Hi! I'm a new member building a Star Orbiter!

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New Member
May 16, 2017
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I have already learned a ton from reading this forum. There is so much information here, though sometimes it hard to find exactly what your looking for. I currently have 10 completed rockets including my prized SR-71 Blackbird. I started building rockets in 1968 at the age of 10.

I recently picked up a Star Orbiter Kit from HL with that wonderful 40% off coupon that I learned about on here. I'm a typical engineer and research things to death...it's a curse. I have decided to make just a few modifications to the standard build. First, I want to convert the front 6 inches of the BT to a payload compartment. Simple enough.

I am also using wood hardner on all body tubes to add strength. Questions: Should I also apply wood hardner to all balsa parts too? Should this be done before or after sanding? Should I fill the BT spirals before or after applying wood hardner?

I have decided not to use DD on this rocket, instead I'm planning on using a JL Chute Release. This brings me to the shock cord design. Rubber bands are short lived here in the desert. I want to use Kevlar cord inside the BT to just below the tube end where I will knot tubular nylon 3X the length of the longest rocket component. I think shrink sleeving over all the knots should provide a nice clean installation. The BT is fairly long from the engine mount to the tube end and I was considering attaching the Kevlar cord at the BT Coupling instead of the engine mount too minimize exposure of the cord to the ejection gasses. Question: How can I safely and securely attach the Kevlar cord at the body coupling?

I'm sure I'll have more questions as the build progresses. This is my first rocket using an "F" motor and I want to get it right the first time!

Thanks in advance! GrandpaTerry
I am also using wood hardner on all body tubes to add strength. Questions: Should I also apply wood hardner to all balsa parts too? Should this be done before or after sanding? Should I fill the BT spirals before or after applying wood hardner?

I did my Dig Baddy this way: stripped the glassine, Wood Hardener, sand, WH, sand; WH on the fins, airfoil, WH. Woodglue for the fins, no filler.

I don't have an answer for filler-first vs. hardener-first, got any scrap tubes? :)

Welcome aboard!

I have never used wood hardener on body tubes; I would say that is not needed. Maybe someone who has done it can add their two cents.

Probably a good idea to use something on the balsa parts; they do get beat up. A lot of people use superglue. Do it outside though; nasty stuff when using a lot of it like you need to on nose cones and such.

I use 3 or 4X times the body tube of Kevlar. I attach it to the motor mount. If I use elastic I tie it to the end of the Kevlar and then to the nose. The Estes rubber bands wear out to fast no matter where you are at. If you attach it below the coupler I would use a variation on the Estes tri-fold mount (this assumes you have a body tube big enough to easily get fingers or dowels inside the body). Take a piece of cardstock or heavy paper about 3 inches long and wide enough so that it is about 1/3rd of the way around the inside of the tube. Put 3 or 4 small slits in it evenly spaced on the 3 inch length. Lace the Kevlar through the slits. Add knots at the end (and between the slits if you like). Liberally glue (or epoxy) the thing into the tube making sure you are below the coupler. Use fingers or a dowel to press it against the inside of the tube.
I've just built two more Star Orbiters (with payload sections) after my first was blown apart by an E16 CATO. I like baffles and so have a Qualman baffle in one and an Uncle Mike's baffle in the other. The Qualman baffle is just above the coupler that joins the two BT-60s together. I just put the UMRS baffle plates on the coupler for the other. In both cases my Kevlar line is attached to the baffle and the supplied rubber shock cord is tied to the Kevlar.

That said, I've had good luck just using the Estes trifold shock cord mount with Kevlar. You could put that inside the coupler before you make that joint, or even just below where the coupler goes in the lower half before doing the joint if you like. But if I were doing it I'd just put it in the upper section down as far as I could reach below the payload section break (a few inches).

JLCR and the Star Orbiter is a great combo. I'll be flying it that way at NSL. That's how I flew all the flights on the first one on E16s, F15s and F23FJs.

I can't say about hardeners and such. I've never used it.
Welcome to the party Grandpa. My paper tube strengthening method is to coat the inside with whatever's handy: white glue, yellow glue, polyurethane glue, or thin CA. Strength plus protection from the heat and debris of repeated ejection charges. I just mop in from some point forward of the motor mount tube. Sometimes I've used various laminates to strengthen balsa fins: printer paper, aircraft tissue, used dryer sheets, 1/32 plywood. Lately I've just filled and finished and accepted the fact that they're gonna get dinged up because they're, ya know, balsa ! :) I've also added hardwood strips to leading and trailing edges on some models. For a little inspiration, here is a Star Orbiter build from our friend across the pond, Leo:

I have a Star Orbiter on the build pile also. You've got me thinking about potential mods. Yours sound good. (Wish a JLCR was in my budget right now). I was thinking about turning the coupler into a baffle, and mounting the shock cord there.