MAC Performance Rayzor 3" Build Thread

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Jozef

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You can get by with one cup instead if two. Put the cup on the scale. Press the zero button. Add part 1 of the epoxy to what ever 1/2 of your desired weight or volume will be. Add part 2 to the same cup to equal your total desired weight or volume. Done. For Rocketpoxy, you do not need a cup. Use a piece of cardboard or plastic instead. this helps when you want the Rocketpoxy to used for fillets as the air bubbles escape more completely
 

MikeyDSlagle

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Check out US Composites. They sell mixing cups, mixing sticks, and squeeze bottles. And their epoxies, in smaller amounts, comes in the squeeze bottles. Even have scissors, gloves and dust masks.
 

kswing

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I've got all three sets of fins glued on now and I've started working on the external fillets. Here's a picture of the internal fillet produced using the triple-dipping method:
internal_fillet.jpg

As you can see by the picture, the internal fillets this technique produced aren't huge, but, they should be big enough and they didn't really require much effort.

Now that all three sets of fins are on, I've started working on the external fillets by taping off the area with blue tape and then using a popsicle stick to spread the epoxy and shape/size the fillet. I'll post a picture of the external fillets when I have a chance.

After the externals are done then I'm going to foam the fin can and install the bottom centering ring. I've been doing some calculations on the amount of foam needed for the fin can (using the worksheet on John Cocker's site) and it looks like it shouldn't take much to fill it, so, there shouldn't be much weight added.
 

soopirV

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I've got all three sets of fins glued on now and I've started working on the external fillets. Here's a picture of the internal fillet produced using the triple-dipping method:
View attachment 308838

As you can see by the picture, the internal fillets this technique produced aren't huge, but, they should be big enough and they didn't really require much effort.

Now that all three sets of fins are on, I've started working on the external fillets by taping off the area with blue tape and then using a popsicle stick to spread the epoxy and shape/size the fillet. I'll post a picture of the external fillets when I have a chance.

After the externals are done then I'm going to foam the fin can and install the bottom centering ring. I've been doing some calculations on the amount of foam needed for the fin can (using the worksheet on John Cocker's site) and it looks like it shouldn't take much to fill it, so, there shouldn't be much weight added.
This is the first I've encountered the idea of "dipping" internal fillets, and I like it- was a little worried given the lack of space between the airframe and the MMT. I've never foamed before, and am not sure I'd be able to use up the product before it kicks. I've seen warnings to avoid the GreatStuff versions, but not a good explanation as to why...
 

MikeyDSlagle

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From what I understand the Great Stuff requires air to fully cure. Enclosed in a fin can it can't get that air. Two part foam doesn't need air. I'm sure there is more to it but that is a simple explanation... I think.
 

pondman

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DO NOT USE GREAT STUFF TO FOAM FIN CANS, NOSE CONES, ETC! You will be sorry if you do; trust me on this one........
 

Maxter

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Aerosol style needs air to dry. Will never cure in a fin can. Just make a small batch to practice with to get your timing down, do it outside.....don't ask how I know not to do it in the kitchen.
 

AdAstraPerAspera

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I tried to use "great stuff" foam from a can once for a nosecone. It never cured and therefore never came close to holding my nose weight in place. The weight turned it into a gooey mess that didn't resemble foam anymore as soon as I turned the cone over.
 
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soopirV

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DO NOT USE GREAT STUFF TO FOAM FIN CANS, NOSE CONES, ETC! You will be sorry if you do; trust me on this one........
Again, warning not to use a product but without any details! I get that I shouldn't use it, but can you elaborate on what happens? Those above and below you have mentioned that curing is the issue...I'm assuming this is the reason?
 

blackjack2564

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Designed to be used in open area as a sealant against weather......cracks- voids- etc. Around window casings,electrical outlets, areas that get overlooked with sheet goods insulation.Squirt in -expands-hardens in few hours ...unless cold, then takes days.

No adhesive properties what so ever.

In fin cans/nosecones/etc. it will never fully cure correctly.

Needs air & moisture/humidity in it for full cure.
When sun hits rocket on pad & heats it up [or left laying on ground, back of car, in truck, where it gets real hot]...even months later it will begin to expand again/more....bulging out side of rocket....moving fins out of position and any other nasty thing you don't want.

Sometimes when inside sealed area like fincan, it will just stay gooey making a mess, then you try and get it out, starts to cure making a real big mess.

