MAC Performance RainMaker 54 Build

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mpitfield

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Upon reading MAC's announcement post of their limited edition Rainmaker 54 I realized that I had a hole in my fleet and that the Rainmaker just happened to fill it perfectly. Thanks Mike, I am not sure what I would have done without this. :facepalm:

For anyone not familiar with MAC performance component quality, this will be a treat. Mike @ MAC is a perfectionist for components, details and fitment, and this rocket exceeds that growing reputation.

This will be a fast build, or to qualify that better, this will be a fast build for me which likely means a month or even two.

When I came home yesterday this was waiting for me. Besides a bit of Ace Ventura damage to one corner, she arrived alive.



Now onto the proverbial un-boxing. I will post more details of each components as I work through them. Suffices to say the fit and finish is second to none, as you will see in the next pic.

23902797388_bee8f81c22_b.jpg


I joke with Mike about being able to fly his kits without glue, due to the very tight tolerances, but you really need to hold these components in your hands to really appreciate this.



So here is a rough overview of what I am leaning towards for electronics, general build options, and theme.

Electronics: I am hoping the nosecone tracker sled I built for my 54mm Tomach will fit with minimal tweaking in this nosecone. If so this will host a TeleGPS as well as one of my tried and trusted Comspec AT-2B trackers for back-up. Altimeter wise I am leaning towards an Eggtimer Quark and an SL100, both of which I have spares in my altimeter stock. For switches I will use two of the new Featherweight Magnetic switches, which I also have in stock.

General AV Bay: Mike supplies an AV bay band, however I am undecided if I am going to use the band or not. For the AV bay lids I have some charge canisters in my stock that will work well for these lids so I will use those. I will likely remove the non-welded eye bolts and replace them with a Stainless Steel welded ones, for more piece of mind.

Retainer: I will have to check hardware inventory however I think I may a spare GLR slimline retainer and an Aeropack both of which would suite this well. The GLR has a longer tailpipe look to it and that may suite the overall look. I will confirm my stock and mock up the options, and post pics for opinions, but my preference is the GLR slimline hands down.

Fin attachment: No T2T for this one, not because it does not need it, as one could argue that none of my T2T reinforcements are required, however they serve a longer and bigger picture for my goals. In this case the Tailcone looks so good I see no need for the T2T practice which will just mess up the look and add weight were it's not needed. I typically use AeroPoxy ES6209 Structural adhesive for the fin root attachment however I may use some JB-Weld for the root then use the ES6209 to inject some minor internal fillets. External fillets I will use some Proline 4500.

Recovery: I have not done a final weigh in however I think a 30" FruityChute Iris Ultra may work well, with a 12" FruityChute Classic Elliptical for drogue. I have a 12" for the drogue but the smallest Iris Ultra I have is 36". I do have a 30" Classic Elliptical which may be an option once I run the numbers. However I like the Iris Ultra Compact because I can undersize the chute package and still get really good performance. For the recovery harness I think I might reach out to Teddy at One Bad Hawk and look at picking up two 3 loop 25' 3/16th braided tubular kevlar harnesses.

Rail attachment: I have had very good results using the fly-away rail guides and so I may just use them and not put any rail buttons on this one.

Theme: I like the name Rainmaker and it would be a shame to cover up all of the carbon fiber so I am leaning towards clearing or polishing the airframe and adding some details here and there. I recently picked up some Molotow Liquid Chrome after watching Adam Savage use it on a foam replica 1 day sword build, and I like the idea of painting one fin extending down to the fillet and flowing out onto the airframe, kind of like a raindrop. I may also add some detail here and there on the airframe as well as paint the nosecone with something, but I don't want to introduce anything that would depreciate the radio and GPS transmissions to an unreliable point.

At the end of the day, although this is a carbon fiber rocket, it has a 38mm MMT so it's not an extreme MD performer. It is more a 3-10,000', Mach 1.4ish profile which is perfect all of the club launches I typically attend. So tracking is not extreme nor would any of the build techniques require anything more than a moderate approach. I see this rocket being one of my favourite and easier to prep, recover, and maintain rockets which I look forward to flying many times.
 
That is a slick looking bird. Sounds like an interesting paint plan, can't wait to see it. I'm still undecided on how to clear/polish accent mine.

One day we really need to just slap together one of mikes kits and fly it on a G.
 
Man I wish I would of picked this one up, I have 3 Mac rockets in my arsenal and quality is unmatched for sure.
I also seen that video with adam savage hope it looks cool have a plan to use it on something also.
-Subscribed
 
That is a slick looking bird. Sounds like an interesting paint plan, can't wait to see it. I'm still undecided on how to clear/polish accent mine.

