RW Mad Dog 6 Build Thread--parts to flying on an M1939W in 46 days

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Viperfixr

Born Again Rocketeer
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This Rocketry Warehouse Mad Dog 6 kit has been in my garage for longer than I care to admit. It was my 'backup' kit in case my primary L3 rocket was destroyed, but was not needed to certify. Like most of you, I do not have as much build time as I would like, and the Nevada heat kept me out of my garage more than it should have. With the weather cooling off some, it is time to build.

To force my hand with this project, I ordered an Aerotech M1939W today from Balsa Machining! My aim is to fly this rocket on that motor in 46 days at the Tripoli Vegas Oktoberfest launch, but today it is nothing but parts.

I will post this build thread part to keep me focused and building, and part because I strangely enjoy making build threads. I will not claim to be a gifted builder, but I have learned a little from some very smart rocketeers. This build will be largely 'stock' & naked (as intended) to keep it simple and on time.

Tonight, I yelled and cursed at the nosecone coupler and av-bay coupler stuck deep inside the airframes. With PVC pipe, a hammer and far too little patience, I got them out. Then I washed the whole shebang on the back porch with dish soap and a sponge, because there is no way I was going to fit this monster in the bathtub or shower. Here is what it looks like post-washing on Day 1.
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I already have on-hand a large Rocketman chute, a Onebadhawk kevlar recovery harness, an Aeropack motor retainer and a 1/2" ply centering ring from UpscaleCNC/Wingarcher pre-drilled for the Aeropack motor retainer.

Bring on the Aeropoxy ES6209 soon!
 
Vegas or Bust baby !

Geez 46 days..that is coming up quick !

Kenny
 
Took my UpscaleCNC ply centering ring and fit it to the motor tube (i.e. dremel'ed it a bit). Then I took the Aeropack threaded inserts, dabbed them with a bit of epoxy, then installed them. Once done, I flipped it over and installed the retainer while the inserts were still somewhat movable. Each screw got a dab of vasoline in case there was any epoxy in there. Put them all in, test fit with a motor and on the motor tube and fit checks were good. Done.

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Last night I doubled up two of the FG centering rings and installed a 5/16" U-bolt. I also decided to permanently installed the Onebadhawk kevlar recovery harness; one less connection point I will forget to connect!
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Then I got the spacing right with the middle and aft centering rings so that the fins will be adhered on each end, marked it all off, taped off where the middle ring would go and epoxied it in place.
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With the pieces/parts being so darned large, it makes handling things easier. Rings are less likely to disappear in the abyss of doom (under my bench) if dropped.

That is enough for tonight. Sure feels good to build!
 
Felt like I spent hours in the garage today but did not get very far. Didn't help when I did not measure the rail button distances correctly to clear the motor mount....grrrr. Anyway, here it goes.

Put the switch band on the av-by coupler.
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Two centering rings on the motor mount. I have so many of the Aeropack stickers that this one will live forever within the rocket, never again to see daylight (I hope).
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I decided to 'inject' the internal fillets, so four tiny holes just outside the slots for that later on.
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I also decided it would be easier to drill the rail guide holes now rather than later when the darned tail section weighs 20 lbs. Chose Doghouse Rocketry 1515 rail buttons with 1/4"-20 screws. Each rail button will get a 1/4"-20 nut on the inside, epoxied down to allow rail button changes. Bottom (aft) rail button rests against the aft centering ring for support. Once the holes were drilled with a #7 drill bit, I tapped each hole to 1/4"-20.
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Then I screwed in the rail buttons, perfect fit.
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Except one problem...the forward rail button is BELOW the forward most centering ring. I filled that hole with Aeropoxy and will drill a new one AFTER the motor mount goes in. Grrrrr again.

Oh, and with some leftover epoxy I put together the first of two av-bay lids. With plenty of vasoline on the centering 1/4"-20 guide screw.
IMG_0271.JPG
 
Looking forward to more build pics and pics of the flight. I got my L3 last Oktoberfest at Jean with a blue Mad Dog 6. Should have gotten it in red.

The build was modified a bit with the nosecone coupler as the av-bay so that it could fly on a 6XL 98 CTI motor in the future (N5800). I found out later that I should probably add another 12" between the nosecone and av-bay for flights above mach. Unfortunately I won't be able to make it to Oktoberfest this year.

