Coolest Amateur rocket "hoops" from Thailand: Girandolas.

https://sploid.gizmodo.com/these-are-the-coolest-amateur-rockets-ive-ever-seen-1594656055/+jesusdiaz

You've got to see these to believe them.

Is it possible to scale these down or back so that we could fly one at a club launch?

Has it been tried before? Or have they been banned in the USA or by NAR?

I'm told they are called Girandolas. and that they are launched as part of a festival in northern Thailand that celebrates the end of the dry season and welcomes the rainy season. Does anyone know more?

Kirk G said:

https://sploid.gizmodo.com/these-are-the-coolest-amateur-rockets-ive-ever-seen-1594656055/+jesusdiaz

You've got to see these to believe them.

Is it possible to scale these down or back so that we could fly one at a club launch?

Has it been tried before? Or have they been banned in the USA or by NAR?

I'm told they are called Girandolas. and that they are launched as part of a festival in northern Thailand that celebrates the end of the dry season and welcomes the rainy season. Does anyone know more?

Click to expand...

Girandola's are commonly seen at the annual PGI conventions and to some extent regional firework events depending on the membership. They require a significant amount of work and I've never seen any with parachute recovery like those shown by the OP, which are cool nonetheless. I'm not sure what exactly constitutes a Girandola, but as it relates to fireworks they most certainly include a "happy ending." For example: https://www.youtube.com/watch?v=Jn04oRZ11fI

My buddies and I dodged an ~ 6' diameter Girandola at the 2000 PGI convention. It was sweet!

They aren't so different from some of the rotary style odd-rocs that many fly, especially those uni-rotor (that may not be the right word) things. I'd bet you could build something like that on a reasonable scale powered by two or more LPR motors.

Peartree said:

They aren't so different from some of the rotary style odd-rocs that many fly, especially those uni-rotor (that may not be the right word) things. I'd bet you could build something like that on a reasonable scale powered by two or more LPR motors.

Click to expand...

Model Rocket Motors just don't have the Burn Time needed for these. Some Girandolas burn for like half a Minute.

There are some long burn motors such as the I49 that might do the trick (for a HPR version obviously)

These must be what the Song "Wheel In The Sky" by Journey is about.

I saw a few videos, and finally realized there are no clustered engines, one engine with multiple nozzles. The engine is the big "tube", which might be a steel pipe. A close-up view showed what seemed to be "nozzle outlets" in a few spots, like say welding a lug nut to a steel pipe (Not saying they were lug nuts, but something stuck out, it was not just a hole). They were located in the appropriate locations to produce angled thrust to make it spin.

So how does the thing burn? I wonder if they fill the whole pipe with propellant. Or if the propellant is a slurry (sorta liquidy?), pour it in but leave a bit of space, seal the other end, lay it horizontal, and let it cure nozzle-side-up with a small air gap between the top of the surface of the curing propellant and the pipe.

In any case, a type of rocket engine configuration I've never thought of before. Well, there are some old fireworks stand-sold classic fireworks, "helicopters", with plastic paddle blades, and a hole in the side of the casing. But that side-nozzle is near one end and it is like a normal burning rocket engine where the flame front is still burning along the length of the tube. This one is apparently burning from the lower "side" of the horizontal pipe's propellant, with the flame front all along the engine length of the tube.

Or it could be all solid, no air gap, and they have super-reliable ways to ignite the propellant in all those nozzles. That could explain why it takes so long to finally get flying, the multiple flame fronts are eating up more propellant surface to finally expose enough burning surface area to produce the thrust to get off the ground. But the air-gap idea could also have that effect if there's only a small air gap at first.

- George Gassaway

georgegassaway said:

I saw a few videos, and finally realized there are no clustered engines, one engine with multiple nozzles. The engine is the big "tube", which might be a steel pipe. A close-up view showed what seemed to be "nozzle outlets" in a few spots, like say welding a lug nut to a steel pipe (Not saying they were lug nuts, but something stuck out, it was not just a hole). They were located in the appropriate locations to produce angled thrust to make it spin.

- George Gassaway

Click to expand...

This is one of the reasons I hesitated calling them Girandola's. That, and no happy ending........

Oh yes, and steel components are hardly a good thing in pyro...

what ever they are they are cool, I wish I could make something like this, like a 6 Cmotor with a 15sec burn time....that would be cool

Perhaps the term "Girandola's" is not accurate. Someone else labled it as such, and I just copied it.

There has been a report of one of these wheel things detonating two seconds after launch at a height of ten feet...killing five or ten of the villagers.... about two or three years ago.
So there must be some risk involved in making/launching them.
(Hope it was worth it to them to take the risk.... not for me!)

Being that it's the 4th, here are some pictures of actual Girandola's I've seen over the years. I believe the first picture was at the Western Winter Blast in Lake Havasu, AZ many years ago while the 2nd was at the PGI Convention in Gillette, WY. All circa 2000.

I'm thinking that we've got a confusion of terms here.
"Girandola's" appear to be a cluster of fireworks or sparklers that whirl or burn off in a display.
I'm guessing that's not the right term for the wheels that build up speed and lift-off, trailing smoke, and actually fly in a competition.
Happy 4th of July, everyone!