I have been experimenting with rocket launcher ideas. I have been using estes D-12 booster engines. They supply the most thrust out of the D class engines I beleive.. but its not really enough. I have experimented with my own compacted black powder as fuel but its not good really. The research I did gave me plenty of rocket fuels for vertical launches which seem mostly to use power of lift over speed. I figure a vertical launch needs more speed. Can anyone help me with a good fast burning rocket fuel? I can get chemicals.. I sort of have a chemical supplier.. sort of.
I make my fins from peices of coke bottle which bend down and suspend the rocket in the tube and then pop up again when the rocket leaves the tube. Is it worth it to invest the time in proper pop up fins?

Where to begin...

1. BP is a fast burning propellant (note spelling!). Sometimes too fast, one of the reasons its not used in bigger motors.
2. Think about what produces speed in a rocket. Its thrust! Equates to lift power. So if you need more speed (I think the term you want is acceleration) then you want more thrust.
3. To get more thrust the easiest way is to burn more fuel at once. This is usually done by putting a hole down the length of the propellant grain, giving a much larger burning surface
4. Extend your research into 'motor design'
5. Use candy propellant, mixed with a large dollop of 'motor design' and you will get the result you want.
6. If coke bottle fins work, keep using them. If not, try something else. :rolleyes:

I sure hope you've read all the threads here pertaining to rockets...

If you want really high acceleration, I suggest whistle mix or other KClO4 based propellants. Optimally they should be used with a good binder ( not solvent evaporated NC ) as they burn so fast they tend to erode the core, which often leads to CATO.

There's a page at www.unopar.br/portal/space/artigos/sugar-rocket.doc where some Brazilian students tried to create a rocket that would fly to 2000m using a NaNO3/Sugar mix. They managed to get it to fly to 1400m, but this was vertically. Still, the altidtude attained was impressive.

Hi,

You may find a lot of rocketry information at http://nakka-rocketry.net. I think I found this link through Mr. Cool's web site.

Rgrds.;)

More thrust isnt always the best way to achieve speed. Lower thrust but longer burn sounds more efficient to me, because the acceleration is lower then and drag is lower too. Impulse is what counts anyway:)

Actually higher thrust is more efficient , if you're going vertically, and simply want speed. Remember you've got gravity working against you all the time, so if you take the motor thrust to the lowest extreme where it just balances gravity, then you can burn your entire motor and go nowhere - not very efficient :p
Since you're going for speed, the final drag is irrelevant.

Height is a different story ...

Thankyou for your help. I will go with cored black powder rockets next I beleive. Thanks again.

Asylumseaker - NOT an auspicious start.

New thread by a newbie, pretty much in the wrong section, something that you could find elsewhere if you looked and a pretty dappy question at best.

You're lucky that people are feeling generous - although there's no guarantee you won't still be banned.

1. Read the rules

2. Search

3. Watch your step from here on in. You're unlikely to get any second chances.

You want a high speed fuel for horizontally fired, flat trajectory projectile right?

Then forget Estes, forget any model rocketry you see on the Nakka site and elsewhere, they are ALL too slow burning. As Tuatara said, making things go faster involves burning more fuel in a shorter space of time. I've fire 66mm LAW's and RPG7's, and in both cases, the fuel is all burnt before the rocket leaves the launcher. There's just a big WHUMP and it's gone. I used to have a LAW motor kicking about, and it's a very strong aluminium body, with venturi something like half the size of the overall bore. The fuel is in the form of a load of thin rods. You could do that sort of thing with home made rockets, but you're going to have to forget everything you read about models - pvc/cardboard/rolled metal tubing and the rest. Your rocket will have to be made from a piece of solid metal, and in any case, I wouldn't dare fire something like that home-made from over your shoulder - you'll die sooner rather than later.

But anyway, you started off this thread like a retard, so piss off and do some actual THINKING before you post again

I believe that as soon as the rocket leaves the launcher, it will start accelerating downwards at around 9.8 m/s/s.

In a vertically launched rocket, all of the rocket's thrust is being spent in opposing gravity. However, in a horizontally launched rocket, very little thrust will be directly downwards to counter the pull of gravity.

This means that you will have to add some kind of force to counter the effects of this (e.g. lift), or have a very fast flight time. You could also try launching the rocket at an angle, instead of launching it horizontally, which would also counter the downwards acceleration at the expense of accuracy (a direct line weapon is generally easier to aim).

