nozzleless rockets construction

[dan999ification]

so the nozzles wont stay in, in fact the 60/30/10 riced fuel wont consolidate enough to avoid cato's with ramming, the motors blow the nozzle and rupture the casing halfway up the spindle before the delay is lit,, could it be the pink visco? My bet is the fluffy fuel, quite impressive but.

Attempting a nozzleless design how would one go about it?

I understand the thinners/oil,vaseline and making the composition, but before proceeding, how to?

Small incriments of half id ( once rammed ) how many full incriments above the spindle without a bulkhead should be used, the plan is to use the same fuel all the way.

Im open to all ideas and input on this including trying something different.

The spindle is 6mm at the throat tapering to about 5mm ( not that the taper matters, only to release ) 75mm long 3/4 inch id, i know of powerfull short bp nozzled motors 4 inch long ( rammed ) lifting 4 shells and many fp shots, specs... 45mm core ( including nozzle ) 7mm throat, the most impressive in the uk and the tube from what ive seen.

I will shorten the spindle to 40mm as a last resort and use no retardant but there is no going back from that ( endburner tooling)

ive used too many tubes already to keep testing ( plus its loud ) so i ask the experts.

 

Dan.

[Col]

I`d try plain unriced bp so its easier to consolidate, (could be a dusty job), strong tube with a support sleeve, smaller increments and maybe a bigger mallet.

[dagabu]

I hate to go against your recomendation Col but in speaking with many rocketeers over the past few years and seeing thier workstations, i have to say that granulated BP compresses better, is less likely to crack and will consolidate better.

 

In almost every case, it is the charcoal that is the issue with the lack of consolidation, it springs back and causes cracks throughout the fuel grain. The test to see if any of our recomendations work is to take an awl and scratch the top of the fuel grain, it should not chip the BP but scratch a white line across the surface. If it flakes off the top of the grain, you will will CATO the rocket.

 

Change your charcoal and try again with granulated BP, you may find thet your rockets burn well.

 

Nozzleless will not change the cracks in the fuel, the pressure is less so you may not CATO every time but it is not a solution long term.

 

-dag

[Mortartube]

I made some nozzleless rockets last year with standard 75/10/15 BP with elder charcoal, milled and pretty fast. They were 18mm ID with an 8mm spindle with hardly any taper. There was about a 10mm heading above the powder. It had some mineral oil added (Baby oil) and well mixed. Consolidated on a ramming post with a 2lb club hammer. Worked brilliantly. In fact went too high. Case length was 125mm

[Col]

no worries dag, its been a while since i`ve used a mallet on a motor. I dont granulate i just keep the increment size down and press the hell out of it..no cato`s to date

I`ll make a few nozzled and nozzleless with the same fuel and pressure and see how they compare. If nozzleless get off the ground faster than nozzled it`ll probably be too fast to follow it with the camera

Edited September 28, 2012 by Col

[dagabu]

no worries dag, its been a while since i`ve used a mallet on a motor. I dont granulate i just keep the increment size down and press the hell out of it..no cato`s to date

I`ll make a few nozzled and nozzleless with the same fuel and pressure and see how they compare. If nozzleless get off the ground faster than nozzled it`ll probably be too fast to follow it with the camera

 

LOL! Looks like you may need to step back to film them then.

 

You should try granulating some time, it presses very nicely and almost no mess.

 

-dag

[PyroAce]

so the nozzles wont stay in, in fact the 60/30/10 riced fuel wont consolidate enough to avoid cato's with ramming, the motors blow the nozzle and rupture the casing halfway up the spindle before the delay is lit,, could it be the pink visco? My bet is the fluffy fuel, quite impressive but.

Attempting a nozzleless design how would one go about it?

I understand the thinners/oil,vaseline and making the composition, but before proceeding, how to?

Small incriments of half id ( once rammed ) how many full incriments above the spindle without a bulkhead should be used, the plan is to use the same fuel all the way.

Im open to all ideas and input on this including trying something different.