Here is a link to my L3 Mad Dog 6 build if you are interested - https://miles2go.com/rocketweb/Miles Anderson Blue Moon Cert. Doc.pdf
 
Mark very nice start on the build. Looking forward on seeing the rest of the build. Miles nice good on your build. The blue color is nice also. Heck I really like all RWs colored tubes. Floyd at RW says to use clear shoe polish to really make the tubes shine.
 
I don't want to co-opt this thread but I originally used clear shoe polish for all of my RW kits. It melted and ran in the Tucson heat. After removing the polish, no mean feat on the 9' tall Mad Dog 6, I went with Future floor polish 3:1 with concentrate Simple Green. Much faster and easier to apply, easier to touch up, easier to remove.

Mark very nice start on the build. Looking forward on seeing the rest of the build. Miles nice good on your build. The blue color is nice also. Heck I really like all RWs colored tubes. Floyd at RW says to use clear shoe polish to really make the tubes shine.
 
That build is coming along great Mark...
That is one huge rocket...
I can't wait to see the flight ( pic's anyway,, lol )...

Teddy
 
Sorry, no pictures yet, but I just got done putting in the motor mount with more Aeropoxy that I have used on on an entire 38mm kit. One reason the big boys weigh so much, I suppose. Because of the placement, also had to put in the aft rail button. So, spent a while shaving down the lock-nut and making a divot in the centering ring so the spacing between it and the centering ring placement was just right to ensure fin clearance (if that makes sense). My daughter was invaluable help, since even Aeropoxy ES6209 sets kinda quickly when the garage is still about 95F--the 4-6 hour pot life turns into 30 minutes in large quantities. Also had enough epoxy left over for the last av-bay lid combo.

I have never before put in a 98mm motor mount, but that was FUN. Makes me wonder what a 6" motor mount would be like...
 
Go Mark Go!

I will be pushing you along.......no excuses....unless WWlll.

Mark's doing a marathon build!!


I'M watching, lurking in the shadows & not taking no for an answer............:wink:
 
CJ, keep pushing me along all you like--mentor pressure is great for finishing on time!

Ordered the electronics today--Missile Works RRC3 and RRC2+ in a 98mm dual av-bay (3D printed). I plan to offset the av-bay to accommodate the 6" airframe, and potentially use a third 1/4"-20 all-thread with some weight on it to reduce coning from off center of mass weight (read about that in a JimJarvis thread somewhere, I think). Maybe 1/3rd the weight of the 98mm av-bay ready to go on the third all-thread in the form of washers. Any thoughts or inputs on this much appreciated.

First massive fin gets stuck tomorrow night.
 
I'm wondering about the third all-thread and balance weight and coning? Are you sure it's needed? or has any real effect? If a little off center weight can cause coning, I would think the drag from rail buttons would be a much larger cause. I always thought coning was a combination of off center thrust and fins that cause spin.

Just trying to learn a little more.
 
Used a technique from CJ on the fins, scoring the bottom with a file a little. Also used rough sandpaper on the fins anywhere epoxy was going, and then cleaned everything with alcohol.
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After a little sanding to get the fin in the slot without much fuss, into the large guillotine jig it went. I recently bought this from Apogee, although I think TMackin is the one who designed/made it. This is the second HP rocket I have used it with, and I wish I had bought this jig a long time ago. Not cheap, but the more you use it, the less than cost really matters. I plan to use it on ALL rocket builds with 54mm or larger airframes. {my home brewing rig in the background, a digital PID RIMS tube mashing setup}
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Dry fit good, so I mixed up some Aeropoxy ES6209 and stuck the first fin. I don't know about you all, but I LOVE "sticking fins" on a build.
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Alignment good!
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Next couple days will be the other two fins, and then on to the fillets with black Aeropoxy.
 
Fin #2 on...starting to look like a ROCKET. Also, got from UpscaleCNC ab-bay like lids for the nosecone, mostly to make a tracker bay. Should be here in a few days, along with the electronics.

CJ, I'll give Hunt's a try next time I need "Epoxy Dispensers"! :wink:
 
All three fins on now...internal 'injection' fillets starting tomorrow. Photo updates soon.
 
I am overdue for an update! The build continued, but I ran short of time to take picture and update here. Howwwwwever, I am now on what we USAF-types call "use or lose leave", meaning I must use up my vacation balance above 60 days before 1 Oct when the DoD cuts off anything above that. So, I am on leave until 1 Oct; lots of building time. And a little work from home...

