1lb BP rocket fuel for wolter tooling

[metalhead]

Hey all,

 

I was curious if anyone else has a set of 1lb rocket tooling from Rich Wolter and was willing to share some fuel formulas. The first 1 pounder I made with the tooling cato'd. I think I have some idea why. Probably because I used a 60:30:10 formula as fuel. I looked at the packet provided with the tooling and he recommends using 60 pts kno3 20 pts 80 mesh charcoal 10 pts charcoal AF and 10 pts S. I'm assuming the coarser charcoal burns slower thus producing a slower burning fuel as opposed to using just AF which would explain why my rocket blew to kingdom come. I know these things take some time to tune but I'd appreciate any fuel comp suggestions as I don't want my neighbors becoming uneasy, as if they already haven't.

 

Thanks

kyle

[sparksnsky]

I don't have wolter tools but I have made several rockets using many kinds of cores. I always use 60/30/10 with AF charcoal not having problems with the burning rate. Coarser charcoal is mostly used to produce a long tail.

I'd say that most probably you do not put enough press to the fuel. It has to be consolidated enough in order not to explode.

You may need a sleeve to avoid the tube bending. Do you use a press or you ram your rockets?

Edited May 25, 2010 by sparksnsky

[dagabu]

Metalhead,

 

I have several sets and I use the tried and true 60:30:10 recipe in most of them with no trouble with CATOs. I agree with Sparkinsky, it sounds like you dont have enough compression on the BP to get a solid grain of fuel.

 

Lets take a big step back and look at the whole process.

 

-Overly dry fuel will NEVER compact correctly, whet and rice your fuel but don't dry it to the beginning weight, if it was 100g when you started and add 10g of water and rice it, dry it to 98 or 99 grams and leave the 1% water in it for consolidation. I am now adding 1% paraffin wax diluted in camping fuel in all of my BP for rockets due to the better packing it provides instead of water and rice.

 

-Add small increments when making rockets. I use 3/4 of the tube ID compressed for each increment because any more leaves soft powder at the bottom of the increment and a hard top.

 

-The hammer (if ramming) or press (if pressing) has to be able to make a rock hard grain in the rocket tube. Failure to do so will most always result in CATO.

 

-Almost all tubes will bulge or split if you compress the fuel enough to make a solid grain. You need to make or buy a tube support to hold the pressure and not allow the tube to bulge or break.

 

-The nozzle needs to be soild, it may be a blow out and not a CATO. Go find the motor and see if it still has the nozzle. CATOs will often retain the nozzle.

[metalhead]

thanks guys. I think my fuel increments were to large when I was ramming now that I think of it. I guess my impatience got the best of me :/ Unfortunately, I haven't found a trace of the rocket so I can't check for a blown out nozzle. I can tell you when it blew up, it was just one boom. I didn't hear any sound resembling a rocket before it blew. just..BOOM. Guess I'll need to find a sleeve now.

 

 

thanks again for the advice

kyle

[dagabu]

thanks guys. I think my fuel increments were to large when I was ramming now that I think of it. I guess my impatience got the best of me :/ Unfortunately, I haven't found a trace of the rocket so I can't check for a blown out nozzle. I can tell you when it blew up, it was just one boom. I didn't hear any sound resembling a rocket before it blew. just..BOOM. Guess I'll need to find a sleeve now.

 

 

thanks again for the advice

kyle

 

Sleeves are easy to make, all you need is a hack saw, a file, a torch (no, not a flashlight you limeys) and hose clamps. You want the sleeve to completely close yet still be very tight. Find the right PVC that is larger then the casing and cut it lengthwise in a vice. You may need to make another cut but guess carefully, a gap in the sleeve will cause blow outs.

 

Once the sleeve looks good, file the edges of the cut to smooth it out, wrap three wraps of kraft around the casing, put it into the sleeve, use enough hose clamps to completely cover the length of the sleeve.

 

Find a safe place to heat the assembly, use the torch to heat the PVC tube and let it cool before picking it up. You will find that the sleeve now conforms to the casing in a circle and it is tight. Remove the casing and peel off the kraft, the casing should slide in easily and should be impossible to move once the hose clamps are tight.