Heard enough? Chemicals in it are highly toxic when left inside something for awhile, never meant to be sealed highly when used.....Google Great Stuff MSDS here:

View attachment 090003e8806e64d0.pdf

Read that, you'll never use it.:wink:
 

soopirV

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Designed to be used in open area as a sealant against weather......cracks- voids- etc. Around window casings,electrical outlets, areas that get overlooked with sheet goods insulation.Squirt in -expands-hardens in few hours ...unless cold, then takes days.

No adhesive properties what so ever.

In fin cans/nosecones/etc. it will never fully cure correctly.

Needs air & moisture/humidity in it for full cure.
When sun hits rocket on pad & heats it up [or left laying on ground, back of car, in truck, where it gets real hot]...even months later it will begin to expand again/more....bulging out side of rocket....moving fins out of position and any other nasty thing you don't want.

Sometimes when inside sealed area like fincan, it will just stay gooey making a mess, then you try and get it out, starts to cure making a real big mess.

Heard enough? Chemicals in it are highly toxic when left inside something for awhile, never meant to be sealed highly when used.....Google Great Stuff MSDS here:

View attachment 309060

Read that, you'll never use it.:wink:
BRILLIANT! thank you! (And to the others who pointed to the lack of curing). Will definitely stay away.
 

kswing

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Tonight I did the second set of external fillets. I use blue tape to protect the area and catch any drips and I use a popsicle stick to actually shape the fillet. I also use a heat gun on low heat if needed to help the epoxy smooth out a bit.

Here's a picture of the latest fillets with the rocket all taped up:
fin_fillet_with_tape.jpg
And here's a picture of one of the previous sets once they dried:
fin_fillets.jpg
 

kswing

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I finished the final external fillets on Friday, so, yesterday I foamed the fin can and then after a while glued on the bottom centering ring which also acts as a thrust ring. In case anyone is thinking of trying the foam, it worked well but it does stick to everything it touches so be sure to protect anywhere you don't want it. It is also very temperature sensitive, so, be sure to test how much it expands in the temperature you are planning to use it in.

Today, I worked a bit on the sled for the tracker which will be in the nose cone and I also started sanding a bit in preparation for painting. My plan is to use Rust-Oleum Ultra Cover 2x primer and paint and sand everything with 220 prior to applying the primer. Also, the wall of the upper body tube was just a tiny bit (about 1/32") thicker in one area, so, I had to sand it a bit so that the transition with the nose cone was smooth.

I've also started work on the Eggtimer Quantum I'm planning to use, but, after a few issues with uncooperative solder I ordered a new soldering station and I'm going to wait for that before proceeding on the Quantum. If all goes well I'll have this rocket ready for the February launch at BattlePark.
 

kswing

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I got my new Weller adjustable soldering station a few days ago, so, today I finished soldering the Eggtimer Quantum. At first it didn't work quite right, but, I followed their troubleshooting, checked all of my solder joints and after touching-up a few it started working fine. I've soldered things before, but, this was definitely a challenge for me as some of the parts are very small. I don't fault the Eggtimer folks on this, their instructions are good and they do warn you that it shouldn't be your first SMD project.

I'm planning to use e-matches for the dual deploy and so far I'm planning to use a 2S 500mAh LiPo battery. During my Quantum test-fire it worked to fire both the drogue and main. It is nice being able to test just using a web site. Next I'm going to start work on setting up the e-bay and also mounting the rail buttons.
 

kswing

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Yesterday and today I arranged and installed the dual-deploy electronics onto the e-bay sled. I mounted the LiPo battery by wrapping it with some foam sheet and then used two zip ties, one vertical and one horizontal. I mounted the Eggtimer Quantum using nylon mounting posts that I got from Apogee Components. To install the nylon posts, I drilled the canvas sheet using a #43 drill bit and then used a 4-40 tap to thread the sheet for the nylon posts. I also put on an extra zip tie for use as a stress relief for the wires. I'm using JST connectors between the sled and the terminal blocks on the end caps so that it is easier to remove the sled to connect and/or charge the battery. I'm planning to use some dense foam (from a pool noodle) to ensure that the sled doesn't slide around in the e-bay.

