43 replies to this topic

[sasman]

Hi
i thought i would share my first ever test firing of my Bp rocket find the clip here Bprocket
Now i cant belive my first rocket flew! and more or less went straight into the sky ...I'm still buzzing from the excitment several hours after i fired it...
I made the fuse about 10" long so i could get faraway whilst my girlfriend filmed.. i expected either a nozzle blow out or cato ..and to my joy i just witnessed this massive whooooosh..and luverly charcoal tail...all over in 2 seconds but i cant belive that 30 years after i last tried making a rocket i finaly did it ...Ill edit this post later with more details on tube size core size etc...
Right the Rocket was 22mm Id 6mm wall thickness 100mm approx long..The Bp was 75:15:10 +25% 40 mesh Charcoal..
The length of the Bp charge was about 55mm The core was about 40mm drilled with a 6mm drill bit The nozzle was bentonite clay 25mm thick End plug was bentonite clay 20mm thick all pressed on my press until i could feel the wall starting to bulge.. Now i have no way of estimating the height the rocket went it looked good to me but viewing the tape afterwards gave no hint to how high it flew...

So i made 3 more further rockets using smaller tubes about 19mm Id 25mm Od 100mm long Same Bp mix smaller 4 mmDia drilled core 45mm long ,length of Propellant was about 55mm ,Nozzle 20mm thick End plug 15mm thick..To give some sense of height i fired them of near an old unused Bridge (i have dropped a stone off this bridge and it takes nearly 4 seconds to fall into the river that works out at over 100 foot high ... )

So when i fired the first rocket i was more than pleased to see the rocket shoot way past the bridge in fact well over double the height of the bridge...my girlfriend filmed the first 1 but it was out of focus and because the rockets go so fast she couldnt follow em,But you can see in the video that thay went well over 100 foot in the first second of flight..In the excitment i forgot to press record on the second rocket and the third rocket i tried to film just goes to prove that im totaly usless at fiming pyro So i wont post the other 2 clips.. All 3 rockets rockets went up without a hitch..
Ill add a link to my Rocket Video Here later..
Sasman
Ps all measurements are approx but i have learnt its best to right everything down and measure every thing properly so that if it works then i can reproduce the results..

Edited by sasman, 11 May 2004 - 10:41 PM.

[chim-chim]

...I'm still buzzing from the excitment several hours after i fired it...

What a rush, huh? You have me feeling it remembering my first flight.
I wasn't smart enough to film it though .

You'll be able to feel it over and over.

I need to start filming, I've had this feeling of "I'll film it later when I know I have down pat", then when I think I have it, I change something or move on to something else.

You've inspired me Sasman.

[Yugen-biki]

When you have got your camera with you that?s when the stuff you have made never works. I bring my camera when I test a device for the first time.

[alany]

Very nice, well done!

Can't wait for the details...

[adamw]

My outlook is also 'I wont bother filming until I get it right'.

Then it works great first time and I wish I recorded it!

GRR

[pritch]

Very nice. I hope mine is half as successful as that.

[BurlHorse]

Hi
    i thought i would share my first ever test firing of my Bp rocket find the clip here Bprocket
          Now i cant belive my first rocket flew! and more or less went straight into the sky  ...I'm still buzzing from the excitment several hours after i fired it...
          I made the fuse about 10" long so i could get faraway whilst my girlfriend filmed.. i expected either a nozzle blow out or cato ..and to my joy i just witnessed this massive whooooosh..and luverly charcoal tail...all over in 2 seconds but i cant belive that 30 years after i last tried making a rocket i finaly did it ...Ill edit this post later with more details on tube size core size etc...
sasman

Good Job for a first attempt, Heck, that was a Good Job for a 200th attempt! your well on your way!!

Regards,

Stay Green,

Bear

[sasman]

Hi
........ have tested 10 rockets so far all with homemade tubes all flown 100%..but my hand rolled tubes were a bit iffy so i have just bought a few 100 commercial cardboard tubes..to improve my reliabilty..
last week i bought an old metalwork lathe off ebay so i can now make my own tooling . And today i have fiddled about and made some proto type tooling..all made of aluminium and wood, until my stainless steel bar arrives next week...I have also manged to add a pressure gauge to my hydraulic bottle jack so i can press at a consistant pressure..
....Now i pressed only 1 rocket using propellant from my previous batch which worked so well...the tube was 3/4" Id 1" Od length 5"(actual carboard tube was 7 1/2" but for testing i made it shorter)...the spindle was 4" long tapered?..6mm to 3mm at narrowest end..i used 4 rammers 1st rammer had a 45 degree angle the rest had flat ends.. the final rammer for the end plug had a small nipple in the end to help drill out the delay plug hole..