Also, a rocket launcher is not the best covert weapon :D
so you will have to consider what you want to use the weapon for.

Horizontially fired missiles have both high speed and lifting bodies (wings) to counter-act gravitational dropping.

Otherwise you'll have to fire the rocket as a ballistic projectile and aim at an angle like a gun projectile to counter it.

When firing horizontially, you either have to

A) burn up enough propellant in the launcher to get sufficient velocity for the projectile to generate adequate lift when the wings deploy, otherwise the projectile will sort of fall out the tube and shoot off along the ground.

This is usually achieved by using either a bursting diaphragm that allows the propellant to generate enough pressure to create the required thrust when the diaphragm ruptures, like the MLRS.

The other way is to use an extremely rapidly burning propellant like the "sticks" in the LAAW's rocket, which burns up in a few milliseconds.

B) Use a gas generator to heave the projectile out of the tube far enough away so that when the rocket kicks in, it doesn't roast the operator. (JAVELIN)

C) Use counterbalancing weights with a small central propellant to heave the projectile out of the tube far enough away... (ARM-BURST)

another thing is the #s on the side of the engine actualy tell its characteristics... you said you were using D-12 boosters... the 12 is thrust measured in newtons. there are aproximatly 4.45 newtons per pound, so your D engine is putting out about 2.5 - 3 pounds of thrust , but it is in around the first few seconds which is what you want. you can make your D engine create maro thrust the first fractions of a second by (VERY CAREFULLY) taking a really small drill bit and drilling less than 1/4 in into the bp core from the hole you ignite. this will create more thrust faster but do not mess up the clay surrounding the hole or the engine will not work . another thing to try is another engine such as an E-9 it will not produce as much thrust but it will produce thrust longer(better in upward performance than for a rpg but do what you want)

Ok, let's try and get this straight, before anyone posts any more.

Asylumseaker - what are you hoping to achieve. Do you want your rocket to go up, or go horizontally?

If it's horizontally then 90% of what people have posted here is irrelevant crap.

If it's vertical then why the confusing title to the thread? And since I'm on the subject, how come your post doesn't mention the word horizontal? How come you don't give a fucking clue what you're actually trying to do?:mad:

Maybe you should be banned, I certainly wouldn't cry about it. Maybe this thread should be left open as an example of why newbies should NOT start threads, and a bit of a sad reflection on the fact that some other (some of who ought to know better) members seem capable of responding to such a shit thread without really reading it?:rolleyes:

So PEOPLE, might I suggest that we leave this thread alone until Asylumseaker has got off his fat arse and explained himself?

Arkangel- Basicly what I mean is a rocket which will be launched horizontally from a tube. Research I have been doing includes looking into ww2 rocket launchers, particularly the german panzershrek. I think I have the design of the rocket down how I want it, except what fuel to use. The question I was asking was what fuel would give me the highest acceleration which I could obtain or make without to much hassel, ie- without breaking into any sort of military facility. Thanks for your help. No need to ban me, I will leave now.

Keep it simple and just use KNSU propellant.

If I might make a suggestion.

Build a large crossbow. Fire your rocket from it, with a clever 1 second delay fuse on it.

I will leave you to figure out the rest. Then you can explain it to us.

In that case Asylumseaker (and I'm not a mod, so I couldn't ban you anyway), it's pretty easy to work out some parameters:

As Wild Catmage explains, fired horizontally your rocket will start accelerating DOWN at 9.8m/s/s, just the same as a bullet does.

In this respect, you should be able to make a simple table of how fast the rocket will have to be going to get certain distances from your launcher.

For example, if you want the projectile to travel 100m and drop only an 10cm,

The formula you need is s=ut+1/2atsquared

where

s=0.1m
u = starting velocity(0m/s)
a = 9.8m/s/s
t = the time you have to get the projectile the 100m.

I can't be arsed to work it out for you, but you should be getting the idea.

So, once you've worked out how much time you have, then you can work out the average speed for that distance, or the acceleration you'll need to give the projectile. With a bullet it's a bit easier, as it's easier to get the average speed - muzzle velocity is maximum, and it will only decellerate after the barrel.

However, once you've roughly worked out the acceleration you need, you can work out the thrust needed from the rocket and all the rest of it.

But I can save you all the trouble.:p

Forget it unless you can burn all your propellant in a fraction of a second. Motor design is going to be critical and pretty much beyond anything model rocketeers can achieve. Fuel type is less relevant than giving it the largest surface area you can. Watch a LAW being fired, close up. Have a look at the design and you'll understand what I mean.

