I finally launched my rocket with your nozzle design!!!! Was just on a bamboo stick and 6in long 2in pvc to a reducer and that thing ripped. I have never made a sugar rocket that was that loud.
For a better nozzle, use a set of Estes nose cones. The ones that go on the minimum diameter D motor are the ones. They come in two lengths and shapes. The inside one is a short nose cone, while the divergent is the long one. They come in parabolic/ogive and cone. You'll be able to build a supersonic c/d nozzle just as easily as you build this one.
So, I've been brainstorming and experimenting a bit with nozzles, since it's the second most important part of the rocket. I've found that plastic eggs are the perfect size and shape for casting these. The longer end for the divergent, and the shorter end for convergent. You have to use an end piece without the lip, but with the right casting material, that shouldn't cause a blow out with the right throat size.
I wanna thank you, this helped me alot by making a proper nozzle for my smaller E/F motors, i used fireproof concrete, and it really can take alot of pressure!! Thanks!!
Thanks for the compliment! I am considering going to a machine shop and having them fabricate a 2 piece mould for me. That would take at tremendous amount of guess work and inconsistancies out of the process.
Now I understand what you are talking about. Ok, no disagreements from me on this. I have had a few rockets go super-sonic but I used a different casting design than what I have here. As I stated in the video a year ago, it is not the intention to get these rockets super-sonic, as I do not have a launch area where such a rocket could ever be recovered. For the most part - you are correct...aiming for a constant super-sonic results is too technical for what I do.
enjoy your video presentations. I am accumulating products to begin building rocket engines. I have collected some 1/4 inch thick rigid cardboard (laminate) cylinders 4 inch diameter 12 inches in length. I have some some stoneware modeling clay (cone 10) that I plan to mold the motor around a 4 inch cone-shaped funnel and a stainless steel bell-shape (hip flask funnel) for the nozzle which will remain in the motor when it is kiln-fired. Going to add Fe2O3 and Al powder to the KnO3 + sugar.
I filled the top of the mold with putty previous to using it as the mold so it would not get stuck. Even at that, I have to use a pair of pliars to pull the mould out as the putty/concrete mixture does grab the pours in the mould. It isn't always easy!
This one I believe is 5/16 inch. It is designed specifically for a 4 BATES Grains motor. You could use a 3/8 Inch as well. 8MM would be a near-equivalent.
Control the depth of the throat by building the nozzle in 2 stages...should be about 1/2 inch deep. You can put a mark on your nozzle mould to accomplish this.
Hi Walrus: Carmelization of the Fuel is a result of both Time AND Temperature. Given the amount of time it takes to properly cook recrystallized fuel, I would not worry about a yellow color or tint unless your fuel performance is suffering negatively during burn rate tests. Let me know - I'd be interested to know what test results reveal. Recrystallized should be burning around 7-8 seconds per linear inch.
I can only vouch for what I've used. I can tell you that most people find that when they come up with a "good" idea, they find out the same thing I have: Many things can sustain it's shape under intense heat - but combine heat and high pressure and it will be a different story.
To simplify this process take a 3/4 ich piece of pvc pipe, cut it to about 4 inches long.2. purchase some of the cone shaped disposable drinking cups.3. place cone inside one end of the pvc. (about one inch)4. hot glue the cup to the pvc pipe with cone end inside pipe.5. mix Durams water puddy and pour it or push it into the other side of the pipe.6. when its dry remove cup and drill a 1/4 inch hole through the center of the new coned nozzle.7. Add rocket mix solid or powder then pack benite clay at end. - glue to a stick, insert fuse and fire away. cost about 5 cents per rocket
To easily center your nozzle... We will make a simple and inexpensive tool. Get a dowel that will slide easily in and out of that funnel. Next...Cut a thick wood disk (3/4" plywood) that has the interior diameter of the PVC casing. Sand the edges so that it slides in and out easily. Drill a hole in the center of that disk that the dowel will snugly fit inside. Use a drill press as you must have this hole perpendicular. Make the appropriate height measurement and glue that dowel to the disk. Using the tool which you fabricated it is now easy. Slide that tool into the PVC pipe and fit the funnel on the other end. Then anchor that funnel with tape Then remove the tool. Then add your Ready Mix. Perfect and consistent centering each and every time.
it is an excel spread sheet that calculates Initial, Maximum and Final know of your motor taking into consideration the BATES grain configuration, core diameter and nozzle throat diameter.