Got all three fins on! After this dried, I did all six internal fillets, injected with syringes left over from a family medical issue awhile back (I kept them all, like 70+).
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Used my excess epoxy on a Wildman V-2 2.6"...
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Got these COOL nosecone bay lids from UpscaleCNC...which fit perfectly with no sanding.
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Injected the internal fillets with US Composites epoxy (runs easier than Aeropoxy). Afterwards, still had some gaps near the top of every fin and the injection holes. So, I have some Aeropoxy lightweight filler and filled all the holes. I used Rocketpoxy black pigment to try and darken it, but dark gray is the best I could get.
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I moved on to the av-bay. After making the airframe a little more even at the top to get a better coupler fit all around, I drilled four holes for the av-bay fasteners. Each hole got a PEM nut in 10-32 size with a dab of epoxy in the hole, Vaseline on the screw, screwed it in tight, then more epoxy around the base of the PEM nut.
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Moved to the nosecone coupler. My problem was how to make the upper nosecone coupler bulkhead removable so I could tighten the AL tip if needed (learned this the HARD way). The solution I used was to slice about 0.5" from the top and botton, and it slides into the coupler and in place easily. Put the coupler in to gauge depth with the bulkhead on the coupler, ran tape around at the depth limit, spread black Aeropoxy around the coupler and slid it in. Removed the tape and left no mess at all--nice. Thank you CJ for that technique!
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Time to let the epoxy dry some. More to come soon.
 
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Wow Mark,,
Really nice neat meticulous work..
Good for you..
That build is coming out really nice..

Teddy
 
Took one day to brew 5.5 gallons of an Oatmeal Stout. The two hobbies actually work together great...when kept in order. Rocketry THEN brew consumption, not the other way around.

Moved onto external fillets. First, tape off the area. Second photo shows the 29mm coupler that I used the first time to draw the epoxy into the right shape. That did not work too well, as it left too much epoxy and it ran like crazy. For fillets pairs #2 and 3, I went back to using my good ol' standby fillet maker--a plastic spoon. I have used a plastic spoon on everything from 54mm airframes to now 6" ones. Depending on the angle you hold the spoon at, it will accommodate everything in that range nicely. Make fun if you want, but it WORKS!
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All three done, movin on.

Moved onto the nosecone bay. The 1/4-20 all-thread running down the center needed to be cut to length. I don't know about you all, but I have a heck of a time making all-thread acually *thread* after being cut. I bought this cool tool on Kickstarter called the "Uni-burr", and in the below picture you can see what it does to smooth out all-thread that's been cut. Easier than an uncut end to thread, no kidding.
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And, after some fuss fitting the whole thing so that it comes out without too much trouble, the nosecone bay is done! My BigRedBee GPS tracker will go in here, since this flight is going (hopefully) to 11k AGL.
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Here is the mostly finished bottom half next to a 2.6" Wildman V-2 and a can of spray primer.
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Annnnnd, the brains of the deal, from Missile Works! This is an RRC3 and RRC2+ in a 4' sled. I plan to offset the sled to make this smaller size work.
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I found a way to make and print a drilling/clearance template for my av-bay lids with Microsoft Publisher. That's up next.
 
After some finagling in Microsoft Publisher, and getting a PDF file to print without any scaling, I think my av-bay lid template is done. Spray adhesive onto the underside of one lid, tape them back to back, then some drilling.

View attachment Av=bay lid FINAL v2.pdf
 
After 5 or 6 tries to get the av-bay template to something I thought would work, I printed it, cut it out, sprayed it with adhesive, and put it on the bottom of one of the av-bay lids. After taping the two together, it looked like this on the drill press.
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And, after drilling.
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Darned 5/16 U-bolt alignment was off some (not sure why, I measured everything with digital calipers beforehand), but I caught it before drilling the second hole--hence the lopsided offset. Everything else looked okay at this point.

Then I measured the all-thread length, cut three, mounted them, and then everything else on both lids.
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Here is the offset Missile Works 4" av-bay alignment (on the template end).
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I am actually getting to the point where I need to think of the remaining tasks. I think the list goes like this:
- Drill 3x 4-40 shear pin holes
- Drill av-bay switch holes (double as av-bay vent holes)
- Drill pressure relief holes in bottom and upper airframes
- Outfit the upper airframe recovery gear and lower drogue
- Ground test ematches with RRC3
- Ground test ejection charge sizes (tentatively planning for 3.5g primary, 5-6g backup each side; each side is about 18" of 'empty' space)
- Wire up the av-bay terminal blocks
- Fly the damn thing on an M1939W

Whew! I sure love building rockets. I am already thinking of the next couple projects...
 
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