Static Tests
Performed on the electronic test stands

Year 2007

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Excel File
Thrust Curve
(click for spreadsheet)

38-240 Casing, Dextrose rcandy

Peak Thrust: 51.6542  Lbs-force 
Average Thrust: 44.0518   Lbs-force (1)
Burn time: 0.70  Seconds (1)
Total Thrust: 31.02  Lb-Seconds
Total Thrust: 137.98  N-Seconds
Propellant weight: 0.1105  Kg 
Propellant weight: 0.244  pounds
ISP, Delivered 127.41  Seconds

Evidence that KN/DX rcandy works and can be used in my motors.  Burn time is longer than with recrystallized KN/Sucrose.
1 meg,
3 seconds

.mpg file

(click for spreadsheet analysis)

38-240 casing, Malt Extract/Dextrose propellant.  Approximately 2:1 dextrose to malt extract, plus about 0.3% RIO

Peak Thrust: 106.7679  Lbs-force 
Average Thrust: 85.0181  Lbs-force (1)
Burn time: 0.31  Seconds (1)
Total Thrust: 26.57  Lb-Seconds
Total Thrust: 118.18  N-Seconds
Propellant weight: 0.1022  Kg 
Propellant weight: 0.225  pounds
ISP, Delivered 117.99  Seconds

This made a sharp little burn, surprising, since the malt extract propellant would not burn at all unless a torch was held to it (see Video 0) and dextrose propellant burns more slowly than KN/sucrose.  Why should the combination of two slow propellants be faster than a fast one?  Beats me.  But I'll do some more experiments to find out.
Video 1
1 meg,
5 seconds, .wmv file

Video 0
3 attempts 
2 meg .wmv file,  14 seconds


38-240 casing, Malt Extract/Dextrose propellant.  Replication of 2-24-07C except that propellant contains about equal proportions of dextrose and dry malt extract.  It was barely non-continuous at 1 atmosphere, and expected to burn moderately in the motor casing.  

Peak Thrust: 106.7679  Lbs-force 
Average Thrust: 85.3167  Lbs-force (1)
Burn time: 0.30  Seconds (1)
Total Thrust: 26.31  Lb-Seconds
Total Thrust: 117.01  N-Seconds
Propellant weight: 0.1012  Kg 
Propellant weight: 0.223  pounds
ISP, Delivered 117.98  Seconds

Surprise!  Burn is almost identical to the previous test.  This propellant contains slightly more RIO than the previous motor, approximately 0.5%  
Next tests will be made without RIO, to eliminate this complicating factor.
5 seconds .wmv file

2-27-07A 1-27-07A static test thrust curve 38-240 casing, Malt Extract/Dextrose propellant.  Replication of 2-24-07C except that propellant contains more dry malt extract than dextrose, 3:1 ratio.  

Propellant is made with 21% malt extract, 7% dextrose, and 14% Karo syrup.  Doped with 0.01% (0.2g in whole 170gram batch) red iron oxide, it is a non-continuous burn, "chuffy" under propane-torch flame.

3-3/4 inch long fuse-paper ignitor used, extending full length of propellant grain.

Peak Thrust: 67.3778  Lbs-force 
Average Thrust: 54.0618  Lbs-force (1)
Burn time: 0.48  Seconds (1)
Total Thrust: 26.36  Lb-Seconds
Total Thrust: 117.23  N-Seconds
Propellant weight: 0.1006  Kg 
Propellant weight: 0.222  pounds
ISP, Delivered 118.91  Seconds

Ignitor is expelled immediately upon ignition, followed by an ignition delay of about 2 seconds, but then by a quick ramp-up to full thrust and nominal burn thereafter.  

Burn time, pressure, and thrust are similar to KN/sucrose motors of this configuration.  
5 seconds .wmv file

38-240 Static test, Fuse Paper/Thermite ignitor.  Grain is uninhibited, very tight fit in case liner so no wrap of fuse paper around grain this time.  Ignitor is strip of rich fuse paper 1.5 inches wide x 5.5 inches long.  Last half of the roll is spread with 0.2g RIO/Al mixture, 3:1 ratio.  Ignitor secured with full covering of green masking tape.

Used new casting base and rod by Bob Gunar, made more precise grain, and the better-centered core may have contributed to the even burn.