Hi WizzBang75, Love this and I am anticipating the rest and all of your ‘Scratch’ built rockets and the fuels. It shows that with just some common sense and basic engineering and science knowledge and the ways you think about what might work and by trial and error what you make work to give a great and really interesting hobby which you can say "I did it all!" I have subbed and look forward to viewing your other videos thank you. Take care!!!!!!!!!!!!!!!!!! mrbluenun
Subsonic flow increases in velocity as the path converges. But once it hits sonic speed, the opposite happens: the flow becomes choked and so a further decrease in diameter for sonic flow will DECREASE the flow velocity. To INCREASE from sonic to SUPERSONIC, the diameter needs to diverge, but ONLY after the flow has reached exactly sonic speed at the throat. To find the proper sonic area you would need to know the ratio between the pressure inside booster and ambient pressure.
I think I want to try a massive nozzle about the size of a lamp...and then take it from there. Any advice on making a welded motor casing made from high quality metal? Light and sturdy? This baby is going to probably never be seen again though because I might not want to get caught with that kind of rocket. Better to just wear gloved hands and kiss it goodbye. Someone will report the findings so it will save me a lot of research time as well.
I do not use ratios like that. I base my nozzle upon the length and diameter of the BATES Grains and the length of the motor. If you know these variable, I can provide you with an optimized nozzle size for your motor.
If you don't reach sonic speed at the throat, the divergent section of your nozzle will REDUCE the exit velocity, hence why I suggested maybe just doing a convergent that cuts off maybe right before or right at sonic flow. Getting a supersonic exit velocity may be too technical for your methods?? I'm not sure. I'd like to see what anyone else has to say about it.
Was wondering how long you left the mold in before removing? I see you mentioned that you had to use pliers in order to remove the mold and was hoping to make that part of the process easier. Enjoyed this series of videos, thanks for sharing them.
hi Which Wabbit....I have been able to take the mold out in as little as 10 minutes...sometimes I have to wait over night. Depends on the temperature and humidity or lack of humidity in the environment.
beefy172, those are really good question! If my thinking is right, a higher pressure would be built up using the convergent I have resulting in more power than no convergent at all, but I could be very wrong about this. Is my divergent narrow enough to reduce power? I'm not sure. I do not have the gear to make an accurate test stand, so I look to the results for success' or failures. I am sure there are many ways to improve upon what I do - but by the time I do that, I'll be buying a lathe!
Hi WizzBang, I have a problem. I use Jimmy Yawn's method of cooking rocket candy. However, when I am at the liquid stage of the fuel, it is already yellow. I thought it may be because of impure fertilizer grade kn03 so i switched to "technical grade" kno3 from skylighter. This still resulted in yellow rocket fuel. I don't I am burning the fuel because I have had white batches of fuel in the past and I believe my fuel cooking technique has improved since then. Thanks!
Also...have you thought about scaling up the rocket? Just make all the parts three times as big? What results could one expect from scaling up...pro's and con's?
Sounds like a lot of fun my friend, but I'd really discourage based upon the old addage that most fun things are either ILLEGAL, fattening or immoral :) As far as welding goes....closest i've ever come to that is JB Weld...sorry.
So please don't mistake me for being rude or anything, but can I ask why you are doing a convergent/divergent nozzle if it isn't supersonic? (referring to your comment at 1:59.) The divergent would slow down the flow at the exit, reducing power. Is this just for a more legit look? If you were going for power it would be better to just do a convergent nozzle and cut it before (or right at) the supersonic throat diameter.
hey i dont have that brand of cement you used, could i use a similar fibreglass putty stuff as a replacment, fibreglass iis strong and very heat resistant ?
It seems as though this part 1 is a follow-up to a previous video? The convergent and divergent parts of the rocket engine have already been built using... (looks like some sort of filler).
how heavy are your nozzles? you seem to use A LOT of cement... my nozzles work out to be approx 50% of my fuelled rocket weight so im looking to bring that down...
