3 replies to this topic

[Sambo]

I've been experimenting with strobes recently, eventually got them to fly after the 8th attempt..
Well Here it is.
It strobed as you can see from the tail but I'm sure it didn't make the "popping" sound, just the wind playing tricks. Has anyone played with these and could point me in the right direction to get the noise as well as the strobe?

Ill share some vids of the failures to keep everyone amused.
ClickyClicky It had a nice tail, again no popping sound. I think the wind caught it sending it into the side of the mountain lol.
Click Me This was one of the first I made, chems weren't fine enough so strobe gave no thrust and burned for ages. It used 70/30/1 NaBenz whistle, I have now moved to 76/23/1 with NaBenz and found it to me much faster.

I've settled now on milling all except the mgal then diapering the metal in. On the mgal front, I'm currently using 20 parts 200-250# and 5 parts 120-180#. The mgal use in the first experiments was too fine so it almost burnt without strobing at all.

[Vic]

Nice to see someone making strobe rockets Sambo.

Can't help you out much, so much depends on the mesh of mgal used as you found out.

Did you do any static test with the strobe mix on it's own to get the Hz?

Much depends also on your increments of whistle/strobe mix and your spindle geometry.

You didn't say what strobe mix you are using?

Vic

[Sambo]

I have done static tests and found the correct ratio mgal for my needs, I use 20 parts 200-250# and 5 parts 120-180# this gives a nice frequency. You can see in the second vid the smoke tail is nice and consistent, but no noise

What do you mean by spindle geometry?
I tried the original spindle size and found I needed extra whistle to get it up . I machined a longer spindle with a 1 degree taper to keep the surface area at the tip a bit larger. This way I can press lots of whistle and still have enough spindle to core the strobe part 2" - as stated on SLD drawings.
Oh, I'm using SLD strobe formula Here

[Yugen-biki]

I have experimented with these rockets for a while. What I found was that the mesh of the MG (or MGAl if you prefer) is very important. The mesh in the comps I found were to coars, but I trusted the formula so I started to suspect the whistle and tools etc. If you use tools from wolter as I do, you can decrease the ammount of whistle and use finer metal in the strobe formula. I went for only 63µm Mg coated with K2Cr2O7 with great success. It does not seem to be important to use salicylate whistle either.
Another project I had were to make a rocket fly with no whistle. If worked but they can't really carry anything. 1lb red strobe rocket made with a whilste tool from skylighter:

Oh yes, one more thing. Testing the comp open on the ground will only tell you if it will strobe or not. The behaviour in the rocket is different. I made funny "multi-firecrackers" with to slow comp (for stars) they did not fly but hovered a meter or two from the grund untill they fell down and continued to go "bang-bang-bang" in the dirt.