MAC Performance VTS-6 build thread

[Crash-n-Burn]

Post #1 – Intro and initial observations

Hi folks,

Well, I guess the subject line sums up why we are here on this thread. Before I get to the kit, I'll share just a bit about myself. I’m a NAR L2 and would categorize myself as more of a builder than a flyer. By that I mean that I have quite a few built rockets that have never left the ground. Life stuff (read: kids) tends to get in the way of club launches.

This will be my first build documented on TRF. I’ve never felt like I have had much to contribute in that space. I don’t use new/novel construction methods and most every kit I own has been built and documented by someone here already. [email protected] encouraged me to do this, so thank (or condemn!) him based on the value of this build thread.

First off, for all construction methods I give due acknowledgement and credit to the TRF community that I learned them from. I’ve learned so much from you all.

Now about the kit. I’ve lusted after this one since it first came out. It is a real beauty to me. I’ve also wanted to work a MAC Performance kit due to the high praise Mike gets from Forum members. Black Weekend led me to pull the trigger on this.

This kit is a 4” diameter dual-deploy rocket. The website says it had 76 pieces in total! The rocket looks complex and for anyone that has built an Estes QCC Explorer you can agree that this rocket is not for the faint of heart. That said, I think it is important to point out my first major observation –

• THIS IS JUST A 4FNC ROCKET -

At its core, that’s all it is. Sure, it has these spectacular air intakes that can be intimidating to build, but these are ornamental. They provide a great look but don’t contribute to the fundamental soundness of the rocket itself. I bring this up as a message of encouragement. If you are on the fence about your skills to build this rocket, I submit to you that this rocket is very buildable for people with experience building fiberglass high-powered rockets. I would not recommend this to someone unfamiliar with epoxy building techniques, but I also don’t think this rocket appeals to a first time HPR builder.

If you are unfamiliar with MAC Performance, their rockets are made of canvas phenolic tubes and plates. These are seamless – like fiberglass – and therefore require no seam filling for a smooth finish. I don’t have technical details on the tube strength relative to fiberglass, but they feel similar in weight and rigidity. The canvas phenolic has more radial flex under compression when compared to fiberglass, but I don’t expect that to affect performance. Stated another way, I can squeeze the tube out of round with my hand but it returns to shape when I let go. The tube is rigid and does not give me any reason to think it would perform worse than fiberglass.

The kit comes with a big plastic nose cone, av bay with hardware and 3D printed sled for electronics. I'll show all the components in upcoming posts.

Unboxing is next.

 

[Andrew_ASC]

Okay I had a rigid fiberglass tube kit fall a mile and it will fly again. I'd trust the phenolic canvas tube by Mac more than PML phenolic.

 

[Nytrunner]

Will follow!

I love the QCC explorer!

 

[Tim51]

Very interesting kit. Thanks for posting what promises to be a great build. Do you intend to finish it as a VTS 6 / ALVRJ test vehicle (I suppose the latter would require shortening the payload section and adding NC weight) or in the QCC explorer rocketship style livery?

 

[Crash-n-Burn]

Very interesting kit. Thanks for posting what promises to be a great build. Do you intend to finish it as a VTS 6 / ALVRJ test vehicle (I suppose the latter would require shortening the payload section and adding NC weight) or in the QCC explorer rocketship style livery?

Although it has been done before, QCC style is my plan.

 

[neil_w]

This will be my first build documented on TRF. I’ve never felt like I have had much to contribute in that space. I don’t use new/novel construction methods and most every kit I own has been built and documented by someone here already.

This seems to be a common misconception. The build thread *is* the contribution, regardless what methods you use. Just post lots of pictures and all will be OK.

This is a great kit, I look forward to this one.

 

[[email protected]]

Alright Crash! Glad you are baring your Rocketry soul to TRF . Just kidding, really looking forward to your build, we will enjoy the ride. Personally I’m a sucker for anything QCC and anything MAC Performance so best of both worlds.




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[Crash-n-Burn]

This seems to be a common misconception. The build thread *is* the contribution, regardless what methods you use. Just post lots of pictures and all will be OK.

This is a great kit, I look forward to this one.

Fair point and I appreciate the encouragement.

 

[Crash-n-Burn]

Post #2 - unboxing goodness

Two days after placing my order, a box showed up.

In that box was a bag.

In that bag were some parts.

Many people familiar with MAC products comment on the exceptional tolerance of their components. I had the same observation. Fin slots married up nicely with fin thickness. The coupler fit well in the airframe. Tube ends are clean. Centering rings fit clean and tight. I will not have to perform any fitting activities to get components to, well, fit.

A couple items of note – this kit comes with a decorative/non-structural 3d printed (I think?) tailcone. It has a stepped shoulder to fit the end of the airframe. As with all other pieces, the fit and finish were spot on.

