You've taken two great steps (for me): minimizing cost, and perfecting PVC rocket motor construction. Not just this video of yours, but several others. More motivation to get a bigger lathe than my micro Sherline.
Really appreciate the comment. BUT this is an old video. If you want to see my newer and MUCH simpler designs, have a look at these videos... ua-cam.com/video/pzK8RQdJTSE/v-deo.html ua-cam.com/video/WrvOPYNQv_g/v-deo.html
Very well thought out process and super clear instructions! I like the clean setup that produces a nice finished product. I don't ever return the pot back to the hot plate but instead put it on a thermal pad. The propellant can run down the outside of the hot pan and into the burner. If you forget to turn off the hot plate and return the pot then that could turn out to be a bad day for everyone. Just my 2 cents.
Yeah, I did screw up a bit there... I usually take it off the hot plate as soon as it reaches temperature and put it on a piece of wood. I was under pressure with making the video and messed up on that one.
Amen to that! I found out the hard way that this can happen. I was using a standard hot plate with exposed burner and casting the propellant grains nearby. A small blob of propellant dropped on the still hot burner and it ignited, throwing another tiny blob of flaming propellant onto the rack where I was casting 4 1" x 2" grains. They ignited, also. Fortunately nothing exploded, nothing else caught on fire and I was in a large outside workshop so no real damage except a bit of charring to the workbench top. And the smoke....! I could not see 4 feet. All of this took place in what seemed like nano seconds and it was all over in less than 30 (spectacular) seconds. Once the fuel grains took off there was nothing in the world that was going to stop it until they were all burned up. I think that even a fire extinguisher would not have helped because the propellant is providing it's OWN oxygen for combustion, not oxygen from the air. Would have been a much different story in a basement or garage workshop lol. Since that happened I now use a double boiler arrangement. I have an electric skillet that I fill with melted candle wax and I put the mixing pan into that. I also use a candy thermometer to monitor the temperature of the wax. There is zero chance of an accidental ignition with this arrangement. It has the additional advantage of allowing you to make very incremental changes in the amount of heat. I am also using Sorbitol instead of sugar and it melts at a much lower temperature, is more stable at that temperature (does not caramelize) and also remains pourable for quite a bit longer. So -- be safe! You are working with extremely flammable and potentially explosive materials and sh*t happens if you're not careful.
If you glue the motor assembly to the nozzle assembly, how can you reuse the nozzle assembly? Great video but not sure I understand how the nozzle assembly can be reused.
Also, if you are looking to build a really easy sugar motor, we will be releasing a new video in about a week that is a complete tutorial for building our newest motor design. It's very easy to build and a lot more powerful than this one.
For this motor, the metal nozzle is re-useable but the PVC case is one time use. The liner helps protect the PVC during the burn. This is an old design... If you're looking to build this type of small PVC motor, we have a simpler design, check out this video: ua-cam.com/video/pzK8RQdJTSE/v-deo.html
When we are developing a new motor, we just mix up a batch of fuel that we know will be more than enough to fill the motor. Then once the motor is filled, you weigh the leftover fuel. So then I know how much it takes to fill that motor and then I can make the correct amount for the next one.
Enjoy your content. My question is.. I've only experienced making disposable sugar rockets with bentonite nozzle ends, it's hard to imagine the extra weight of a steel nozzle and other components added with model rocket and being able to fly? Is the extra power gained from this nozzle? I notice flight differences in disposable stick rockets with merely adding additives to the mix for reports or stars in the end of tube?
The steel nozzle on this is not all that heavy. When we were using this design, it was flying very well with rockets that were 2" diameter x 24 to 30 inches long. It may have worked for rockets a bit larger but we never tried anything bigger. I like building reusable steel nozzles but to be honest, it is simpler to build single use motors & nozzles. As far as power is concerned, it is not the nozzle that is the weak part of the motor. It is the PVC casing and caps. You can only build up pressure until the casing explodes. So that said, metal nozzle vs cement nozzle makes no difference. I have designed two newer motors that use anchoring cement for the nozzle instead of steel. They are super easy to build. Here are the links to the two motors we have been launching recently. ua-cam.com/video/WrvOPYNQv_g/v-deo.html ua-cam.com/video/pzK8RQdJTSE/v-deo.html
When casting a fuel grain (cell), why not build a wooden jig with a hole big enough for the bolt head and put the bolt in first and pour the hot fuel around it?
You are very correct... It would have been better to have the bolt in place or at least pushed into the bottom of the jig before pouring the fuel. I realized that after shooting the video and you can see some fuel coming out at the bottom of the jig while I try to insert the bolt.
