Making our simplest homemade rocket motor even simpler?
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- Опубликовано: 16 ноя 2024
- Rotary Rocketry Merch ➤ rotaryrocketry...
Today we are taking our simplest, easiest to build, homemade rocket motor and we'll try to make it even simpler and cheaper to build.
This is a PVC case motor filled with flexi-fuel sugar fuel.
How to built the original Dart Monkey rocket motor:
• Class 1 Sugar Rocket M...
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Heyo, I thought I was a relative master of doing things very precisely on the cheap, but you're apparently a real master, too.
I could make a thousand comments, but I'll make just one: flexi-fluel can be made perfectly reproducibility by using a large pressure-cooker canner with an internal container holding the ingredients, absolutely reproducible. It does actually get thicker at a given temp without boiling off any water because the heat/temp makes the sucrose fully dissolve, but since it's hotter to start with it's still pourable.
An easy way to get your holes drilled evenly into your 6 holes would be to measure the holes out on a piece of tape. Wrap it around the pipe and then your holes will be clearly marked. As a bonus you will get cleaner holes too.
FYI, Grainger has your 1-1/4 Sched 40 end caps at $0.77 ea and if you want to order online Zoro has them for $0.59 ea..
If you have a local electrical supply distributor and make friends with the head counterman. Over the course of the year they will throw out hundreds of feet of damaged PVC pipe each year that could end up in your hands... If you are interested in higher pressure lighter weight pipe, when you are down at the supply house see if they stock fiberglass RTRC (Reinforced Thermosetting Resin Conduit). I personally prefer Champion brand.. The stuff is available in 3 wall thickness.. The lightest (SW) is half the weight of PVC and is significantly stronger and stiffer in every direction while being significantly more heat resistant than PVC.
I know they can be purchased cheaper but because I only buy a few at a time, I get them locally to avoid shipping costs.
I will look into that RTRC... Sounds interesting, thanks.
The military has been using fiberglass tubes in weapons for a long time. The tubes MLRS fire out of are fiberglass. LAWs and AT-4s too. The Carl Gustav recoilless has a fiberglass tube too.
It's impressive what fiberglass can take.
Gloves and power tools can be a dangerous combination, if the drill/blade catches the material it can pull your hand into the mechanism. Cheers
Therein lies the problem... If I make a video without using safety equipment, people complain that I wasn't showing others how to do something safely... If I use safety equipment people say I should not have used it. It's really a lose-lose scenario. I suppose the overall lesson here is DON'T PUT YOUR HAND NEAR THE DRILL BIT - GLOVE OR NO GLOVE. I appreciate your concern though.
@@rotaryrocketry I'm sure you're good at assessing your own risk mate, just throwing it out there for viewers to consider. No shade and thanks for the vids
You are right but also can be dangerous without gloves. Carpenter for more than decade and i have caught my finger in drill bc i was wearing gloves, but then when i didnt wear gloves i stuck the drill bit in my hand when then boom lift i was on shifted and destabilized my force on drill causing bit to take sharp turn into my hand that wss holding wood in position.
@@julybliss4440 Sounds pretty severe, I wonder if gloves would have even helped you there. Hope you didn't suffer permanent damage :O
@@jeremiahbullfrog9288 certain gloves I wear have made stabbing yourself with driver bit less deep, still hurts though. No not any glove will stop the average force you use for some of the fasteners. Yeah I healed. Just bleed pretty bad and deep infection from oils on screw.
Any more the Only gloves I will use with drilling are these tight Kevlar coated(similar to nitrile or rubber coated) called "ninjas", they tend to slip instead of catching on bits if they make contact. They make different colors ones for different purposes or job task.
But heck even the time I was wearing looser gloves and caught in bit, it about dislocated my finger, hurt like hell and jammed knuckles and finger joints.
Journeyman was yelling at me that he has seen it snap the bones in fingers when getting caught.
Power tools are dangerous no matter what, but like you say it's important to not be careless and dont use loose, holey, or frayed gloves.
Years ago we made our PVC motors like that. We formed the convergent by making the coring rod tapered to form the convergent. We also added an extra hole or two in the bulkhead end for additional strength so that in the event of overpressuring the nozzle would blow out instead of the bulkhead. If faster startup is desired, you can roughen up the core surface so the motor comes up to pressure quicker.
We also did the top of the motor differently. We would add a solid section of propellant on top of the cored section, it would provide tracking smoke/delay and adding a small hole in the top epoxy or cement would create a passageway to make the motor ejection. You neglect to say building the motor with end caps not only makes those motors more expensive but also adds weight to the motor end that may require ballast weight for stability that further increasing the weight and reducing the performance of the rocket/motor. Also, adding those end caps would require a larger diameter rocket airframe.
Now for safety, the propellant should be made outdoors and the coil cooktop and pot is second most hazardous method for making sugar propellant only to cooking it on an open flame burner.
So it turns out that this new design is nearly 30 grams lighter than the end cap design. Both designs fit nicely into a 3" diameter rocket that I mentioned was the style we use for this motor. But rocket design and stability are a topic for another video.
nice change in motor keep them coming.
