Launch Rod Length
Greetings again. I am trying to determine whether to plan to add guide tubes or rail guides to my rocket. The rocket's total length is 37 inches. 3 inch tube tapering up to a 2 inch section with a nose cone (of course). The rockets total weight without the motor is going to finish around 370 gm. The motors I am planning to power it with are Estes F-15s. Soooooo... guide tubes or rail buttons?
Thanks in advance for guidance.
F motor or higher? Buttons!
3" diameter or larger? Buttons!
3ft or longer? Buttons!
You could use 1/4" lugs (straws, tubes, etc), and it would be fine. You're at or close to the crossover point in the above aspects, so either will work. But if you ever want anything stronger in it, or want to fly it at other clubs less accepting of 1/4" rods, you'll be better off with buttons. You could even go crazy and put both on it. But generally speaking, I'd recommend
BUTTONS!
😁
NAR is now recommending that rockets flying on F-class motors and higher use rail button when feasible.
Your rocket's weigh suggests that it's paper tubing airframe. Conventional screw-in rail buttons are probably not going to work well there. In that case, I'd suggest you look into glue-on conformal guides. I believe Apogee has several options. Also, if you've got access to a 3D printer, look on Thingiverse for STLs to print your own. Jack Hydrazine (not his actual name) has many rocket components on Thingiverse. Search for his.
I'm assuming this isn't a rocket for competition, so why not include both rail and rod guides? For F-class and greater, ¼ inch rod guides. The additional drag induced my both rod and rail guides is minuscule.
Quote from Admin on February 10, 2026, 9:04 amYour rocket's weigh suggests that it's paper tubing airframe. Conventional screw-in rail buttons are probably not going to work well there.
??? I've installed plenty screw in buttons on cardboard tubes. Never had one fail. A variety of ways to do it.
Stiffen the paper with thin CA.
Put a backing washer, curved to conform with the tube, and a nut inside. (secure it with adhesive too)
Screw into the centering rings.
Screw into a small block of curved wood inside.
Add some epoxy clay to the screw inside the tube, which secures it, and supports the tube, while also preventing a snag for the shock cord to get stuck on (one of my favorite ways).
Conformal guides work well too of course, and I've used them as well. But without a 3d printer, you have to source the correct version for each rocket you build. With buttons, I can keep a handful among my parts and use them on anything. They also come in different colors!
The rockets final length shook out at 35 inches. But, it is a bit heavy. I installed 1010 buttons on it to take advantage of the extra stability the rails provide. What is the length of the rail used at Wall HS? Just asking so that I can feed it into Open Rocket to get an exit velocity estimate.