MHSSR-1 (From the beginning to the end)

[D3vil5ro53]

Introduction – Skip if you don’t like reading

First I like to thank all of you for a lot of information - that has been gathered around this forum. And this has helped me much on my fun journey.

So why did I register and post this thread? – Simple as I got a lot of feedback and ideas I thought that I would share mine so if anyone would read it maybe they would also find it useful someday.

How did I discovered spud gun? – It was a sunny day and my gf was getting ready so we could go to a BBQ event. And as I waited and waited for her to get ready I used my time as best as I could surfing YouTube. And discovered a video on YouTube that featured a nice combustion gun with a big BANG. After this I searched YouTube for basic introduction/tutorial on potato gun build. And before we went to the BBQ fest I brought some PVC from the hardware store and a car starter spray. And from that my journey began. I had many problems’ on my way to completion. First was the ignition system. I started off with a simple fireplace pieso igniter. But hey that was a joke. Then came a BBQ pieso igniter ok was better but not what I hoped. Then I made a schematics http://www.rmcybernetics.com/projects/D ... driver.htm with a car ignition coil. The spark was ok but it was too heavy to transport and was like from the prehistoric age. After this I started to look around the internet more to look what people have made. Not that it’s fun to reinvent the wheel but hey we have Google and YouTube. So my next step was an electronic BBQ igniter. And this works like a charm. Now I have a nice spark but needed to know what detonates the best so I started to look around http://www.aaroncake.net/spuds/boom.asp and found that my end product would use pure propane and pure oxygen. And to accomplice the best I can I started out with a prototype gun that I could mod test and just have fun with. But as with all hobbies I want more –more –more. And this is how my one time fun product became this.

First Prototype gun for testing my ideas
Specifications:
Name: No name (Just for testing out ideas how they work in real life not just on paper.)
Type: Combustion spud gun
Fuel: Everything that I could get my hands on that burns I tested out
Atmosphere: 0 bar
Material: PVC
Barrel: From short to long so I could see the difference
Chamber: From small to big so I could test what happens
Ignition system: Lighter > pieso igniter > starter coil > electric BBQ starter and so on (also used matches)
Sound: From nothing to so loud that I got a whistle in my ears for 10 min
Recoil: From nothing to almost that the gun exploded (fortunately the fueling cap blow off)
Danger: Nothing (as it didn’t work) dangerous (almost exploded)
Reliability: Bad to great depending on what I used for testing
Overall quality: Poor
Extras: Fan
Total Price: 34€

So here is my prototype spud gun that is for testing out different ideas in the realworld!


Back view of the gun.


This was an extra center piece with a fan for circulation and an ignition system for the car starter coil. But as the pressure thx to the bigger chamber got to dangerous I removed it.


Center piece top view.


Electronic BBQ igniter with 6 outputs.


Spark plug and a spark from the igniter.


MHSSR-1
Specifications:
Name: Mobile Hybrid Spud Sniper Rifle Version 1
Type: Hybrid spud gun
Fuel: Pure propane + Pure oxygen
Atmosphere: not yet specified (will be available when testing begins)
Material: Iron
Barrel inside diameter: 53mm
Barrel outside diameter: 57mm
Barrel length: 1500mm
Chamber insinde diameter: 102mm
Chamber outside diameter: 104mm
Chamber length: 250mm
C:B ratio: 0.6
Ignition system: 400kv Boost Step-up Power Module (high voltage generator)
Sound: not yet specified
Recoil: not yet specified
Danger: High
Reliability: not yet specified
Overall quality: not yet specified
Ammonition: Red Bull Can (53mm*135mm)
Extras: Scope, laser, safety switch, electrical ignition system, pre pressurized and metered fuel inlet, silencer, radio signal remote switch, mobile solution for gun build, piston valve, ammo reload system
Total Price: not yet specified

Item list and prices
Location - Name - Price
Sweeden - Barrel, iron steel rod - 18,85€
Sweeden - Main fraim material, iron steel rod - 20,68€
United States - Steel Coil Springs - 23,40€
Estonia - Performance Steel Coil Spring - 10,18€
China - O-Rings - 21,31€
Hong Kong - 400kv High voltage generator - 4,11€

This is my idea what I want to build. I thought that I would model the device first in 3d and in cad but it’s not that complicated mechanism so pen and paper will be faster. I just have to calculate first the barrel size and length and also the size of the chamber.


