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Author Topic: EMiR’s 5.5” Defender  (Read 3351 times)
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EMiR
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« on: February 03, 2013, 09:35:34 PM »

Howdy,

I've started work on 5.5" BT 75mm MMT Rocket

Not 100% sure whats it going to be yet, I tossing up over, ether a up scaled Binder Excel or a rocket called Defender.



Anyway, Today I got the first FG tube rolled up, using 6 layers of 180gsm plain, and 4 layers of 90gsm plain over the top.

gave me a 2mm wall thickness, which is a great outcome, nice mix of strength and weight.

I already have a 5:1 nose cone and a 5.5" Blue Tube AV bay to use.


I'm building this for AURORA and for a very special long burn L class motor.
This will be a very low and slow flight, to get the full effect.
to hear that very nice throaty roar.

Sim puts it at around 6000-7000 feet with a lift ratio of about 6:1

I'll get some pics posted this week


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wolflair
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« Reply #1 on: February 04, 2013, 06:44:57 PM »

defender sounds good  blsmiley
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EMiR
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« Reply #2 on: February 05, 2013, 05:15:37 AM »

Excel is a very stable design, and though I started rolling the tubes to make an upscale version,

I've decided to go the defender, being something a little different




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Goffa
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« Reply #3 on: February 05, 2013, 03:54:12 PM »

Nice Emir!
love a big slow HPR lift off
hope you got a nice long rail/tower to get that launch velocity up high enough!!!
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EMiR
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« Reply #4 on: February 05, 2013, 04:08:23 PM »

Rocsim has it at 4m for stable flight

So 8m 1515 rail should do the trick..

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EMiR
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« Reply #5 on: February 10, 2013, 06:27:49 PM »

Well, I've got the tubes rolled..

Just not sure how I want to build this one, whether to have it in 3 pieces, or just 2



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EMiR
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« Reply #6 on: February 21, 2013, 09:21:07 PM »

Updated Design....





Got the Fins cut out and CR's - 7mm 5 ply



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Rocketmad
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« Reply #7 on: February 21, 2013, 11:29:57 PM »

looks good.
keep looking at the tools you are using and think .... i wish..lol
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EMiR
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« Reply #8 on: February 22, 2013, 07:05:02 AM »

no need to wish mate,

little bench drill and hole cutter, was like $100 all up from Bunnings.

best thing I've bought over the years, one of the most used things I have.


So the Drill and cutter, plus a set of BlueTube 48" joiners to use as mandrels and a good tenon Wood Saw

and that's pretty much all you need to scratch build any rocket up to about 6"

all up might cost you $300-$400, but when you look at the price of Kits, you will soon save money on it all

and after awhile it becomes so quick and easy just to slap together your own rockets, just with these basic tools

for example, this 5.5" Fibre Glass rocket has cost me so far

Plastic Nose Cone - $50.00
Plywood; 7mm 5ply - $8.00
2 x 5.5" FG tubes - $50.00
1 x 75mm FG MMT tube - $15

taken about 4hrs of labour,

and I'm at the kit stage, ready to start assembling


Nothing I've have done to build this, takes any great skill
Anybody could do this with a little practice.
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EMiR
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« Reply #9 on: February 23, 2013, 08:24:41 AM »

What a beautiful design.... credit to DG&A rockets

This is just a quick look at the design, the finished rocket will have 2 Joiners

I'm doing a joiner just after the fins, as to have a mid section that I can change out for an extend tube, to fit the longer hybrids
then the next joiner will be the AV Bay as per normal.




Here's the original DG&A design


http://www.rocketreviews.com/dga-high-power-rocketry-defender-billy-dahlberg-and-osgood-conklin-9351.html


 
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EMiR
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« Reply #10 on: February 26, 2013, 12:15:13 AM »

Adding some Carbon goodness to the internals.

A little over kill I know.

I was going to just use a little bit of FG, but there was a heap of Carbon off cuts on top of my pile of scrap, So I though why not.

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EMiR
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« Reply #11 on: March 13, 2013, 06:20:37 PM »

Ok, FinCan complete,

Got Fillets done, and 2 layers of Tip2Tip 180gsm Glass on, finished epoxying the CR's in, added the ShockCord Mounts, and Rail Button.
It's ready for Sanding and painting.

The 2 other Body tubes are ready, just started making up the AV/Bay today.
So rocket should have its under coats on this weekend, if the weather holds up.


So who's idea was it to make a 5.5" rocket, these bloody things, chew up heaps of everything.

I am up to 12m of 180gsm and 4m of 90gsm Fibre Glass, I've used about 2.5lrs of Epoxy.
Even the fillets used up like 200g of epoxy.

not looking forward to sanding this bad boy....

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EMiR
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« Reply #12 on: March 23, 2013, 06:59:05 AM »

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Rocketmad
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« Reply #13 on: March 23, 2013, 01:31:43 PM »

looking good, what colours you going to paint it?
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