One more tip, take a look at PVC knockout caps. The could simplify your build even more. They fit entirely in the pipe with a flange to hold them in place. HD has them for 40 cents where I live.
hmmm... I am familiar with the test caps. Not sure where I would integrate that into the build but definitely something I will keep in mind. Thx.
You can actually forgo the holes and put grooves inside the PVC to help retain the rock type nozzle cap and plug
This was really great...😍
Nice channel.
I make molds from silicone calk or sand, i wonder if we can make a mold of the caps and then use art epoxy?
When you drill plastic with your drill press, run it in reverse and it wont grab the workpiece or crack it or make it crawl up the bit.....
Interesting... Unfortunately, neither of my drill presses have a "reverse". I guess the manufacturer thought it would be of no value to turn drill bits backwards.
@@rotaryrocketry Google "reverse spiral drill bits" or "left-handed drill bits" - Harbor Freight have them for not crazy money. That lets you run the drill press in "FORWARDS" and still spin the bit in the opposite direction. I'm not convinced that this makes better holes in UPVC though...it just makes me wonder if I'm some kind of tool hoarder to actually own a set!!
Is that what your using to power your space ship ? Just curious because if it can do that then ..... I'm sold ! Nice video bud .
The space ship belongs to a friend so I don't have to power it. Glad you liked the video :)
Hey, just wanna know why you used corn syrup? What is the pros and cons?
Using a liquid sugar in the mix makes the fuel extremely easy to cook and cast. In fact, we tested other liquid sugars such as molasses and honey and they worked great also. Corn syrup is just an inexpensive and readily available product here in the USA.
Excellent as always. I know you do not use software to designe your motors. However, would the outer surface of your propellant be considered inhibited or exposed? Thank you.
I have used Richard Nakka's SRM spreadsheet quite a bit to help in motor development. Mostly just to get an idea of a good starting size for the nozzle and then I fine tune it with trial-end-error from there.
For this design, the outer surface, top & bottom are inhibited. The only uninhibited surface is the core.
@@rotaryrocketry thank you very much.
does the fuel shrink abit after drying?
I guess in theory, yes, it would have to shrink a small amount.
Nice motor. Do you have enough sugar to get home from Alpha Centauri? How’s the weather over there?
Liked the background I take it. I have a few of those from the same maker... They are really well done. Link is in the description for anyone who wants it.
Maybe use wax instead of epoxy for the top cap?
Just melt in a layer for separating the fuel and the top cement cap.
As long as the wax does not disintegrate instantly from the heat in the motor. If it were to disintegrate before the motor was finished burning then that would expose an area of the PVC to the hot gasses.
@@rotaryrocketry I imagine it would melt, but I wouldn’t think a coating of wax would make that big of a gap.
Maybe a coat of some spray can sealant to create a moisture barrier would be enough?
Either way, it’s a minor step, and epoxy already works! 🤙
"that nineteen sixty-fourths of an inch drillbit" Geeze who uses a system like that.
hmmm... Only everyone who makes rocket motors in the USA. Nozzles are measured in 64ths of an inch so this is a #19 nozzle.
Lol if 64ths get ya wait till you find out there are number, letter, fraction, metric and SAE sizings.
@@rotaryrocketrypppp❤❤❤
Unless you are using a machine shop grade mill to drill it, I's gonna be 3/8..
Blame the king of england
Any idea what class this would fall in? Approximately...
No, I've never bothered to do a thrust test with either of the motors shown in this video.
Only think I can tell you is that we use this size motor to launch our 3" rockets that weight about 1000 grams. That's the complete launch weight including the motor.
@@rotaryrocketry Thanks. What altitudes are you acheiving?
900 to 1100 feet.
And the easiest way for me to make this cut is by using the most dangerous cutting saw ever made by man and Craftsman.
Well... ANY tool can be dangerous.
@@rotaryrocketry My 6" spirit level is only dangerous if you attempt to swallow it - but otherwise, you're right. But it is a matter of degree of injury and odds of it happening. Any circular cutting device that doesn't have some kind of retracting blade shield is inherently a LOT more dangerous than one with such a shield.
Just shut up would you does this guy seem stupid to you or something. Do you wear a helmet when you go for a walk?
I think the word approximately needs to be added before pretty much every step of this. Basically, eyeball every measurement by locking your finger and checking the wind.
True, not all measurements need to be exact... But it worked... That's what matters in the end.
Sure, there ARE measurable differences in performance with fuel-load variances, but how WOULD you measure them from the ground, and why?
I think the original comment was talking about the fact that my measurements for drilling holes was not very accurate. But the design of this motor is so simple that the measurements don't need to be accurate.
As for ground testing... I just have not had any need to do a ground thrust test on this motor. It lifts our small 3" rockets to around 800 to 1000 feet high so I really don't need to know any thrust data at this point.
@@rotaryrocketry If you know the length of the rocket - then a video of the launch - viewed frame-by-frame will allow you to at least do comparative tests of two designs by looking at how many rocket-lengths it travels in each frame of the video. Some simple math would get you an actual thrust versus time graph - but that doesn't matter if all you're doing it comparing two designs to see which is better.