I was wondering about adding pearlite or vermiculite to the mix. It would bring the weight down. Try a 50/50 mix and see how it holds up. I'm looking at refractory cements. Staying away from pvc motor casings though.
3:22 you also may want to use Hydraulic Cement (used for in ground pools) or Something called 'Fibercoat" which has little hairs of Fiberglass Embedded in the mix. Makes you want to ask me "How do I know that?" I cannot divulge. :)
Bastiaan Kolster YES you need fins and a launch rod. perhaps not a proper launch pad though. something solid to put a rod into. concrete drilled, or.wood (heavy) with nuts washers and bolts. but you need a strong 1/4" stainless steel rod either way. around 4 ft long. or a launch rail. and ALWAYS fins!
Fer crying out loud... if you want to make a cone of a specific angle, or a diverging nozzle with a proper bell... all you have to do is rig a SCREED that pivots around a vertical rod that has the profile you want cut in a thin piece of sheet tin. Make one for the converging side and another for the diverging profile. Mix some PLASTER... and as it gets thicker, pile it up around the vertical rod and use the revolving screed template to shape the plaster to the contour you want. You can mix more plaster as the first batch sets and fill in any dips or gaps, until the profile is as perfect as the cutting edge of your template. Add a separation agent to the surface of the set plaster and that’s the FORM for casting your supersonic nozzle. Easy and cheap and perfectly accurate.
Divergent part visually looks too short, shorter than minimum length nozzle, it means that initial divergent angle is too large resulting shock losses. I just eyeballed it, so I may be wrong.
The part about supersonic nozzle is weird. The nozzle is definitely supersonic, the angles dont matter that much, you only loose some efficiency. I am little concerned about your expansion ratio (throat/nozzle exit area ratio). With high chamber pressure it would be good, but our rockets operate at low pressure, and ideal diameter of nozzle exit is about 2 times the throat diameter (thats 1:4 area ratio). 1:3 diameter ratio is too much, nozzle gets seriously overexpanded, and your ratio seems even more. But otherwise I like your building techniques very much!
This is a very nice series and it looks to me he does a good job explaining everything. Unfortunately, he does not ever state or say what specific PVC sizes he's using, nor does he give a size for the fender washer. These are usually the very FIRST things you want to state right up front, the materials list. This isn't listed so you'll have to eyeball all the materials used and make an educated guess. Not particularly a very elegant way of doing it and kinda of a waste of time. If you're going to do a multi-part tutorial on YT, please DO make EVERY effort on putting up a materials list so everyone can go out get the right stuff the first time and not have to guess about it. Just common sense.
Thanks for the feedback. I did not list those simply because I did not want to be responsible for someone who failed to do their own research on pressure calculations. Hope this helps... later in the series I get very specific about the PVC diameter size and throat diameter. For example: on a 2 Bates Grain motor using 1.25 inch PVC I used a 1/4 inch washer. On a 7 Bates Grain motor I used 7/16 inch washer. I had a Bates Grain calculator that enabled me to enter the number of grains, their width and length so I could keep pressures within safety margins. Hope this helps. Have fun!
Dude the throat diameter is 5/16th but you said you use a 1/4 or 3/4 washer? Why not use a 5/16th washer...I don't get it. What's the purpose of the washer if you have to drill through it if its too small...or defeat the purpose of it being there if it is too big. Once and for all...DOES THE WASHER HAVE TO MATCH THE NOZZLE DIAMETER. I don't want to know what you used on other rockets. I'm making this one and I don't want to get blown up or waste money doing it.
Hi Gary, this video was made a long time ago, I can't remember the exact diameter of the nozzle or throat...but you should make your determination based on the washer..that is your throat diameter.
WizzBang75 I think you have a 5/16th washer and throat diameter....and your grain core is 3/8ths. I will be building this rocket with 4 bates grains. Does that sound good? I hope so because that's what Ill be building based on this tutorial. I think Ill test this design with stick stabilization.
I have made many motors with 5/16 inch nozzle and 4 BATES grains. This is pushing the safety margin, so stick to the formula and do not put in any catalyst such as Red Iron Oxide.
