Build Thread: MAC Performance Rocketry 4" Extended Villain

Ahh nice...time to get to my favorite part of the build...fin installation! The point where OCD kicks in and is always slightly let down. Despite spending most of the cure period of the epoxy on aligning the fin, it seems like I can never quite get it perfectly straight. Regardless, the roots are parallel with the length of the tube and therefore should not impart any spin.

I'll be using RocketPoxy for the initial tack to the motor tube and body tube. All surfaces are sanded with the same emery cloth as before, permitting epoxy and foam to grab.

The entire root that will be under fillet and inside of the tube (and therefore foamed) gets scuffed. I figure out the upper bound by dry fitting the fin in the slot and applying a line using the dowel with sharpie method that we've all been doing for years. In this case, the fillets will be formed with a 7/8" OD Delrin rod.

Once that is marked, I apply a piece of tape at the bound as a protective barrier while sanding.



Hit the tab with the emery paper...



Then mix up epoxy and apply it like so:



As you can see, I "buttered" the root with epoxy, as is typical. I also applied a small line of epoxy 1/4" to 3/8" up the side of the root so that it gets caught by the main body tube and forms a micro-fillet once the fin is pressed all the way into the slot. This locks the fin at the motor tube and the body tube. Not a ton of strength added, but it will seal the joint for the foam application and prevent any seepage when I apply the external fillets.



I've employed my handy dandy Estes fin alignment guide and tube marking tool. Is it accurate? Probably not, and probably the source of my slightly tiled fins, but it's better than if I used nothing at all...

You can also see that I used a bamboo skewer followed by a finger tip to make sure all gaps are filled to seal the root. MAC uses a round bit to cut the grooves (obviously) so there are half circles at the ends of the slots to fill. No biggie!

Here's a crappy picture of the inside showing the epoxy squish when installed.



I'll do this a few more times (2 to be exact) and then foam the fin can. Pics won't be as in depth for the next fins.

And if you wonder why I am only on fin #1, blame DizWolf. These are the first parts for his first EX motors slowly coming off my lathe. 38-2G are perfect for beginning EX'ers!!!

Meant to add more pics to that post, this is what I get for posting from my phone...

patelldp said:

And if you wonder why I am only on fin #1, blame DizWolf. These are the first parts for his first EX motors slowly coming off my lathe. 38-2G are perfect for beginning EX'ers!!!

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Why are you posting? back at the Lathe slave!


I am seriously excited to be getting these cases.

Fin #2 curing.



Proof that a lathe really is a rocketeer's best friend and most versatile tool!

Numero Tres.



Now that all 3 fins are installed and any gaps filled with RocketPoxy, I am going to foam the fin can cavity. I'm curious how much this will add in weight to the rear end, so first step is to weigh the booster. 4' x 4" booster, motor mount assembly, 3 1/8" thick fins all weigh 3# even. It's becoming quite obvious that this build will be SIGNIFICANTLY lighter than my FG 4" rockets.



Next step is to tape off where you don't want foam to go. It's easier to prep for this than it is to clean up afterwards, so be sure to cover areas that you know will need to be clean. I used electrical tape this time due to the fact that it resists tearing a lot better than masking tape, we'll see how it performs.



Last step is to mix the foam in a Dixie cup and pour into the cavity. No pictures of that as it's "all hands on deck." I poured the foam and then moved the assembly up to my 3-season room to overlook my neighborhood and to cure in elevated temperatures compared to my basement.



Now it's time to hurry up and wait for the foam to fully cure. The website (www.rocketrywarehouse.com) states that it cures completely in 5 minutes, but I will allow it to cure for several hours. I'll then dig out the tape and trim it to the final desired dimensions and weigh the booster!

These body tubes seem very interesting - with the canvas phenolic, do you need to coat the avionics bay and inside of the body tubes where the avionics bay slides in and out with thin CA? I always coat mine and sand really well and the cardboard is sealed and holds up better with less wear & tear.

Thank you for this build thread, I had never heard of this company. I have their website up in another browser window and I'm checking them out!! Oh, and great job on the build.

neond7 said:

These body tubes seem very interesting - with the canvas phenolic, do you need to coat the avionics bay and inside of the body tubes where the avionics bay slides in and out with thin CA? I always coat mine and sand really well and the cardboard is sealed and holds up better with less wear & tear.