Peak Thrust: 73.8053  Lbs-force 
Average Thrust: 62.2407  Lbs-force (1)
Burn time: 0.46  Seconds (1)
Total Thrust: 29.05  Lb-Seconds
Total Thrust: 129.20  N-Seconds
Propellant weight: 0.1130  Kg 
Propellant weight: 0.249  pounds
ISP, Delivered 116.67  Seconds

Ignition quick, rise to pressure very fast, and thrust "curve" is amazingly flat.  This bears replication.

1 meg
5 seconds .wmv file


38-240 Static test, Fuse Paper/Thermite ignitor.  Essentially the same as 3-17-07B1 but with slightly smaller grain.  

Peak Thrust: 88.3372  Lbs-force 
Average Thrust: 70.9673  Lbs-force (1)
Burn time: 0.42  Seconds (1)
Total Thrust: 30.16  Lb-Seconds
Total Thrust: 134.16  N-Seconds
Propellant weight: 0.1101  Kg 
Propellant weight: 0.243  pounds
ISP, Delivered 124.34  Seconds

Similar quick rise to pressure, not quite as clean a curve but quite acceptable.
1 meg
5 seconds .wmv file

3-18-07A 38-240 static test, Fuse paper/thermite ignitor, RIO catalyzed propellant.  Grain is made from same batch of propellant as used in both 3/17/07 tests, but 0.5% red iron oxide is added.  

Peak Thrust: 105.1762  Lbs-force 
Average Thrust: 85.7379  Lbs-force (1)
Burn time: 0.35  Seconds (1)
Total Thrust: 30.72  Lb-Seconds
Total Thrust: 136.65  N-Seconds
Propellant weight: 0.1133  Kg 
Propellant weight: 0.250  pounds
ISP, Delivered 123.07  Seconds

Burn is somewhat quicker, pressure and peak thrust considerably higher.  Peak thrust on this test was about 1450 psi, peaks on the two 3/17 tests were 1000 and 1200 psi.  
1 meg
5 seconds .wmv file
(click for spreadsheet analysis)
38-240 static test, fuse paper/thermite ignitor, Dry Malt Extract propellant.  Grain is made of remnant from 3/9/07C, two parts dry malt extract, 1 part dextrose as primary fuels.  This propellant does not support its own combustion at 1 atmosphere, requires continual flame source, and even then it chuffs.

Peak Thrust: 44.2390  Lbs-force 
Average Thrust: 36.7784  Lbs-force (1)
Burn time: 0.51  Seconds (1)
Total Thrust: 18.85  Lb-Seconds
Total Thrust: 83.84  N-Seconds
Propellant weight: 0.0953  Kg 
Propellant weight: 0.210  pounds
ISP, Delivered 89.77  Seconds

Upon ignition, motor started slow burn.  After about 6 seconds, it almost extinguished, then started chuffing.   The chuffing continued to increase for about 6 seconds after which there was a strong thrust.

Apparently the thermite ignitor does not ensure full igniton.  Nor is it necessarily to be credited with the fast rise to pressure in the last 3 tests, as this one shows a fast rise once it gets past the chuffing, and by the time that had happened the ignitor was long gone.

I'm going to name this propellant "Chuffmaster."
2 meg
17 seconds .wmv file

Click for Spreadsheet
3-25-07D Loki 2000 Moonburner, Dextrose Rcandy
Propellant made with KNO3, Dextrose and Karo Syrup, just like tradtional rcandy but using dextrose instead of sucrose.  
Igniter is fuse paper roll with a little CuO/Al thermite.

Peak Thrust: 127.4768   Lbs-force 
Average Thrust: 90.4549   Lbs-force 
Burn time: 2.74   Seconds 
Total Thrust: 248.00   Lb-Seconds
Total Thrust: 1103.09   N-Seconds
Propellant weight: 0.9550   Kg 
Propellant weight: 2.106   pounds
ISP, Delivered 117.86   Seconds

A little bump on the captured data graph suggests that igniter fired 0.63 seconds before pressure began to rise.  Looks like a good flight motor.
No video, sorry!