So I've been making these sugar rocket motors for a few months now, and the ones which don't explode, will strobe shortly after ignition and restart the burn a couple of times. Does anyone know how to stop this from happening?
These motors are doing that??? If that us the case the throat diameter of your nozzles I'd way too small or you have air pockets in your fuel. If it is strobing then something is off with your fuel ratios.
Is your fuel packed tightly because when they sputter, or even explode, it's because there's an air pocket somewhere in your fuel. As long as it's packed very tightly there won't be any air pockets and it will be a smooth consistent burn.
been making it the same way as is in every video I see, using the same tools, made of the same stuff. I'm as careful as I can be so as to not have pockets.
Pity you didn't display this in metric units. There are only 3 countries in the world which don't use the metric system - US and for good company, Liberia and Burma! That's a total of only 5% of the world population...
And still the world is riding on the USA and it economy even when we use such barbaric measuring systems. As far as the other two the are just trying to mimic what has been successful up till now. The USA id slowly switching the tooling over to metric though. After that you will be able to finally build this guys nozzles allowing you to get involved in rocketry after all this time.
Make a six inch rocket (diameter)...bout 5 ft long attached to a heavy wooden pole for stabilization. Call Guinness book and make some cash on worlds largest bottle rocket...by product worlds largest beer bottle. I want a couple hundred for the original idea.
I finally launched my rocket with your nozzle design!!!! Was just on a bamboo stick and 6in long 2in pvc to a reducer and that thing ripped. I have never made a sugar rocket that was that loud.
Congrats and be SAFE!
Can you make a video on how you made that rocket?
For a better nozzle, use a set of Estes nose cones. The ones that go on the minimum diameter D motor are the ones. They come in two lengths and shapes. The inside one is a short nose cone, while the divergent is the long one. They come in parabolic/ogive and cone. You'll be able to build a supersonic c/d nozzle just as easily as you build this one.
So, I've been brainstorming and experimenting a bit with nozzles, since it's the second most important part of the rocket. I've found that plastic eggs are the perfect size and shape for casting these. The longer end for the divergent, and the shorter end for convergent. You have to use an end piece without the lip, but with the right casting material, that shouldn't cause a blow out with the right throat size.
I wanna thank you, this helped me alot by making a proper nozzle for my smaller E/F motors, i used fireproof concrete, and it really can take alot of pressure!! Thanks!!
Great work!
And well explained
thanks
Thanks for the compliment! I am considering going to a machine shop and having them fabricate a 2 piece mould for me. That would take at tremendous amount of guess work and inconsistancies out of the process.
Now I understand what you are talking about. Ok, no disagreements from me on this. I have had a few rockets go super-sonic but I used a different casting design than what I have here. As I stated in the video a year ago, it is not the intention to get these rockets super-sonic, as I do not have a launch area where such a rocket could ever be recovered. For the most part - you are correct...aiming for a constant super-sonic results is too technical for what I do.
I enjoyed all of your vids good job. What would really tie it all together tho, for a few reasons, is a detailed Materials list in your description.
Nice job on the nozzle and great instructional video!!!!
enjoy your video presentations. I am accumulating products to begin building rocket engines. I have collected some 1/4 inch thick rigid cardboard (laminate) cylinders 4 inch diameter 12 inches in length. I have some some stoneware modeling clay (cone 10) that I plan to mold the motor around a 4 inch cone-shaped funnel and a stainless steel bell-shape (hip flask funnel) for the nozzle which will remain in the motor when it is kiln-fired. Going to add Fe2O3 and Al powder to the KnO3 + sugar.
Love how you refer the Water Putty as CONCRETE
He also said it's a mixer...putty/Quikrete. So it's correct.
I filled the top of the mold with putty previous to using it as the mold so it would not get stuck. Even at that, I have to use a pair of pliars to pull the mould out as the putty/concrete mixture does grab the pours in the mould. It isn't always easy!
This one I believe is 5/16 inch. It is designed specifically for a 4 BATES Grains motor. You could use a 3/8 Inch as well. 8MM would be a near-equivalent.
Hi, could you post all the materials that you use for all the rocket? THANKS!
