3" mac rocketry villain

[The_Quacken]

Im starting a new build after finally getting my L1. while my L1 bird (LOC caliber) still flies amazing I want to expand my skills into dual deploy, composites, and tracking, especially after I lost my Blackhawk 29 lol. currently only in the sim and realize again rocketry is expensive stage but Im starting the thread to commit myself to actually building it lmao. I've already got my shopping list all planned out but Im now in the all-important naming/ planning stage. ill be mostly following DizWolf's Build but without the extended booster

current leading name is the cursed "lawn dart" because I love tempting fate IG and I kinda love this paint job

That said I am very open to any other names or livery ideas


My end goal is to fly it on a K 2050 ST but ofc not the first flight

More details:
recovery
- 18" top-flight drogue
- 40"recon main
- eggtimer quantum/quark redundant altimiter
tracking
- eggtimer tx mini


will continue to update as work progresses

 

[kenstarr]

Looking good! I like the simulated paint job work. I still haven't figured out that yet. Keep us posted on what your progress!
Ken

 

[The_Quacken]

Things finally started shipping or are in the process of being ordered (unfortunately eggtimer is having some struggles with gps stuff so that will just have to wait) but I have been able to make some progress!
I found some nomex at my dads place and decided to try my hand at making some chute and shock cord protection. I started out hand sewing the seems and all that and I got a lot of progress (as long as you ignore my amateur hour sewing)
After a while I finally broke out the sewing machine and finished it all up
So all in not much progress but the project moves forward and that’s what matters

 

[The_Quacken]

So I have a bit of a dilemma when it comes to engines. As the kit stands it will accept up to a 4-grain casing which is great except I'm on a relatively tight budget and do not want to purchase every casing length and the starter sets are 6 and 3 grains which I could just run only 3-grain engines but I want to fly the K2050.
As I see it I have a few solutions
- call MAC performance and get a 30-inch booster tube however they are out of the tube I need and I simply don't have the budget for this
- just buy an Aerotech 54/1706 and use that for all my K engine needs. This might be the best option especially because I was planning on mostly flying cti reloads anyways. unfortunately, this is also expensive
- only fly up to 3 grains. this is the cheapest and most sensible option and is definitely the short-term solution but sorta lame lol. after that h550 I flew I need to see more of those fast-burning super thunders and doing one in K impulse seems so cool
of course, all of this requires an airframe to put them in so I may be jumping the shark slightly. Speaking of airframe however that should be arriving tomorrow!

 

[3stoogesrocketry]

So I have a bit of a dilemma when it comes to engines. As the kit stands it will accept up to a 4-grain casing which is great except I'm on a relatively tight budget and do not want to purchase every casing length and the starter sets are 6 and 3 grains which I could just run only 3-grain engines but I want to fly the K2050.
As I see it I have a few solutions
- call MAC performance and get a 30-inch booster tube however they are out of the tube I need and I simply don't have the budget for this
- just buy an Aerotech 54/1706 and use that for all my K engine needs. This might be the best option especially because I was planning on mostly flying cti reloads anyways. unfortunately, this is also expensive
- only fly up to 3 grains. this is the cheapest and most sensible option and is definitely the short-term solution but sorta lame lol. after that h550 I flew I need to see more of those fast-burning super thunders and doing one in K impulse seems so cool
of course, all of this requires an airframe to put them in so I may be jumping the shark slightly. Speaking of airframe however that should be arriving tomorrow!

Or you just call Tim and see if he can give you the 54mm starter set with a 6 grain and 4 grain case ( you need to pay the few dollars extra between the cases IIRC ) and then your all set .

 

[The_Quacken]

Or you just call Tim and see if he can give you the 54mm starter set with a 6 grain and 4 grain case ( you need to pay the few dollars extra between the cases IIRC ) and then your all set .

Thanks, I'll keep this in mind. all this engine speculation is a decent time off in the future tho unfortunately so I guess I will cross this road when I get there (the joys of student disposable income).

 

[The_Quacken]

So the kit arrived today! Or at least the airframe parts from Mac performance and I know this is echoing almost every other mac build but this kit fits together beautifuly. Practically feels like I could fly it without glue lol.