One day we really need to just slap together one of mikes kits and fly it on a G.

I am just writing an email to Mark @ Stickershock with some ideas on some masks for it. We need to convince Mike to put together a snap-together kit

Man I wish I would of picked this one up, I have 3 Mac rockets in my arsenal and quality is unmatched for sure.
I also seen that video with adam savage hope it looks cool have a plan to use it on something also.
-Subscribed

Mike just announced that he will be putting together just another 4 kits, so it looks like a limited edition of 10, for November. https://www.rocketryforum.com/showt...ed-Edition-Carbon-Fiber&p=1734469#post1734469

That's awesome, Mike. Can't wait to see this fly...

Thanks Rick I am also looking forward to seeing this one leave the pad and maybe even land somewhere on the field where I can see it for once!
 
Time to make a retainer decision. So as it turns out I have three choices. They are, as presented below, the Aeropack Quick-Change, GLR Bell Shaped Retainer System, and the GLR Qwik-Lok Slimline Retainer.

First up is a side profile of each system, all of them are black anodized aluminium



Next an aft profile of each system



First retainer to model is the Aeropack

23932564058_d0f9b947d4_b.jpg


Next to model is the GLR Bell

23932564648_598d3dd4cd_b.jpg


Last but not least is the GLR Qwik-Lok System

23932565148_b3a761f899_b.jpg
37736632106_e53cc3c588_b.jpg


And for anyone considering weight as part of the decision below is how they weigh in:

Aeropack - 21.12g
GLR Bell - 50.62g
GLR Qwik-Lok - 31.8g

I know what I like, hands down, but before I give my opinion I welcome yours.
 
To me it's the Qwik-Lok.... but I'd bet the best look would be internal retention...

My $0.02.
 
I think the one with the bell shows the best aesthetics. But it is heaviest and isn't exactly MD. Too bad there isn't some sort of slight boat tail (a boat tail on a boat tail?) that could be used. I'd probably go with the Aero Pack, make a small 3D printed fairing for it, similiar (but different) to what Riley did on his 54mm Scorpion.
 
To me it's the Qwik-Lok.... but I'd bet the best look would be internal retention...

My $0.02.

I sure about the Qwik-Lok, which I have used on my PML Bull Pup, a second dual-deploy Aerotech Arreaux, RM Formula 38 and two little RW Mouse kits for my kids, and it is a great design. But having stared at the pics I am not so sure now. Also a big question for me now that I am getting into the 38mm Loki hardware is will the thrust ring on the case sit inside the retainer. I need to make sure these three retainers are all still candidates because if I can't fly Loki in this then they are not an option. I know the Aeropack is fine but not sure about the other two.

Also internal retention, besides friction fit, is not an option becasue this is not a MD rocket. It is a 54mm air-frame with a 38mm MMT. That was a big selling feature for me as I already have two 38mm MD rockets and one 54mm MD, with a second scratch project about to hit production, but that is a different bird all together.

I think the one with the bell shows the best aesthetics. But it is heaviest and isn't exactly MD. Too bad there isn't some sort of slight boat tail (a boat tail on a boat tail?) that could be used. I'd probably go with the AeroPack, make a small 3D printed fairing for it, similar (but different) to what Riley did on his 54mm Scorpion.

I would like to see what Riley did, and if I go with the Aeropack I may want something to transition from the tailcone to the hump, as it is too bulky looking for my liking. I am not as concerned with aerodynamics although that bulky retainer certainly negates some or even all of the advantages of having a boat-tail if base drag reduction is a goal. Realistically it's not but I would prefer not to introduce it.

I do admittedly like the look of the Bell retainer, as it has grown on me. I used this on the rocket in my avatar (Madcow Tembo), which you can barely make out in the pick, it's silver, however my concern is the Krushnic Effect. This is something I have brought up a couple of times in other threads and have no real evidence that it robbed my Tembo in the pic of performance, but it is the only rocket I have built that was so far off it's simulation that it was stood out. I will have to do some more launches on that rocket to find out but I am not sure that I want to risk it on this rocket, so it's 3rd on the list just for that.
 
And for anyone considering weight as part of the decision below is how they weigh in:
Aeropack - 21.12g
GLR Bell - 50.62g
GLR Qwik-Lok - 31.8g

I know what I like, hands down, but before I give my opinion I welcome yours.

Frankly, I don't like any of the above options.
All of them ruin the airflow and look of the elegant boat tail.

