Static Test 1:

1" PVC pipe x 5.5" long, 3/8" core, 65/35 ratio KN03/sucrose, 5/16" throat, paper inhibited outside grain.

Convergent cement nozzle with 5/16" steel washer cast into PVC adapter then glued to PVC pipe. Divergent nozzle area poured after convergent section cured, then divergent cone cut with 30 d. counter sink tool.

Static Firing Result: Appeared to be good burn. Divergent cone section blew out. 5/16" steel washer blew out. Concrete nozzle eroded to 3/8"

Click Here for a poor quality video of my first home built motor firing.


Launch Test 2:

1" PVC 5.5" long, 3/8" core, 65/35 KN/SU 5/16" throat, paper inhibited outside grain, KN03 epoxy delay.

Convergent cement nozzle with 5/16" steel washer cast into PVC adapter then glued to PVC pipe. Divergent nozzle area poured after convergent section cured, then divergent cone cut with 30 d. counter sink tool.

Launch Report. Motor loaded into 2" d.x 24"l. pvc rocket body, pine nose cone. Good ignition. Rocket cato at about 100'. Nose cone and parachute ejected and not found. ( I assume they are in a low earth orbit ;) Rocket body recovered intact, motor recovered intact but the delay section had blown out the top.


Launch Test 3:

1" PVC 5.5" long, 3/8" core, 65/35 KN/SU 5/16" throat, paper inhibited outside grain.

Convergent cement nozzle with 5/16" steel washer cast into PVC adapter then glued to PVC pipe. Divergent nozzle area poured after convergent section cured, then divergent cone cut with 30 d. counter sink tool.

Launch Report. Motor loaded into a 2" d. x 24" l. pvc rocket body, pine nose cone. No delay was used in the motor design, this rocket was to test an air speed trigger of R. Nakka's design. Surface area of the air speed switch was tested by holding the rocket body outside a car window. The trigger speed was set to about 45 mph. Which, in hindsight, was probably to slow. Rocket was launched in fairly high winds, 15 to 20 mph. Launch was perfect, the rocket weathercocked into the wind slightly and the ejection system never fired. The rocket flew great, reaching a good altitude before it was lost from sight. The rocket could not be found. I assume the weathercocking and rather low speed setting of the air speed switch resulted in non-deployment of the ejection system.


Static Test 4:

1" PVC 5.5" long, 3/8" core, 65/35 KN/SU 5/16" throat, paper inhibited outside grain, KN03 epoxy delay.

Convergent/divergent nozzle was cast into the motor tube at the same time. Divergent cone was trued after cement cured. 5/16" washer was again cast into the nozzle.

Test Report. Good ignition. Motor cato at about .5 sec. into burn. Good thrust, as the motor pegged the 70 pound springs on the test stand. Another cato with a delay built into the motor. This cato was complete, only small pieces remained.

Click here for a video of the test, good quality.


Static Test 5:

1" PVC 5.5" long, 3/8" core, 65/35 KN/SU .32" throat, paper inhibited outside grain.

Convergent/divergent nozzle was cast into the motor tube at the same time. Divergent cone was trued after cement cured. 5/16" washer was again cast into the nozzle.

Perfect test fire.

Click here for a video the the test.


Launch Test 6:

Motor was exactly the same as in static test 5. Rocket was a 3" d. pvc body, sheet metal fins, and a solid maple nose cone. Parachute was newly made 36" d. nylon. Ejection system was the air speed trigger as used in test launch 3. Rocket is very heavy relative to motor size, so not much altitude is expected. This is really another test of the deployment system.

Launch Report: Perfect day to launch, no wind and clear blue skies. Good ignition, good flight. Better altitude than anticipated. No deployment of recovery system. After recovering the mostly intact rocket, I remembered that I had forgot to turn on the switch to activate the recovery system. So, a good flight but I didn't learn anything because I forgot to turn on a switch.

Click here for a video of the flight.



Launch Test 7:

This launch was a bit of a whim, quickly put together. I had some extra propellant, so I cast it into a 7" length of 3/4" pvc pipe. So it was case bonded and cored to .25" for about 1/2 the length of the grain. The rocket was an old 1 1/4 pvc body rocket I used with commercial 24 mm motors. I was worried about the case bonding, and it was justified. The motor cato'd just after liftoff.