(and I should be clear at this point that such a design WOULD be possible for an experienced rocketeer who had the right tooling, but for you, it's out of your reach at the moment)

The best you're going to achieve with a model rocket is a semi ballistic trajectory over any distance, estes rockets aren't designed to be anything other than end burners and if you drill a full core, stand well back as the chances are they will explode.

(And for the record, I'm about as evenly pissed with you as I am with members who have responded to your thread by missing the point totally, of a thread they should have dissed in any case. I hope you learn something from this. I don't want to flame you, but the answers are all there if you THINK about it. Try that a bit more in future eh?;) )

For the record, I don't think this is such a bad thread. The proposed project is not much different from gyrojet type systems, which don't burn all the fuel at once and which are well within the capabilities of an experienced amateur.
I have built several rockets that will travel 80-100 m horizontally without discernible drop, although the scale was probably smaller than what the poster had in mind ( 6-12 mm diameter ).
These systems used KClO4 based whistle mix, as this type of propellant burns very fast and delivers high thrust.
And just for the record, I understood the question from the beginning.

another suggestion for fast acceleration is to build the rocket with multiple cores...I remember hearing that this is how stinger missiles go super sonic to catch their targets. Multiple cores means a lot more surface area which means a much fast burn rate...this will however reduce the amount of fuel you can have in there...

Thankyou for the multiple core suggestion. I don't plan on shooting at planes or anything, so I don't require a very long range. I won't need too much fuel in the rocket. I think i will: Make a Whistle mix rocket with multiple cores (3 maybe). I will have to engineer a shaped thingy to go on the end of my press which will press the cores for me because I don't feel like drilling whistle mix. Here are some CGI plans I whipped up for you to look at. Sorry if they don't make sense.

http://fire.prohosting.com/asylumse/engine.htm

http://fire.prohosting.com/asylumse/rocketview.htm

http://fire.prohosting.com/asylumse/shapedcharge

Unless you already have experience with whistle mix, you should do a little experimentation with it. In my opinion, multiple cores will be asking for trouble with a propellant this ferocious.

If you are looking for complete burning on launch (what is the acronym? BOL? I don't remember), I'm not sure if cores produced by simple drilling will be the answer. You may want to investigate several different core-shapes, especially the star-shaped ones and possibly even more elaborate snow-flake designs, because these patterns seem like they would offer the most available surface area for burning. However, using these designs, there is a significant decrease in the amount of propellant... I don't know how these compare with the simple cylindar-type cores (I have not stumbled across any comparison information to date), but it may be worth a try.

Something that will help acceleration is to put pressure on the escaping gases by funneling.
for an example watch a jet take off a air craft carrrier. the after-burners go from "00" to "oo" thus producing higher thrust.

The burning of the propellant causes gases. It is the Gases that make the rocket move. so by funneling them you are compressing them. The more you compresse them the faster they move. The faster the leave the rocket the faster your rocket should travel.

Take equal amounts of propellant and fill two rockets. make one with a quarter size exhaust tube and one with a dime size exhaust tube. which goes faster? in most situations the smaller.
Now I am not saying take a cup ful of black powder and force it out a hole the size of a bb. Use your brain hehe. I am saying max the pressure output of the exhuast tube by funneling.

I have had success with 37mm hand held parachute rockets firing from a horitontal firing position. The rocket's flare and parachute are removed making the spin stabilized rocket much lighter, read much faster initally too. It is a bit of a long arched shot though, where over a 100 yards you aim about a foot high to hit near the target. I have not yet substituted the payload for an exploding one. My launcher is a PVC fabricated tube with an Estes ignitor pack attached to it, handle, electronics, etc. I remove both ends of the rocket flare tube insert it into the launcher, connect rocket ignighter leads aim and fire. I pick up the rocket parachute flares at a local gun show for $10.00US Ea. this is a bit pricey but success is worth the cost. Huve fun and be carefull.

If you are intrested to open more cores to the propellant you should read this site http://members.aol.com/ricnakk/th_grain.html
there in a very intresting analysis of the way a propellant grain is burnt

The M72 laws rocket launcher as said before, uses all of its propellant before the fins leave the tube. If this was not the case the person firing the weapon would have thier face burnt off. The russian RPG uses a slightly different method where it has an initial exit charge that propells the rocket out to a safe range before the rocket motor fires. Using aluminum popcans for fin material will result in eratic performance......spend some time and dont cut corners by improvising too much. Putting stacked donuts of propellant in a rocket motor will allow more air to reach the propellant and will cause extremely high and unpredictable pressures.

