lugs vs buttons

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watermelonman

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I have ordered my next rocket kit and have a stack of modifications to make after some feedback here. Thanks!

One item sticking out at me, though, is launch lugs. It appears that they are out of fashion, or at least more restrictive, than some kind of button that slides down rails. I can imagine the mechanism but I have not used these or seen them in person. Could someone give me the quick rundown of when to use one or the other? I will probably be launching with a local club 99% of the time, so if these rails are less common at low power sport launches that part definitely matters.
 
Where we launch, lugs are generally used for low- and mid-power, and buttons are used for high power. 1/8" lug for up through E/F, 1/4" lug for the bigger stuff, 1" rail button for H-J/K, and 1.5" rail button for everything else. Those aren't strict rules, but that seems to bee the pattern. It really all depends on the loads that buttons and lugs will see.
 
Not all clubs have a large number of rails, especially at LPR launches, so that is a valid concern. I personally would not use rail buttons on anything smaller than a G, or maybe F motor. Above that, I would definitely use a rail guide or rail button.

When I do build a smaller rocket, I almost always use a larger 1/4" lug, even if the kit comes with something smaller. That helps keep your options open.
 
Agree with the post two above. It also depends on what launch equipment you have available. If you fly by yourself, then use whatever you already have.

Many clubs can accommodate all of the above, plus 3/16" rods, and some may still have 3/8", 1/2" and 3/4" rods. I only mention these last as I had a design that required a 3/8" rod - not enough clearance for rail buttons.

If you are starting fresh, check out the mini rail buttons at rail-buttons.com - https://rail-buttons.com/minimicro.html. I have a kit that uses these, and plan to add them to several other rockets. You may need to supply your own rail, but they are relatively inexpensive, and there is no rod whip. Expecting to see more of these for TARC launches, but that's just an opinion.

I'm also starting to build with multiple options - 1/4" lugs on one side and 1010 railbuttons on the other for my King Kraken (build currently stalled). I figure that way I'm pretty much guaranteed that no matter what equipment a club has available, I can fit one or the other. Yes, it's a bit more drag. Meh.
 
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I agree with everything that has been said, but I would strongly recommend rail buttons if you club has them (even for the Arreaux). Also, as soon as you move to rockets more than about 20 oz, rail buttons help a ton to prevent the rocket from wobbling on the launch rod and veering off course at launch.
 
With the mini and now micro buttons available I would hope more clubs can start to purchase smaller rails that can accommodate these....:cool:
 
My personal rule of thumb... >24mm motor, I'm now using buttons. 24mm motors, buttons or lugs. <24mm motor, lugs only.
 
My local club just got some of the rails for the mini buttons. I think you should fly off of a rail if you can. You get much longer time on the rail to help with stability and you don't get that crazy rod whip. You also don't have rockets moving all about when a gust of wind comes along. Minus my Estes and smaller type rockets I can't remember the last time I used a rod about 3/16 inch in diameter.

One thing about button placement. I usually mount one pretty close to the aft. About an inch up on a typical rocket design and then the next one as close to the center of gravity.

Bill Beggs
TRA 5258
NAR 70094
 
Thanks everyone! So while I see how the buttons work, I do not yet understand why the characteristics are different. Is it simply because the buttons can be spaced out over a longer distance, fore to aft, than lugs? Why would one or the other be more prone to whip?

Is it common to find a rail set up at a low to mid power sport launch?
 
The rocket can't rotate on the rod and the rod can't bend, so it's much more reliable. Distance between buttons is less important.
 
Our club as almost all rails. We keep one pad with a 1/4" rod out at the HPR pads for some of the old timers. At the LPR pads we have a 1010 rail, one 1/4" rod and everything else is 3/16" or 1/8" rods. We recommend rails for anything larger then F.
 
I won't use Lugs anymore on anything but the smallest of Rockets. I made the mistake of using them on my TLP Indigo because I was trying to build it as close to stock as possible, and now I can't fly it because I don't have a long or wide enough Launch Rod. I will be cutting off the Lugs and screwing in some Buttons as soon as I get around to it. I have only launched 7 Times from my 1010 Rail, but fell in love with it after the first time.
For me it has to be a Rail from now on.
 
I'll never install a lug again unless it's a little kit. Even then, I would prefer mini rail. Can't hardly wait until those become more prevalent.
On that note, I'm building a Loc Aura. It's either giant 1/4" lug or buttons... 1010 buttons for me.
Oh, finally, here's a plug... Go to rail-buttons.com Randy is awesome, his prices are awesome, and you can get everything you want... Even colors!
 
If you have access to a rail, use buttons. You can also "dual purpose" rod/rail, by building with buttons and lugs, on two sides of the bird.

I always use t-nuts with buttons (Some #6 have a collar (the threaded part) that actually fit inside a 1010 button) so that the buttons can be removed for painting or replacement. Drill a hole thru the BT, and put the flange inside the BT and pull the collar thru using a screw (dipped in something like Vaseline), and then epoxy the flange inside the BT (the Vaseline prevents epoxy from sticking to the screw threads.) For the rear t-nut, you may need to wait until you're installing the MMT to install it, so you can have the front CR past the hole when you install it.
 
