Launch Rods?

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Well-Known Member
Apr 29, 2009
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I'm flying D and E powered large model rockets from a 4 foot long 3/16 rod made from mild steel. I don't want to convert to a rail at this time. What is the optimal length for various diameter rods?
Would spring steel rods increase rod whip? Or is length more important? Any info is appreciated. Thx Ted
i use a 5' 1/8"
6" and 8" 1/4
6" and 8" 5mm

all stainless steel from lowes
For our club stuff, we typically use 4' for 1/8", 5' for 3/16" and 6' for larger; in addition to a rail (although I think I'm the only one that uses rail buttons on MPR).

The reason I didn't go 6' on everything is simply because of the launch pad heights. For the smallest of rockets (1/8" lug), a child can't put his rocket on a rod. With a 4' rod they stand a good chance.

We also use stainless steel rods.

Also don't forget it's not only the length of the rod, but the velocity the rocket is at when leave the rod that counts. I forgot what the formula is, but I think it's somewhere in the neighborhood of 30' fps for stability. I might be off though.
Thanks for the info! It appears rod whip isn't much of an issue with longer rods? The reason I use mild steel is that's what was cheap and available, I did have to polish it as it was a little oversized. I've been using it for over a year and it's still straight in spite of some abuse.
I'm flying a few cluster rockets and some others with large fin areas and I'm thinking of using a longer rod for windier conditions. I generally don't fly underpowered, the opposite is closer to the truth. Ted

Rocket Fleet April 09.jpg