.......i pressed the bentonite clay using the 45 degree rammer then pressed in the propellant(very messy i will be granulating the proplleant next time)....I used a casing support to stop the tube deforming..Once i removed the spindle i was left with a nice shiny finshed nozzle..
Now i attached a stick to the rocket and then placed it in a large 2" metal tube(which the end was placed against a wall so the rocket would stop!!) and lit the fuse after a very fast burn 1 maybe 2 seconds i had expected the nozzle to have blown out but every thing looked ok!! But on further examination i found a small hole in the casing .....ruptured casing
i have put a red object behind the casing so you can see through the hole more clearly
here is a look from outside the casing outercase rupture
and another this time with cross section of the nozzle altho the hole apprears as a grey blob ....
cross section nozzle
Now is this a one off? or have i made a design error?the hole was about 1 or 2mm just above the nozzle?..what would have happend if the rocket was in flight? or is it a possibilty that firing it in the tube caused the problem due to confinment?
or is it just unlucky..also i made a test pressing just of the clay nozzle and noticed some fine clay around the edges on the inside of the tubing maybe this clay made a hotspot which caused the problem?..any ideas or am i being to nitpicky and should do some more testing....


sasman

[BigG]

Looks like a very clean burn to me. The hole is peculiar; it does not look like rapture at all! I did not understand what you were saying about a metal tube to hold the rocket ? you better off with a strong wood arm ? but you?ll need to explain that point better.

It?s hard to say what would have happened in flight with this hole size. The majority of the thrust will still go through the main thrust opening, but some will slip through the side forcing the rocket sideway ? now, depending on the size of the stick attached to the rocket, you can have one of three options:

1) It rotates in big loops in mid air.
2) It keeps going up but veers in the direction opposite to the hole (possibly toward the crowd)
3) The stick is big enough to keep the rocket from de-stabilizing and it keeps strait.

What presure were you on?

[chim-chim]

The hole is peculiar; it does not look like rapture at all!

I agree. I think a faulty tube is to blame on that one.

You said you were ordering some tubes though?

[Phoenix]

I like the cross section of the nozzle. Looks like you've made some good tooling.

You say you are using a sleeve around the rocket motor. Do you think that there could have been anything trapped between the sleeve and the rocket motor tube that would have punctured the tube as you pressed it? If there was, then the result would probably look rather like what is in the picture.

[pritch]

If your thinking about making any tooling and selling over ebay or whatever make sure you tell me first!
Do you have that url for carboard as well? Im finding it hard to make carboard tubes that don't bend under the pressure of my vice, unless I wrap metal straps round it. Even then the case has to be very thick and I strip some layers off before flight.

[sasman]

BigG Let me try to explain what i mean i sellotaped the rocket to a large alumiunium tube about 2"" diameter about 4 foot long, thick walled weighed at least 500grams..i then placed this inside a steel tube 3" diameter 5 foot long very thick very heavy...............
...........my idea was to get some idea of how much thrust the`rocket produced..i layed this on the floor when ignited the`rocket shoots out of the big steel tube along the ground not verticaly!!!,but as it travels along the ground it reaches the brick wall so cant cant travel any further?
....what i figured was if it can drag this big aluminium tube it will definatly fly!....not very scientific but it was just a test....chim chim i think you were right it was hopefully a faulty tube? as i have tested a few more and no sign of a rupture .......
'''''Pheonix i have looked at the case support and it was perfectly clean so i dont think it was that...
Pritch my cardboard tubes i got was a one off offer no longer availble... ..thats why i bought 400 of em should last me a long time

Now i have just fired the following rocket made with my tooling..Rocket made with tooling..
At least it flew but i dont like the chuffing ,Also notice a nice titanium tail near the end of the burn ...What causes the chuffing???

[pritch]

Your rockets are seriously impressive. I love that titanium effect. Is titanium expensive for say 100 grams?

[BigG]

At least it flew but i dont like the chuffing ,Also notice a nice titanium tail near the end of the burn  ...What causes the chuffing???

Well done - very nice! Now you will have to start working on a bit of payload. And don't forget to post some details about how this was made .

What do you mean by chuffing?!?!?

Edited by BigG, 22 May 2004 - 10:03 PM.