Hey mate, Luke - again!!!!! Excellent job, but ill admit I never watched all the tutorials as I dont need to!!!! But........ Im curious what propellant composition your using, as I believe I can head you down abetter path. Without going into detail, "flexi-fuel' ( as in Dan Pollinos recipe ) is excellent for big, single grain, case bonded motors, dont use it for multi bates grain motors. KNDX is by far better. Let me know if u want more info, Luke
I have made one piece, steel nozzles... many many times. It's a LOT more work that what is shown here. That just wasn't the design of the motor in this vid. In fact, I don't even use this method anymore. I have a new motor design that is similar in size to this but uses a really easy to make, single use nozzle. It's both faster and easier to make. Links to the new motor designs are in the description.
@@rotaryrocketry Well I am to poor to own a lathe and would probably get arrested if I got caught with any explosive so I accept it would be more work. It just dont seem like it should to me. And i have watched most of your videos already. the alograthom just put this one in front of me again for some reason. Honestly i have this video downloaded on my computer somewhere for the apocalypse entertainment when the internet goes down.
I would like to give you 2 words to Google to see what you can do with them, tig cup. They are ceramic and designed for gas flow and there is different sizes to choose from. The tube mill at work have one of the largest I have seen and most likely to be best for your motors.
Primer color is not really important on a one-time use rocket motor... But sometimes I use Acetone on PVC craft projects when I don't want purple stains. Sorry, it is not called "welding". Plastic welding involves a hot tool to melt plastics together as seen here: ua-cam.com/video/4DAqwvZoBVk/v-deo.html
No the primer softens and cleans the pipe and cement chemicaly melts the pipe and when u twist its actually smearing the melt together .. welding. Irrigator 30 years
I realize it is chemically melting the plastic parts together but that is not technically "plastic welding" which requires a hot tool. We can agree to disagree on this definition.
Not everyone has a lay!. I have a lot of friends and only a couple of them have a lay. It would be cool if you Show us a way he can do this with out one
True. This was really to show the overall concept. The nozzle work could be done with other tools but the lathe certainly makes it easy. One thought would be to use a "step drill bit" to drill out most of the material in a cone shape and then hand file it smooth. The cast iron piece is really a soft metal that is easy to drill and file.
It's typically called an e-match. They are used to light fireworks. That is then ignited with a remote control. Here are links to the ignitors and the remote control on e-bay: www.ebay.com/itm/334607182774 www.ebay.com/itm/325500694728
So funny story here... First, I will translate the viewers comment to English: "That rocket has the center of mass very far back, so when it comes out, it moves its head." Actually, the rocket design was great. It was designed in OpenRocket and the CG, CP & Stability were all fine. The reason the rocket wobbled when launched was because of a mistake I made when making the nozzle. If you look closely at the video at 10:31 you can see the divergent cone is crooked in the PVC piece. I noticed this too late and it could not be fixed without re-making the nozzle part so I decided to just keep going with this defect. But that is what caused the rocket to wobble when it came off the rod.
Instead of making that "orifice" out of a bolt, could you have just used a 1/4 inch galv bushing? No need to re-tap the reducer threads.........Or do you just like playing with your lathe?
I DO like playing with the lathe :) We are thinking about designing a larger version of this motor in the future so I will look into this "bushing" you refer to.
I love how he casually throws in the list of expensive tools used for this "DIY" project. I'm sure most of us have lathes, bandsaws and tap&die sets laying around. What BS.
O.k... first off... Rude. This is a guide... Modify as needed based on your skills or tools. Second... Here is our newest design that is ridiculously simple to build with no "special" tools. ua-cam.com/video/WrvOPYNQv_g/v-deo.html
I use the tools I have available to me. Also, this is an old design. We have a much simpler motor that needs no special tooling. Link is in description.
You've taken two great steps (for me): minimizing cost, and perfecting PVC rocket motor construction.
Not just this video of yours, but several others.
More motivation to get a bigger lathe than my micro Sherline.
Really appreciate the comment. BUT this is an old video. If you want to see my newer and MUCH simpler designs, have a look at these videos...
ua-cam.com/video/pzK8RQdJTSE/v-deo.html
ua-cam.com/video/WrvOPYNQv_g/v-deo.html
@@rotaryrocketry Thanks, great stuff!
Very well thought out process and super clear instructions! I like the clean setup that produces a nice finished product.
I don't ever return the pot back to the hot plate but instead put it on a thermal pad. The propellant can run down the outside of the hot pan and into the burner. If you forget to turn off the hot plate and return the pot then that could turn out to be a bad day for everyone. Just my 2 cents.
Yeah, I did screw up a bit there... I usually take it off the hot plate as soon as it reaches temperature and put it on a piece of wood. I was under pressure with making the video and messed up on that one.
