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  #1  
Old 12-23-2019, 11:06 PM
jjp161 jjp161 is offline
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Default Launch Lugs

I build low to Mid-Power rockets. Instead of rockets with 3 different size lugs and 3 different rods I was thinking of using 1/4 on everything I build or 3/16 on everything A-E and then 1/4 for E-G. Was also going to build a new launch pad out of PVC so let me know what you guys think. Thanks
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  #2  
Old 12-24-2019, 06:30 AM
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ghrocketman ghrocketman is online now
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The larger the lug diameter, the more drag.
I wouldn't use 3/16 on anything 13mm mini-motor powered; you WILL lose altitude.
I wouldn't use 1/4 on anything powered with less than a G.
Just not needed.
I would and do use 3/16 on most everything.
I also use 1/8 and 1/4 where appropriate.
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Old 12-24-2019, 08:06 AM
jjp161 jjp161 is offline
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Thank you and that makes sense. I very really build anything with 13mm. So I will probably just go with the 3/16 on A-F and save the 1/4 for the Gs. I usually angle my lugs on the front and back to reduce drag anyways I just wander how much difference the lug makes? Also does anyone know of a threaded 2 piece 3/16 rod? I was looking to build a launch pad where I can store the rods in the legs.
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Old 12-24-2019, 10:28 AM
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ghrocketman ghrocketman is online now
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Drag on the rod is directly proportional to lug surface area contact with the rod.
Since 1/4" has more contact area than a 3/16" lug, given same rod/lug material, drag will be higher.
I dont know of anyone selling launch rods with a few threads at one end. You could cut them yourself if you have a die set.
Use STAINLESS rod. Trust me on this.
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Old 12-24-2019, 01:32 PM
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astronwolf astronwolf is offline
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I say , suit yourself. Do what works for you and increases your enjoyment of this hobby.

An option that you may wish to consider is the use of mini-size rail buttons and a 20/20 rail. Many of my newer model rocket builds are getting these instead of launch lugs.

http://www.rail-buttons.com/minibuttons.html

You can buy the rails from McMaster Carr.
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  #6  
Old 12-24-2019, 10:43 PM
jjp161 jjp161 is offline
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Default Launch Rod

I have considered buttons before and Im sure as I get into larger rockets I will definitely use them. One of the reasons I really like the 1/4 launch rod is you can find them threaded for easy disassembly. I am going to build the new launch pad so I can store the launch rod in the PVC leg. I have tried to find a 3/16 launch rod that is threaded for easy disassembly but have not had any luck.
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  #7  
Old 12-24-2019, 11:51 PM
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tbzep tbzep is offline
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A 1/4" launch lug will look hideously out of place on anything BT-60 sized or smaller. It won't look bad on a BT-70 (hair over 2" dia.) and it is needed on heavy wall tubed rockets that fly on F and above motors. I have a large supply of old aluminum shaft arrows that I use for 1/4" lugs that are fairly thin walled and look good on anything from 2" on up.
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Old 12-25-2019, 01:46 PM
djmartins djmartins is offline
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Quote:
Originally Posted by tbzep
A 1/4" launch lug will look hideously out of place on anything BT-60 sized or smaller. It won't look bad on a BT-70 (hair over 2" dia.) and it is needed on heavy wall tubed rockets that fly on F and above motors. I have a large supply of old aluminum shaft arrows that I use for 1/4" lugs that are fairly thin walled and look good on anything from 2" on up.


I have bought marked down arrows for the carbon fiber tubing they are made of too as another option.
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  #9  
Old 12-26-2019, 05:45 AM
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LeeR LeeR is offline
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Quote:
Originally Posted by astronwolf
I say , suit yourself. Do what works for you and increases your enjoyment of this hobby.

An option that you may wish to consider is the use of mini-size rail buttons and a 20/20 rail. Many of my newer model rocket builds are getting these instead of launch lugs.

http://www.rail-buttons.com/minibuttons.html

You can buy the rails from McMaster Carr.


I really like the mini buttons for most of my midpower builds. I also use the micro buttons from rail-buttons.com.

Randy Milliken used to sell the 20mm rail, and I bought my first from him. They are available from Amazon. The micro buttons use the MakerBeam rail, available from Amazon in 2-packs. My first one was 900mm (~3 ft.) and I have since bought the 1500mm length (~5ft.) A two pack from Amazon was $27. Ordering rails from Amazon may be the cheapest way to get them because of free shipping options.

The one potential drawback to small rails Ive noticed is inadequate spacing between fins on some designs. One I ran into is a two-stage rocket like a SuperNova, which has booster fins positioned centered between upper stage fins. There is only room for a 1/8 rod to fit between fins. Ive tested the micro-buttons on an Estes V-2 (BT-80). Worked great. Id normally use a mini on a rocket this big, but wanted to see how well it worked.

Here is picture of mini and micro buttons, the 20mm rail, and the MakerBeam rail. A 1/8 launch lug is in the picture for reference.
Note: MakerBeam is available in silver (clear anodize) which should be better if out in the hot sun. Also shown is my adapter to drop a MakerBeam rail into a standard pad. It has a piece of 3/16 rod in a dowel, lathe-turned to fit in a piec3 of brass tubing. The rail is epoxied into the tubing. I have found trapezoidal nuts to fit into the slots of both rails, so they can be mounted that way, or accessories like standoffs can be bolted onto he rail.
Final picture is my Super Orbital Transport on my Rockwell JawStand pad. Shown is an 8 20mm rail, as well as ducting from Home Depot.
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  #10  
Old 12-26-2019, 07:15 AM
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astronwolf astronwolf is offline
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Nice pics Lee...

If I had to pick just one type of launch guide, it would be the mini-button. They might be a little large for an Alpha-sized model, but not so out of proportion like a 1/4-inch launch lug.
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