The nose cone has an eyebolt preinstalled. I’m on the fence about using as-is or modifying the nc for some custom Crash components.

The fins all had a nice bevel on them. The instructions have a caution statement that they are sharp, but these had a dull edge. I've cut my fingers on several occasions with my razor-edge fins before so I was sure to check.

The coupler/av-bay caps are stepped and fit beautifully together. These will not need an o-ring to protect against ejection gases affecting the electronics. The av-bay was pre-assembled, which may come in handy for someone that can’t conceptualize how to assemble a bag of parts. All hardware was included.

The top CR had the Kevlar strap pre-installed with the retention pin. You can sort of see it in the parts picture but I missed getting a detail shot of it.

The kit came with tiny shot glasses. Weird.

Then, paperwork. This kit came with three documents:
• Itemized list of components and some key information (i.e. CP location, motor recommendations)
• A brief history of the VTS-6
• Instructions, sort of

About the instructions… these are helpful but also rightly presume the builder has some working knowledge and experience to draw on for constructing this kit. The instructions do not detail step by step everything a builder should do. That makes sense as there is more than one way to build this rocket and surely some builders will modify to suit their needs. I found as a moderately-experienced builder that the instructions gave good information and that I could readily fill in the blanks. I am glad I read the three pages of instructions and acknowledge that if they were explicitly detailed in step-by-step style I would likely have skipped over them.

 

[Crash-n-Burn]

...aaaaaaand everything is upside down. Awesome.

 

[Bat-mite]

...aaaaaaand everything is upside down. Awesome.

I was wondering what the heck was wrong with my eyes.... :grin:

 

[Nytrunner]

...aaaaaaand everything is upside down. Awesome.

Evvvvrything is Awesommmme!

 

[jd2cylman]

Evvvvrything is Awesommmme!

Thanks for the earworm. Now I have to go roto rooter my brain...

 

[neil_w]

 

[Crash-n-Burn]

Post #3 - motor mount

The motor mount was a logical first place to focus. I think a key to any successful build is dry-fitting parts prior to permanency. For this step we'll need all the centering rings, the motor tube, two fins, the airframe, that tailcone piece, your motor retainer of choice, CA glue, and epoxy.

Let's go over the motor retention assembly. Here is an exploded view of the motor tube, third CR, tailcone, and an Aeropack retainer.

This is a close-up of that stepped tailcone. The shoulder will slide into the end of the airframe.

Our goal is to have the aeropack be even with the end of the motor tube and the tailcone abutting the aeropack.

That way, when we finally install this into the airframe we get a a tight fit without gaps between components. Hopefully that helps conceptualize the fit of the aft components. Now on to the actual assembly.

First, I positioned the fore CR. Leave 1/8-1/4” of the mmt extending beyond the fore CR for epoxification. Tack in place with CA.

Everything else is positioned working from the aft end forward.

I slid the middle and aft CRs into estimated positions. I then installed the tailcone and a motor retainer as described above.

Next, I lined the mmt up next to the airframe and tweaked the CR locations. The key reference point here is the tailcone shoulder. I carefully aligned this with the aft end of the airframe and ensured that the aft CR is positioned right at the back edge of the fin slot.

I confirmed that the fin tabs will fit between the CRs. In other words, I set the middle CR in place based off the fin tab length when oriented against the aft CR.

Then I tacked the mid and aft CRs in position with cyanoacrylate glue. Just a drop on three spots around the mmt each. Once dry, slide the mmt into the airframe and check that the fins can be installed without interference.

Also check to ensure that tailcone shoulder is tight against the airframe.


This process did not take long but I did fiddle with things to get the alignment just so. I want the fin tabs sandwiched tightly between the mid and aft CRs and I wanted the motor tube to neatly marry up with the aeropack end with the tailcone installed. It did feel like a lot of positioning but take your time, check a couple times and think it through. If I can get this right, you can too.

Pull the mmt out of the airframe and remove the motor retainer, tailcone, and aft CR. It didn’t take much to pop the glued aft CR off the craft phenolic tube.

Next step is to mix epoxy for the fore and middle CRs. This was done in two steps. Put epoxy on the fore and mid CRs on the fore side.

Once dry, flip the mmt and put epoxy on the fore CR aft side. It is KEY that you do not put epoxy on the mid CR aft side or else it will impede the fit of the fin tabs. The instructions say to cover the harness attachment point with epoxy to ensure it doesn't come loose, so do that while filleting the rear side of the fore CR.

Note – for all epoxy activities I am using Rocketpoxy measured by weight. I sand all areas to be epoxied with 100 grit sandpaper and wipe excess dust away with a rag.

That'll do for now. Let all that dry and let's start on the av bay.

