Launch lug mismatch with launch rod - any problem?

[Dotini]

Last year I launched a couple of rockets with 3/16" launch lugs on a 4' length 1/8" diameter launch rod and experienced no problem. Each rocket was equipped with two lugs, one astride the CG and the other very near the aft end of the tube. Now I'm building a slightly heavier and more powerful rocket that I propose to equip with 1/4" lugs and launch on a 3/16" rod. The new rocket weighs 9.5 ounces ready to launch, and uses a D12 or E14 motor. Other than a minor drag penalty, could there be any objections to this mismatch?

 

[Zeus-cat]

I do the same thing occasionally. In my opinion as long as the rocket isn't bending the rod or sitting cockeyed on the rod you are fine using a smaller rod than the lug.

 

[Joekeyo]

I modified my Astron Explorer using 1/4" LLs. It was a tight fit, so I launched from a 3/16" rod. It was a great flight: straight and true. Low to no wind.

 

[rocketgeek101]

I do the same thing occasionally. In my opinion as long as the rocket isn't bending the rod or sitting cockeyed on the rod you are fine using a smaller rod than the lug.

Agreed. If common sense (and not go-fever) are telling you it is fine than it most likely is. I've seen a number of less than nominal flights attributed to the rocket binding on the launch rod so a bit loose in my opinion is a good thing.

 

[RokitFlyr]

If you have 1/4" lugs, why not launch it on 1/4" rod? Why complicate things?

 

[afadeev]

I do the same thing occasionally. In my opinion as long as the rocket isn't bending the rod or sitting cockeyed on the rod you are fine using a smaller rod than the lug.

For that reason, I usually replace all of the 1/8" and 3/16" launch lugs (included in kits) with 1/4" lugs instead. I got a bag of those from one of the online vendors years ago, and still have way too many on hand.
This way, I never need to worry about swapping launch rods for each rocket, cleaning 1/8" rods so that they don't bind, etc, etc.

YMMV,
a

 

[Dotini]

If you have 1/4" lugs, why not launch it on 1/4" rod? Why complicate things?

My stainless steel 1/4" rod is cumbersome at six feet long, and really only truly required for one of my fleet at the moment. In the past year, I've built 30+ rockets, having built none in the previous 25 years. But as I learn I'm moving away from the 1/8" lugs and rod.

 

[BigMacDaddy]

I have 3D printed adapters that I could slide onto a Makerbeam rail guides and launch from a rod. If you consider moving to a rail launch at some point could be an option to give you flexibility. I have not yet gone the other way (i.e., adapted rod lugs to rail guides) but I assume it could be done. You could also 3D print a combo rail guide / launch lug or put one on either side of the rocket.

 

[CalebJ]

Rod whip would be the biggest concern imo. The larger lugs were supplied based on the rocket's weight, so there's obvious concern for a narrower rod not being up to the task.