UpDate 24.07.2014

red 1: propane tank
red 2: oxygen tank
red 3: combustion chamber
red 4: valve
red 5: valve
red 6: valve
red 7: valve
red 8: manometer for propane mesurment
red 9: manometer for oxygen mesurment
yellow 1: locking and rearmig the gun
yellow 2: the piston system
yellow 3: piston braker spring system
bluish 1: bolt action system for loading ammo
bluish 2: muzzle
purple: barrel holder with spring system
green 1: a system when you want to shoot potatos or other veggies so you dont have to precut them
green 2: hatch that is meant for potato cating when reloading the gun


UpDate 29.07.2014

The last hours of the test gun before i trashed the old components.


Hey to all as I had a little time on my hands at work I did a 3D image of the planed spud gun to see if the mechanical system would work. The 3D object is not in 1:1 ratio it is only for the purpose to see if the system would work. (As I implanted a hydraulic recoil system.) In addition, do give some help on knowing what is what then here is a small map:

Red: ignition system (car spark plug)
Yellow: gas measurement system
Dark yellow: silencer
Black: spud gun frame (non moving parts)
Green: oxy and propane tank holders and tanks
Dark green: laser (just for fun)
Blue: Front stand for the gun
Dark blue: hydraulic recoil system
Pink: scope
Grey: moving parts (barrel, loading system, chamber, and so on)

Front


Back


Down


Up


UpDate 30.07.2014

So as the piston is the first thing in my rig that I am going to build then here is a more detaild drawing of the piston valve system that’s on my mind. The problems that I am facing right now are. That I have to order the parts from different countries. For the iron pipes need to be ordered from Sweden, the spring needs to be custom made for my specs, and this comes from Finland. Therefore, I do not know, when in the next month I get the basic components to start building this thing.




Looking forward on your feedback on what could be done better what to add or what not. So I don’t reinvent the wheel. So feel free to post your ideas and thoughts (Criticism is the best method!). If you want more detailed information on some parts let me know and I’ll give them. If you want diagrams or blueprints I’ll do that so I don’t make any mistakes that could have been prevented.

UpDate 25.08.2014

At last i got my components to start building my spudgun


The diameter and sigaret pack for comparison

[Juggernaut12121]

As my username indicates I am a bit of a noob (especially compared to some of the other people on here) so take my words with a grain of salt.
Anyhow, your first cannon looks incredibly dangerous. The PVC you used looked to be very thin walled. For a simple combustion cannon you'd want to use at least Sch40 PVC. As for a second build, I would highly recommend you take some time to study the forums before contemplating it, in doing so you'll be able to generate better functioning designs and safer cannons.
You also want to be pretty careful with the oxygen propane thing, I'd probably just stick with propane (or if you wanted more power you could bump it up to Mapp gas). And if it's legal where you live then a stun gun makes for a terrific ignition system.
A little intro:
If it's power and performance you want you should check out the world of pneumatic spud guns, they're much safer than combustion guns and can be more powerful. They're also more consistent and variable in the amount of power they produce.

If you like making big booms and loud noises and powerful feeling guns then look into making a combustion cannon (this time out of decent building materials and proper fueling techniques), do keep in mind that these types of guns are less safe due to the fact that they produce a large amount of pressure in a short amount of time (which can stress and fatigue materials easily)

And finally there's the hybrid cannon. The ultimate in power and performance and very capable of producing a very nice report and recoil. it is also the most difficult cannon to make, and can take a lot of studying to fully understand (lest you accidently blow yourself up). I recommend that you don't attempt to build one, at least not with out venturing into the other types of cannons and gaining some experience with it all first (you mess up on a regular pneumatic or combustion you're hurt, you mess up with a hybrid and you're dead.