 

[Crash-n-Burn]

Post #4a - av bay switches

While we wait for the mmt to cure, I fiddled with the av-bay. For this step you'll need the coupler tube, switchband, and two rotary switches. The coupler and switch band are epoxied together, but first let’s tweak the setup. I like the look of switches. I’ve done the twist and tape method and it works great. I’m hopeful for a nice finish on this, though, so thought I would dress it up with switches for electronics. I’m using these rotary switches.

We’re going to prep this bay in steps to accept the switches. First, position the switchband in the middle of the coupler tube.

The body of the switches are ½” diameter. We’ll drill two holes all the way through the switchband and the coupler. I found the canvas phenolic drilled out remarkably well and did not splinter at all (splintering can happen with fiberglass). Drill one hole.

Install a switch in that hole to ensure the switchband doesn’t move.

Drill another hole.

The switches have a lip on them that is 5/8” diameter so we’re going to drill the switchband ONLY to accept that lip. We don’t want to drill all the way through the coupler or there will be no shoulder to mount the lip against. We also cannot drill the switchband without support, lest we crack it. The solution? Rotate the switchband ~180 degrees on the coupler and carefully drill the 5/8” holes without going through the coupler itself.

I used a Forstner bit for this. Take your time and be careful. You need to align the bit so that it takes an even amount off the diameter of the existing hole. If you don’t you will compromise the fit of the switches.

After drilling both holes, you have a switchband with expanded holes and a coupler with only minor markings from acting as a backer. These marking will be hidden under the switchband.

Switchband repositioned on coupler. This should give you a sense of the end product.

 

[Crash-n-Burn]

Post #4b - av bay switches

But wait, there’s more! We left off here...

These switches have a little notch of plastic. This is there to keep the switch from turning when you move the selector.

In order to get a tight fit and finish, we need to accommodate that notch. I did this with a couple quick passes of a file.

Now with those notches, the switches will sit as flush as we plan to make them.

I thought a profile view would help.

With all that done, we are ready to epoxy the switchband in place. I marked a stop with tape, which will also serve to catch excess epoxy pushed down during installation. I also traced a line along the switchband so I had my area for spreading epoxy marked. When we spread the epoxy, we want it everywhere between the tape and the line except for around the switch holes. Leave that area clean from epoxy.

Mix your epoxy (don't forget to scuff-sand the mating areas), spread the epoxy between the tape and the pencil line, slide the switchband into place, and remove the tape. Check fit and add switches to hold everything in place while the epoxy cures.

That concludes these steps. Much more to come on the av-bay.

 

[[email protected]]

Nice work with the flush switches - wish there was more meat on those, you could round off to match the airframe!


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[OverTheTop]

Welcome CnB. Looking forward to the build thread. Everyone does different stuff and everyone else can learn from that.

...aaaaaaand everything is upside down. Awesome.

Special thanks from those of us in the Southern hemisphere. It is nice to be considered occasionally :wink:

 

[Misfit Flats HPR]

Hi Crash-n-Burn. This thread is very, very helpful. Thank you. I am having trouble with the intakes. Did you post anything on intake construction for the VTS-6 ? I cannot find it if you did. Could you point me towards it? Thank you.

 

[bobbyg23]

Hi Crash-n-Burn. This thread is very, very helpful. Thank you. I am having trouble with the intakes. Did you post anything on intake construction for the VTS-6 ? I cannot find it if you did. Could you point me towards it? Thank you.

Is there anything in particular you are wanting to know?

 

[bobbyg23]

MAC Performance VTS-6 build

I have been wanting this rocket for a long time now and finally pulled the trigger. If you have never had a mac kit before, you are missing out. The fit and finish on these kits are amazing. Mike builds your kit after you order it. It comes with everything test fit to ensure it is all...

www.rocketryforum.com

 

[hobie1dog]

Hi Crash-n-Burn. This thread is very, very helpful. Thank you. I am having trouble with the intakes. Did you post anything on intake construction for the VTS-6 ? I cannot find it if you did. Could you point me towards it? Thank you.

the last time he was on TRF was 4 years ago

 

[bobbyg23]

the last time he was on TRF was 4 years ago

His reply was in January so I thought I would ask just in case.

 

[hobie1dog]

His reply was in January so I thought I would ask just in case.

The original poster Crash-n Burn who started this build thread was last seen Oct 2018. You can put your mouse pointer over his name over on the left hand side and a screen will come up telling you when he joined and when the last time he was on here FYI

 

[bobbyg23]

The original poster Crash-n Burn who started this build thread was last seen Oct 2018. You can put your mouse pointer over his name over on the left hand side and a screen will come up telling you when he joined and when the last time he was on here FYI

Yup, but misfit asked a question in January. That is who I was replying to.

 

[hobie1dog]

Yup, but misfit asked a question in January. That is who I was replying to.

oh,,,,,sorry