This noob here will make a Girandola for 2016/17

[Ubehage]

I have watched a lot of videos about Girandola-construction, and most of them are not very informative - they are purely visual.

 

From that, I have convinced myself that a light-weight frame and a bunch of retail-rockets will work.

And, being the crazy guy that I am, I'm obviously considering the largest legal rockets available.

 

I have a few questions though, before I feel like I can get started:

 

What material would be best suited for making a 'dola - wood or plastic? And, which kind of wood?

And, probably the most important question:

How would you secure the rockets to such a constuction? Can they be glued and pasted with gummed tape?

 

 

For those who don't know what a Girandola is, here's a video of a VERY nice one:

https://www.youtube.com/watch?v=18uVtCVNTvo

Edited December 6, 2016 by Ubehage

[Mumbles]

The best available source of information on Girandolas is available on Passfire and from some books via Tom Dimock. I included links to the book, video and a combo. The combo is $10 cheaper than ordering both separately. I'm not sure what shipping to the EU is like.

 

http://www.fireworksnews.com/Item/Girandola

http://www.fireworksnews.com/Item/D8u

http://www.fireworksnews.com/Item/C_D8u/M24

 

The biggest issue with using commercial motors is that they all are basically core burners. They don't really need to be made in the traditional method. Namely they don't need horizontal drivers. In a from scratch girandola they provide gyroscopic stability. With the thrust from core burners, this isn't really as necessary. I'd attach them all as vertical drivers, maybe with a bit more of an angle.

 

If you want to get your feet wet, I'd probably use plastic. It'll be easy to drill and cut and basically pre-made. If you want to go down the wood route, I'd suggest checking out the above resources and finding something light. Bamboo, reed, and sometimes pine tend to be pretty popular.

 

As far as attaching, tarred or waxed twine is traditional. That said some people use hot glue and zip ties especially on the less traditiona or more thrown together plastic framed versions.

 

I'm not sure if you've seen this but it might give a little more info and perhaps a place to start. The same concept can work on slightly larger scales using flower pots or 5 gallon/20L buckets.

http://wpag.us/learn/Mini%20Girandolas%20by%20Jim%20Biersach.pdf

[Col]

You can use round embroidery hoop frames but they are quite heavy for the size. I steam bent some ~12" hoops out of thin wood and glued 2 together using a circular jig. If you have a table saw you could knock up a thin strip rip jig to cut wafer thin strips for laminating into hoops.

 

Edited December 7, 2016 by Col

[Arthur]

There really is no actual line between a rocket motor and a stage gerb but a driver for an effect like a giro is somewhere between the two extremes. -Some thrust and long burn are the required features, if you can add a pretty tail so much the better.

 

The frame you use is determined by your practical skills! If you are a woodworker then a nicely steamed ring of fine thin wood with a nice scarf joint would be good Otherwise you could get a plastic bucket and cut slices from it.

 

One of the challenging parts of the job is the fusing and delays. Usually a giro is spun up to speed before being lifted, so you need well rammed drivers to create the spin then a delay before the drivers that will create the lift come to power.

 

What you don't want is a rocket motor that burns with high thrust for three seconds, Try aiming for a driver that burns for 30 seconds.

[Arthur]

The only rules of giros are 1/ it goes round, and 2/ it goes up.

 

Anything else is a part of your design. Some giros rise twice because a second set of lift motors come to thrust after the first have started to fade. Balance is good so that the thing spins and rises safely, the problem with giros is that they wander off course if they are unbalanced, and they must always land down wind. they NEED space

[Arthur]

Some far eastern giros use a bamboo pole full of BP with a ring of bamboo wood as a body and the BP filled pole as a diameter rod. Two holes in the BP filled pole act as rocket nozzles, light both nozzles at the same time to make both spin and lift.

[Redrocketman]

1st time I've seen one. Unreal!!!