Whatever you choose to do with your next venture, please study up on it. I don't mean to be too critical or mean but looking at your last cannon you could really benefit from putting some time into the knowledge aspect of it. Fell free to message me or post a thread on spudfiles with any questions!
(Btw this post might've been better suited towards the combustion gun forum, instead of the hybrid one )

Update: I almost forgot, as far as barrel size goes, it's more or less personal preference to what you're looking to use as ammo, as for the length, the longer the barrel the more time the projectile has time to accelerate, but what you have to keep in mind is that the larger the barrel volume, the larger the chamber volume, so you'll have to find what suites you. (If you look into the forums or ask around you should be able to find the best C:B ratio for you're setup)

[Juggernaut12121]

Your update looks interesting, could you give me more information on the piston valve though?

[D3vil5ro53]

As my username indicates I am a bit of a noob (especially compared to some of the other people on here) so take my words with a grain of salt.

"Long Post made short by D3vil5ro53"

Hey mate thx for the feedback

Don’t worry around your criticism as it is the easiest/safest way to learn anything in life. If you can handle criticism and know how to deal with it!

That’s true as my first project looks dangerous and it is really dangerous. I have hurt myself a little bit using and testing out stuff (as it was only meant in the beginning only for one time use and with simple deodorant). But as time ventured on. So did the fuels but the housing stayed the same! Sad but true. For everyone out there if you use explosive material then always use the right housing so you don’t hurt or in worse situation kill yourself.

For legal concerns on the stun gun. Then it’s legal to have them but you need a license to use it as far as I remember but our laws changes so fast that last question I asked from the police about some driving license issues they told me that they are not able to answer it and I need to go to a higher legal justice department. And I hope that I mentioned that I will dismount the teaser and will build it in to a spark system.

For pneumatic spud guns then I don’t like those. My personal opinion. They are more easy and safer to build. And can have a nice mechanical parts and a detailed frame. But I LOVE the so called BOOM and recoil effect on the combustion spud guns!

And yes if you look at only the beginning of this thread then yes this would go 100% under combustion spud guns. I had a hard time to decide under what category I would post this but as the final product is going to be a hybrid system then. I was convinced that the thread name should contain something that would let people see the very beginning of the project to the bitter end (hope it isn’t where I blow myself up).

On the safety part. Then I always use protective gear as I have built many project’s including a mini hydrogen (device that displaced air rapidly). Of course I had my own hydrogen generator that worked really great. Used the same system to power a lawn mower and other combustion engines including boosting a car’s engine and so on. But that all is another story that should be told somewhere else. As this is a Spud Gun related forum and the info should be about this!

To better describe what I am going to build I added a better drawing that I did. Sorry don’t have that much time at work to make a 1:1 blueprint but I hope that it’s better than the picture from the paper.

For the barrel and chamber size and the total gun size I am going to build the gun starting my calculations from the ammo that I am going to use. As I want to build explosive ammunition for the final gun. Then for the ammo frame I am going to be used Red Bull cans. They have a shape and size that does not changes over time and I can use them the easiest way possible and they are cheap and tasty. So my barrel and anything else is going to go from this dimension. For the C:B ratio I am going to use HGDT http://www.thehalls-in-bfe.com/HGDT/ and wiki http://www.spudfiles.com/spud_wiki/inde ... rrel_ratio. Information about pistons was a great post here http://www.spudfiles.com/pneumatic-cann ... c8157.html. The current ratio is 1:0.68 C:B more detailed calculation are going to be done when I get to that part.

The building of the gun parts will start beginning of the next month. I hope to catch as much information as I can on camera so everyone can comment and say what they don’t like and hopefully like. Testing will be done when a component is finished so I will also have the option to give out information on the performance of smaller details also, not only on the completed gun.

Once more thank you for your concern, but I will go with this project to the end. And I think it’s best to discuss stuff on the forum so that people who are also interested can give a word on their opinion on the subject. The more - the better it is with opinions.

The only question I have at the moment is that? How long or how many posts to I have to make before I get permanent permission to edit my own posts. So I does not go to reviewing by administrators? As I will add information to this post. But it’s going to be fun when all the time someone has to look it over. Ok I did a mistake first time to give a link to the video on YouTube that started it all As much as I understand then the first picture in the post is going to be the main picture shown in the forum. So when everything is finished the first pic needs to be the picture of the final product.