Click here for a not too interesting video.


Launch Test 8:

1" PVC 5.5" long, 3/8" core, 65/35 KN/SU .32" throat, paper inhibited outside grain.

Convergent/divergent nozzle was cast into the motor tube at the same time. Divergent cone was trued after cement cured. 5/16" washer was again cast into the nozzle.

Launch Report:

This was my standard motor I had been using with great success. The only thing was, this motor had been assembled some 2 weeks before it's launch. I had sealed the nozzle with masking tape, but that was not adequate. The motor absorbed moisture from the air and did not fire properly. Upon examination after the launch, the motor was actually still wet inside. I now keep my motors/grains in a desiccant box. The purpose of the flight was to test my new home made timer for the recovery system.

Click here for a rather comical video of a wet motor launch.


Launch Test 9:

1 1/4" PVC 7.5" long, 3/8" core, 60/40 KN/SU, paper inhibited outside grain.

Convergent/divergent nozzle was cast into the motor tube at the same time. Divergent cone was trued after cement cured. Washer was again cast into the nozzle. I seem to have lost my notes on the 1 /4" series of PVC motors. I think I used a 3/8" washer for the throat, maybe .42" actual diameter.

Launch Report:

Good ignition. Flight was a bit "corkscrew" you know what I mean! This rocket used my home built 555 timer with relay and dual 9 volt batteries. The problems with the deployment initiator are documented in the Parachute Deployment Charge page. This rocket deployed the parachute just in time! If you watch the video, you can hear me say Ohhhh! just at the end. That's when the chute deployed saving the rocket.

Click Here for a video of the flight.


Launch Test 10:

1 1/4" PVC 7.5" long, 3/8" core, 60/40 KN/SU, paper inhibited outside grain.

Convergent/divergent nozzle was cast into the motor tube at the same time. Divergent cone was trued after cement cured. Washer was again cast into the nozzle. I seem to have lost my notes on the 1 /4" series of PVC motors. I think I used a 3/8" washer for the throat, maybe .42" actual diameter

Launch Report:

This was the same rocket and same motor design as in launch test 9, only the result was a little different. Good ignition, good start to the flight but shortly after lift off I believe the motor cato'd. Post flight revealed the body tube cracked at the base, and the lower motor centering ring missing. Upper bulkheads were intact, but as can be seen in the video the nose cone and parachute separated from the body tube. The motor was not found. It may be possible the rocket went unstable, causing it to tumble and the force broke the lower retaining ring and ejected the motor. The video clearly shows the motor, or at least propellant going skyward after the event. Let me know if you come up with any other good theories, I'm still a bit mystified as to what went wrong.

Click Here for a kinda cool video.

Launch Test 11

1" PVC 5.5" long, 3/8" core, 65/35 KN/SU .32" throat, paper inhibited outside grain

Convergent/divergent nozzle was cast into the motor tube at the same time. Divergent cone was trued after cement cured. 5/16" washer was again cast into the nozzle.

I went back to smaller 1" PVC x 5.5" with this flight. Since it's real purpose is to test deployment, a large motor was not required. The igniter used was my standard nitrocellulose lacquer/black powder with stainless steel wool resistance wire. The launch and recovery went perfectly, which led me to go ahead with my launch of a wireless video camera on the next launch.

Click Here for a video of the flight from ignition to touchdown.

Launch Test 12

1" PVC 5.5" long, 3/8" core, 65/35 KN/SU .32" throat, paper inhibited outside grain

Convergent/divergent nozzle was cast into the motor tube at the same time. Divergent cone was trued after cement cured. 5/16" washer was again cast into the nozzle.

This was the same rocket and motor type as in launch test 11, only I added an extra bay to the rocket for a wireless video camera. The camera is the X-10. It's compact and runs off a 9 volt battery just fine. I've had the camera/receiver for a couple of years now, and really didn't have a good use for it (other than in a rocket). The picture quality is only fair at best. I did use a different nose cone for this flight, I used a latex covered foam nose. I wanted to lighten the rocket a bit, and hoped the foam would soften the landing if the parachute didn't deploy.