Control the depth of the throat by building the nozzle in 2 stages...should be about 1/2 inch deep. You can put a mark on your nozzle mould to accomplish this.
Hi Walrus: Carmelization of the Fuel is a result of both Time AND Temperature. Given the amount of time it takes to properly cook recrystallized fuel, I would not worry about a yellow color or tint unless your fuel performance is suffering negatively during burn rate tests. Let me know - I'd be interested to know what test results reveal. Recrystallized should be burning around 7-8 seconds per linear inch.
For the lower end of the mold I would use a piece of maple and turn it on a lathe. you could get exactly what you want
Thanks for the video! I enjoyed it.
What size pvc bushing and coupling did you use?
The funnel itself is just plastic. The Mixture is roughly a 50/50 mix of quickcrete and water putty with a steel washer to maintain throat diameter.
Design one to be 3D printed out of Ceramic from Shapeways. It's like 18 cents per cm^2.
I can only vouch for what I've used. I can tell you that most people find that when they come up with a "good" idea, they find out the same thing I have: Many things can sustain it's shape under intense heat - but combine heat and high pressure and it will be a different story.
I made these motors from plans I found at Richard Nakka's website. Turned out awesome, and we had almost no tools.
To simplify this process take a 3/4 ich piece of pvc pipe, cut it to about 4 inches long.2. purchase some of the cone shaped disposable drinking cups.3. place cone inside one end of the pvc. (about one inch)4. hot glue the cup to the pvc pipe with cone end inside pipe.5. mix Durams water puddy and pour it or push it into the other side of the pipe.6. when its dry remove cup and drill a 1/4 inch hole through the center of the new coned nozzle.7. Add rocket mix solid or powder then pack benite clay at end. - glue to a stick, insert fuse and fire away. cost about 5 cents per rocket
To easily center your nozzle...
We will make a simple and inexpensive tool.
Get a dowel that will slide easily in and out of that funnel.
Next...Cut a thick wood disk (3/4" plywood) that has the interior diameter of the PVC casing. Sand the edges so that it slides in and out easily.
Drill a hole in the center of that disk that the dowel will snugly fit inside. Use a drill press as you must have this hole perpendicular.
Make the appropriate height measurement and glue that dowel to the disk.
Using the tool which you fabricated it is now easy.
Slide that tool into the PVC pipe and fit the funnel on the other end.
Then anchor that funnel with tape
Then remove the tool.
Then add your Ready Mix.
Perfect and consistent centering each and every time.
Depends on the motor size and the results I am looking to achieve. I' ve used as little as 1/4" and as large as 3/4".
it is an excel spread sheet that calculates Initial, Maximum and Final know of your motor taking into consideration the BATES grain configuration, core diameter and nozzle throat diameter.
to get rid of the air bubbles, use a vibrator with a small stiff stick on the end.
Hi WizzBang75,
Love this and I am anticipating the rest and all of your ‘Scratch’ built rockets and the fuels. It shows that with just some common sense and basic engineering and science knowledge and the ways you think about what might work and by trial and error what you make work to give a great and really interesting hobby which you can say "I did it all!"
I have subbed and look forward to viewing your other videos thank you.
Take care!!!!!!!!!!!!!!!!!!
mrbluenun
Subsonic flow increases in velocity as the path converges. But once it hits sonic speed, the opposite happens: the flow becomes choked and so a further decrease in diameter for sonic flow will DECREASE the flow velocity. To INCREASE from sonic to SUPERSONIC, the diameter needs to diverge, but ONLY after the flow has reached exactly sonic speed at the throat. To find the proper sonic area you would need to know the ratio between the pressure inside booster and ambient pressure.
Happy to be your #200 thumbs up....bravo!!!
Ok, thanks for the advise!
I think I want to try a massive nozzle about the size of a lamp...and then take it from there. Any advice on making a welded motor casing made from high quality metal? Light and sturdy?
This baby is going to probably never be seen again though because I might not want to get caught with that kind of rocket. Better to just wear gloved hands and kiss it goodbye. Someone will report the findings so it will save me a lot of research time as well.