I will give you more info when i am back on mondey.
Have a nice weekend all!

[Juggernaut12121]

With a piston valve hybrid the operation is kind of the opposite from a pneumatic cannon (which was the thread you posted, I'm not sure if you just got the wrong link though), I'm not the best source for the information but with a hybrid instead of letting the pressure behind the piston out, you increase the pressure in front of it. Also I've never seen a hybrid that ran off of a propane oxygen mix (probably for a reason I would imagine, then again I'm sure it could be done with the help of someone who has tried it). About the ignition system I've seen plenty of people make their own taser (I don't know if that would be any more legal), if you're handy with building electronics then it should be a snap with a diagram off the interwebs.
I also have to agree with you that nothing is quite equal to the satisfaction you get from the feel of a powerful combustion cannon
I believe you can start making posts without review after about 5 posts or so, and as for the photo I believe you just have to manipulate the photos so that the first photo appearing in the thread is the one you want to be your thumbnail.
Finally, explosive ammunition is frowned upon on this site, so try not to get kicked off
And HDGT is great to figure out C:B ratio, but you need to keep in mind that the higher the mixes go, the more a longer barrel will increase performance. So try and determine what sort of limits your shooting for (haha get it?) as far as mixes and chamber sizes and barrel lengths go.

Update: A piston valve hybrid works by filling the pilot area with an amount of pressure (this pressure is like the pressure at which the disc in a burst disk hybrid ruptures). Once you've done this you'll fuel and pressurize your chamber (just like a burst disk, you'll set your pilot area to a higher pressure so that your chamber has time to reach a higher pressure before firing). After everything pressurized you can fire, this will create a higher pressure in front of the piston forcing it backward and allowing pressure to fire the projectile. The act of the piston going back will trigger the spool valve (I believe it's called) which is basically a rod coming off of the back of the piston. When the piston is forward so is the spool valve (which has a sealing face on the end to seal a hole in the pilot area), when the spool valve is triggered (when the piston moves back from higher amounts of pressure) then the hole it was sealing is opened and the pilot area is released from pressure. If you're going to attempt making a piston valve hybrid then you should try and find a machinist who could help you make your piston, so that it seals the barrel, fits in the housing, and seals the two areas off from each other all correctly.

[mark.f]

There have been a few people who have used propane/oxygen mixes in the past without complication (with a safely built steel launcher). Use the program GasEQ for fueling calculations when using exotic mixes...

[DYI]

I'm one of those people who have used propane/oxygen mixes in the past (and I still do, although more propylene nowadays). The one you really want to speak to on this is SpudBlaster15, as he has actually built a large bore piston hybrid (he invented them in their modern form) and used propane/oxygen in it. The higher combustion temperature of the oxy/propane mixes tend to cause seal damage, and you'll want to use considerably rich mixes. You can play with that in GasEq, and they're easy enough to test out. I tend to use something between 25:75 and 30:70 fuel/oxygen when using oxy/propylene mixes, with a view to attaining low molecular mass in the propellant gas without too much soot formation (and subsequent fouling) during the shot.

You are, in fact, "reinventing the wheel", as you put it, with your valve design. There has been a lot of work put into piston hybrid valves in recent years. Have a look at MrCrowley's and Spudblaster's builds to see how they're done.

Just to add to what Mark mentioned about GasEq: you can model some hybrids using GGDT and property information for the combustion products found using GasEq. It's a bit ad hoc, but probably more accurate than pretending that your gun is burning an air/fuel mix. I'm hoping to write a full hybrid model at some point in the next few years, but don't hold your breath...

[wyz2285]

Check this out [youtube][/youtube]
Sort of what you want to build. It uses Oxy/Prop and looks like a damn fine sniper rifle.

[jackssmirkingrevenge]

Good to see new blood with some idea of what they're doing, and "European Grey" PVC

I'm one of those people who suggests you steer well clear of oxygen, and posts photos like this to remind you of the danger:

[DYI]

Getting effects like that requires fairly high oxygen pressure, on the order of hundreds of psi at least. I was under the impression that the OP was looking at something which would only require a few tens of psi oxygen pressure. Obviously there are design and operational issues involved with high pressure oxygen systems which can be fatal if handled improperly.