Unless you can hide the retainer inside the boat tail (none of the 3 above will work, but a classic slimline retainer with a circle ring might fit), I would explore some form of positive internal retention solution.

Take a look at slimline tailcone retainers here:
https://giantleaprocketry.com/products/components_retainers_adapters.aspx

... or MD retainers here:
https://www.rocketarium.com/Build/Minimum-Diameter-Retainers

a
 
I'd probably go with the Aero Pack, make a small 3D printed fairing for it, similar (but different)
You don't have to have a MD rocket to use the MD retainer. How about using a 38mm MD retainer for the motor and the suggested 3D printed (or otherwise) boattail? 38mm motor in a 54mm airframe suggests this to me. Do the 38mm casings suit the MD top-end retainer style? I have almost no experience with 38mm.

I do think if you go big and bulky you are likely to regret it later.
 
Frankly, I don't like any of the above options.
All of them ruin the airflow and look of the elegant boat tail.

Unless you can hide the retainer inside the boat tail (none of the 3 above will work, but a classic slimline retainer with a circle ring might fit), I would explore some form of positive internal retention solution.

Take a look at slimline tailcone retainers here:
https://giantleaprocketry.com/products/components_retainers_adapters.aspx

... or MD retainers here:
https://www.rocketarium.com/Build/Minimum-Diameter-Retainers

a

I hear you and I feel the same way but there seems to be limited options.

I don't know how the classic slimline differs from the kwik-lok slimline as far as the overall size but I would have the same concern that Loki hardware does not fit.

Those MD retainers are the Aeropack MD retainers and I use them in my 54mm 38mm MD rockets and the issue with them is I would have to use a 54mm one and locate it so it can accommodate the largest motor then use extension rods for smaller ones. This will result in additional weight.
 
You don't have to have a MD rocket to use the MD retainer. How about using a 38mm MD retainer for the motor and the suggested 3D printed (or otherwise) boattail? 38mm motor in a 54mm airframe suggests this to me. Do the 38mm casings suit the MD top-end retainer style? I have almost no experience with 38mm.

I do think if you go big and bulky you are likely to regret it later.

When you say "Do the 38mm casings suit the MD top-end retainer style" I am not sure what you mean. I completely agree with you on going too big, this is not the build for that. This is going to take something creative or very basic.
 
Those MD retainers are the Aeropack MD retainers and I use them in my 54mm 38mm MD rockets and the issue with them is I would have to use a 54mm one and locate it so it can accommodate the largest motor then use extension rods for smaller ones. This will result in additional weight.


Not necessarily - don't epoxy the retainer, make it movable!
Tap 3 holes + epoxy nuts to the circumferences of MD retainer, then drill 3 holes (120 degrees apart) into the rocket body/MMT to allow re-anchoring for different length motors. This would be a bit easier on MD rocket, but also doable on one with a separate MMT.

The only thread with pics I could easily find is the one below, but I remember reading others:
https://www.rocketryforum.com/showt...er-placement-and-fit&highlight=motor+retainer

HTH,
a
 
Not necessarily - don't epoxy the retainer, make it movable!
Tap 3 holes + epoxy nuts to the circumferences of MD retainer, then drill 3 holes (120 degrees apart) into the rocket body/MMT to allow re-anchoring for different length motors. This would be a bit easier on MD rocket, but also doable on one with a separate MMT.

The only thread with pics I could easily find is the one below, but I remember reading others:
https://www.rocketryforum.com/showt...er-placement-and-fit&highlight=motor+retainer

HTH,
a

lol check out that link you provided and see who posted those pics :)
 
lol check out that link you provided and see who posted those pics :)

I knew I should have searched harder :lol:

I suspect a similar design can work with RM54, especially since the gap from MMT to airframe looks to be fairly small, enough to cover with M6x15 or M6x20mm allen grub screws:
https://www.ebay.com/itm/M6-M8-M10-...hash=item2840e22cb9:m:mtjXs3jvHJeKxI9alJblkog

You could glue a threaded bridge from MMT to airframe to firm up anchoring points, and serve as repositories for grub screws on unused anchoring holes. Alternatively, just insert plastic push plugs to cover and protect the unused holes.

a
 
When you say "Do the 38mm casings suit the MD top-end retainer style" I am not sure what you mean.
The 54mm and larger motors have a thread in the top which I use to screw onto a stud that is mounted inside the motor mount tube. The motor is just inserted from the rear and screwed into place. No retention at the rear. The 75mm and 98mm versions have the threaded hole as part of the forward closure. The 54mm motors (talking CTI here) need to have an adapter screwed into what is the charge well at the top of the motor to provide the thread. I am completely unaware of what system(s) are used at the front of 38mm motors.
 