I do not use ratios like that. I base my nozzle upon the length and diameter of the BATES Grains and the length of the motor. If you know these variable, I can provide you with an optimized nozzle size for your motor.
If you don't reach sonic speed at the throat, the divergent section of your nozzle will REDUCE the exit velocity, hence why I suggested maybe just doing a convergent that cuts off maybe right before or right at sonic flow. Getting a supersonic exit velocity may be too technical for your methods?? I'm not sure. I'd like to see what anyone else has to say about it.
Was wondering how long you left the mold in before removing? I see you mentioned that you had to use pliers in order to remove the mold and was hoping to make that part of the process easier. Enjoyed this series of videos, thanks for sharing them.
hi Which Wabbit....I have been able to take the mold out in as little as 10 minutes...sometimes I have to wait over night. Depends on the temperature and humidity or lack of humidity in the environment.
beefy172, those are really good question! If my thinking is right, a higher pressure would be built up using the convergent I have resulting in more power than no convergent at all, but I could be very wrong about this. Is my divergent narrow enough to reduce power? I'm not sure. I do not have the gear to make an accurate test stand, so I look to the results for success' or failures. I am sure there are many ways to improve upon what I do - but by the time I do that, I'll be buying a lathe!
I used a chopped down funnel bought from a local grocery store.
Hi WizzBang, I have a problem. I use Jimmy Yawn's method of cooking rocket candy. However, when I am at the liquid stage of the fuel, it is already yellow. I thought it may be because of impure fertilizer grade kn03 so i switched to "technical grade" kno3 from skylighter. This still resulted in yellow rocket fuel. I don't I am burning the fuel because I have had white batches of fuel in the past and I believe my fuel cooking technique has improved since then. Thanks!
Also...have you thought about scaling up the rocket? Just make all the parts three times as big? What results could one expect from scaling up...pro's and con's?
thought, perhaps use powder perlite in the mix to decrease weight.
Lowes or Home Depot sell it in small quantities. Just have to make sure you are not buying the stuff that has rocks in it.
Sounds like a lot of fun my friend, but I'd really discourage based upon the old addage that most fun things are either ILLEGAL, fattening or immoral :) As far as welding goes....closest i've ever come to that is JB Weld...sorry.
So please don't mistake me for being rude or anything, but can I ask why you are doing a convergent/divergent nozzle if it isn't supersonic? (referring to your comment at 1:59.) The divergent would slow down the flow at the exit, reducing power. Is this just for a more legit look? If you were going for power it would be better to just do a convergent nozzle and cut it before (or right at) the supersonic throat diameter.
So the washer is between the two layers of putty you put in by the throat? Also, how did you control the length the throat would be?
Hi Abbot, I do not have a blueprint, just what you see here...the combination of 6 pvc components to make the build.
3 Times the Cost/3 times the damage in the event of failure.
hey i dont have that brand of cement you used, could i use a similar fibreglass putty stuff as a replacment, fibreglass iis strong and very heat resistant ?
Will the mold not form with the drying Water putty that you just put in though?
Could you make a mold for the perfect converging nozzle
I wonder if coating the core (i.e., funnel) with vaseline would function as a release agent...
what class engine is that and can you use that for an o class rocket engine. please respond and how do you attach a booster to a rocket
Haha. I know. But I meant what is is actually made of?
It seems as though this part 1 is a follow-up to a previous video? The convergent and divergent parts of the rocket engine have already been built using... (looks like some sort of filler).
Is there a simpler bates grain calculator than the one in excel form?
If you have a lot of pressure ,could we us 80 grade pvc
can you pleas tell me which cemicals do you use? My english knowledge is not the best i couldnt understand you and whats the washer for?!
Hey Wizzbang. Great video. Just one question. What did you use to make the mold for the divergent?
Can you send me a blueprint design of the entire rocket engine? I love your design!
What size threads for the aft end of the bushing? I'm guessing 1" NPT
how heavy are your nozzles? you seem to use A LOT of cement... my nozzles work out to be approx 50% of my fuelled rocket weight so im looking to bring that down...
I was wondering about adding pearlite or vermiculite to the mix. It would bring the weight down. Try a 50/50 mix and see how it holds up. I'm looking at refractory cements. Staying away from pvc motor casings though.
