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Author Topic: Binder Excel Plus - My L2 Build  (Read 15697 times)
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Mr F
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« on: April 29, 2011, 05:08:23 PM »


I can still hear the echoes of past conversations... "it's ok, babe, I'm only planning on getting my Level 1 cert... nah, I really don't see the point of spending $100 per launch - who'd be that crazy!?!?!?!"

Well... here I am, documenting my L2 build Tongue good thing I never got the above convo in writing or it might have come back to haunt me.

I figured I might as well take a few happy-snaps while building this thing, but first, a few thanks:

First and foremost: cheers to WRL Rocketry! I was one of the lucky recipients of the certification sponsorship program. My L2 motor, a J350, has been kindly donated by WRL Rockety.
Thanks also to Maurice, Scotty, Goffa and the AARC crew who've always been great launching with (when I can get there).
Thanks to my wife, who tolerates my eccentricities with grace Smiley

Righto, enough of that, on with the build!
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
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« Reply #1 on: April 29, 2011, 05:13:57 PM »


haha, love the "dry fit" photos. The dry fit really is a self-indulgent exercise but isn't the whole hobby?
The little brown bottle features rather heavily in this series... it is the school holidays after all.


There you go! C'mon, that looks horrible. If that was your "prom" photo the parents would never let you see her again.


Much nicer.



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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
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I am your father!


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« Reply #2 on: April 29, 2011, 05:18:02 PM »


I decided to shape the fins before I did anything else.
Oops... one other thankyou is to my father-in-law... the bulk of the build was completed in his "man-cave" at Streaky Bay. It is one helluva man-cave. The only thing was, even from the start of the build there was a whiff of some kind of terrible smell. I thought it was old bait or a rotten fish because the boat was in the shed. Someone else thought "dead-mouse" because we're on the brink of the next mouse-plague, unfortunately. Someone else said dirty-nappy. Anyway, it just meant that every now and then there was a whiff of something rank.

In this pic I'm about to use his belt-sander to work the fin edges. It beats the hell out of sanding/shaping ply fins by hand. The whole process was done in about 10-15 minutes compared to the hours it would've taken by hand.


Sweet as. Yeah, they're not perfect. I bank on the fact that the imperfections, on average, will balance out over the three fins.
Logged

They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
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Posts: 919


I am your father!


WWW
« Reply #3 on: April 29, 2011, 05:23:01 PM »


That night, I took Emir's advice and made myself a fin-guide. This would later come back to haunt me. You can see in the corner of the photo that it wasn't my first attempt! In fact, it took me about three goes to get a guide I was happy with. I don't have a jigsaw/cutty thing or a spare stack of ply so I made mine out of cardboard. I figured, for one use, it would work the same. It seemed rigid enough to stand up to the job required.

I'm not prepared to say how long I spent with my hobby-knife etc completing this part of the build. At the time it seemed like time-well-spent as it would make the fin attachment process stress free. No big deal, anyway, as I was at Wudinna with nothing to do but dream about building the rocket, at this stage. So I made a fin-guide.
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
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I am your father!


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« Reply #4 on: April 29, 2011, 05:26:19 PM »

Next morning and I'm back at the man-cave! First things first... the pre-cut fin slots are a bit tight. I want the fins to glide in when I'm tacking them on so they'll need a sand.



Haha, at several points in this build my wife's dad walked in, shook his head, and handed me something. This is one of those times:



This bit of steel made sanding in the fin-slots much more enjoyable.
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
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Posts: 919


I am your father!


WWW
« Reply #5 on: April 29, 2011, 05:32:37 PM »



Time to get out the glue! I used 5-min "cheap-as-chips" epoxy for tacking small stuff. The first part of the motor mount build was to attach a thrust-plate. This is the first build I've done that used one... great idea, really! The thrust plate is essentially the very rear (aft?) part of the rocket. Every other one of my rockets is "dinged up" at the back from landing on rocks at Spalding. This thing will be tough as, well, a really tough thing... I hope! Just to be clear, the thrust-plate is a ring of ply that is the same diameter as the Excel (4").



Next step was to lather up the thrust-plate and tube for the first centering ring.



Here they are, joined. I had to wipe off a fair bit of excess after this pic. Got a bit carried away.
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
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I am your father!


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« Reply #6 on: April 29, 2011, 05:38:59 PM »

Fin tacking time!



The front centering ring is just dry-fit for alignment purposes at the moment. Everything is ready for the fins to be tacked onto the motor tube.



First fin is in and fitting snugly. At this point, I'm chuffed with my efforts at building that fin guide... this is going to be easy!



Looking good! Next fin, eh? Hang on, let's have another look at the fin guide...
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
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Posts: 919


I am your father!


WWW
« Reply #7 on: April 29, 2011, 05:44:09 PM »



Uh oh... that can't be good!!!! After a few swears, head-scratches and more swears... I figure I'm an idiot that couldn't line up a 120 degree angle if my life depended on it. So I checked one more time:



Then spun it 120 and checked again...



