Friday, September 15, 2017

A tubular build...

Quest Totally Tubular (Click to enlarge).Tube fin scratch build - the Algol
(Click to enlarge).
I must confess to not being a big fan of rockets with tube fins - they violate my 1950's conception of what a rocket should look like. However, I do have 2 in my existing fleet - the Quest Totally Tubular and a scratch built tubular payloader, which I christened the Algol. The Totally Tubular is one of those pre-colored quick build kits with "peel n cuss" stickers, which means it spends a lot of time on the shelf; it's hard to be fond of something that takes no work to assemble. The Algol involved more labor, but it exhibits a bit of shimmy when it leaves the rod, which also results in it getting a huge amount of shelf time. Given this, it is hard to imagine that I would construct another tube fin rocket, but that it is exactly what I am doing.

1972 Centuri catalog pages showing the Groove Tube (Click to enlarge).
Back in 1972, Centuri released what I believe to be the first commercial tube fin rocket kit, the groovy "Groove Tube." In my opinion, it is the best looking of the lot, with a nice red, white, blue, and black paint scheme, silver trim, and a hippie-looking name decal. I had one in my teenage years - the lack of balsa needing sanding appealed to me - but soon lost it via my standard "C6-7 in very small field" practice of those days. Several days ago, I ran across a Groove Tube thread on Ye Olde Rocket Forum, and the pictures of the model sparked a new interest. The instructions and parts list were easily obtained; I had them all in my stash.

  • 1  PNC-89 Nose cone    (Semroc/eRockets BC-846)
  • 1  Shock Cord  
  • 1  Body Tube                 ST-813
  • 6  Stabilizing Tubes       ST-83
  • 1  Thrust Ring               TR-7
  • 1  Centering Ring          HTC-8
  • 1  Motor Tube                ST-73
  • 1  Motor Hook      

This build is not as simple as it appears, at least in terms of finishing and painting the model. Should I build it, then apply primer and paint? It might be difficult covering all of the rocket, especially in the gaps where the tube fins join the main body tube. And how to deal with the black interiors of the tube fins? Paint the inside black (might be a little tough with spray paint), use a black marker, or cover the inside with black chalkboard paper or trim monokote? I decided to follow Chris Michielssen's approach, which is to paint the components separately and glue things together at the last. I am also leaning towards using the chalkboard paper or monokote on the tube fin insides, as that will avoid masking off their exteriors.

Groove Tube parts (Click to enlarge).
Having settled on the approach, I have started the build - the motor mount is assembled, and the first primer coat has been applied to the tubes. This weekend I will finish the balsa cone with Brodak sanding sealer and prime it. The decals have also been downloaded from JimZ's site and cleaned up - I think I am probably the 1000th person to do this, as no one bothers to post their cleaned up decals online. A shame, as the decal in the JimZ scan is pretty ratty, and it takes a bit of work to get it usable.  So, in an attempt to set things right, you can grab my decal set (300 dpi png) here - it also includes the Arrow 300 set and Centuri logos.


  1. I did a Groove Tube upscale back around 2004 using my stash of BT-56 parts. I loved how it turned out, but one Sunday at VOA, what looked like a routine flight and landing turned into a lost rocket. One of the guys I was flying with swore that he saw someone stop and pick it up, then take off. As you might imagine, I was not happy. The following spring I showed up to a launch and found the remains of my GT on the launch control table. The winter had not been kind to it, but it was such a cool flyer that I felt like I wanted to keep it in my flight rotation. (Did I mention that it was E-powered and RIPPED?) Took the remnants home and picked off what I could reuse, then took it to the NARAM at VOA and lost it in the veggies, not long before the big fire. Never even got the decals on the replacement.

  2. I was trying to remember how I did the paint inside the tubes on my Starlight Saber ( ... red at the back end and black at the front. Finally realized I'd wanted to spray the gold body-and-tube-fin color over a black undercoat anyway, so I'd just done something like sprayed the red, masked that (just by putting rolled up scrap paper inside the tubes, sprayed everything else black, masked the fronts of the tubes, and sprayed everything else gold. Doesn't work with the Groove Tube color scheme, though.