There are two videos here. The first one is the rocket flight from my perspective with a video camera. The second is from the camera in the rocket. If you watch the view from the rocket, you will be able to see me with my camcorder, and in front of me is a tv and vcr with the x-10 receiver on top. I used a power inverter to power the electronics on the ground.

The video from the rocket didn't last very long, and the signal would cut in and out as the rocket spiraled slightly. But it's still interesting. As my luck would have it, the parachute didn't deploy and the rocket crashed into the ground. After this flight I went on to change my deployment initiation. The foam nose cone was destroyed upon impact, and the x-10's antenna was broke, but the rest of the rocket and camera survived.

Click Here for a video of the flight from my camcorder.

Click Here for the in flight recording.

Static Test 13a: Same motor and grain as Launch Test 13.

Launch Test 13:

1" EMT Steel Motor Casing x 9.5" long, 3/8" core, .32" throat. (2) Bates grains 1"x4.75". 65/35 KNSU outside paper inhibited grain.

History:

This motor was built more out of frustration than anything. I'd been trying to buy a used lathe for some months, with no success. Ironically, a number of years ago my father gave away 2 large metal lathes, now I can't buy one for my life. So I went went out to my workshop and just decided I was going to build a motor any way I could.

I found some 1 1/4" steel bar, center drilled it and tapped the hole with 1/4" threads, I then ran a couple of bolts into the tapped holes (the bolts gave me a handle and allowed me to apply pressure while the rod turned against the grinding wheel) and proceeded to turn the diameter to fit the 1" EMT pipe I had, using my bench grinder. I cut off about 1/2" of the rod for an end closure, and about 1" for the nozzle. I then drilled the nozzle convergent and divergent cones using progressively larger drill bits. I then used cone shaped grinding tools to smooth and true the nozzle as much as possible. I just welded the nozzle into the casing, and drilled and tapped the end closure with (4) #10 x 3/8" screws.

I inserted the grains into the motor, and sealed the top closure with a thin bead of high temp RTV. I test fired the motor on my test stand, while the motor burned properly, the video was lost. After firing, the motor inspection revealed no blow by. The paper inhibitor was about 50% intact, the rest charred or gone.

Launch:

Launch conditions were near perfect, clear skies and low winds. In addition to the new motor, this was my first use of my new parachute deployment charge. The flight was flawless, everything worked just as planned. The rocket landed without a scratch within 100' of the launch pad. The video of this flight is poor quality, I used my cheap digital camera that takes up to 9 seconds of video, with no audio. There are three videos:

Click Here for the launch.

Click Here for parachute deployment.

Click Here for landing.

Launch Test 14:

1" EMT Steel Motor Casing x 9.5" long, 3/8" core, .32" throat. (2) Bates grains 1"x4.75". 65/35 KNSU outside paper inhibited grain. This was my first motor/nozzle made on my new metal lathe, it was actually the first piece of metal in the lathe. I didn't intend to make a nozzle, I just started practicing, and ended up with a useable nozzle. While it's not perfect, it was a vast improvement over the drilled nozzle.

Launch:

Launch conditions were again great. Mostly clear skies, wind about 10 mph. This was a perfect flight, everything performed as expected. While the motor was essentially the same as the last flight, this motor used the newly turned nozzle. This flight had a noticeable increase in altitude. I'm theorizing the new nozzle was responsible for the increase in altitude.

Click Here for a good video of the flight from lift off to parachute recovery. Please excuse the expletive from my friend!

Launch Test 15:

1.5" EMT case, 2) 5.5" x 1.51" paper inhibited grains, 65/35 KNSU, .4" dia. throat. This was my first 1.5" motor. While I usually do a static test before a flight, I didn't with this one. My rockets are very inexpensive to build, and a loss of the rocket would not be a big deal. The one aspect of the motor that I was concerned about was the nozzle retention to the case. I used (8) 1/8" steel pop rivets to retain the nozzle. I tried to find the shear strength of these rivets, but was unsuccessful. The top closure has (6) #10-32 x 3/8" steel set screws.