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Nope, no sealing at all. These tubes behave similarly to fiberglass in that they are non-porous and the layers are all cured together with resin. No delaminating like paper tubes.

neond7 said:

Thank you for this build thread, I had never heard of this company. I have their website up in another browser window and I'm checking them out!! Oh, and great job on the build.

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You're welcome! Snag a kit or two, you won't regret it. I love the design of this kit, hopefully it flies just as awesomely as it looks. Thanks for the compliment!

Dan, I might try foaming my Scorpion. Do you use the 4# or 8# foam?

Bat-mite said:

Dan, I might try foaming my Scorpion. Do you use the 4# or 8# foam?

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4#

It's plenty strong. I'd be confident flying this rocket without fillets, those fins are locked in.

The foam added 3.5 oz and an immense amount of strength. The booster now weighs 3 lbs 3.5 oz without motor retention, aft CR, fin fillets, or rail guides.

That reminds me...I never drilled rail button holes! Not a big deal in this case. I have some smaller width angle aluminum that will allow me to mark the straight line for the guides, and the foam will give me something to drill and tap into for the aft button. I'll outline my process when I get to that point.

I may also need to rethink my retention plan. Stay tuned.

Fillet time! I'll be using RocketPoxy, masking tape, and a 2" long piece of 7/8" Delrin for this step.

Step one is to hang the rocket from my bench vice with a piece of schedule 40 pipe.



Step two is to level the rocket.



Once the rocket is ready and level, I use the tried and true Sharpie method for marking the fillet range. Take your fillet tool (7/8" x 2" Delrin rod), mark the edge with Sharpie, then drag it along the tube and fin as if you were spreading a fillet. Rotate the tool a few times and make sure you have a nice line along the root. This is your masking guide line.



Apply masking tape on the line, making sure to press down on the edges so you get an adequate seal. This will be immediately pulled off after you pull the fillet.



Press epoxy into the valley. Be sure to press the epoxy into the fillet to avoid the formation of bubbles. Drag the tool down the fillet until it's uniform. Epoxy will squeeze up into the masking tape.



Pull off masking tape. Enjoy your beautiful fillets and wait for them to cure! I'll need to do some filling on the aft edge of the fins due to the sweep, but it won't be hard.



Next up will be more fillets...

Awesome job! I found blue painters tape is easier to use, it pulls up nicely with no residue.

...where were we?

Now that I completed the fillets and foaming, I allowed the epoxy to fully cure for a few days before sanding.



Here's what the foam looks like after a few minutes of trimming.



Now that the fin can would survive a second Hiroshima, it's time to attach the aft CR. Despite my early threads of developing an awesome custom machined retaining device, I went back to a tried and true Aeropack. First step is to drill the holes for the anchors.



Then you epoxy the ring onto the motor mount, foam, and outer tube with a buttload of 30 minute epoxy.

With the tail end almost completely buttoned up, it's time to shift focus back to the altimeter bay. First step is to make a second set of charge canisters because I'm too cheap to buy a second set from Mike



Next step was to strip off all of the components that I had previous mounted so that I could seal the bulkhead with epoxy.

Before:



After:



After that cured, it was time to load up all of the components again, this time for good.

Drogue end:



Main end:

Lastly in the electronics stage...here's the sled and altimeters that I will be using. The primary altimeter is a Telemetrum 2.0, while the back up is a Stratologger CF. I'll be using a LiPo for the Telemetrum and a 9V for the SLCF. Both will be powered on via the Missile Works PCB screw switch. All of these combine for an awesome and super capable recovery set up!



Mmmmmmmmm paaaaiiiiiinnnnttttttt....





Mmmmmmmmm propellllaaaannnnnttttt....



More to come!!!

Oh, and I got these stupid things done for DizWolf somewhere in there.

patelldp said:

Oh, and I got these stupid things done for DizWolf somewhere in there.

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Yay! Those look nice. Can't wait to blow them up.

LDRS will be rather red for me. I'll be bringing my MAC Arcas, Hawk Proteus, and MAC Villain, all shown here:



The motors:



54/1750 K247 Plain Jane moon burn

76/4700 L1050 White

98/10,000 M2125 Plain Jane

Not pictured is the second load for the 4700, a red (of course) L1000.

Some of the final steps...