Here are some pictures:
sled_altimeter.jpgsled_battery.jpg
 

kswing

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I've made some progress on this in the past few days. I've started sanding and priming and I've drilled the holes for the rail buttons. I started the finishing by sanding everything with 220 sandpaper. Next I started coating it all with Rust-Oleum Ultra Cover 2X flat gray primer. The paint sticks well, but, it is taking a few coats to fill in all of the weave of the canvas. I'm letting the primer dry for 4 or 5 days on the plastic nose to help it bond before sanding and over-coating.

So far I'm thinking I'll use removable plastic rivets to keep the e-bay/coupler section connected to the top tube and use friction fit for the nose cone and connection between the booster and the e-bay. I've also considered using shear pins for the nose cone, but, I've had good luck with friction fit on my Excel, so, I'm thinking it will also work here.

Here's a picture of the primer coat:
primer.jpg
 

Bat-mite

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Looking forward to the final paint job.

I currently have two flying MAC kits, and one in the build pile. Good stuff.
 

kswing

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I made some progress on this kit this weekend. I got a few coats of paint on it and I also tested the main side deployment charges. Here's a view with at least one coat of paint on everything:
first_coat.jpg

As far as deployment configuration goes, I've decided to just friction fit the nose cone and I think it will work. I've got the nose cone tight enough that I can hold up the rocket by it and shake and it doesn't come out. Also, I'm using plastic rivets to connect the upper tube to the e-bay. I tried 1.2 grams of black powder in a ground test and it was enough to push the nose cone out to the end of the shock cord with enough force to pull the booster out of the hammock I had it sitting in. Based on that test I'm thinking 1 gram will be enough, so, I'll try that when I have a chance. I also need to test the charge for the drogue side. Also, I've drilled a 1/8" vent hole in the top tube for pressure relief and I'll probably put a similar hole in the booster section. Here's a video of the deployment charge test: [video]https://youtu.be/ws2n6S3Npe4[/video]
 

Buckeye

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Looks good. I agree, I think 1.0 gram will be fine. I plan on shear pins, probably (2) #2-56, on my Thunderstick build.

Got any CG, CP, stability info?
 

kswing

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Looks good. I agree, I think 1.0 gram will be fine. I plan on shear pins, probably (2) #2-56, on my Thunderstick build.

Got any CG, CP, stability info?
Since the rocket is mostly done, tonight I checked the overall weight and found the CG and then entered that into OpenRocket to verify the stability. As a starting point, I used the .rkt file for this rocket which is available from MAC Performance and then adjusted the .rkt file to match both the weight and empty CG location of my version. Based on those calculations stability shouldn't be an issue for any of the motors I plan to fly.

Tonight I installed the Aero Pack flanged motor retainer. It comes with threaded inserts and over the weekend I tried drilling for and installing three of those, but, even though I took my time they still didn't quite align correctly. I don't have a 54mm motor casing yet, so, I'm sure that contributed to my slight mis-alignment. I searched around here on TRF and I noticed that others also had trouble getting everything lined up correctly, so, I thought I'd try something different. Tonight, instead of messing around with the threaded inserts, I used a makeshift 54mm coupler (made out of some sliced 2.6" LOC body tube) for alignment and then used #6 stainless steel pan head screws to mount the retainer. With the coupler keeping things aligned I drilled three 5/64 tap holes and then put in three screws to verify alignment prior to putting in all six screws. The screws are well anchored and it looks straight both with the tube coupler and with the 54->38 adapter, so, I think it will work.

This rocket is almost ready to fly.....I think all I have left are some stripes on the fins, a little touch-up paint, a few more charge tests, and the name sticker from stickershock23.
 
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soopirV

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I've made some progress on this in the past few days. I've started sanding and priming and I've drilled the holes for the rail buttons.
Would you be able to go into more details on this point? I've got my own Rayzor build going, and am now contemplating how to mount the buttons. My cardboard birds came from Madcow, and have instructions for mounting rail guides (and the tiny woodscrew to get the aft one into the lower CR). When I marked out the awesome aft CR/thrust plate on my rayzor, I don't have a lot of room to hit the wood, and I'm using Delrin 3-piece buttons from railbuttons.com (#10 screw, by default). I was planning on doubling up that area with a small chunk of plywood, but then I'm left with the issue of the forward button. Conventional wisdom is to locate it around the CG. On full FG builds, I've just drilled and tapped the FG and threaded in a machine screw with the button. Will that technique hold for canvas phenolic? It somehow seems more brittle to me, but that's just irrational sensibility, I have no basis for it.
 

