50 replies to this topic

[jeffrocket55]

hi as ever playing catch up, heres a hybrid 3lb spindle made on a 1930,s lathe! similar to a whistle spindle, half id, but longer for thrust two and a half inch long [list=1][/list]and if you have a spare five mins with nothing better to do, which i guess you haven't because your reading this! check out the vids of me making it( my first go on a lathe) ho anybody know a good cutting fluid, cooling for ali an old boy said paraffin. tapering the spindle and parting off

and I gave my unimat away,kick!great stuff thanks

[dr thrust]

i turned this a while back before the bearings in my headstock went bye bye but what is it can you guess?

its dual purpose and 12mm dia, one use is as a star pump as there is a long brass bar that runs up inside one of the ends a bit like a syringe you fill it up with comp and it pushes out a 6mm "snake of comp" which i chop up into stars its just a fast way of pumping stars that works well for me, but whats with the fancy curved middle?

Edited by chris m, 13 May 2009 - 09:01 PM.

[knackers]

eey up sky puke, i think you are being a little tricky somewhat there ,
my guess is, it is not actually joined in the centre, and the female half is not only part of your pump but also the rammer for a 1/2" cored motor, and the male half is your plunger for your pump,

[Mortartube]

Chris, I reckon your fancy curved middle is for making chokes. Either pulled in chokes on wet cases and/or pressing clay chokes.

[dr thrust]

blast! Wright on the money mortartube, it is indeed a former for pulled chokes on wet cases, copied from a design in kentish's book and apparently it just needs a minimal amount of clay to help it from burning through.
i found it surprisingly easy to make a pulled choke and also very satisfying as i can now make authentic looking old school drivers for wheels , etc.

Edited by chris m, 14 May 2009 - 05:46 PM.

[Mortartube]

Hey that is a really neat and tidy choke. Old thick guitar strings are useful for pulling in thicker cases I have found.

Glad I cracked your little question.

[PyroMan LTU]

Hello,

I was thinking to make my own rocket tools here is the designs:
http://i326.photobuc...one24/image.jpg
So few questions... is the dimentions of spindle ok?
and is the *first* rammer needed?
the fuel going to be used is KP/Nabenz based.

Greetings

PyroMan

Edited by PyroMan LTU, 08 June 2009 - 08:37 PM.

[mike_au]

Hello,

I was thinking to make my own rocket tools here is the designs:
http://i326.photobuc...one24/image.jpg
So few questions... is the dimentions of spindle ok?
and is the *first* rammer needed?
the fuel going to be used is KP/Nabenz based.

Greetings

PyroMan

Yes, the first rammer is required to press the fuel around the spindle. You *MUST* not use the second rammer until the level of the fuel is above the spindle or else you risk crushing a small amount of fuel between the spindle and rammer. This is suspected to have caused accidental ignition in the past.

[PyroMan LTU]

Thank you. and what about the 10mm distance between the beging of the spindle and the base? is it long enough? and for 12mm rocket is the spindle dimentions ok? thanks for help!

Grettings

PyroMan

Edited by PyroMan LTU, 10 June 2009 - 06:51 AM.

[knackers]

it looks ok but if you tubes are 75mm long ? make your spindle 30mm and taper it, ( the more the better ) and the hole in you rammer, make it 4.5mm, the whistle doesn't properly start till the core has burn't abit and you are up into the delay, ho yea no need to make your end plug too thick, 3 or 4mm would be sufficient

these 2 spindles are identical except for the taper, the acute taper goes quite alot harder than the slight taper

http://img291.images...ng1mm9mmx55.jpg

http://img30.imagesh...inchspindle.jpg

this is my link from the whistle rocket thread, its the slight taper

slight taper tool

this is with the large taper

Large taper

these were tool tests i did on another forum on whistle rockets,... Thanks to psyco for you help

Edited by phill 63, 09 June 2009 - 11:35 AM.

[PyroMan LTU]

phill, I dont know, what do you sugesst about paper tube? 75mm for 12mm ID right? I heard from one very good rocket specialised pyro that spindle should be dwice the distance of ID of the tube and one third wide. but ok if it is better I will make it 30mm. And the 10mm distance between spindle and base is good right? So how does this look:
http://i326.photobuc...e24/image-1.jpg
Thanks for help!

Greeetings

PyroMan

[dr thrust]

hi pyroman, the spindle should be half the id on a whistle motor and one third on a bp motor as for spindle length, the Sky's the limit lol.
in general spindle length all depends on how fast your fuel is, which you will find out through practical experimentation, i presume you have access to a lathe? if so try your design and if it goes like a bat out of hell every things fine! if not look at a longer spindle, and dont forget these need pressing!.
Another good tip when pressing is however fine the tolerances are on your tooling small amounts of whistle will extrude up into the rammer whilst pressing and this can lead to the rammer getting stuck on the spindle.
so take your time and press each increment a few times starting off with a low pressure pressing, then take out rammer, inspect/clean rammer/ press again with a little more pressure.. repeat, take your time over these rockets.
ho! and a bit of Vaseline on the spindle before you start really helps the finished motor to release off the tooling

Edited by chris m, 21 July 2009 - 08:19 PM.

[PyroMan LTU]

Thank you for such comprehensive explanation so many things cleard out now... yes, my friend has access to lathe. And last thing If there's going to be a possibility to choose a metal what do you seggest? he definitely has aluminium for all sizes and maybe chill brass or sth...

PyroMan

[knackers]

phill, I dont know, what do you sugesst about paper tube? 75mm for 12mm ID right? I heard from one very good rocket specialised pyro that spindle should be dwice the distance of ID of the tube and one third wide. but ok if it is better I will make it 30mm. And the 10mm distance between spindle and base is good right? So how does this look:
http://i326.photobuc...e24/image-1.jpg
Thanks for help!

Greeetings

PyroMan

hey pyroman, you didn't mention the length of your tubes so i took a guess at them being 12mm ID x 75mm long,
the longer your core the longer thrust curve and less whistle noise, the shorter your core the less thrust curve and longer whistle sound, but if your core is too short your rocket will whistle all the way back to earth, my rocket core diameters are 1/3 of the ID and they go like a bat out of hell, the tapering of you spindle i was refering too is to taper it the full length, it will give you alot more power due to the exhaust pressure flow, taper you spindle something like the following picture, it will also make removal of your motor so much easier



this spindle is for a 1" ID x 4" tube and the core length is 56mm x 9mm diameter

Edit :- Aluminium, brass or stainless is all good, so whatever is easier to get

Edited by phill 63, 10 June 2009 - 07:05 AM.

[PyroMan LTU]

Thanks! As soon as the tools are made, I will write.