I started work on getting it all together because I couldn’t wait. The first part I put together was the nose av bay which I started off cutting the base off the nose cone and then gluing everything together. I did have a minor issue where I slightly crushed the flange nut and had to drive the all thread in with a drill but other than that it went together beautifully I also got to work on the motor mount marking the position of each ring and epoxying the top two in place. I’m just using bsi 30 minutes for this but it has treated me well on other rockets so I’m not too worried. last thing I did was getting somevent holes drilled. They are all 6/32 holes three for the booster and payload bay each.

 

[H_Rocket]

With respect to your motor mount tube dilemma, you don't need a tube that fits the entire motor. As long as you have roughly half of it, you are good. If you want you can sew a Kevlar or Nomex sleeve to cover the exposed part, but it's not really necessary.

 

[The_Quacken]

With respect to your motor mount tube dilemma, you don't need a tube that fits the entire motor. As long as you have roughly half of it, you are good. If you want you can sew a Kevlar or Nomex sleeve to cover the exposed part, but it's not really necessary.

The issue is actually the booster length anything above a 4 grain would be inside the av bay lol. There’s a reason that in the build I reference in post 1 the boater was extended to 30 inches. One day I may extend the booster but honestly I don’t know how often I’ll be flying anything above a K so it’s not too much of an issue more of an inconvenience with hardware

 

[The_Quacken]

The fins have been glued in using the double butter method that the instructions use and by visual inspection the fillets don’t look terrible but I may reinforce them

 

[SmurfTacoSupreme]

If you're doing foam I wouldn't worry. If no foam I'd do internal fillet where the fin meets the body tube.

 

[The_Quacken]

If you're doing foam I wouldn't worry. If no foam I'd do internal fillet where the fin meets the body tube.

I’ll probably go in with a dowel and try to add a bit more epoxy but the edges of these canvas fins have a ton of texture and little holes even more than wood so I trust the mechanical bond quite a bit. Luckily adding those internal fillets on the body side isn’t too hard

 

[Tim51]

Great build. One suggestion: seal the bevelled leading and trailing edges of the fins. I do this by putting some 30 min epoxy on a gloved finger and thumb, then running them along the bevels in a pinching motion. The thin layer of epoxy soaks into the exposed canvas matrix, and this stops it raising up when you paint. Once cured, a very light sanding with the same motion and a folded piece of fine grit paper completes the job.

 

[SmurfTacoSupreme]

Great build. One suggestion: seal the bevelled leading and trailing edges of the fins. I do this by putting some 30 min epoxy on a gloved finger and thumb, then running them along the bevels in a pinching motion. The thin layer of epoxy soaks into the exposed canvas matrix, and this stops it raising up when you paint. Once cured, a very light sanding with the same motion and a folded piece of fine grit paper completes the job.

This ^^

I did the same and works great.

 

[The_Quacken]

Great build. One suggestion: seal the bevelled leading and trailing edges of the fins. I do this by putting some 30 min epoxy on a gloved finger and thumb, then running them along the bevels in a pinching motion. The thin layer of epoxy soaks into the exposed canvas matrix, and this stops it raising up when you paint. Once cured, a very light sanding with the same motion and a folded piece of fine grit paper completes the job.

Thanks for the advice! I was slightly worried about that so I will definitely do this

 

[Tim51]

Thanks for the advice! I was slightly worried about that so I will definitely do this

You're welcome. I just used Devcon on these with good results:

 

[The_Quacken]

So I have discovered a minor problem with my plan of flying 4 grain k engines. The lower mark is the end of an aerotech 4 grain and the upper is the end of the av bayso that’s not enough space for recovery so unless I want to fly drogueless that’s just not enough space for a parachute and deployment charge.
I may commit to extending the body tube in the future but I guess it’s maxing out at three grain for now. Luckily it should be relatively easy to extend with a coupler and 8 inches of body tube at any point in the future.

 

[Tim51]

So I have discovered a minor problem with my plan of flying 4 grain k engines. The lower mark is the end of an aerotech 4 grain and the upper is the end of the av bayView attachment 524029so that’s not enough space for recovery so unless I want to fly drogueless that’s just not enough space for a parachute and deployment charge.
I may commit to extending the body tube in the future but I guess it’s maxing out at three grain for now. Luckily it should be relatively easy to extend with a coupler and 8 inches of body tube at any point in the future.

That seems strange. The MAC website does state the 3" Villain can fly K motors. Did you specify a shorter booster section when you ordered?
On the other hand - CTI do a baby K that fits a 3G case - the K360. But I realise that's not what you had in mind.