Just quickly, has anybody had any success with incorporating an impact sensitive HE charge into the nose of their rocket. I am toying with the idea of packing the nose of a rocket with Ammonium Triodide crystals but I have reservations about the whole idea. Fear of making the shit and the possibility of it taking my face off while packing the charge being 2 that come to mind! So...what is everyone else making their rocket tips out of??

Don't put ni3 in a rocket. if it didn't go off from the movment of the rocket it would from the rocket banging against the sides of the tube or from the centrifugal force of the rocket spinning or from a million other reasons. AP might work.. you'd be better off going with a proper electrical or percussion cap.

Alchemist you fool, NI3 is only EVER going to be used as a novelty, it is too sensetive, you can't "Pack" it as you said, it would go off. Ap may work but it may not, better to use a rifle primer in the same way as is being said in the land mine thread. Have the entire nose attatched to what would be the trigger for the mine so that even if the rocket dosn't hit a hard surface completely perpendicular the nail will still trigger the cap as it is spring loaded and therefore not dependant on hitting force. I may post a picture later to make myself clear as it is a bit hard to explain.

Here is the design once the mods attatch the pic it will make sense.

Basically as the nosecone hits something it pushes down on the lever arm which pulls out of the notch cut into the end of the nail. The nail then powered by the spring rams into the primer, which detonates. The primer then sets off the primary cap which is connected to the trigger assembly by a short length of metal tube also packed full of a primary. The primary cap is embedded in the main secondary HE charge. The design is mostly stolen from the landmine thread so most credit goes to there.

Sorry about the double post but I just learnt that I couldnt attatch a pic after the post had been sent :(

Blackhawk, the design that you posted looks interesting, but I'm not too convinced that it would work. The success of the mechanism depends on whether the impact forces act on the trigger rod to displace it in the direction desired. Further, wouldn't the trigger rod damage the spring/nail/washer arrangement if the missile crashes exactly perpendicularly to the target surface?

I think I have an alternative design to do more or less the same thing:
http://mercury.walagata.com/w/joydeepb/T_Pyro/Missile-percussion-design.jpg
During impact, the inner cone (see diagram) is compressed, and the fluid pressure exerts enough force on the percussion to set off the impact-sensitive charge like mercury fulminate, which in turn sets off the main charge. The only possible disadvantage of this design that I can think of is that it would be rather top-heavy.

The problem I was thinking with having a direct initiation path between the impact point and the primer composition would be that if for some reason the impact was well gentler than expected (for instance it hits water or is slowed by plants draging on the fins as it enters dense vegitation) the impact may not be enough to set the primer off, hense using a spring system, the impact on the primer will always be the same reguardless of velocity or angle of impact.

Of course that picture only shows the main active sections of the trigger, and there would be a structure holding the triggering rod in place so that it could only ove in one axis and there would be built in stops to ensure that it could not travel further than would be needed for proper triggering.

Making a trigger that will activate on impact is very easy. What's difficult is to make sure that it will not go off before that, for instance when the warhead is accelerating.
One method of doing this is to use an inertial trigger:
The trigger system consists of a small heavy object ( eg. a ball bearing ) contained in a tube of some suitable length and diameter. The tube is placed parallel with the axis of the warhead, and the impact sensitive cap is placed at the forward facing end of the tube.
When the warhead is launched, the ball bearing is pressed against the back of the tube where there is no trigger device, thus there is no danger of detonation on launch. However, when it impacts something and is suddenly stopped, the ball bearing gives the cap a sharp whack, setting it off.
Reliability can be increased by using a weak spring to hold the ball bearing against the back end of the tube to ensure that it does not descend gently on the cap in mid-flight due to the drag-induced deceleration ( and of course also acts as an added safety during handling ).

I haven't tested this myself, as it requires a rather large warhead to accomodate this kind of trigger.

A mechanicaly operated detonating system like the ones described will work but if you have a shaped charge warhead the best system is to use a piezo electric detonator. Imagine a barbecue ignitor on the nose cone with the wire going to a blasting cap in the shaped charge......thats how they work. The spring loaded firing pins and inertia firing designs will destroy a shaped charge before it has a chance to detonate on impact.