Launch:

Launch conditions were good. 35 degrees F. wind 5 to 8 mph. Rocket was prepped for flight at the launch site. After countdown the motor ignited quickly, shortly after ignition the nozzle retention rivets sheared and the nozzle was ejected from the motor. The burning propellant was ejected before the rocket even left the launch rod. The rocket continued upward for perhaps 200', then rapidly returned to earth with an all too familiar "thud". The motor casing was ejected from the rocket body at apogee and recovered undamaged about 50' from the launch pad. The motor nozzle was recovered intact within 3' of the launch pad. The rocket itself suffered damage to both upper and lower sections. Recovered to fly again were the parachute, upper bulkhead, nose cone, recovery harness and the timer.

Click Here for a good video of a rather short flight.

Launch Test 16:

This is the same motor as launch test 15, with the nozzle attachment modified by using (8) 1 /4" set screws. The top closure remained the same. Grain size and all other aspects of the motor also remained the same. Rocket body was my typical 3" thin wall PVC with 1/2" plywood bulkheads and plastic fins. A change was made to the timer initiation circuit by using a sub mini plug and socket. The pin holds the power circuit open until the pin is pulled, upon pulling of the pin the timer circuit starts. The plug wires are simply tied to the base of the launch platform, when the rocket lifts off, the pin is pulled out and the timing starts. I also included a small PCB mounted buzzer as a warning when the circuit closes.


Launch:

Launch conditions were good. 62 degrees F. wind 6 to 14 mph. Below are some still captures from the launch. The frames are in increments of .033 to .034 seconds each frame. Note the rapid ignition and short time to full thrust. From first sign of the igniter smoke to leaving the launch rod is an incredible .067 seconds.

3.142 Seconds

3.176 Seconds

3.209 Seconds Ignition

3.243 Seconds Thrust

3.276 Lift Off

3.309 Seconds Launch Rod Cleared

3.343 On its way

3.376 A perfect launch... But....

Unfortunately, shortly after liftoff. The top closure in the motor failed and the rocket was violently destroyed. It would seem I will need to lower the Kn somewhat. Either a larger throat diameter or a more neutral Bates grain geometry. The design as is, was progressive. Very few parts of any size were recovered. The parachute had most of the grommets torn out, but is repairable. The nose cone will fly again. The timer was found badly damaged, the 555 IC was gone from the socket. The buzzer and a few parts from the timer may be salvaged. The motor has yet to be recovered. The top closure I'm sure is history, but I hope to still find the motor casing and nozzle. Note in the video you can hear a buzzing after the event, it sounds like a bullet tumbling. I assume the sound was the top closure flying off at a great velocity.

Click Here for the video. Note this is a Divx avi file. Please let me know if you have download problems.

Launch Test 17:

1" EMT Steel Motor Casing x 11" long, 3/8" core, .32" throat. (2) Bates grains 1"x4.75". 65/35 KNSU outside paper inhibited grain. This motor is basically the same 1" motor I have used in previous flights, with a newly machined nozzle and top closure. The motor casing is 1.5 " longer to accommodate a 1.5" smoke grain. The smoke grain was simply a 1.5" length of cpvc pipe with the standard 65/35 propellant mix, and the outside end inhibited (glued with RTV to top closure). The smoke grain seemed less than successful, as the duration of extra smoke was negligible.

Launch:

This launch was conducted immediately following launch test 16, so conditions were the same. The rocket was prepped for flight at the site. I wasn't really sure I was going to launch this rocket, but after the first rocket cato'd, I decided it was too nice of a day not to send a rocket into the clear blue skies. The launch platform was reset, the prior launch had left an impressive divot about 6" deep and over a foot in diameter. Countdown, ignition... the motor lit quickly and the rocket soared skyward at a nice leisurely pace. Parachute deployment occurred as scheduled at 8 seconds. The rocket came down under the inflated chute and landed gently within 100' of my parked van, about 1000' from the launch site. Total time from launch to landing was about 59 seconds.


Click Here for a video of the flight.