You can also get the duration of the burn from a static fire test...and armed with both pieces of information, you'll be able to get a decent estimate of the ISP.
All very true... but a bit more that I was interested in doing for this video. I really just wanted to prove that the anchoring cement end caps would not blow out.
My idea for a rocket is a ceramic tube, with a capacitor made of graphite and ceramic like those in some uf in ceramic capacitors suspended by ceramic in the center of the tube. A magnetron is the input and a working gas goes into the tube for the reaction. That is the rocket. Coils or magnets outside the tube may be used to accelerate the gas out of the tube faster. That is the electrodynamic propulsion system.
A bit off topic for this video. Also, fair to say that I don't have a clue what you are talking about :)
@@rotaryrocketry Basically a microwave driven plasma rocket.
@travismoore7849 has this been done or is it just theory?
@@Cantbreakitifitsnotfixed I tested the plasma capacitor that arced in the microwave that when turned off had a powerful electrical field. I shocked my self so I know it can make a arc plasma. Andstore energy like a tv flyback system. As for the magnetic accelerator stage I have not made it.
U're a real rocket scientist, for sure!
Why not just put earplug back to keep fuel filling nozzle? It also keep moisture out, just unplug before launch.. Probably silicone or ptfe are better as lubricant, wd40 is water displacement.
Excellent question... I did use the earplug to block the nozzle in one of our other motor build videos and it works great... Except... The fuel gets stuck to the earplug and the earplug tends to break when you try to pull it out. With this current system, the earplug is reusable.
Silicone, ptfe or spray cooking oil all work well for core rod lubricant.
I make my rockets using kitty litter and PVC
I tried that kitty litter cap thing a few years ago and could not get it to work. I'm sure it was just that I didn't do it right.
@@rotaryrocketry Looks like you have better ways of doing it anyway. My rockets are a little smaller. The biggest I've done was 1 inch so far using kitty litter
I'm pretty sure when I was trying that, it was with 1" PVC also. I was trying to copy something I found on RUclips... Of course for him it worked great... For me, it was an epic failure...lol
anchoring cement + 🥃 = 🚑+ 🏥 😆
I guess I don't speak that language.
Don't ever use PVC if it was to explod sharp bits of PVC will go into you body.Use rolled up paper and white pva glue,they sre really strong.
First off... We have proven over and over and over that PVC can be used successfully for rocket motors. They just have to be designed and built properly.
Secondly... These are always ignited with people a very safe distance away.
Hi,
Has anyone ever told you that you have a resemblance to George W Bush :)
No, but I think you just did.
Never ever use gloves when running a drill press or any rotating spindle machine
Looks more like a pipe bomb
Glove with a drill press is a very very bad idea! You can loose I finger that way.
19/64.. Why not 3/8 nothing about his seems exact.
The nozzle size is extremely important. Reduce the size and the motor is likely to explode. Increase the size and you reduce the thrust. We don't just pick these numbers randomly, we experiment to find what works. Nozzles are measured in 64ths of an inch, so 3/8 would be a #24 nozzle. That's 5 sizes bigger and would greatly reduce the thrust, possibly to the point where the motor would not even be able to lift a rocket.
Many common drill bit sets have 1/4, 5/16. and 3/8" bits. There is not a lot of difference between the 5/16 (=20/64) and 19/64" bit you used. That's just a tiny bit larger and would be a small percentage of thrust less but a bit longer burn time.
True, 5/16 would be a safe alternative. However... As you know... If One is going to be building rocket motor nozzles that are measures in 64ths of an inch then One should have a good drill set with 64ths.
@@rotaryrocketry You could also say if one is going to be building rocket motor nozzles then one should be using a lathe. I was just pointing out that many of your viewers might not have the section of tools you have and bits that others do have that would work just as well. It's not hard to adjust the grain length or core diameter to get the pressure you want that works with the drill set they have.
True... When I used my lathe in some videos a while back, I got slammed a bit in the comments with statements like "You know most people don't have a lathe"
THIS ISNT SIMPLE THERES ALOT OF PROCRDURES,AND TIME TO MAKE 1 ONE TIME USE ROCKET MOTOR
If you care to read the title for the video, it is a question... Making our simplest rocket motor even simpler?
Nobody is forcing you to make this so please don't yell about it in the comments.
So much more simplified, I think you confused this video with some other more complicated video that was marked illogical.
It might be simple but not easy, and even if it's easy it is in no way simple.
Well, the title is actually phrased as a question... And I did make it clear at the end that this new new design was actually more difficult to build.
@@rotaryrocketry For a one-off build, the extra effort is pretty significant - but if I was batch-building a dozen of them - I think it's unimportant.
Very true. It was a lot more work in the end for basically the same results. However, I found the experiment very interesting and I'm hoping to integrate this new anchoring cement nozzle and bulkhead technique into a much more powerful motor in the near future.
@@rotaryrocketry I do appreciate the technique of softening the pvc, I'n going to incorporate that into my design. Looking forward to your next video.