The spindle is 6mm at the throat tapering to about 5mm ( not that the taper matters, only to release ) 75mm long 3/4 inch id, i know of powerfull short bp nozzled motors 4 inch long ( rammed ) lifting 4 shells and many fp shots, specs... 45mm core ( including nozzle ) 7mm throat, the most impressive in the uk and the tube from what ive seen.

I will shorten the spindle to 40mm as a last resort and use no retardant but there is no going back from that ( endburner tooling)

ive used too many tubes already to keep testing ( plus its loud ) so i ask the experts.

 

Dan.

 

I'm not sure on your particular circumstances, but my biggest issue was my ramming procedure, do you ram yours with the tooling sitting on a solid base? I used a post on a concrete floor. My fuel was the same as yours but only milled for a few hours, it was not riced/granulated. Also what clay did you use for your nozzles? I use a nozzle mix which consists of fine clay with larger particles also in it. Interestingly I only used standard visco fuse for ignition and it was only pushed about halfway up the core of the rocket, the fuse burns slow so I doubt by the time the base lit the fuse wouldn't have even got a chance to ignite the whole core.

[Col]

The clay is replaced by bp in a nozzleless motor, the shape of the nozzle is the same though.

Dan, If you`re having another go at it over the weekend, an inch of comp above the spindle should be enough to create a decent bulkhead. You could try piping some bm to the top of the core in place of the pink visco.

[Juiceh]

Pink super fast visco? Try some standard visco just J hooked past the nozzle.

[dan999ification]

thanks for the replies guys, busy weekend but have some nice bm to try now, i dont think its the pink visco, well partly it is lighting the core too quick for the grain to handle, green visco will do that, the fuel is like dag says, springing back it is the pine charcoal at fault, maybe it needs milling well but i doubt it will ram either way due to the high charcoal content, my bp motors will scratch a white line, this will let comp come loose and wont leave a smooth surface after ramming

My ramming is good it is only this fuel, it would be fine for fountains without the core, but wont pack well enough for one.

Bp will ram better due to the high nitrate in my mind oiled bp better still.

So we'll try milled 60/30, and bp see how that goes.

Back on topic: is one id above the spindle enough on nozzleless rockets?

Light the top of the core, adjust the oil accordingly, have fun.

 

Dan.

 

 

[Col]

I`d go one increment above the spindle and at least one id on top of that. I gave in trying to hand drill a core into a pressed motor,it took me 30 minutes to drill 1/2" deep with a brand new titanium bit..should`ve used a masonry bit Edited October 2, 2012 by Col

[dan999ification]

nozzleless endburner it is then, it is a pain to drill them col, you could make a spindle in that time.

I'll try that, its more or less either way, a bit of loose bp ti to judge the height and delay, it would be nice for one to go up for once.

 

Dan.

[Col]

If you make a lot of rockets its worth knocking up a simple press. You get more consistant results,less cato issues and zero ear ache about the noise

[dagabu]

thanks for the replies guys, busy weekend but have some nice bm to try now, i dont think its the pink visco, well partly it is lighting the core too quick for the grain to handle, green visco will do that, the fuel is like dag says, springing back it is the pine charcoal at fault, maybe it needs milling well but i doubt it will ram either way due to the high charcoal content, my bp motors will scratch a white line, this will let comp come loose and wont leave a smooth surface after ramming

My ramming is good it is only this fuel, it would be fine for fountains without the core, but wont pack well enough for one.

Bp will ram better due to the high nitrate in my mind oiled bp better still.

So we'll try milled 60/30, and bp see how that goes.

Back on topic: is one id above the spindle enough on nozzleless rockets?

Light the top of the core, adjust the oil accordingly, have fun.

 

Dan.

 

From my experiences with nozzleless, I would suggest that you use the standard 75:15:10, well milled fuel that is whetted and riced and dried for the fuel. There is a long list of reasons why this is the widely accepted method but for you it is the ability to consolidate the fuel grain into a solid mass.