The 54mm and larger motors have a thread in the top which I use to screw onto a stud that is mounted inside the motor mount tube. The motor is just inserted from the rear and screwed into place. No retention at the rear. The 75mm and 98mm versions have the threaded hole as part of the forward closure. The 54mm motors (talking CTI here) need to have an adapter screwed into what is the charge well at the top of the motor to provide the thread. I am completely unaware of what system(s) are used at the front of 38mm motors.

Okay I see.

The 38mm AeroPack adapter for CTI is basically the same thing as the 54mm adapter that screws into the BP charge-well. Ironically that is what afadeev provided a link to just a few posts above this one, which was my post on another thread. The 38mm Aerotech and Loki hardware have a threaded forward closure option, albeit they are different threads where Loki requires a custom adapter for the AeroPack, which I have both of these closures and the custom Loki adapter.

I know I can make an AeroPack MD retainer work for this rocket, my issue with that is the additional weight that it will net out, especially on the smaller motors. As I mentioned and as I am sure you are aware the MD retainer is typically fixed in one spot, this is usually at a point that supports the largest load you plan on flying. If so then I would have to add threaded rods for shorter hardware.

afadeev is suggesting that I can make the MD retainer removable, which is what I always do. However he is also suggesting that I can drill as many sets of holes as required to support different sized hardware, eliminating the need for the extension rod. This is something I have considered in the past, however ultimately decided not to pursue because I did not want to risk compromising the integrity of the airframe.
 
As slick as MD would be, for a fun fast turn around rear is a lot quicker and easier. The bell looks cool and fits that idea.
 
On my Mac Firestick, I shortened the boat tail just a quarter inch or so, and fit a threaded Slimline inside. I'm still working on finishing, but it looks very clean that way.
 
As slick as MD would be, for a fun fast turn around rear is a lot quicker and easier. The bell looks cool and fits that idea.

I don't disagree in the look at this stage as it has grown on me. My biggest issue, beyond the weight, is that I am not convinced that it does not rob some of the performance due to the Krushnic Effect. I need to first eliminate the options based on compatibility with Loki hardware. I also fly AeroTech and CTI and pretty much have the full set of their 38mm hardware but the 38mm Loki stuff is new to me and I cannot let you have all the fun. Once I eliminate the options then I may become more focused. One other option I am considering is something custom, something that seamlessly flows into the tailcone and will be compatible with all three hardware options.

On my Mac Firestick, I shortened the boat tail just a quarter inch or so, and fit a threaded Slimline inside. I'm still working on finishing, but it looks very clean that way.

This is something I had not even considered, great tip. As I said above I am going to check for Loki compatibility, if it is okay my first choice is the GLR Slimline Qwik-Lok system and your solution would help with both the esthetics and moving the retainer forward can only improve the performance.
 
On my Mac Firestick, I shortened the boat tail just a quarter inch or so, and fit a threaded Slimline inside. I'm still working on finishing, but it looks very clean that way.

This is a great idea. Wish I thought of this on my Firestick. I have the Slimline, but it's mounted behind the boat tail, per usual. Not horrible, but could have been perfect if I was thinking ahead!
 
Thank you for all the feedback it has been inspirational so far. Here is where I am leaning.

I confirmed that all three retainers are compatible with Loki hardware. So for anyone looking at these options who fly Loki they you can feel confident purchasing them. I was a bit leery that that the outside two turn snap-ring/thrust ring on the Loki case would fit inside the GLR Slimline and Bell retainers but they did, as a matter of fact they fit perfectly.

37790845852_dfa5bc82c7.jpg
37112612024_4ca8347a4b.jpg
37790846042_9fe3ea821c.jpg


So this process didn't eliminate an option but it did validate. Now that both GLR retainers are options I have decided to eliminate the AeroPack Quick-Change retainer simply because it is a bulky look and in my opinion the least appealing visually.

I like AdAstraPerAspera's idea of trimming the tail-cone and recessing the retainer and recessing it a bit. Dave also has me thinking more about the Bell retainer, however I would have to modify it to keep it as a consideration. Both retainers have the same O/D of 1.817" on the narrow part and the tail-cone has a wall thickness of .033" at the aft. I believe it gets thicker as it moves up however to estimate how much tail-cone I would have to trim to recess the retainers I worked it out to roughly 1.883" OD of the tailcone as my trim first mark and adjust from there. Visually that looks like the following pick with the faint pencil mark.



