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When (if) to go to rails?

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BBowmaster

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At what size or power do you need to go to rails instead of launch rods? My 4H club setup has rods up to 1/4”. Typically we launch on 3/16”. We’ve launched dual-D clusters and Mean Machine size rockets. Is there any real need for a rail if I keep it at F motor or under and sub 1 pound?
 

chrocket

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I do not see that you need to go to rails.
I launch an Aerotech Initiator on a 1/4" rod with a G76 an never had any problems with the rod whipping.
 

tfish

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when you want or need the rocket to go straight. This could be do to wind direction, field size, shape, obstacles, spectators location....etc

Tony
 

dhbarr

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I personally feel like 1010 is right if you're going above FAR101 Model Rockets. Lots of folks draw the line elsewhere, it's all good either way.
 

tfish

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I even have micro buttons on B motor sized rockets that I use for demos..because I want the rocket to go where I point it.

5th aand 6th.jpeg


Tony
 

Trident

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I started using them on a lot of small rockets. Sometimes its impossible (like the internal lug on a Mars Lander), but it also means you can add your rail buttons after painting. I drill the holes prior to painting. And I’ve also added them after painting ... not as disastrous as adding a lug after paiting. :eek:

Two sizes exist, micro buttons (10mm rails), and mini buttons (20mm rails). Some clubs, and national launches, are starting to offer these smaller rails. I also take my own pads. Here is picture of buttons, their rails, and an 1/8” launch lug, for comparison.
431D0D1A-0D6A-4892-989C-1C49099E3101.jpeg
 

BBowmaster

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Ok, so no real NEED to go to rails if rods are working. But some benefits in rigidity for edge cases. Thanks.

plus, buttons might be less visually obtrusive than a lug. Thanks for that comparison pic!
 

prfesser

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Rod whip on ANY rod (except maybe 1/2") is a problem. I bought a mini rail and mini buttons, and will retrofit all my rockets to railbuttons.

It's the smart thing to do.

Best -- Terry
 

DaveW6DPS

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With light rockets rods are okay. If you start seeing rod whip then you should look at something stronger.

Some rockets, particularly including the Mean Machine, are very susceptible to wind issues. If you launch them only in very low wind it is not an issue. In higher wind, rails will not help much, as they will still have issues above the rail. Placement of rod or rail guides is also critical on rockets with a lot of side area, so ensure you have one at or just above the CG and another near the aft end.
 

Alan15578

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If you are launching vertically in light or no wind, you do not need much stiffness; You can launch a 1/100 Saturn V from a 1/8" x 36" rod. However, if you are launching at an angle, or in wind, you need a longer stiffer launch rail, which could well be a rod. Non of the available sport rocket flight simulators deal with launcher dynamics, so apply a generous safety margin.
 

FredA

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Rod Whip sucks.
Even Rail Whip sucks.
Strong, straight guidance is always best.
 

David Schwantz

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I have micro buttons on 1/2 A stuff. The maker beam works great.
 

Trident

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When I first ordered the micro and mini buttons a few years ago, I put micros on an Estes V-2 (BT-80) to test just how big of a rocket could be used with them. Worked just fine. My dividing line is roughly BT-55 tube and smaller for micros on the MakerBeam rail, and anything larger (BT-60 and up) I’ll use minis in the 20mm rail.
 

Ralph M Bohm

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Launch rail/button questions:
1) Is there a standard for rails and buttons such as 20x20 or even smaller 10x10 that is endorsed by NAR for say, E, F and/or G motors? actually, if up-rating my future rockets, for Level 1 certification, is there a standard size of same?
2) Is there also a corresponding button type/size, etc.?
3) While I am at it, does there seem to be a standard length (height) rail for NAR and other industry launches?
 

Nytrunner

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1) Standard high power sizes are 1010 rails (1"x1") and bigger 1515 rails (1.5"x1.5"). I personally put 1010 buttons on anything with a 29mm motor (or clustered 24mm). You would want to use 1010 for an L1 rocket. Now there are mini and micro rails that can be used on smaller rockets, I just don't have much experience with them.
The benefit of the rail is that they're stiffer than a rod, doesn't whip as much, and are generally longer providing more guide time before the rocket exits to free flight.
2) 1010 buttons for 1010 rails, 1515 buttons for 1515 rails
3) 6' or 8' 1010 rails are common. My club (HARA) has mainly 8' 1010s and 1515s with a 10' 1010, a 12' 1515, and some extensions for use in a pinch
(remember to subtract the distance from bottom of rocket to forward rail button from the overall rail length. That is your effective rail length that should be plugged into sims)
 

boatgeek

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For upper limits, I've used 1010 rail buttons for everything up to full K/baby L power. If the rocket is really heavy, the bigger buttons may help.
 

Mike Haberer

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I have an NCR 1/4 scale Patriot, ten years old, that has flown many times (on G80T's) on a 1/4 rod. It has rarely gone straight up. It comes off the rod too slow and weathercocks if there is any bit of wind over a couple of MPH. I added rail buttons last year and flew it once in the fall on a 6' rail. Went straight up with about a 8 mph wind. The best reason for a rail is not to avoid rod whip, it's to have enough length to get adequate speed off of the pad, especially if it is on the heavy end for a particular motor or if it is over stable.
 

Ralph M Bohm

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1) Standard high power sizes are 1010 rails (1"x1") and bigger ...
Thank you for the reply, Nytrunner,
That's what I needed to know. I've not yet been to a function and just needed to know what to standardize my builds to.
 

Ralph M Bohm

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I have an NCR 1/4 scale Patriot, ten years old, that has flown many times (on G80T's) on a 1/4 rod. It has rarely gone straight up. ..
Mike,

That reminds me of a time way back when flying an old AstroCam. The rocket loved to kick over off a flimsy, whipping launch rod hence my concern today as I get back into the hobby.

Ralph
 

Ralph M Bohm

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BTW, for clarification purposes:

Are the following lines accurate (correct)?

1) 1010 rails are SAE 1" x 1" extrusions
2) 1515 rails are SAE 1.5" x 1.5" extrusions
3) 2020 rails are metric 20mm x 20mm extrusions
 

o1d_dude

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BTW, for clarification purposes:

Are the following lines accurate (correct)?

1) 1010 rails are SAE 1" x 1" extrusions
2) 1515 rails are SAE 1.5" x 1.5" extrusions
3) 2020 rails are metric 20mm x 20mm extrusions
That’s correct.

Then there are the MakerBeams that are 10x10mm and require micro buttons.

FWIW, I have MakerBeams (they came in a 2-pack from Amazon) and a 6’ long 1010 rail that I ordered through walmart (!) of all places. The launch pad (minus the rail) was as a result of a trade. I had a ‘glass kit I wasn’t really interested in building and the other guy liked it well enough to trade for his launch pad. I didn’t need the 8’ rail.

Most of my small rockets have both rail buttons and launch lugs just in case one or the other type of launch pad isn’t available.
 

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