Aeropack installed:



Rail buttons installed:



Coupler installed in the upper tube with 3 8-32 screws into PEM nuts installed in the coupler:



Next step is to finish the nosecone, which has already been foamed. Needs a bulkhead to encapsulate the foam and we're good.

I have some good wire on the way to finalize the electronics bays for my Proteus and this kit.

This is a lovely build, with great attention to detail. Thanks for sharing.

Ready to go fast at LDRS. Will weigh it later today all up without the motor. I'm guessing 8 lbs?

So, I wasn't able to fly this rocket at LDRS. I showed up with the Villain and my Hawk Proteus ready to go but when it became apparent that Friday was the only good weather day the Proteus got the nod. I'm glad I went that route, as the Proteus turned in a great flight on the largest motor I have made myself.

The 4" Extended Villain weighs 9 lb., 8 oz. completely loaded and ready for flight, less motor. This includes the Aeropack, foam in the fin can, foam in the nose cone, 20' shock cords in both sections, cord protectors, nomex pads, a Skyangle Medium deployment bag, a Skyangle 60" Main, Telemetrum, Stratologger CF, Printed sled, 9v battery and LiPo for the TM. This rocket is extremely lightweight for its size...even lighter than my Intimidator 3 FG rocket when loaded.

Assuming the forecast remains the same (read: goooooooooood), the rocket will fly this weekend at CTRA-Narconn in Cobleskill, NY on a 54/1050 White. Should turn in a really nice flight. The 4700 loads I have for it will have to wait, unfortunately.

The build turned out great, I hope you get to fly at CTRA. Question; it may be just me, but 9lb 8oz seems a little heavy for a rocket less the motor; is this due to the tubing materials used by MAC? I do realize that you have recovery, electronics (& batteries) and foam included in the weigh-in, so I was just a bit shocked when I read this. I have a 4" build where weight is a concern, and the rocket has much fiberglass and hardware in it that I am trying to be weight contentious. My concern centers around the fact I will be flying hybrids, and weight is a huge issue to overcome (apples & oranges).

Oh, and your machining abilities are excellent, love all the hardware and goodies you are putting out!

DRAGON64 said:

The build turned out great, I hope you get to fly at CTRA. Question; it may be just me, but 9lb 8oz seems a little heavy for a rocket less the motor; is this due to the tubing materials used by MAC? I do realize that you have recovery, electronics (& batteries) and foam included in the weigh-in, so I was just a bit shocked when I read this. I have a 4" build where weight is a concern, and the rocket has much fiberglass and hardware in it that I am trying to be weight contentious. My concern centers around the fact I will be flying hybrids, and weight is a huge issue to overcome (apples & oranges).

Oh, and your machining abilities are excellent, love all the hardware and goodies you are putting out!

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Thanks for the kind words!

9.5# for a rocket of this size is actually quite remarkable. It's a 4" rocket with a 3" motor mount capable of flying on L and M motors. Put it this way...this 4" rocket will weigh ~12.25# on the pad with the 54/1050 vs. my Intimidator 3's 1050 weight of 13.5#. That I3 also had one altimeter and no foam. My Hawk Mountain 4" Bad Attitude weighs 18.5# loaded with a 76-3500 motor, vs. 13.75# for this rocket (some consideration needs to be given to the BA which has 4 massive fins).

It's certainly heavier than a rocket made out of LOC cardboard, but it's also much more capable.

Noted, thanks for the reply. That rocket will scream on one of your 3" motor creations... I can envision a flame as long as the rocket.... or longer even.

Nice build thread....so these canvas wound (sorry, I forgot exactly what they are called) body tubes do not need to be glassed? I am assuming they are similar to fiberglass tubing or even blue tube?

kelltym88 said:

Nice build thread....so these canvas wound (sorry, I forgot exactly what they are called) body tubes do not need to be glassed? I am assuming they are similar to fiberglass tubing or even blue tube?

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Sorry for the lathe response.

They do not need to be glassed. They are not brittle and do not need reinforcement for most applications. I plan to approach Mach 1.2-1.4 speeds later this summer.

Imagine fiberglass at half the weight and you'll be in the ballpark.

patelldp said:

Sorry for the lathe response.

They do not need to be glassed. They are not brittle and do not need reinforcement for most applications. I plan to approach Mach 1.2-1.4 speeds later this summer.

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Bat-mite said:

Imagine fiberglass at half the weight and you'll be in the ballpark.

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A material that is definitely worth looking into for builds...