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LL placement

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mkmilion

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How do I determine lauch lug placement?
 

flying_silverad

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I normally place it around where the CG is. If it's split then I place each section equal distance away from the CG. Sometimes, like in the case of the Cherokee D, the launch lug is at opposite ends of the body which seems to work fine.
 

jflis

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yep, that's where you want it, near the CG

That's the CG when the rocket is loaded for flight (motors installed, recovery system installed, ready for flight)

jim
 

limd21

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Sure, CG would be ideal/best, but I think there's a lot of leeway here. For convenience, I put most all my lugs in one of the fin fillets. Works fine for all my low-power rockets.

Quest's Viper (educational pack) kit has the lug molded into the plastic fin unit. Way below the CG, just like my own fillet lugs, but it's proven to be no problem in that location.

(BTW, I'm a newbie to this forum, and just getting back into the hobby after 25+ years away. It's great to now have a kid of my own so I can play with this stuf again!)f
 

KermieD

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I'm a fan of getting it as far back on the rocket as you can, particularly on rockets that are only marginally stable. This way you get guidance as long as possible to get the speed of the rocket up before it's flying on its own.

limd--welcome aboard!! I too got started again with the kids, but, quite frankly, I've got the bug more than they do! Who needs excuses? :D
 
A

Austin

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mkmilion,

Balance the rocket on your finger...where it balances is CG.

Now, install the largest motor you plan on using into the rocket, along with the parachute, etc...as if it is ready to launch. This will give you the maximum Cg reading when balanced once again. this is important when designing stable rockets.

Carl
 

rbeckey

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Unless the rocket is very small, I often use 2 LLs, placed high and low. Usually I just cut one in half. I always mount the LL on a sliver of balsa or other wood, like a thin coffee stir stick, just to get it up off the paint.
 
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