Based on where this cut mark lines up it is still a reasonable option for me. So it comes down to the Qwik-Lok Slimline and the Bell retainers. I have two issues with the bell retainer, the mass and my lack of confidence that it will not introduce the Krushnic Effect, to a degree, and rob my motors of their potential performance. To keep the Bell retainer as a viable option for me I am considering the following, trimming some of the mass from both the front (marginally say up to .2", it has .6" of retention) and the aft at a min of .25"- .35". This should remove roughly 25-30% of the overall mass as well as bring the exit nozzle closer to the aft of the retainer.

The overall impact on the length of the rocket would be pretty much on par however the MMT would more fore by about an inch.

37790846472_152993a1a8_z.jpg


Thoughts and opinions are all welcome.
 
I wouldn't worry about performance as it's not a minimum diameter. I'd go for looks and "what hasn't been done". The bell retainer is the coolest looking thing going and would look fantastic on that build. I have always wanted one myself. I'd trim the base of the tailcone so that it is the same diameter as the bell retainer. Sooooo sexy.


Sent from my iPad using Rocketry Forum
 
I had Mike cut the boattail of a custom kit so the slimline would slip inside. Works and looks great! I would really like to showoff a picture of it, but the photo uploader seems to be broken...
 
I wouldn't worry about performance as it's not a minimum diameter. I'd go for looks and "what hasn't been done". The bell retainer is the coolest looking thing going and would look fantastic on that build. I have always wanted one myself. I'd trim the base of the tailcone so that it is the same diameter as the bell retainer. Sooooo sexy.


Sent from my iPad using Rocketry Forum

I agree if performance was a priority I would do away with the MMT, but then I would have to also remove the tailcone and then it would not be a Rainmaker. This is a 10K rocket and that is perfect for my needs. I also like the idea of going with what has not been done.

Personally I would use the low-profile Slimline for this build and save the bell retainer for a fancier build (example: https://www.rocketryforum.com/showthread.php?p=316639)

From the Ether...

That is a pretty cool Axe rocket and the fact that you used the Bell helps me get a bit more comfortable with it. Tell me did you sim the rocket, was the sim and actual close? I have only used this retainer once and it was a 38mm silver one, same as yours. My sim was way off from the actual, to the point where I can't get it out of my head that the Krushnic Effect played a role. This is why I may shave a bit off the Bell if I go with it, just for a bit of margin and the added bonus of weight loss.

I had Mike cut the boattail of a custom kit so the slimline would slip inside. Works and looks great! I would really like to showoff a picture of it, but the photo uploader seems to be broken...

Ah I just finished doing this. I figured I have made the decision to go with either the Slimline Qwik-Lok or Bell retainer, and both require the same trim job of the tailcone. I used my oscillating belt sander and shaved it down from 6.5" to 5.227" which is just a bit too big for the retainer to slide in. Then I manually used a sanding drum and shaved down the inside edge of the trimmed edge just enough to allow the retainers to slide inside. Overall I am very happy with the results and the fit works well.

Here are some pics with both retainers mocked up.

Up first is the Bell retainer. If I slide the retainer up so the aft edge of the tailcone meets the bell, the transition looks seamless, however the neck of the retainer interferes with the fin slots. This is not an issue because my intention if using the Bell would be to trim the fore edge by at least the amount to fit maybe more. I would also create groves in the neck of the retainer and when I glue it in place this would help to retain it on both the motor tube and the tailcone. I would also consider shaving a bit off the Bell, which if I did I would re-anodize the retainer assuming the tolerances on the thread for the retainer part could handle the process.

In the pic where I mocked up the fins I had to slide the retainer out in order to fit the fins so the ultimate look is not what it would be but it provides a visual idea.

37866546781_f4df00ae2d_b.jpg


And here is the Slimline tailcone mocked up, at the same length protruding out the end. With this one I have a bit more play as far as how much extends out the end, but as with the bell there is quite a bit of neck on the part that the motor tube slides into. Also because the tailcone is so narrow at that point I could easily shave a bit off the retainer and scuff up the outside so that the retainer adheres to both the motor tube and the tailcone.

37866547251_bd33482b53_b.jpg
37866547791_d67cf82cd7_b.jpg


Final thoughts?
 
I would notch the fins so you can slide the MMT and retainer forward into the airframe and make the aft end look less clunky.

From the Ether...
 
just use a really big motor...I dont think the bell will matter much then....
 

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