Amen to that! I found out the hard way that this can happen. I was using a standard hot plate with exposed burner and casting the propellant grains nearby. A small blob of propellant dropped on the still hot burner and it ignited, throwing another tiny blob of flaming propellant onto the rack where I was casting 4 1" x 2" grains. They ignited, also. Fortunately nothing exploded, nothing else caught on fire and I was in a large outside workshop so no real damage except a bit of charring to the workbench top. And the smoke....! I could not see 4 feet. All of this took place in what seemed like nano seconds and it was all over in less than 30 (spectacular) seconds. Once the fuel grains took off there was nothing in the world that was going to stop it until they were all burned up. I think that even a fire extinguisher would not have helped because the propellant is providing it's OWN oxygen for combustion, not oxygen from the air. Would have been a much different story in a basement or garage workshop lol.
Since that happened I now use a double boiler arrangement. I have an electric skillet that I fill with melted candle wax and I put the mixing pan into that. I also use a candy thermometer to monitor the temperature of the wax. There is zero chance of an accidental ignition with this arrangement. It has the additional advantage of allowing you to make very incremental changes in the amount of heat. I am also using Sorbitol instead of sugar and it melts at a much lower temperature, is more stable at that temperature (does not caramelize) and also remains pourable for quite a bit longer.
So -- be safe! You are working with extremely flammable and potentially explosive materials and sh*t happens if you're not careful.
This is a great description of the whole process and very well explained, thanks!
If you glue the motor assembly to the nozzle assembly, how can you reuse the nozzle assembly? Great video but not sure I understand how the nozzle assembly can be reused.
It is not reusable. That's one of the problems with masonry nozzles. Easy to make but it basically gets destroyed during the burn.
14d 1/2 angle u mention at 3:20
so thats set at 14d on the lathe not 7d to get 14 ?
Correct... Lathe is set to 14 degrees. So the total angle from side to side of the nozzle is actually 28 degrees.
Also, if you are looking to build a really easy sugar motor, we will be releasing a new video in about a week that is a complete tutorial for building our newest motor design. It's very easy to build and a lot more powerful than this one.
@@rotaryrocketry sound good thank you for the reply
So is the PVC reusable? Is the cardboard put in the PVC tube so you are able to reuse?
For this motor, the metal nozzle is re-useable but the PVC case is one time use. The liner helps protect the PVC during the burn. This is an old design... If you're looking to build this type of small PVC motor, we have a simpler design, check out this video: ua-cam.com/video/pzK8RQdJTSE/v-deo.html
Caps go on the outside, plugs insert into the bell or socket, and a slip coupling is for repairs, you are using a “coupling “
How did you determine your ratios for the potassium nitrate, sugar, and syrup?
I know you mentioned %, but how did you get the correct grams?
When we are developing a new motor, we just mix up a batch of fuel that we know will be more than enough to fill the motor. Then once the motor is filled, you weigh the leftover fuel. So then I know how much it takes to fill that motor and then I can make the correct amount for the next one.
Enjoy your content. My question is.. I've only experienced making disposable sugar rockets with bentonite nozzle ends, it's hard to imagine the extra weight of a steel nozzle and other components added with model rocket and being able to fly? Is the extra power gained from this nozzle?
I notice flight differences in disposable stick rockets with merely adding additives to the mix for reports or stars in the end of tube?
The steel nozzle on this is not all that heavy. When we were using this design, it was flying very well with rockets that were 2" diameter x 24 to 30 inches long. It may have worked for rockets a bit larger but we never tried anything bigger. I like building reusable steel nozzles but to be honest, it is simpler to build single use motors & nozzles.
As far as power is concerned, it is not the nozzle that is the weak part of the motor. It is the PVC casing and caps. You can only build up pressure until the casing explodes. So that said, metal nozzle vs cement nozzle makes no difference.
I have designed two newer motors that use anchoring cement for the nozzle instead of steel. They are super easy to build. Here are the links to the two motors we have been launching recently.
ua-cam.com/video/WrvOPYNQv_g/v-deo.html
ua-cam.com/video/pzK8RQdJTSE/v-deo.html
When casting a fuel grain (cell), why not build a wooden jig with a hole big enough for the bolt head and put the bolt in first and pour the hot fuel around it?
You are very correct... It would have been better to have the bolt in place or at least pushed into the bottom of the jig before pouring the fuel. I realized that after shooting the video and you can see some fuel coming out at the bottom of the jig while I try to insert the bolt.
@@rotaryrocketry Yup, it's a learning curve! I had to make 3 videos on how to replace the hose in my Shark vacuum - finding better ways as I go.
Ficou muito bom 👏 vou fazer um para testar 🇧🇷
How to make nozzle rocket pcv?
This is an old design... Take a look at the newer one, it is MUCH simpler and probably what you are after. ua-cam.com/video/pzK8RQdJTSE/v-deo.html
Hey mate, Luke - again!!!!! Excellent job, but ill admit I never watched all the tutorials as I dont need to!!!! But........ Im curious what propellant composition your using, as I believe I can head you down abetter path. Without going into detail, "flexi-fuel' ( as in Dan Pollinos recipe ) is excellent for big, single grain, case bonded motors, dont use it for multi bates grain motors. KNDX is by far better. Let me know if u want more info, Luke
If you have a lathe why not make the nozzle all out of one piece?