[Col]

The Thai dola`s are ideal for daytime as the smoke trail is the main effect. For normal dola`s, its best to start by testing the sustained thrust of a basic bp end burner using a kitchen scale. Figure the total weight of the dola and use enough drivers to provide 1.5x that weight in thrust. So if one driver provides 0.5lb of sustained thrust and the dola weighs in at 2lbs, attach 6 drivers (3lb thrust) and go test it in a10 acre field

Edited December 8, 2016 by Col

[Arthur]

Go test them in a 10 acre field (or bigger) with no houses or property for miles when the vegetation is wet. The first ones will fall short of your intentions and land somewhere else.

[dagabu]

Ubehage,

 

There are many, many varieties of girandolas out there, I have made them as small as 4" across all they way up to 4 feet wide. OK, the outriggers were 4 feet, the outer hoop was 24 inches across.

 

If you have access to commercial Class-C whistle rockets (screaming whistle to crackle), you can make the Jim Biersach style, Ice Cream Bucket Girandola.

 

https://youtu.be/FW37OKnJhuQ

 

I still have the dola frames, I can snap a few pics for you if you wish, they are very easy to make.

[dagabu]

Another idea is to harvest a used dola from a show. Here is one I picked up and re-used.

 

 

Here is the frame with about 1/2 of the plastic tubes, cleaned and reloaded with BP and a clay plug. They all got drilled out to the same depth with a 1/8" drill bit before fusing.

 

 

Here it is in action

 

https://youtu.be/dbEKtSErBiY

[dagabu]

The 24" ones are a LOT harder to make and fly! Here are several frames I made last year, four have flown, 1 flew TWICE!

 

 

A better look from the side.

 

[dagabu]

Here are my two 24" dolas at PGI starting off the Rocket Rodeo using the frames show above.

 

https://youtu.be/4rg_NaL0KpA

[dagabu]

I would be happy to deconstruct any of them for you or work on a tutorial if you like. I want to do a week long class on them next year or the year after.

[Boophoenix]

I saw those Dave. I didn't know they were yours. Congrats!! That was my first rocket rodeo too. Caleb warned to keep an eye out for the rogue rocket, but the excitement came from August shortly after as I was coming back from the parking above the rocket line. That night was the highlight of my PGI adventure.

[Ubehage]

I would be happy to deconstruct any of them for you or work on a tutorial if you like. I want to do a week long class on them next year or the year after.

That would be awesome! If you find the time to do it, I'm sure others will also appreciate it.

 

And thanks for your pictures and explanations.

You are awesome!

[dynomike1]

I am also looking at building one, but i am going to cheat starting out and buy my first one. Whats $6.00? The problem i am at i am not a rocket person. Everything i read is end burners, so what is the difference in end burner tooling and Gerb tooling and or Whistle tooling. I dont to spend money for something i cant use. Going to have a lot of questions before this is over. Col ol buddy you said 1.5 times. Is that the thrust of the 2+ that start the lift or is that for all of them? Stay with us Ub we are going to do this.

 

 

 

MIKE

Edited March 4, 2017 by dynomike1

[OldMarine]

Mike, Ned is putting a lesson in 201 just on Girondolas using the ready made frames.

[dynomike1]

[dagabu]

The thrust to weight ratio differs from person to person, I try to keep it somewhere in the 2.1 to one ratio so that I have a slower Ascent. Others like as much as a three or even four to one, such as those little red frame plastic ones you can buy. If you get an burner tooling set, you can use it for many things other than just girandolas , you can also use it for drivers for ground set pieces,rockets and even some gerbs.

[OldMarine]

Mike, I have the spindle. press and support to make your motors. do I need to plan a road trip?

[dynomike1]

Thanks Patrick i dont think that will be necessary yet.

[OldMarine]

If your gerb tooling forms a proper nozzle it should work for nozzled end burners.

[dynomike1]

I dont have Gerb tooling. What size tubes are you using in your Girandola or do you have it yet? I have some 9/16" tubing that fits just a touch loose. Never mind i found it.

Edited March 7, 2017 by dynomike1

[lloyd]

Mike,

I use 1-gallon tubs for small 'test' batches, 5-gallon tubs for larger batches, and 20-gallon tubs for 'production' batches.

 

I use 3/4" i.d. tubes for girandoli drivers.

 

 

Lloyd