vikram
kashyap


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Rocketry

This page is currently formatted as a set of log entries. The old entries are on the bottom. Once the project is finished, a writeup will be posted.


September 2, 2018

Turns out iron nails are hard to find. Even common, non-galvanized nails are still steel and pretty resistant to oxidation. Steel wool is much more pure and still the best bet.

In order to better oxidize the steel wool, I soaked it in vinegar (5% acetic acid) for about 36 hours. This removed any oils it may have been treated with. On removing it from the vinegar, the wool bales were a little warm, evidence of the exothermic oxidation process having already started. I layed out the steel wool on a paper plate, ripping it up a bit to increase exposure to the air, and sprayed it with hydrogen peroxide mixed with a little table salt (NaCl) for good measure. (At this point, the steel wool actually sizzled a little bit. My guess is oxygen was being released, likely from the H2O2.) After another day, I had some lovely red steel wool. But naturally, all of it was not oxidized, so to separate the red iron oxide (RIO) from the unoxidized iron and salt crystals, I put the wool into a jar full of water and mixed it all up. Most of the unoxidized iron sunk, so I could then put the salty, red water through a coffee filter. The dissolved salt went through, leaving a cake of RIO on the filter. After drying the cake, it easily powderized and the last iron bits could be taken out magnetically.

This process made more than 5 grams of RIO, which was more than what I needed to do an inital test. Today I tried a static test of 70% KNO3, 30% Su, and 1% RIO. (Yes, that adds up to 101%, but dirty math says 100 =~ 101. I added RIO equal to 1% of the mass I already had.) I bumped up the KNO3 concentration to 70% because I'm still dry packing the fuel and I figure it's better to put more than the optimal amount of oxidizer since it's not being mixed perfectly. Loading a few grams into a short length of PVC, making a core through it, and lighting it from the top, I was able to produce a short spurt of orange flame that lasted about a second. Success!

I now have something that (seemingly) burns fast enough for a rocket. For the future, I've got a couple things to figure out:

  * Measure the actual thrust of the fuel during a static test. A force scale of some sort?

  * Capping material better than quikcrete. Quikcrete is too strong once dampened and set, but too powdery and crumbly when dry to be used for packing the ends of the tube. Clay, even if costlier, may be the way to go.

  * A reliable ignition system. To do today's test, I put some steel wool on top of the tube and lit it on fire. The sparks set it off. That is not a good way to go about things. I considered using steel wool connected to an electric model rocket starter, but steel wool isnt reliable because it needs to burn in air. I'm looking into making an electronic sparker using nichrome wire and nitrocellulose.


August 22, 2018

To increase the burn rate of the Su-KN mixture, it's reccommended to add red iron oxide. I could simply buy a 5 pound bag of rust powder on amazon, but considering the fact that I'm trying to DIY the complete rocket, I think its more fun to try to produce it myself.

For the inital test, I tried two methods of rusting some fine (#0000 grade) steel wool. The first was to spread a thin, light layer of the steel wool on a plate and then spray it with 3% hydrogen peroxide (H2O2) until it was fairly soaked. The second method was to simply toss a bale of steel wool, still wound, into a cup of water. I let both sit overnight. The wool in the plate rusted about 1/2 the mass. By crushing the wool, I was able to extract the powder. Then I used a magnet to filter out any leftover iron (Iron (III) Oxide is not ferrimagnetic). The wool in the water actually produced black iron oxide (Fe3O4 rather than Fe2O3), likley because being submerged exposed it to less oxygen. I filtered the water to get the black iron oxide, but I'll likley not produce any more because red iron oxide is a better catalyst.

Unfortunately, I was only able to produce 0.5 grams of Fe2O3. In order to generate usuable amounts, I need to a) use a larger mass of iron than steel wool and b) oxidize it completely. Next, I'll be trying iron nails in Clorox.


Red and Black Iron Oxides
Left: Red Iron Oxide (Fe2O3), Right: Black Iron Oxide (Fe3O4)
August 19, 2018

I made my first attempt at a sugar rocket using 60% potassium nitrate (KNO3) and 40% sucrose. The KNO3 was from some stump remover and the sucrose was common table sugar. I packed the powdered mixture into some PVC. For the end caps, I used quikcrete because it was cheaper than the reccomended kitty litter (betonite clay). Sadly, when it lit it just spewed smoke from the core hole and didn't go nowhere. I think I made quite a few mistakes:

  1. The bottom cap did not blow out. I actually wet the quikcrete and let it set and that was likely too strong. For the next iteration, I'll pack it dry.

  2. The fuel didn't burn fast enough. I'm going to increase the concentration of KNO3 in the mixture and also add some Iron Oxide to increase the burn rate.

  3. The core was not drilled the full way through the fuel. This probably didn't matter much because of the other problems, but to properly direct the burn, I need to drill a core almost the full way through the fuel layer.

  4. PVC might be too heavy. I used 1/2 inch pipe, and the walls are pretty thick compared to the cross sectional area. I'll try PVC again, because it's been used by others, but I'll eventually try making my own paper or carboard casing.


First Sugar Rocket
The first attempt at a sugar rocket. 60% KNO3 and 40% sucrose in 3 inches of 1/2 inch PVC. The straw taped to the side is for mounting on the launch rod.
August 6, 2018

I got a couple of model rockets as a gift a couple years back, but never got around to actually launching them, so I went with a couple friends and set 'em off. I'm excited to do more launches and try my hand at making my own rockets and rocket engines.


Rocket Launch: C Engine
This was the 4th launch, using a C class engine. It went so high it was out of sight, but we were able to spot the parachute and retrieve it a few minutes later and a couple hundred meters away.