LOC Viper IV build

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getoutside3274

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As a member of CATO, it's becoming the "in thing" to have a Viper IV so I figured I would join in on the drag racing fun!.

Didn't alter the kit too much, mainly changing the shock cord mount, adding motor retention and using 2 - 1 1/2" launch lugs rather then 1 - 6" lug.

Here's the shock cord anchor. 3/16" eyebolt with 2 nuts lock tited on (see the red) and tightened against each other. The nice part about these 3/16" nuts is that they don't rotate in the cluster of 4 - 24mm tubes. Stuffed a piece of wadding into the hole and filled it with epoxy and inserted the eyebolt:
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For the motor retenion, a 1/4-20 coupler nut again fit into the cluster of MMT's and didn't rotate. Packed the wadding into the MMT gap and some into the bottom of the coupler nut to keep out the epoxy. Sanded the nut with coarse sandpaper to create ridges for the epoxy to bit into and stuck it in. Took a couple of tries to be able to get the nut in flush with the MMT without the epoxy over flowing:
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Had a bit of a scare with the fins. I was ready to bevel the fins and attaching them to the MMT and had a thought. Why don't I use the mower blade sharpener attachment on my dremal to bevel the fins!! At least the rough sanding, then I could touch them up after by hand. Well, got it all set to go, grabbed a fin and started grinding away...only to discover I was sanding the ROOT edge of the fin. AAAHHHHH. Dropped it in panic, thinking I will now have to trim all the fins to match...UNTIL I remembered that you have to bevel the root of the fins to fit in between the tubes. Duh.

Getting ready to bevel the fins:
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Now the tricky part. How to hold a 4 motor cluster onto a base designed for one motor. The cylinder to the left is what is supposed to fit in the center hole in the fin jig. The eyebolt with the washers and nuts is what I inserted (from underneath) to screw into the motor retention nut to hold the motor tubes centered and straight. This photo was taken after they were epoxied in:
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All clamped up and curing. The 2X4's under the base plate are needed because of the eyebolt:
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Applying the fillets:
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Ultralight weight shock cord mount on the NC. Cut 2 slots for the nylon strap to fit through:
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The drying booth:
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The build is almost complete. I've epoxied the MMT to the body tube and should have finishing photos by the end of the week.
 
Very nice, My Grandpa has one of these. It flies great. wonderful on D12's and not too overwhelming on E9's. But he was too scared to fly it on composites, so I flew it for him on 2 E30's for a most excellent flight. I like your paint job as well!:cool:
 
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Where did you get this, do you make them? That looks real handy and I'd love to have one.
 
I built one of these back in '96 or so and flew it MANY times. I was more than pleased with the performance of this kit. Had a D-12 CATO on me once and it blew the nosecone right after take-off (but left the chute in the tube), the rocket hit the ground from about 60 feet up and didn't even scratch the paint. I'll try to post some pics of it when I find them.
I'd recommend this kit to anyone who likes clusters! I'd love to see videos of that drag race if you can get any. And very nice job on your build.

:) Mike
 
I think he was asking "is the fin jig" worth the money, rather than the Viper...
 
Just a question, are these worth the money? BTW, great build. Looks beautiful!

I think so. I don't like any "squirrliness" in my flights and the rockets fly arrow straight with the jig, providing other forces don't affect the flight too much.

I think I have a pretty good eye for aligning fins (unless you count that 3" Phoneix I built about 16 years ago...I look at those fins and say "my god, what was I looking at!) but this jig allows me to get good pressure on the fin towards the MMT and clamp it there as it dries. Without the jig, attaching one fin at a time the tape is generally used to hold the fin vertical as well as apply some pressure into the MMT. Not sure if there is any really benifit to holding the extra pressure on the fin but it makes me feel good :D
 
Just add some lead to the bottom of it and the nose will always stay pointed up :kill: Yup eight ounces should do it hehe. Just some help from the competition lol ;)
 
Originally posted by dasein668
I think he was asking "is the fin jig" worth the money, rather than the Viper...


Oppsie, your right Dasein...My bad...Although if I had an extra 130 bux I'd consider buying one...Looks like a really well made jig..

Mike
 
OK it's coming to the end. I'd have to say that my first (and second!) experience with water slide decals wasn't the best. It looks OK (from about 10' or so). I have the one Viper iv decal to put on then clear coat:
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A close of the lethal end!
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Let the games begin!
 
That looks great! Where did you get the decals from?
 
So tell someone that has never touched off a multi-engine bird what kind of ignighters are you using?? Just curious..

Matt
 
Standard Estes igniter's, it was my first time at lighting multiple motors. I thought there was a trick, nope just take your time and it works great. You or rather I attached them in parallel with one piece of tape on each motor and used a clip whip to attach them to the two trigger wires.
 
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