 

[The_Quacken]

I have a question. I need the nose cone to come off of the payload bay so I can’t just glue it in but I also want to predict where the rocket will separate so I definitely need the av bay to payload bay to be the weak point (unless that’s incorrect and I don’t know what I’m doing) so how do I attach the nose cone

 

[The_Quacken]

That seems strange. The MAC website does state the 3" Villain can fly K motors. Did you specify a shorter booster section when you ordered?
On the other hand - CTI do a baby K that fits a 3G case - the K360. But I realise that's not what you had in mind.

It’s hypothetically possible drogueless but I didn’t specify it to be shorter or anything. I guess I could pack it insanely tight but it’s just such a small space with a 4 grain aerotech motor

 

[Tim51]

It’s hypothetically possible drogueless but I didn’t specify it to be shorter or anything. I guess I could pack it insanely tight but it’s just such a small space with a 4 grain aerotech motor

Yes, if the motor mount is shorter than the motor casing, you can usually loosely coil a thin shockcord in the space between the inside of the airframe and the projecting motor case. Then fly drogueless.

 

[Tim51]

I have a question. I need the nose cone to come off of the payload bay so I can’t just glue it in but I also want to predict where the rocket will separate so I definitely need the av bay to payload bay to be the weak point (unless that’s incorrect and I don’t know what I’m doing) so how do I attach the nose cone

Usually in a dual deploy set up the NC is retained with shear pins until blown off by the main chute charge. If you haven't flown DD before I recommend studying some ground testing videos on YT etc, and speaking to a DD flyer at your club

 

[The_Quacken]

Got the fins filleted and the aeropack retainer installed
here is unfortunately where the project stalls. To do the av bay I need to get the Mach 1 av bay delivered so I don’t mess up the switch band placement and have to do annoying funky things
Additionally I’ll probably leave it unpainted until I properly decide to extend it or not. I probably will but I need the money for the extra tube and coupler

 

[crossfire]

So I have discovered a minor problem with my plan of flying 4 grain k engines. The lower mark is the end of an aerotech 4 grain and the upper is the end of the av bayView attachment 524029so that’s not enough space for recovery so unless I want to fly drogueless that’s just not enough space for a parachute and deployment charge.
I may commit to extending the body tube in the future but I guess it’s maxing out at three grain for now. Luckily it should be relatively easy to extend with a coupler and 8 inches of body tube at any point in the future.

I would guess most of the shock cord will fit between motor case and booster tube. Than you could go with chute and JLCR. Should be plenty of room.

 

[The_Quacken]

I would guess most of the shock cord will fit between motor case and booster tube. Than you could go with chute and JLCR. Should be plenty of room.

Yeah most likely it’d be fine but I think I’ll look into extending it because that also solves my casing issue

 

[The_Quacken]

So it’s official I will be extending the rocket since I sent mike an email and I’m getting a real good deal on the exact amount of tube I need. I’m going with a 12 inch extension and even tho that pushes it slightly to the overstavle side it never simmed above 3 cal so I’m not too worried about that

 

[Tim51]

So it’s official I will be extending the rocket since I sent mike an email and I’m getting a real good deal on the exact amount of tube I need. I’m going with a 12 inch extension and even tho that pushes it slightly to the overstavle side it never simmed above 3 cal so I’m not too worried about that

You could always move the fins foreward a little. Mike does custom work so would probably position the slots appropriately as you require

 

[The_Quacken]

Ok this might be a slight hack but if I ever really felt the stability caliber is too high (which I believe is like 5? or that's like the absolute max?) I can use weighted motor adapters because it's only really a problem with the 38mm or the 1 and 2 gran engines and since I'm running 3 grain cases on both of those it will help somewhat

 

[The_Quacken]

additionally, I've been simulating the flights and since as you pass transonic the cg starts to shift dramatically forward whats the minimum safe stability caliber at those speeds. Id imagine that the restoring force becomes much higher at mach 1.5+ so it would seem to follow that a lower cal would be ok I just don't know

 

[The_Quacken]

Playing around in open rocket I’ve discovered that actually on the 6xl grains and pretty much anything that breaks Mach by a decent margin nose weight will actually need to be added in order to account for the co being dragged forward in the supersonic regime