetone and mix it in a baggy with the Na Benz mixture, adding more solvent when necessary. Some have theorized that the Na Benz will dissolve in the acetone, reducing its particle size further. I then add the 36 mesh charcoal and the perc and knead until everything is well mixed. I intentionally add more acetone than needed to granulate the fuel to make it easier to mix. Let the mix dry until it is stiff enough to granulate, run it through whatever screen you like for the final size and dry. I'm not really sure where ~100 lbs of thrust stands with other builders using this tooling and fuel. Not to many people have posted results from thrust stands with this tooling / fuel combination. One club member gets around 80 lbs of thrust, using the same fuel and a 1" BP spindle from Rich Wolter. I would have expected the Universal spindle to get a litlte less powerful, but I do not know his method or if he uses perc with anti-cake in it. About the contents all being burned, when I make a motor to burn on a test stand, I press fuel around the spindle and just one increment with the solid rammer. I follow this with a stout clay plug to protect the stand from any fuel burning through. The thrust from any delay is negligible. I have found this fuel as a delay to give 3 or 4 lbs of thrust. That is way more than BP, but not enough that I think it offers any significant gain to lifting a shell. Edited June 8, 2014 by nater Link to comment Share on other sites More sharing options...
Peret Posted June 19, 2014 Share Posted June 19, 2014 Nater, it's a 100kg load cell, so full scale is 220 pounds or thereabouts. The rig will correctly read and report up to 200% or 440 pounds, but the load cell may be damaged, as its maximum overload is 150%. Also it may not be linear over 100%. Still, you're well in the safe zone at 100 pounds. Link to comment Share on other sites More sharing options...
ddewees Posted June 19, 2014 Share Posted June 19, 2014 So that means if a fat guy stands on it... it's done? Link to comment Share on other sites More sharing options...
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