Static Test 18:

1" EMT Steel Motor Casing x 9.5" long, 3/8" core, .32" throat. (2) Bates grains 1"x4.75". 65/35 KNSU outside paper inhibited grain. This motor had been flown previously, but the propellant was prepared differently. I tried mixing the KN03 and sugar with water before heating. The KN03 was weighed and added to my electric kettle, then the sugar was weighed and added. About 1/4 of a cup of water was then added, just enough to form a good runny mix. Then the mixture was completely mixed before heat was applied. As heat was applied, the water boiled off quickly, I turned the heat off as soon as it was apparent the water in the mix was gone. In hindsight, I should have continued heating, I don't think the sugar actually ever melted. The propellant was actually thicker than if melted using no water. I went ahead and cast the grains, just to see how they turned out. After the grains cooled, it was apparent there was still some water in them, as they were a bit gooey to touch, and seemed somewhat of a crumbly texture. I placed the grains in my desiccant box for about 3 weeks, after which they were solid and seemed very dry. However, they still seemed porous, and not as solid as a normally cast grain.


Test Firing:

This was the first use of my new test stand. A very windy day, so a great day for static testing. The test stand was set up at my usual remote launch area. 100+ feet of launch control wire was run from my test stand to my bunker (old van) and a video camera was set up near the test stand. Countdown, ignition... whoosh, a very rapid burn of the propellant. Much faster than has been seen in this motor before. Video analysis revealed a burn time of .2 seconds. Much too rapid for an outside inhibited grain. Upon opening the motor, the inhibitor was fine, so the rapid burn rate was more than likely due to fracturing of the grain upon ignition. Stress on the forward closure also elongated the retaining screw holes in the motor casing, very nearly causing a blow out of the forward closure.

Click Here for a short video of the test fire.

Static Test 19:

1.5" EMT case, 2) 5.5" x 1.51" paper inhibited grains, 65/35 KNSU, .42" dia. throat. This is a new build of the motor lost in launch test 16. I'm designating the new motor T2. The only real difference between the first motor, now called T1 and this motor is a slight enlargement of the nozzle from .4" d. to .42" d. and a reworking of the nozzle attachment. Rather than threading directly into the nozzle, I machined a groove for the screws to set in, and just threaded the casing to hold the screws in place. The forward closure now has (8) 10-32 x 3/8" screws rather than six screws on the previous motor. The grains are the same size as the previous motor tests, but the KN03 was not ground to a fine powder before melting/casting. Some members of the SugPro list indicated the propellant was easier to cast if the KN03 was not powdered, so I thought I'd give it a try. The viscosity was marginally better, but open air burn tests of the excess propellant was disturbing. The strands burned at a much reduced rate, leaving a residue post burn that I had not seen before. An e-mail conversation with R. Nakka indicated he also had experimented with the non powdered form of KN03 but was disappointed with the results and terminated his experiments. At any rate I had the grains cast, and would fire them in my new test stand, and compare the results with later tests of the ground KN03.

Test Firing:

This test was conducted immediately after static test 18, so this was to be the second use of my new test stand. If there was one thing I learned from the test, I need to get my video camera closer as it was difficult to read the numbers from the gauge. I did the best I could. After a successful firing of the motor, I analyzed the video for the following results.

While the burn was successful, the Isp was lower than would be expected. The unground KN03 is of course, suspected. Examination of the motor post firing revealed no blow by at either end, and no damage.

Click Here for a video of the test.

Static Test 20:

1.5" EMT case, 2) 5.5" x 1.51" paper inhibited grains, 65/35 KNSU, .42" dia. throat. This is the same motor (T-2) as in static test 19, using the same grain geometry as before, only in this test the propellant was prepared using finely powdered KNO3 instead of the prilled form straight from the bag.

Here are the results of the test:

As you can see when comparing test 19 to test 20, with the only difference being prilled vs. powdered KNO3. The powdered KNO3 specific impulse was slightly higher, the maximum thrust was higher and the burn time less. While I believe my test stand is consistent, I'm still not certain the calibration to actual pounds of thrust is accurate. I would think my Isp should be higher than what I'm getting. In any case, the results should be consistent and will give me a benchmark of performance.

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