3:22 you also may want to use Hydraulic Cement (used for in ground pools) or Something called 'Fibercoat" which has little hairs of Fiberglass Embedded in the mix. Makes you want to ask me "How do I know that?" I cannot divulge. :)
and go a 50/50 Mix with the water putty.
How does concrete nozzle look after the use? Does concrete actually stay there? Do you see lots of cracks or erosion?
No cracks, ever. Plenty of erosion though.
Tank you, great videos, very detailed. Do you have video or pictures with used concrete nozzle?
please, please post a materials list. Thanks
Do you think a stabilising stick is good enough for a high power rocket? or do you really need fins and a launchpad?
Bastiaan Kolster YES you need fins and a launch rod. perhaps not a proper launch pad though. something solid to put a rod into. concrete drilled, or.wood (heavy) with nuts washers and bolts. but you need a strong 1/4" stainless steel rod either way. around 4 ft long. or a launch rail. and ALWAYS fins!
I have not done much work with just sticks, so I don't really know.
Yes ive done this same motor with a stick just make sure its long enough.
Fer crying out loud... if you want to make a cone of a specific angle, or a diverging nozzle with a proper bell... all you have to do is rig a SCREED that pivots around a vertical rod that has the profile you want cut in a thin piece of sheet tin. Make one for the converging side and another for the diverging profile.
Mix some PLASTER... and as it gets thicker, pile it up around the vertical rod and use the revolving screed template to shape the plaster to the contour you want. You can mix more plaster as the first batch sets and fill in any dips or gaps, until the profile is as perfect as the cutting edge of your template. Add a separation agent to the surface of the set plaster and that’s the FORM for casting your supersonic nozzle. Easy and cheap and perfectly accurate.
So what size washer do we use!!!!
What the proportion of the throat to motor diameter?
what is a bate gran coucluater
Imagine getting to orbit with one of these
Like, geostationary orbit
where can i buy the concrete in small scale.?
Can you please reply to this with a list of EVERYTHING exactly that i need to make this?
Divergent part visually looks too short, shorter than minimum length nozzle, it means that initial divergent angle is too large resulting shock losses. I just eyeballed it, so I may be wrong.
It isn't perfect, not by a long shot. Having said that, i've never been disappointed in the power these motors produce.
The part about supersonic nozzle is weird. The nozzle is definitely supersonic, the angles dont matter that much, you only loose some efficiency.
I am little concerned about your expansion ratio (throat/nozzle exit area ratio). With high chamber pressure it would be good, but our rockets operate at low pressure, and ideal diameter of nozzle exit is about 2 times the throat diameter (thats 1:4 area ratio). 1:3 diameter ratio is too much, nozzle gets seriously overexpanded, and your ratio seems even more.
But otherwise I like your building techniques very much!
where did you get that funnel, I can't find any that are small enough
Max Weinreb
Try looking in a craft store.
thanks.. :D
What size washer did you use?
7/16
Were did you buy that PVC stuff?
Lowe's
please post all materials used a sits my school project........
Your PVC Bushing is not sold at my local home depot, where do I go?
+Espresso Emperor I go to LOWES
thanks
Does anyone ever build liquid Fuel motors for High Power Rocketry?
Part 2 will come out some time this week - It will be the completion of the nozzles (removal from molds) and cooking/casting fuel.
Can i use grey portland cement powder with dr fixit 301urp liquid to make mixture for noozle..please please tell i am working on project.
@@AnkitSharma-qb8mi Portland cement is fine with water. The other stuff, I don't know
Would'nt these melt?
Knut Storoygard no it’s only firing for short periods of time
Does anyone know the diameter of the hole in the washer?
+Alex Knight looks like 3/8ths of an inch
will this fit a 38mm motor housing?
James Smallwood you will have to find pieces of pvc that will. This design will work for L Class motors.
does anybody have a schematic for a perfectly ideal high power nozzle as I have access to a 3d printer and CAD software
can your 3d printer make a lathe?
You are all going to blow your self up!
Most definitely, I highly doubt that he's even certified
Weebo wobbo Just cause your not certified dose not mean you don't know what your doing.