It looks ok! The only conclusion I can make is that the slots were pre-cut slightly out. Don't know what the lesson out of this is... only make fin-guides for scratchies? I'm not going to can Binder here because I love pre-slotted tubes... they can be a source of great frustration, getting them lined up. Anyway... it looks like the fin-guide is a waste of my time... back to the good-old "line it up against something straight" method Tongue

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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
ARA Member

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Posts: 919


I am your father!


WWW
« Reply #8 on: April 29, 2011, 05:49:18 PM »


Second fin going on and lined up "the old fashioned way"... I hope the old-boy build the wall square!


Third fin tacked on and it's looking pretty good. I did have some pangs of regret about the fin-guide as these fins were going on... but the fin slots make sure, at least, that they're going in straight!
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
ARA Member

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Posts: 919


I am your father!


WWW
« Reply #9 on: April 29, 2011, 05:54:37 PM »



Next step was to extract and build the fin-can. I've never done a fin-can build before but I get the general idea. First step was to cut the tabs off.



Now cut, there's nothing holding the motor-mount / fin-can to the airframe.



It slid out "sweet-as". This was a relief because the destructions mention at this point "if you've been sloppy this could be difficult". No slops here!



You can see from this final photo that the the fins tacked on fine... quite strong, actually. You can also see that the front centering ring is still in the body. This will come back to haunt me later Smiley
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
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Posts: 919


I am your father!


WWW
« Reply #10 on: April 29, 2011, 05:59:48 PM »

Time to fillet these fins!



Haha, control-freak coming through. I used a spirit level to check that the fillets would sit evenly.



The tacking was done with 5-min gear, but the destructions called for 30-min epoxy for fillets. I went to the hardware store and had the choice of 5-min or 2-hr. At this point I probably should've stopped, rung someone, done some internet shopping and had a beer but I bought the 2-hr gear. By 2-hr, I mean, the label claims it is potable for 2 hours. It sets a long time after that.



I also grabbed some shot-glasses to do my small mixes. It turned out they weren't that good during the measuring phase (hard to make sure I'd used equal amounts) but they were good for mixing and applying. Beer is also good.
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
ARA Member

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Posts: 919


I am your father!


WWW
« Reply #11 on: April 29, 2011, 06:05:30 PM »



Here's the first of the fillets. I used a fair bit too much epoxy I reckon! Spent the next 1/2 hour wiping drips away from the motor tube. After half and hour of getting bored I figured I'd read the destructions and see what else I could be doing in the mean-time.

Hmmm... turns out I should've read them first! The front centering ring was meant to be joined by this stage. You know, after reading that, I scrabbled through every pile-o-crud thinking "where the hell did I put that centering ring!?!?!?" of course, we all know that now, don't we?


Before attaching to the motor mount, it needs the eyebolt attached. Had to drill a 1/4" hole for that to take place.


Looking great! Now to see if the drips had made enough mess to stop this thing going on properly.


Ha, phew! Front centering ring in place and no one will ever know, eh? Well, until now.
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
ARA Member

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Posts: 919


I am your father!


WWW
« Reply #12 on: April 29, 2011, 06:11:54 PM »

After all that excitement... waiting for 2+hour epoxy to dry is really boring! The other part of this build is the Av-Bay. The Excel-Plus comes with dual-deploy capability. That's a bit beyond me at the moment... I've got no electronicts for a D-deploy or any intention to use that for my cert flight... so why did I but the kit? Let's see:

  • It was damned cheap! As cheap or cheaper than the standard Excel, I think!
  • It meant that I got an extra couple of feet of length and a few 100 grams of weight on my L2 build... call me conservative but I reckon a nice medium-low flight is a good idea on a cert flight
  • Not to mention that size kind of does matter in rocketry (lame, yes, I know)
  • I will need to get into D-Deploy at some stage if I'm going to do L3 (what's that babe?)
  • It was damned cheap!
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
Mr F
ARA Member

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Posts: 919


I am your father!


WWW
« Reply #13 on: April 29, 2011, 06:16:10 PM »



Here's the start of the Av-Bay. I'm flying blind (a bit) here, as I've only ever had av-bays at the front of the rocket, whereas this av-bay is like a coupling tube with guts. First step was to epoxy two couplers to a section of airframe. I had a heap of spare 2hr gear so why let it go to waste?


The av-bay is completed fore and aft by two sections of plywood... one the same diameter as the coupler, one the same as the inner diameter. Similar setup to the aft centering ring and thrust plate. Anyway, they needed a glue and a clamp. Once again the man-cave came in handy... at my place I would've "clamped" these things with a few heavy books, I reckon Tongue


Both fore and aft seals are done now.... time to go to bed!
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They call me Flinty... they call me Johnno... they call me Freddy... always the same...
that's not my name... that's not my name... that's not my name... that's not my name...

EP Rocketry section head
ARA #120
L2 and scheming...
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