I'll never install a lug again unless it's a little kit. Even then, I would prefer mini rail. Can't hardly wait until those become more prevalent.
On that note, I'm building a Loc Aura. It's either giant 1/4" lug or buttons... 1010 buttons for me.
Oh, finally, here's a plug... Go to rail-buttons.com Randy is awesome, his prices are awesome, and you can get everything you want... Even colors!

Thanks appreciate it! Happy to see this catching on!
 
But this are only 35.4" long. Splicing these things together adds cost and is probably never going to be as strong/straight as a 6 or 8 foot section.

Actually it is 59.05512" long...just under 5'. Microbuttons are NOT for HPR and barely for MPR. 59.05512" should be more than long enough for LPR and the low end of MPR.
 
But this are only 35.4" long. Splicing these things together adds cost and is probably never going to be as strong/straight as a 6 or 8 foot section.

1500mm is 59.05" length (4.92'). A nearly 5 foot length of rail should take care of >90% of all modroc launch needs. For the other ~10% you can bolt on a 600mm or even a 900mm length of rail to get you to 82.68" or 94.49" respectively (6.89' or 7.87').

Greg
 
1500mm is 59.05" length (4.92'). A nearly 5 foot length of rail should take care of >90% of all modroc launch needs. For the other ~10% you can bolt on a 600mm or even a 900mm length of rail to get you to 82.68" or 94.49" respectively (6.89' or 7.87').

Greg
exactly! I want to try a Leviathan off this rail.
 
I'm also starting to build with multiple options - 1/4" lugs on one side and 1010 railbuttons on the other for my King Kraken (build currently stalled). I figure that way I'm pretty much guaranteed that no matter what equipment a club has available, I can fit one or the other. Yes, it's a bit more drag. Meh.

Oh, like this man's thinking....
But since I've never ever seen a kit with a "rail button", where does one get one of these...and are their any guides to their installation? Do they even go on craft paper tube rockets, at all?
 
Oh, like this man's thinking....
But since I've never ever seen a kit with a "rail button", where does one get one of these...and are their any guides to their installation? Do they even go on craft paper tube rockets, at all?

Rail-buttons.com has a variety.
Most vendors sell packs as well.
For smaller rockets, consider the mini buttons available on rail buttons.Com. they're not prevalent yet, but it isa coming trend. I'll certainly make my launch pad capable of launch both small and regular rails. Never use lugs again!
Installing is easy, just ask for help! Pm if you want details.
 
Oh, like this man's thinking....
But since I've never ever seen a kit with a "rail button", where does one get one of these...and are their any guides to their installation? Do they even go on craft paper tube rockets, at all?

There are probably a lot of opinions on how to install rail buttons. So here is mine. Location is similar to launch lugs. You simply want it to guide your rocket. Normally I put one near the aft end and one near the front of the fins or c/g. The farther forward you install the buttons the less guidance on the rail the rocket will have. I often use sheet metal style screws and simply screw into the body tube. Sometimes I use a machine screw and nut if I can get to the inside of the body tube. What I want is a button that rolls and is not tight so that it can roll down the rail instead of binding up. I like to use buttons on rockets of G power and greater.
 
Rail-buttons.com has a variety.
Most vendors sell packs as well.
For smaller rockets, consider the mini buttons available on rail buttons.Com. they're not prevalent yet, but it isa coming trend. I'll certainly make my launch pad capable of launch both small and regular rails. Never use lugs again!
Installing is easy, just ask for help! Pm if you want details.

Thanks for the plug guys!

With the new mini and micro buttons, launch lugs are going to start getting harder to find at a launch. And that's a good thing...rod whip is never a good thing.
Back in the 90's when railbuttons were a new idea, they took a while to catch on, but it's rare to see a high power rocket without them nowadays.
I'm hoping the same thing happens with mid and low power.

Launch lugs will always have a place for things like odd rocs, but for most rockets, there is a railbutton that will fit it.
 

exactly! I want to try a Leviathan off this rail.

FYI, the rails came in, these are the 10mm x 10mm rails...I was thinking they were the 15mm x 15mm like I used earlier. The buttons work with both rails...I may still try the Leviathan off this rail, it is still stiffer than a 1/4" rod :)

As you can see Kirk G, the micro buttons are on a standard Alpha

2014-10-15 21.56.20.jpg

2014-10-15 21.56.46.jpg
 
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I use lugs on low powered rockets, and buttons on mid and high powered rockets.
 
I used ACME conformal rail guides for my first rocket set up to use a rail. They worked great! They are designed with a curve to fit the body tube and they just glue onto the rocket with JB Weld. That makes them super easy to mount. I was amazed at how easy the guide slides in the rail. There really is a lot less friction than with a lug.
 
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