If you plan on using a high pressure oxygen tank in your system, I would highly recommend at least one safety valve on the charge system to compensate in the event of oxygen regulator failure, to avoid effects like those shown in Jack's post. The small disposable oxygen tanks only run around 500psi maximum and are on the borderline in terms of explosive auto-ignition problems. Still doesn't hurt to use a safety valve after the regulator if your system can't handle the potential combustion pressure.

[D3vil5ro53]

Your update looks interesting, could you give me more information on the piston valve though?

Hi, back from a mega short vacation as I promised then a little bit on the piston idea that I had. As I have many safety concerns on the use of high explosive gases. And that I want to use the gun close handed then I don’t like the idea when an iron rod shoots at high speed towards me. (Even if it’s almost impossible for it to break and come out of the system on its own then there is always a changes that it could happen) So I thought out an idea that would prevent this. Also with this design I would use this system as a failsafe when something would get stuck in the barrel and I would need to depressurize the system not just blow up the barrel. But you will see more info when I am starting the build.

With a piston valve hybrid the operation is kind of the opposite from a pneumatic cannon (which was the thread you posted, I'm not sure if you just got the wrong link though),
"Long Post made short by D3vil5ro53"

That’s true but as I wanted to point out the basic principle to how a piston works.
There are some oxy/propane builds out there, not many documented but there are.
For me it would not be hard to build a simple diagram of the stun gun principles but the price for a complete stun gun from EBay costs me less then only to buy the basic components to start welding it together. Sad but true.
Thank you for the info on the explosive ammunition I will ask the site admins before I post info on that part and if they give me green light then you will have that info as well otherwise only videos of showing it in action. If it works as I plan.

There have been a few people who have used propane/oxygen mixes in the past without complication (with a safely built steel launcher). Use the program GasEQ for fueling calculations when using exotic mixes...

Thank you I will look this software over.
One more tool that I use for calculation is http://www.burntlatke.com/calc.html

I'm one of those people who have used propane/oxygen mixes in the past (and I still do, although more propylene nowadays).
"Long Post made short by D3vil5ro53"

Hi and thanks. Seems that you have been here a long time, if you can point me to the beginning of the piston design thread if you remember that one I would love to read that post. But it’s not that important. Have seen both threads that you but up. They both look great would love to meet the makers in person and have a little chit chat but as I am on the other side of the world then the possibility is almost zero.
Yes my piston idea is a lot different in design then the currently used one. But the basic principles are the same. I only added some failsafe items and a spring that regulates the mechanics that regulate the starting pressure. But we will see if my ideas hold what they promise after I have built them.

Check this out.
"Long Post made short by D3vil5ro53"

Yes I have seen that one also and yes it’s something that I am going to aim towards only that my gun will not look 1:1 replica of a gun. It will have manometers and an oxy/propane tanks mounted on the gun so it can be mobile to transport.

Good to see new blood with some idea of what they're doing, and "European Grey" PVC
"Long Post made short by D3vil5ro53"

Hi and thanks. Looks like there aren’t any active European users here. And thank you to point out the pictures. I know that using this can be dangerous but I will implant failsafe systems that will prevent the explosion of the gun. Hope that any of the failsafe systems would be needed.

Getting effects like that requires fairly high oxygen pressure, on the order of hundreds of psi at least.
"Long Post made short by D3vil5ro53"

As I will not aim to rise the pressure that high then I hope that I don’t need to worry that much but I will have safety valves and a system to fire the propane tank away from the gun if two valves fail and the regulator fails. So that if I am fire the gun and for some reason all the failsafe would fail then I don’t blow up but it fires the propane tank away from the gun and it would not explode near me. This feature I will not test out and I will only implant this and hope that it will work if the time should ever come. As it will ruin the gun but would save me.




More… On my vacation I thought about the gun principles and one more feature I will add is a recoil reduction system that would use hydraulics for the dampers. As this idea came in mind then I have a problem as looks like I still need to make cad file for the gun as it gets more and more complicated. But I will make some pencil paper drawings and see how hard it is to implant a hydraulic recoil system to a mobile gun.