Fibreglass!

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Kryten
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Postby Kryten » Wed Feb 18, 2009 7:55 am

Marsboy,
Yes, a fibreglass rocket will be heavier than cardboard and thus not achieve the same altitude on the same motor. BUT it will be much stronger. This isn't really an issue until you get into HPR, where you need "better" materials than cardboard and balsa.
If the biggest motor you use is a "G", you don't need to use fibreglass.
As for the finish on the rocket, this is up to the modeller. You can get extremes of appearance no matter what the rocket is made from
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Postby Wingnut » Wed Feb 18, 2009 8:29 am


I'm so happy that someone has revived this thread. I've been thinking about the airframe for my L2 project, and particularly the virtues of cardboard versus fibreglass versus glass over cardboard. Dyna-Wind from Giant Leap Rocketry seems like a fantastic compromise of strength versus mass. It even looked like a very cost effective solution until the Aussie exchange rate took a dive. Does anyone out there have any first-hand experience with this product?Bye,
Mike

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Postby bpratt » Wed Feb 18, 2009 9:24 am

Mike wrote:
I'm so happy that someone has revived this thread. I've been thinking about the airframe for my L2 project, and particularly the virtues of cardboard versus fibreglass versus glass over cardboard. Dyna-Wind from Giant Leap Rocketry seems like a fantastic compromise of strength versus mass. It even looked like a very cost effective solution until the Aussie exchange rate took a dive. Does anyone out there have any first-hand experience with this product?Bye,
Mike


You bugger, you've got me interested in their Crossbow model again! :P

Then again with the Aussie peso, I'm going to have to put it on the backburner for a bit longer.

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Postby krusty » Wed Feb 18, 2009 10:52 am

Hi Mike,
I picked up a 'Little Dog Dual Deploy' from http://www.libertylaunchsystems.com/ Liberty Launch Systems.

It's a full fibreglass rocket - nosecone, fins, body tube, centering rings, motor mount, e-bay... The finish on the body tubes, fins etc. is outstanding :)

It's not a big rocket 54mm x 1.32m with a 38mm motor mount. You get no build instructions, no recovery hardware - but it's also only $90 (plus $50 freight... ouch!!) however, this will fly on anything from a G to a J. If you take off the top payload bay and omit the e-bay, you can fly it as a single-deploy version, too.

There's a bit of work involved in putting it together - I haven't started yet, but have since purchased kevlar shock cords, dual deploy altimeter etc. and am waiting on Scoop to get back to me on an Aeropack motor retainer. I've tracked down JB Weld (via Home Hardware!) but it will do for Mid-Power, L1 and L2 flights!

Pushing it up on a J350, it should apogee somewhere between 6,000 and 7,000 feet (according to initial work in RockSim)

I really do like the Giant Leap rockets - I was very close to getting an Escape Velocity 2.6 (and if someone is putting together a Giant Leap order, I may be persuaded....)

Krusty

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Postby Scoop1261 » Wed Feb 18, 2009 5:19 pm

I have used the Dyna-Wind on more than one occasion....Very nice stuff!

Kent makes it himself.....and I'm sure Ari will agree....has a very nice set up at GLR in Kansas!

The Dyna-Wind is considerably lighter than the FG tubes of comparable size, and is phenolic tube that has been wrapped with glass cloth and impregnated with Aeropoxy Laminating resin. A wrap of peel ply is used to extricate all the excess resin from the tube under pressure.

Pros

Lighter than FG
Cheaper than FG
Fits standard NC's & Couplers
Comes in many popular sizes
Easy to work with
No hassles gluing CR's or Bulkheads to inside as it is phenolic

Cons

Finishing can be slightly annoying (pinholes from peel ply)
Probably not as tough as FWFG tube

I have built the GLR Crossbow in dual deployment Dyna-Wind and it is a great kit, Yet to fly it.....successfully.

I used 6" Dyna-Wind to replace some of the upscale Thor....wonderful product. I have used various sizes on other projects and found it to be great to work with.............You can send the check for the endorsement of the product anytime Kent!
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Postby october sky » Thu Feb 19, 2009 2:06 pm

Agree with Scoop 100% !! Great set up and even better people ! :)
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Postby The Wombat » Tue Mar 10, 2009 7:37 pm

Okay, I have found a new Australian supplier of FG tube. the tube looks to be 'the right stuff'. I'm just waiting on the list of stocked sizes and prices. More as it comes to hand.
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Postby Kryten » Tue Mar 10, 2009 9:21 pm

What's the name of the manufacturer?
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Postby The Wombat » Wed Mar 11, 2009 4:35 pm

Forgive me if I don't name them just yet, but they are in Sydney.
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Postby The Wombat » Fri Apr 03, 2009 9:30 pm

Well, my samples turned up yesterday. Here they are:

Image


Image

2" and below appear to be pultrusions, the rest are wound onto parallel mandrels.
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Postby Scoop1261 » Fri Apr 03, 2009 9:58 pm

Hey Wombat, any chance you could post the wall thickness and the ID of the 2", 2 1/2", 3", 4", & 6" tubes?
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Postby Kryten » Sat Apr 04, 2009 6:46 am

They do seem quite thick.
Can you also calculate the weight/metre for each of the tubes?

AFAIK, there aren't too many commercial pultruders in Sydney
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Postby The Wombat » Sun Apr 05, 2009 12:14 pm

Nom OD ID WT g/m
2" 45.1 3.1 730
2.5" 57.3 3.1 833
3" 68.3 3.4 1144
4" 93.0 3.8 1762
6" 142 4.4 2874

Of course, these are just the supplied samples. They may have/be able to get them in a thinner wall. Alternatively, you could turn them down on a lathe. That would reduce the wall thickness and weight as well as removing any out-of-roundness and cleaning up the surface finish.

P.S. how do you mono-space a block of text in a post?
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Postby air.command » Sun Apr 05, 2009 12:51 pm

P.S. how do you mono-space a block of text in a post?


Hi Wombat, you can use the "Code" tags around your table:

Code: Select all

Nom OD   ID     WT     g/m
2"      45.1   3.1     730
2.5"    57.3   3.1     833
3"      68.3   3.4     1144
4"      93.0   3.8     1762
6"      142    4.4     2874
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