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  #11  
Old 09-18-2008, 08:10 AM
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Shreadvector Shreadvector is offline
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6 cuts means cut the two tubes into 3 shorter lengths each to form the small tube fin bits. The description of the build tells how to glue them together, so that helps explain it quite nicely.

I use the large (normal looking size) Easter eggs. Still have hundreds of the hemispherical halves for virtually free - just pay for the shipping. I use the longer halves for egg capsules.

Wiper inserts are found in the trash can at the auto parts store or auto repair garage/shop/oil change places. Also on the ground in the parking lot in front of auto parts stores on the first rainy day after a long dry spell.


Quote:
Originally Posted by canada
Great post El Cheapo! Thanks for taking the time to outline your building process - very helpful. If you get any rocket pictures from your build weekend please post! Six 7 yr old girls in your house...man you're brave!!

Just a few questions:
1. Forgive my brain freeze, but I'm not getting your first step with the toilet paper tubes. I'm a bit lost to understand the 6 cuts and what role these tubes serve.

2. Have you found a particular size of Easter eggs to work best?

3. Have you found a cheap source for the windshield wiper part?
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  #12  
Old 09-18-2008, 08:15 AM
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Shreadvector Shreadvector is offline
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By the way, if you select the appropriate brands of paper towels and toilet paper, you can find a TP core tube that will slide inside the PT core tube and this can be used for a tube coupler and for the nose cone shoulder. I cut them in thirds.


if you cannot find a TP core that slides inside, then simply slit them along the length and roll them inside themselves and glue to form a smaller diameter tube.

I ALWAYS use real modroc BT-20 for the motor mount tube and make it 9 inches long to form a stuffer tube and protect the PT tube from delay afterburn so it will not catch on fire. ("fire" = "Bad").
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  #13  
Old 09-18-2008, 11:51 AM
El Cheapo El Cheapo is offline
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Ditto on Shreadvector's comments. He's 100% correct.

This is a tube finned rocket. The tube fins are made of tp tube that are cut to 30mm lengths. There should be six of them which is why you need two tubes to start.

As far as the size for the tube fins, I'd guess cutting the TP tube in thirds will work just fine. I cut off a couple mm from the ends to make sure they're straight as some TP tubes do not have a straight end cut.

The motor retention clip is not necessary if you want to roll an engine block out of cardstrock. I begin by cutting 3mm lenghts of cardstock and roll around a spent 13mm casing to fit for 18mm motor tubes. Friction fit is used in this method for rear motor retention.

Another way of making the engine tubes is to download the instructions for the free FlisKits Caution Rocket. This is a nice, easy motor tube method that uses folded cardstock on the end of the rolled motor tube for forward retention. Friction method is used to keep the motor from kicking out the back. However, I do not use the tape method as stated in instructions. I just use glue and roll around a spent casing as I've found the tape is kind of a pain in the u-know-what to remove.

As far as easter egg size, I just use what I've raided out of last years baskets for the kids so nothing special there.

I honestly don't think there is much cause for concern in the way of the bt catching on fire but I'm sure SV has been doing this longer than I have so to err on the side of caution won't kill you.

One more tip: I use a 4x D cell maglight with a few sheets of paper wrapped around it for snug fit as a mandrel when cutting the tp tubes. I've also wrapped the paper with a sheet of wax paper and coated BT's and fin tubes with 75/20 glue/water mix to stiffen and reshape the tubes if they are bent, creased or have small indentions.

If you're really uptite about it you can coat the insides of the fin tubes with thin CA to add to their structural rigidity.

Boy, this is getting extensive for a rocket that'll cost about $.30 to build....lol
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  #14  
Old 09-18-2008, 03:21 PM
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I've found that connecting cardboard to plastic (plastic egg nose cone) is super easy with a low-temp hot glue gun. It's not pretty but can absorb ejetion charges pretty well when at the nose cone end.

Just my tid-bit...

Also, you may want to try looking at building Birdie Rockets - Do a Google on it.- Andy in Houston
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  #15  
Old 09-18-2008, 03:32 PM
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Shreadvector Shreadvector is offline
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I forgot that I had a photo of my kits. The one on the right uses PT tubes and is the Neanderthal. The Berserker is the same with non-swept fins.

I'm having difficulty with attachments today - browser hangs and dies - so go to link and look at photo on 2nd page...)

http://www.geocities.com/fredeshecter/prdctinf.pdf
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  #16  
Old 09-18-2008, 04:23 PM
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maricopasem maricopasem is offline
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Quote:
Originally Posted by El Cheapo
The motor retention clip is not necessary if you want to roll an engine block out of cardstrock. I begin by cutting 3mm lenghts of cardstock and roll around a spent 13mm casing to fit for 18mm motor tubes. Friction fit is used in this method for rear motor retention.

Amen. An index card, a glue stick, and a spent engine is all you need. Except for the one kit I built stock a few years ago I haven't used an engine hook in years.
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  #17  
Old 09-19-2008, 06:39 PM
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Quote:
Originally Posted by canada

And if anyone else has successfully made a paper towel rocket and wants to pass along any suggestions, please do.
Given the students are in a group setting, I'm trying to keep things simple. [Snip]


Douglas,

Here is another website for reference:

Astrosaint's Recycled Rocket Page


Regards,
Mike
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  #18  
Old 09-20-2008, 02:45 PM
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canada canada is offline
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Thanks everyone for your tips and links - very helpful. Thanks too for your patience with my questions. I do try to understand!

Now I just need to try some of these out...then you know I'll be back with more questions!
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  #19  
Old 09-21-2008, 06:33 PM
El Cheapo El Cheapo is offline
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We built two Y-Wing rockets as featured on Astrosaint's Recycled Rocket Page and flew them this morning. Thanks to Mike Bar. I forgot about that page. They're very easy to build and great fliers. I did coat all tubes with the 80/20 glue/water mix I mentioned on any type of mandrel to make sure they're nice and round. It did require a small amount of nose weight to swing test on a C-6.

Flight report: First flights on A8-3's. Nice flight to about 200'. Perfect recovery on both. Second flights were on C6-5's. Excelent motor for this rocket. It flew to maybe 500'. Deployment was a few seconds after apogee which was nice to watch. Perfect recovery and ready to fly again.

We also built two of the 6 tube finned rockets I described. Zero nose weight required for even a C-6. the tp tubes were cut into thirds and many were a bit taller than the next. It didn't seem to effect stability at all. Excellent flier as well but does get some wiggle if the tube fins are a bit out of round. One of the rockets got stepped on while the girl was trying to catch it "which I advised against for fear of stepping on it....LOL". This version did get a bit more altitude than the Y'wing.

All in all, everyone had a great time.
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  #20  
Old 09-23-2008, 02:40 PM
El Cheapo El Cheapo is offline
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Here are the flight pics from Sunday 9/20/08:

Y-Wing from Astrosaint's Recycled Rocket Page on A8-3






6 Tube Finned Rocket on A8-3







If kids would only listen to adults, this rocket would not have gotten stepped on. It had some wiggle after this flight.....LOL


Last edited by El Cheapo : 09-23-2008 at 03:21 PM.
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