    18mm Paper-Tube Motors with Packed Dry Propellant
2 parts KNO3, 1 part confectioner's sugar, ground in mortar
Core is 1/4th inch diameter, 2-1/4 inches long
First rammed in 1/4 tsp Bentonite, then rammed full of propellant in 1/2 tsp increments
Top sealed with epoxy.  
(click for spreadsheet)
12-21-07A 12/21/07A
Peak Thrust: 2.8992  Lbs-force 
Average Thrust: 1.5580  Lbs-force (1)
Burn time: 0.81  Seconds (1)
Total Thrust: 1.27  Lb-Seconds
Total Thrust: 5.63  N-Seconds
Propellant weight: 0.0089  Kg 
Propellant weight: 0.020  pounds
ISP, Delivered 64.56  Seconds
12/21/07A Video
.wmv file
5 seconds 
12-21-07B 12/21/07B
Peak Thrust: 2.8825  Lbs-force 
Average Thrust: 1.6974  Lbs-force (1)
Burn time: 0.70  Seconds (1)
Total Thrust: 1.19  Lb-Seconds
Total Thrust: 5.29  N-Seconds
Propellant weight: 0.0089  Kg 
Propellant weight: 0.020  pounds
ISP, Delivered 60.60  Seconds
12/21/07B Video

.wmv file

4 seconds 

These little motors are a breeze to make, ignite quickly, and seem to be fairly consistent and reliable.  Their impulse is lower than similar motors made with rcandy, even when the Kn ratio is the same.  

Thrust curve is progressive, as expected from this core-burning grain design.  
Flight Video,

4 meg
.wmv file
33 seconds

Click for Spreadsheet
12-22-07B 38-240 casing, uninhibited grain propellant test.  Standard test motor, to check propellant made with KNO3 from a new source.  The propellant seemed fine, so I made a grain with it to test. 

Peak Thrust: 71.0177  Lbs-force 
Average Thrust: 47.4479  Lbs-force (1)
Burn time: 0.49  Seconds (1)
Total Thrust: 23.33  Lb-Seconds
Total Thrust: 103.77  N-Seconds
Propellant weight: 0.0995  Kg 
Propellant weight: 0.219  pounds
ISP, Delivered 106.42  Seconds

Funny bump at beginning of burn though to be slow ignition of outer grain.  At first, only the core ignited, generating a little thrust, then the outside ignited, generating much more.  

Good burn, but I wonder why the ISP is low...
12/22/07B Video
1 meg

.wmv file
7 seconds

  38-240 Casing, Tests of grains coated with Polyurethane Varnish.  
Propellant is normal Rcandy, burn rate 10 seconds per inch at 1 atm.
Uninhibited grains were dipped in Minwax Helmsman polyurethane spar varnish the night before and hung out to dry.  Next day, grains were easy to handle, not sticky even after being out all humid night.  
(click for spreadsheet)
12-24-07A 12/24/07A
Peak Thrust: 80.4915  Lbs-force 
Average Thrust: 36.6958  Lbs-force (1)
Burn time: 0.63  Seconds (1)
Total Thrust: 23.39  Lb-Seconds
Total Thrust: 104.05  N-Seconds
Propellant weight: 0.1040  Kg 
Propellant weight: 0.229  pounds
ISP, Delivered 102.09  Seconds

12/24/07A Video
.wmv file
5 seconds 
12-24-07B 12/21/07B
Peak Thrust: 59.6626  Lbs-force 
Average Thrust: 23.9064  Lbs-force (1)
Burn time: 0.77  Seconds (1)
Total Thrust: 18.43  Lb-Seconds
Total Thrust: 81.97  N-Seconds
Propellant weight: 0.0911  Kg 
Propellant weight: 0.201  pounds
ISP, Delivered 91.81  Seconds

12/24/07B Video

.wmv file

4 seconds 
Slow ramp-up to full pressure was expected.  It is thought that the "shelf" before the peak is the core burning, as it took a bit of time for the flame to work its way to the outside of the uninhibited grain.  

First one was a bear to ignite.  Fuse paper igniter failed.  Fuse paper with Ti failed.  Fuse paper with a section of strobe match failed.  So I dumped a few short pieces of strobe match down the core and added another fuse paper igniter.  That worked.

Second one, I dumped small pieces of rcandy down into the core, then inserted a fuse paper igniter.  That worked too, after spewing chunks of burning propellant all over the ground.  

The polyurethane coating is promising, but needs some work.

Recrystallized Rocketry
Jimmy Yawn
rev 8/3/08