End Burner

[Flaky123]

Hi,

 

I want to make End Burners which have a little more power than the traditionale ones.

 

My endburners are 10cm long and have 3mm walls.

 

My idea is to take a standart end burner tooling and press at first a bentonite nozzle and then 3cm benzoate +1% fe2o3 whistle and the rest normal black powder.

 

Would that be possible or is the risk of cato too big?

 

And how much force should I apply to it? 3 tons?

 

Thanks

[Mumbles]

What diameter of tube are you using?

 

I know a few people who boost their BP with whistle mix by mixing them together. I've been told that when pressing at a high enough pressure, you can approach 40% whistle without worry of a CATO. You'd probably need to approach 9000psi for this though. I also don't know how hot their BP is to begin with.

[Juiceh]

What tubes and tooling are you using?

 

Smaller tubes can take stronger fuels. NEPT 1oz 1/4" x 2.5" tubes can take 100% of some benzoate fuels behind a bentonite nozzle using Steve Majdali endburner tooling.

For hybrid fuels you can use either sali based whistle or benny based whistle to mix with BP.

 

I've used 75:15:10 6-hour ball milled BP + 76:23:2.5:.5 Sali based copper oxychloride(milled into the perc) catalysed whistle in 50:50 ratio. It worked in SBR nozzleless coreburner configuration. It works in endburner configuration too.

 

I press all motors at 10,000psi on the fuel grain.

 

The coreburner ignition is very energetic and is probably damn close to the red line.

 

Endburner:

http://youtu.be/9WLukm12zgM

 

Coreburner:

http://youtu.be/CQB3ZjhBnkM

 

 

So depending on your tooling and tubes you will need to make a few batches of fuel and experiment with different mixtures to come up with something that will work for your application.

 

If you are going to stack different fuel grains like you mention, I would use BP first. Cover the spindle with BP and then switch to the whistle fuel. The rocket will start off like a regular BP rocket then the turbo boost kicks in just after lift off.

Edited September 27, 2013 by Juiceh

[Jonathan]

Flaky 123,

 

I can't offer advice; I lack the knowledge.

 

It's interesting to me, though, that Estes rockets are all end burners. They use a highly compacted pellet of Estes's own B.P., which includes just about 1 percent dextrin. Makes me inclined to get a press.

[nater]

A press is almost essential for rockets. It is mandatory for any fuels which contain whistle and the higher loading pressures will improve the performance of BP rockets.

 

For the 1/4" SBR kits, a small arbor press works great. In fact if you build a stand to increase the working height they will do just fine for up to 1/2" rockets.

[Seymour]

Smaller tubes can take stronger fuels. NEPT 1oz 1/4" x 2.5" tubes can take 100% of some benzoate fuels behind a bentonite nozzle using Steve Majdali endburner tooling.

 

I'll second this. I don't have any real tooling for end burners, but I've burned up a lot of whistle making 19mm end burners with 100% benz whistle. I was expecting catos when I started trying nozzles 4mm in diameter, but to my surprise they have been reliable, and can in my experience be pushed as far as 3mm, at least for my whistle.

[Jonathan]

Nater,

 

I hear you. Clearly.

 

When I was a 15-year-old kid, fiddling with an aluminum rocket tube, a press wasn't needed. Today it is with cardboard motor tubes.