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Converting a 2 foot Crayon

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georgegassaway

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At the local “Dollar Tree”, I found some blow-molded plastic crayons. They are about 24.5” long and about 2.5” OD in the areas that bulge out. The mass of the original Crayon is 90 grams, or about 3.2 ounces.

Maybe this particular Crayon has been converted before, by somebody.

I do not think I will get around to converting one to fly for awhile, so I wanted to mention it now while these are “out there”, as these seem like great ones to convert to fly. And the price is sure good, $1. Of course, YMMV may vary as to whether your local Dollar Tree has any.

The back of the crayon has a black flexible plastic insert. Well, pop out the insert, and the remaining hole is a PERFECT fit for the Quest 30mm diameter tube. Now, yes, one could convert this to fly on 29mm engines. What I am looking to do, eventually, is convert it to fly on a D12 (maybe C6), so I’ll put a 24mm engine mount inside of the 30mm tube. The great thing is that there is no need to cut a perfectly centered hole, it already exists. And a 30mm tube would be useful as both a stuffer tube and as a tube to glue the fins to. So, at least the back end of the Crayon will center the tube, a custom centering ring will have to be made up to center the upper end of the 30mm tube (or a ring to hold the 30mm tube in a BT-70).

The one bit of actual “building” I did, well, it was not building but disassembly. I cut the upper part to make it into a nose cone. Later on, that nose cone will get a shoulder, and probably a bulkhead since there is a slot in the tip for coins (Ah, yes, I did not mention this is supposed to be a “piggy bank”, which is also why it has the removable plug in the base). The inside diameter of the plastic is about 2.25”. A BT-70 fits almost PERFECTLY inside of it, it would only require a few wraps of tape to get it to center right. Now, a BT-70 tube would add some mass, but would be justified if it was flown on E or above composite engines since the ejection charges tend to be pretty hot and such (Afterburn of Composites). For a model that only used a D12 (or E9), well, it might be OK to have the 30mm tube run about 8” or so up inside of the crayon, as the ejection heat past that distance (and the distance of the 30mm tube sticking out the back) probably would be cooled enough not to melt the plastic.

Now, for stability, I’m not going to mess around with clear fins. They are nice, but a PITA. I want this project to be a nice simple easy to build, and not-too-fragile thing. So, I am going to have the 30mm tube stick out of the back by 4 to 6 inches. Then glue some wood fins on it, such as 1/8” hard balsa for a “light” one to fly on C or D power, or 1/8” “lite” Plywood for one that flew on 29mm E, F, or G power. Then mask off the whole crayon and paint the 30mm tube and fins flat black.

With the above, maybe someone will beat me to actually building and flying one.

- George Gassaway

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Micromeister

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That's a good alternative to using clear fins George. Can be tied into the overall look of the model with a little paint.

When I did my dollar store Caryon, which is Cardboard and Plastic btw, I went with clear Polycarb fins and a 2 D12 cluster motor mount just for fun.

Can't beat the price of a Buck! Good to know they are back in the stores.
 
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soccerdad

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Now that I've joined the board, I can post my pics! Here are photos of my crayon rockets.

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soccerdad

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After several improvements, this yellow one is the definitive design. I used the nose section as a payload bay. With these features I could easily use this as a TARC rocket with the right engine.

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Queeg500

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Cool! This thread made me look for that crayon bank I bought last summer. what kind of glue did you folks use to bond the paper tubes and fins to the plastic?
 

soccerdad

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I used Wilhold RC56 for those joints. It worked quite well for gluing the inner tube sleeve to the nose cone for the coupler. I used it for a fillet at the fin/body joint where it exits the TTW area. No glue is needed for the main tube, its a firm fit. I just anchored it inside with the rings for the engine stuffing tube

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epickett

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Cool! I have crayon rockets as well, but they're the larger ones from Toys R Us. I wish I *could* find some smaller crayons...
Here are some of mine. From left to right:38mm single crayon, 38mm double crayon, 54mm tube-fin, 38mm cluster w/outboards, 38mm 2-stage. I also just finished repairing a 54mm double crayon, and I'm almost done with a 76mm double crayon. Yeah, I think I'm addicted...<g>

Eldred

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Micromeister

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Cool! I have crayon rockets as well, but they're the larger ones from Toys R Us. I wish I *could* find some smaller crayons...
Here are some of mine. From left to right:38mm single crayon, 38mm double crayon, 54mm tube-fin, 38mm cluster w/outboards, 38mm 2-stage. I also just finished repairing a 54mm double crayon, and I'm almost done with a 76mm double crayon. Yeah, I think I'm addicted...<g>

Eldred
I have Crayons in a number of sizes: from actual size (micro-maxx full scale LOL) to 4" 5 -D12 clustered. I found many in between sizes at various dollar stores from time to time. Some have clear plastic bodies others are cardboard body. all need stuffer tubes anyway so if it looks like a crayon it can be converted:)

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jeff_in_AZ

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Nice crayon rockets all around. Recently I found this item at the store,
they are crayon shaped containers of bath gel called "sudsy scribblers":

http://www.crayolastore.com/product_detail.asp?T1=CRA+298100

They are about 5" tall and the empty weight is 6.7 grams. I'm in the
process of building a 13mm rocket with one, will post some details
when it's finished.

jeff
 
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