kswing

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Would you be able to go into more details on this point? I've got my own Rayzor build going, and am now contemplating how to mount the buttons. My cardboard birds came from Madcow, and have instructions for mounting rail guides (and the tiny woodscrew to get the aft one into the lower CR). When I marked out the awesome aft CR/thrust plate on my rayzor, I don't have a lot of room to hit the wood, and I'm using Delrin 3-piece buttons from railbuttons.com (#10 screw, by default). I was planning on doubling up that area with a small chunk of plywood, but then I'm left with the issue of the forward button. Conventional wisdom is to locate it around the CG. On full FG builds, I've just drilled and tapped the FG and threaded in a machine screw with the button. Will that technique hold for canvas phenolic? It somehow seems more brittle to me, but that's just irrational sensibility, I have no basis for it.
So far I've just drilled a hole slightly smaller than the full width of the screw for the rail button and then I used the screw itself to tap the hole. I haven't flown it yet, but, when I pull on the rail buttons they seem pretty solid so I think that will work. I'm using the one-piece delrin buttons from railbuttons.com. I took the buttons off for painting and when I put them back on I'm planning to put some epoxy on the screws to ensure they don't try to work themselves loose. I'll also have one of my kids reach down in the tube to put a piece of duct tape over the upper screw where it sticks out inside the booster so that my recovery harness won't catch on it. Also, I have the upper rail button located near the CG and from what I've read on here and my personal experience I think it will work. When working on a past rocket, I read many forum posts on rail button locations and based on what I've read I think most of the time placement isn't that critical as long as one is near the bottom and you've got a decent amount of space between them.
 

AdAstraPerAspera

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I usually do three, one near the bottom, one near the top centering ring, and one fairly far forward, well ahead of the CG, often on my AV bay. This gives plenty of support on the pad, and two still on the rail as long as possible. A little extra drag? Yes. But I'm usually okay with that.
 

AdAstraPerAspera

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You can also back the button with a nut epoxied into place or even just epoxy. Grease the threads so the epoxy doesn't stick and you'll be able to remove and replace the buttons if you ever need to.
 

soopirV

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You can also back the button with a nut epoxied into place or even just epoxy. Grease the threads so the epoxy doesn't stick and you'll be able to remove and replace the buttons if you ever need to.
That's a neat idea, a blob of thickened epoxy wouldn't be hard to manage. I like that it adds more material for a mechanical (but removable!) bond, and also smooths out the screw to avoid snags.
 

mike2wander

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I also use the one piece rail buttons from Railbutton.com. There is no need to use three buttons. I use the same method as Ken. I drill the holes slightly smaller and use the screw to cut the threads. I never worry about attaching the screw to the centering ring on the booster and never epoxy the screws in. PLEASE this is how I do it........not what I am recommending.

Mike Crupe
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kswing

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I also use the one piece rail buttons from Railbutton.com. There is no need to use three buttons. I use the same method as Ken. I drill the holes slightly smaller and use the screw to cut the threads. I never worry about attaching the screw to the centering ring on the booster and never epoxy the screws in. PLEASE this is how I do it........not what I am recommending.

Mike Crupe
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Thanks for the information Mike.....I'm glad to see that someone else is doing the same thing as what I'm planning and I think it should work. Also, any information on build techniques or best practices I get from the forum I try to validate/verify against my own experience and observations because sometimes a technique will work many times until that one time something goes just a little different.

It seems like there are many paths to success with rail buttons.....I'd be curious to see a thread that lists actual rail button failures/issues so that folks can better learn what to avoid.
 

AdAstraPerAspera

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I've seen them wear out/get chewed up bad, but not had one of mine fail (yet). I have always backed my buttons somehow. I've ripped lugs off before (back before switching to rails) but that was usually in handling, while getting the rocket on the pad and vertical.

A friend of mine used to treat buttons as disposable, single-use items on his spin-stabilized birds, but that was almost to be expected...
 

Bat-mite

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On a MAC P. rocket (and I have three), I use screws like Mike, and just thread them in; but I also put some CA on the screw. And I usually screw the upper one into the nice thick CR, but not the lower.

The problem with three buttons is that you have to be super-extra careful to get them lined up perfectly. I am not good enough with a drill to do that!

Some people say your buttons should be able to rotate after they are affixed, but I don't see the need.
 
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