 

Also, you need to make sure that the charcoal you are using is completely ball milled into the KNO3 and sulfur, why? Not so much for the power increase that comes with finely milling them together but because the particles are more able to make a tight bond with less sponginess. That makes a solid grain.

 

I suggest that you find a bench press to make rockets, they can be had world wide for an affordable price, the pressure to force gauge can also be made for about $50.00 US.

 

-dag

[Mumbles]

Dan, I honestly can't tell if you're suggesting that you want to make a nozzleless end burner. If you are, good luck. All nozzleless rockets I'm aware of use very hot fuel in a core burner configuration. An end burner will likely turn into an upside down fountain.

[Col]

The spindle is 75mm long, tapering from 6mm to 5mm so its not an endburner The core diameter seems a bit on the small side for a 3/4" motor on hot fuel.

[dan999ification]

i was reffering to cols efforts hand drilling, the core is a bit on the small side i expect catos with bp which is why i want to retard it plus for a better grain, this is a bought tool which specified scratch mix, i cant remember if it was bp or 60/30 either way with this charcoal it wont happen.

Normally my tools are built around hand drilled motors so i know what to expect, the wooden ram aint great either,

This thread confirms what i thought about needing a press its getting that way, it seems there is no way without one but i do like to question things from time to time.

Great advice dag thats exactly what i needed.

 

Dan.

[drthrust]

thanks for the replies guys, busy weekend but have some nice bm to try now, i dont think its the pink visco, well partly it is lighting the core too quick for the grain to handle, green visco will do that, the fuel is like dag says, springing back it is the pine charcoal at fault, maybe it needs milling well but i doubt it will ram either way due to the high charcoal content, my bp motors will scratch a white line, this will let comp come loose and wont leave a smooth surface after ramming

My ramming is good it is only this fuel, it would be fine for fountains without the core, but wont pack well enough for one.

Bp will ram better due to the high nitrate in my mind oiled bp better still.

So we'll try milled 60/30, and bp see how that goes.

Back on topic: is one id above the spindle enough on nozzleless rockets?

Light the top of the core, adjust the oil accordingly, have fun.

 

Dan.

willow bp works very well for nozzle-less motors. also i had similar springing back whilst pressing with perc/charcoal based nozzle-less propellants, they didnt work particularly well. one thing i did enjoy about these motors is adding a whistle delay, the willow motor is last

[Col]

The whistle delays add a novel twist.

[dan999ification]

im going to try willow, unfortunately i cant view your video by phone infact nothing but youtube, im gonna have to get to a computer if i want to make the deadline ( bfn )

 

dan.

[Col]

Finally got around to a nozzleless motor, pressed to 6500psi the same as i use for nozzled. Still undecided whether to top fuse or bottom fuse it, i guess i could press another and try it both ways

Here`s the business end

[dagabu]

Finally got around to a nozzleless motor, pressed to 6500psi the same as i use for nozzled. Still undecided whether to top fuse or bottom fuse it, i guess i could press another and try it both ways

Here`s the business end

 

It's interesting to find out what your fuel and tubes can handle, make another one and try both methods, the difference is amazing!

 

-dag

[Col]

I`m not sure if i`ll have time to press another as i`m still up to my eyes attaching shells to motors. Given the choice of one or tother which to go for..piped to top or hooked into the bottom? I have a 1lb whistle rocket to test the tube strength

[Col]

I top fused the nozzleless and it did ok, it was slightly faster off the mark than the nozzled rockets but they were lifting 120g-180g headers. The nozzleless had a teaspoon of bp and half a dozen red microstars dumped in the tube

The whistle rocket left the ground screaming like a banshee and performed great..right upto the point where it cato`d lol, the fuel grain was ejected out the back so i`ll beef up the tube and use more pressure next time, 7500psi didnt cut the mustard.

 

Here`s the rockets minus the nozzleless and whistle

 

here`s the nozzleless

 

http://youtu.be/pVHSTUBgtTk

 

For comparison here`s 2 nozzled rockets using identical fuel and delay, the headers are around 150g

http://youtu.be/q9m1scU4oug

Edited November 5, 2012 by Col