This is a very nice series and it looks to me he does a good job explaining everything. Unfortunately, he does not ever state or say what specific PVC sizes he's using, nor does he give a size for the fender washer. These are usually the very FIRST things you want to state right up front, the materials list. This isn't listed so you'll have to eyeball all the materials used and make an educated guess. Not particularly a very elegant way of doing it and kinda of a waste of time. If you're going to do a multi-part tutorial on YT, please DO make EVERY effort on putting up a materials list so everyone can go out get the right stuff the first time and not have to guess about it. Just common sense.
Thanks for the feedback. I did not list those simply because I did not want to be responsible for someone who failed to do their own research on pressure calculations. Hope this helps... later in the series I get very specific about the PVC diameter size and throat diameter. For example: on a 2 Bates Grain motor using 1.25 inch PVC I used a 1/4 inch washer. On a 7 Bates Grain motor I used 7/16 inch washer. I had a Bates Grain calculator that enabled me to enter the number of grains, their width and length so I could keep pressures within safety margins. Hope this helps. Have fun!
Do I need FAA permission to fly this?
Nah, nozzles don't fly very far when you tape them down like he did.
Loc pham Google it
is this rocket reusable
No.
The nozzle is not re-usable.
Instead of 40 grade pvc
Dude the throat diameter is 5/16th but you said you use a 1/4 or 3/4 washer? Why not use a 5/16th washer...I don't get it. What's the purpose of the washer if you have to drill through it if its too small...or defeat the purpose of it being there if it is too big. Once and for all...DOES THE WASHER HAVE TO MATCH THE NOZZLE DIAMETER. I don't want to know what you used on other rockets. I'm making this one and I don't want to get blown up or waste money doing it.
Hi Gary, this video was made a long time ago, I can't remember the exact diameter of the nozzle or throat...but you should make your determination based on the washer..that is your throat diameter.
WizzBang75
I think you have a 5/16th washer and throat diameter....and your grain core is 3/8ths. I will be building this rocket with 4 bates grains. Does that sound good? I hope so because that's what Ill be building based on this tutorial. I think Ill test this design with stick stabilization.
I have made many motors with 5/16 inch nozzle and 4 BATES grains. This is pushing the safety margin, so stick to the formula and do not put in any catalyst such as Red Iron Oxide.
ok thanks!
So I've been making these sugar rocket motors for a few months now, and the ones which don't explode, will strobe shortly after ignition and restart the burn a couple of times. Does anyone know how to stop this from happening?
These motors are doing that??? If that us the case the throat diameter of your nozzles I'd way too small or you have air pockets in your fuel. If it is strobing then something is off with your fuel ratios.
Is your fuel packed tightly because when they sputter, or even explode, it's because there's an air pocket somewhere in your fuel. As long as it's packed very tightly there won't be any air pockets and it will be a smooth consistent burn.
been making it the same way as is in every video I see, using the same tools, made of the same stuff. I'm as careful as I can be so as to not have pockets.
Melting. uncapped, they burn consistently.
C'mon you missed your line. "It's not rocket science"......
Pity you didn't display this in metric units. There are only 3 countries in the world which don't use the metric system - US and for good company, Liberia and Burma! That's a total of only 5% of the world population...
plenty of conversion kits available on google. I've used them extensively!
Yet there is only one country to land men on the moon....
Unless that was shot in Area 51. :p :D
And still the world is riding on the USA and it economy even when we use such barbaric measuring systems. As far as the other two the are just trying to mimic what has been successful up till now. The USA id slowly switching the tooling over to metric though. After that you will be able to finally build this guys nozzles allowing you to get involved in rocketry after all this time.
LOL...was waiting for the cliche...its not rocket science.....in this case...it IS
Make a six inch rocket (diameter)...bout 5 ft long attached to a heavy wooden pole for stabilization. Call Guinness book and make some cash on worlds largest bottle rocket...by product worlds largest beer bottle. I want a couple hundred for the original idea.
does this type work for APCP? or is it too hawt?
Saad Mirza it will work for that type of fuel as well
it will work for APCP as well, but will not replace a high grade steel nozzle.