1st series of tests May 2017
A new rocket engine: UTES-1 (Universal Test Engine System 1.1)
This engine was designed to be simple to make, robust and has the ability to be used for solid propellants, liquid propellants, hybrid (acrylic + nitrous oxide), and as a peroxide reaction engine with a silver screen catalyst in the chamber. The graphite nozzle was machined on a mini lathe.
The image above is from the first test on
5/1/17 using an RNX like composite propellant consisting of: Potassium
nitrate, iron oxide, aluminum, and fiberglassing epoxy.
The results:
Overall rating: Poor - Low thrust
Grain length: 1"
Average chamber pressure: 10 PSI
Burn time: 32 seconds
RNX Propellant was created by Richard Nakka, here is a link to the page on his site dedicated to it: http://www.nakka-rocketry.net/rnx_pre.html
Direct link to PDF of that page:
drive.google.com/file/d/0B8sB6dDVGO-wZEhlVkVydVJkbEE/view?usp=sharing
Specific chemistry of the May 1st 2017 test:
Oxidizer catalyst mixture (this was placed in a ball mill for 12 hours)
Composition:
164.5 grams of potassium nitrate
18.8 grams of ferric oxide (From an art store, powdered pigment Gamblin Raw Umber $9.55/47 grams. NOTE: real iron oxide will react with concentrated hydrogen peroxide, that is the best way to verify if it's the good stuff. I tried 3 different concrete colorants that claimed to be natural iron oxide but they were garbage.)
Once the mixture was unified in the ball mill we weighed out:
93 grams of the oxidiser catalyst mixture
5 grams of aluminum powder (derived from rustoleum oil paint link PDF)
29 grams of bondo fiberglass epoxy (Home Depot / ACE hardware)
15 or so drops of the epoxy curing catalyst
The materials were thoroughly mixed in a glass jar then packed into a spare 3" aluminum tube from the motor, so the inside diameter is the same. To keep the epoxy from sticking to the aluminum tube I used carnauba wax to coat the tube, this can be found at ACE hardware near the automotive and flooring wax section. car wax would probably work as well.
I used a piece of aluminum that I turned on a lathe that fits inside of the tube and pressed the material with a vice until material started squeezing out like play dough, the key here is to remove any air bubbles, as they will cause a spike in chamber pressure that can cause an explosion and or cause inconsistent burn rates and useless data.
After 12 hours I removed the grain from the aluminum tube and placed it into the lathe to bore out a hole down the center. Final bore diameter is 7/32"
Ignition:
The igniter is constructed out of CAT5 wire leads with a soldered bit of nichrome wire wrapped around a longer section like shown in this image:
Image Source: LINK
The results:
Overall rating: Poor - Low thrust
Grain length: 1"
Average chamber pressure: 10 PSI
Burn time: 32 seconds
RNX Propellant was created by Richard Nakka, here is a link to the page on his site dedicated to it: http://www.nakka-rocketry.net/rnx_pre.html
Direct link to PDF of that page:
drive.google.com/file/d/0B8sB6dDVGO-wZEhlVkVydVJkbEE/view?usp=sharing
Specific chemistry of the May 1st 2017 test:
Oxidizer catalyst mixture (this was placed in a ball mill for 12 hours)
Composition:
164.5 grams of potassium nitrate
18.8 grams of ferric oxide (From an art store, powdered pigment Gamblin Raw Umber $9.55/47 grams. NOTE: real iron oxide will react with concentrated hydrogen peroxide, that is the best way to verify if it's the good stuff. I tried 3 different concrete colorants that claimed to be natural iron oxide but they were garbage.)
Once the mixture was unified in the ball mill we weighed out:
93 grams of the oxidiser catalyst mixture
5 grams of aluminum powder (derived from rustoleum oil paint link PDF)
29 grams of bondo fiberglass epoxy (Home Depot / ACE hardware)
15 or so drops of the epoxy curing catalyst
The materials were thoroughly mixed in a glass jar then packed into a spare 3" aluminum tube from the motor, so the inside diameter is the same. To keep the epoxy from sticking to the aluminum tube I used carnauba wax to coat the tube, this can be found at ACE hardware near the automotive and flooring wax section. car wax would probably work as well.
I used a piece of aluminum that I turned on a lathe that fits inside of the tube and pressed the material with a vice until material started squeezing out like play dough, the key here is to remove any air bubbles, as they will cause a spike in chamber pressure that can cause an explosion and or cause inconsistent burn rates and useless data.
After 12 hours I removed the grain from the aluminum tube and placed it into the lathe to bore out a hole down the center. Final bore diameter is 7/32"
Ignition:
The igniter is constructed out of CAT5 wire leads with a soldered bit of nichrome wire wrapped around a longer section like shown in this image:
Image Source: LINK
Preparation of the engine:
1) First I packed the bore hole of the RNX fuel grain with a mixture of homemade black powder (much weaker than the commercial powder) and leftover fuel from the fuel grain casting that I pressed through a screen while it was still wet, making little grains like gunpowder. I mixed these 1:1 and packed it lightly into the bore hole.
2) I added the 1" section of fuel grain to the engine then closed the end with RTV red silicone and a locking ring.
3) I added more of the ignition mixture through the nozzle and placed the igniter in the nozzle.
The purpose of the mixture is to allow the igniter to burn the gunpowder that then gets the composite fuel bits going that created enough heat to initiate the RNX fuel grain. Without this process the igniter would not ignite the RNX.
(Note to self: Elaborate on the engine construction, materials and nozzle dimensions and geometry)
Engine design theory:
The purpose of the tests I'm doing in May of 2017 is based on tuning the fuel chemistry to the engine and nozzle geometry. The end result is an engine that can easily be replicated and scaled up or down.
TEST #2 May 2nd 2017
The last test was low performance, to increase performance we will improve the burn rate of the fuel by adding 4X the amount of aluminum powder, because I am low on the aluminum I decided to just reduce the other ingredients by dividing by 4.
Specific chemistry:
Fuel renamed to RANX-4
23 grams of oxidizer catalyst mixture
9 grams of bondo fiberglass epoxy
7 drops of epoxy catalyst
6 grams of aluminum powder (I just used the last of what I had, why not just add 1 more gram :)
The last test was low performance, to increase performance we will improve the burn rate of the fuel by adding 4X the amount of aluminum powder, because I am low on the aluminum I decided to just reduce the other ingredients by dividing by 4.
Specific chemistry:
Fuel renamed to RANX-4
23 grams of oxidizer catalyst mixture
9 grams of bondo fiberglass epoxy
7 drops of epoxy catalyst
6 grams of aluminum powder (I just used the last of what I had, why not just add 1 more gram :)
Test 2 Results:
Overall rating: Good - Higher thrust
Grain length: 1"
Average chamber pressure: 40-50 PSI
Burn time: 10 seconds
Grain length: 1"
Average chamber pressure: 40-50 PSI
Burn time: 10 seconds
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