I have made one piece, steel nozzles... many many times. It's a LOT more work that what is shown here. That just wasn't the design of the motor in this vid. In fact, I don't even use this method anymore. I have a new motor design that is similar in size to this but uses a really easy to make, single use nozzle. It's both faster and easier to make. Links to the new motor designs are in the description.
@@rotaryrocketry Well I am to poor to own a lathe and would probably get arrested if I got caught with any explosive so I accept it would be more work. It just dont seem like it should to me. And i have watched most of your videos already. the alograthom just put this one in front of me again for some reason. Honestly i have this video downloaded on my computer somewhere for the apocalypse entertainment when the internet goes down.
What if you don’t have a lathe ?
This one is nearly identical in size and MUCH simpler to build...
ua-cam.com/video/pzK8RQdJTSE/v-deo.html
I would like to give you 2 words to Google to see what you can do with them, tig cup.
They are ceramic and designed for gas flow and there is different sizes to choose from. The tube mill at work have one of the largest I have seen and most likely to be best for your motors.
thanks im making a 20 ft version of that with multi stage boosters
Yikes... Good luck!
Love it!
Couldnt you have used clear primer and its welding the pvc not glueing
Primer color is not really important on a one-time use rocket motor... But sometimes I use Acetone on PVC craft projects when I don't want purple stains.
Sorry, it is not called "welding". Plastic welding involves a hot tool to melt plastics together as seen here:
ua-cam.com/video/4DAqwvZoBVk/v-deo.html
No the primer softens and cleans the pipe and cement chemicaly melts the pipe and when u twist its actually smearing the melt together .. welding. Irrigator 30 years
So like an igniter . Does it need to be all the way in like composite motors or just in like in black powder motors
Then why was it important to use clear cement. Cristies red hot ensures a sure weld
I realize it is chemically melting the plastic parts together but that is not technically "plastic welding" which requires a hot tool. We can agree to disagree on this definition.
Not everyone has a lay!. I have a lot of friends and only a couple of them have a lay. It would be cool if you Show us a way he can do this with out one
True. This was really to show the overall concept. The nozzle work could be done with other tools but the lathe certainly makes it easy. One thought would be to use a "step drill bit" to drill out most of the material in a cone shape and then hand file it smooth. The cast iron piece is really a soft metal that is easy to drill and file.
So you can only use the motor casing once?
Yes. PVC case motors can only be used once. They are inexpensive to build.
How did u ignite it
It's typically called an e-match. They are used to light fireworks. That is then ignited with a remote control.
Here are links to the ignitors and the remote control on e-bay:
www.ebay.com/itm/334607182774
www.ebay.com/itm/325500694728
ese cohete tiene el centro de masa muy atrás por eso cuando sale mueve la cabeza
So funny story here... First, I will translate the viewers comment to English:
"That rocket has the center of mass very far back, so when it comes out, it moves its head."
Actually, the rocket design was great. It was designed in OpenRocket and the CG, CP & Stability were all fine. The reason the rocket wobbled when launched was because of a mistake I made when making the nozzle. If you look closely at the video at 10:31 you can see the divergent cone is crooked in the PVC piece. I noticed this too late and it could not be fixed without re-making the nozzle part so I decided to just keep going with this defect. But that is what caused the rocket to wobble when it came off the rod.
Instead of making that "orifice" out of a bolt, could you have just used a 1/4 inch galv bushing? No need to re-tap the reducer threads.........Or do you just like playing with your lathe?
I DO like playing with the lathe :)
We are thinking about designing a larger version of this motor in the future so I will look into this "bushing" you refer to.
@@rotaryrocketry Sorekarain part# CZC06315 available on Amazon . Sometimes called a reducing bushing, or reducer or bushing
Not everybody has a lathe
I don't have a lathe either. Look at the process and adapt it to your situation or tools. There is always more than one way to do things.
And that is why I like "The Rocketeer" :)
look into a makers space or mens shed to use tools u dont own :)
Nice
I love how he casually throws in the list of expensive tools used for this "DIY" project. I'm sure most of us have lathes, bandsaws and tap&die sets laying around. What BS.
O.k... first off... Rude. This is a guide... Modify as needed based on your skills or tools.
Second... Here is our newest design that is ridiculously simple to build with no "special" tools.
ua-cam.com/video/WrvOPYNQv_g/v-deo.html
Can you say overkill? When you are busting out the metal lathe for a rocket motor, you really have way too much time on your hands.
I use the tools I have available to me. Also, this is an old design. We have a much simpler motor that needs no special tooling. Link is in description.