Estes Star Orbiter Build Thread: As Seen on FaceBook!

[smstachwick]

I documented the build for my Star Orbiter on FaceBook to share with my friends there, but I never got around to posting it on TRF. That changes now!

All of these posts are exactly the way they appear on my FaceBook. No edits, just a straight adaptation to TRF. I structured it as a series of updates, showing off the equipment, supplies, and the rocket while keeping its true size a secret until the airframe was complete

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Alright, here I’m starting to slowly pull back the curtain on my secret project.

My previous builds used instant-bonding cyanoacrylate “Gorilla” glue. Pretty strong stuff, and maybe even a little overkill for low- and mid-power rockets.

But there are much stronger bonding agents, and this is one of the strongest around. It’s an epoxy, a two-part bonding agent consisting of a resin and a catalyst. The longer an epoxy takes take to cure, the stronger the bond, and this one is one of the strongest at 24 hours until a complete cure.

It is so strong that if I mix and apply it correctly, the balsa fins will crack along the grain and the body tube will completely unravel along the spiral seam before that epoxy joint cracks.

Basically it makes your standard Gorilla glue look like the stuff on the back of a Post-It note, and it will be very necessary for this build

Speed of Balsa? Never heard of it.



Secret Project Update 2: Motors.

On the left is an E12-6, a motor that’s sort of in the middle of the power range that’s compatible with the Hi-Flier XL. There are more powerful motors in these dimensions but they use plastic casings and composite propellant, so they’re more expensive and I haven’t ordered any.

On the right is an E16-4, on the extreme low end of what’s compatible with the incoming secret project. It’s also an E motor, about as powerful as the smaller one, but the longer and larger-diameter casing allows more propellant to be packed into it, so there are much more powerful motors that can be made in this size. I’ve seen Type G motors in these dimensions, which are roughly 4 times as powerful as these “E” motors right here.

That just gives you an idea of what kind of power the new project will need and be able to handle.



Secret project update 3: Fin attachment.

These fins are not merely glued onto the body tube. No, they actually go THROUGH THE WALL of the body tube, so that they’re glued onto the body tube AND the motor mount tube. When you do it this way, that attachment is very, very strong. This kind of fin installment failing due to drag forces, especially when using 24-hour epoxy, is pretty much impossible.





Secret Project Update 4: Assembly begins.

Step 1: Pop out the centering rings. These rings are bonded to the motor mount and keep it centered in the body tube. The disks and rectangle are scrap.



Step 2: Mark the motor mount tube. These markings are at 1/2 inch, 4 1/2 inch, and 7 1/2 inch from the aft end.



Steps 3 and 4: The instructions say to put a glue ring around the motor mount tube and then slide the rings on. I ended up doing it in the opposite order but it should still be plenty strong.




Secret Project Update 5: Motor mount installed.

Three rings of epoxy applied to the inside edge of the body tube, motor mount centering rings sanded down for a good fit, and the whole assembly inserted. I also went a little crazy with the epoxy trying to get a reinforcing fillet on the back end. It’s challenging to make a good ring-tube joint with only a few millimeters of room, so I don’t know if that will actually do anything to improve the strength. Hopefully that doesn’t add so much weight that it makes it too tail-heavy.




Secret Project Update 6: Fins Attached

I found a great printout template for fin alignment that I taped to a cardboard box, then I cut out the pattern to make a neat fin alignment jig. That was yesterday’s work, so those are all cured now and I’m getting started on the next bit.

 

[smstachwick]

Secret Project Update 7: Epoxy fillets applied.

Upon removing the tube/fin combo from the jig, I was pleasantly surprised to find that I hadn’t bonded the model to the jig, as I fully expected would happen. It came off easily and I only had to sand and tweeze out a few small bits of cardboard.

I grabbed a Q-tip, mixed up some new epoxy, and applied these fillets to the fin/tube joint for some additional strength. Once that cures tomorrow evening I’ll sand off the excess.

Of course I might instead do this earlier so I don’t have to try to sand off a full-strength cure, just to make things easier so I won’t have to apply so much elbow grease.



Secret Project update 8: Fillet sanding/grinding

The epoxy is cured. I didn’t end up doing much except some sanding last night and grinding this evening with my Dremel tool, at the suggestion of Mr. David Huber. It’s not perfect but it’s much cleaner than it was.

I’ll probably go to The Home Depot tomorrow to buy some wood putty and spray glue, which I’ll need for the next step.



Secret Project update 9: Fin papering

This is the last structural reinforcement for the fins. The paper bonded onto the fins with spray glue will help prevent the wood from splitting along the grain and will also make getting a nice finish easier. Once I’m satisfied that those are entirely dried and bonded, I’ll cut off the excess and they’ll be more or less ready.




Secret Project update 10: Paper trimming

I’ve been doing a little bit of work every couple of days. Papering fins is not a breeze, I tell you. Every time I work on them, I find a new spot where I have to reapply spray glue. It’s also tricky to get a neat trim right on the edge of the fin.

I think what I’ll do next time is glue and paper one side of a fin, then trim, and then move on to the next side until all six are done, instead of papering them all at the same time and trimming later. This way I may also be able to use my hobby knife instead of the less-precise scissors.

At this rate, I’m considering flying the rocket in a “naked” configuration, without any paint or decals. If getting a nice finish is going to be as challenging as it was on my previous builds, skipping that will be very necessary if I’m to get it into the air when I go out to Holtville.


A very, very rough cut


Trimmed a little bit, but still a work-in-progress


Secret Project update 11: Fins complete, shock cord mount assembled.

After trimming the fins a bit with scissors and my knife, I sanded them down so that the paper fits smoothly against the surface at the edges. I also gave four or five peeling paper edges a brief spray of glue. Hopefully nothing else pulls them up and I can mark the fins as complete.

The shock cord mount is under the shop lamp, which is acting as a weight to keep the thing together while the epoxy cures.




Secret Project update 12: Launch lugs

Not a ton of work today. I just installed the launch lugs, the two smaller tubes you can see epoxied onto the airframe. They allow the rocket to slide over the launch rod, which will keep it stable in the first 3 to 6 ft of flight. The forward one is epoxied just to the tube, while the aft one is epoxied both to the tube and the fin. It’s not exactly where the instructions say to put them, but this way the aft one gets extra support from the fin.

I’ve also installed the shock cord mount in the forward body tube. The epoxy is curing right now.





Secret Project Update “Unlucky” 13: Estes Star Orbiter Revealed!

When I said earlier that I had installed the shock cord mount into the forward body tube, many who have been following this project probably thought that I meant I mounted it in the forward end of the body tube I had previously showed you. Well, you’d be wrong. This is the surprise I’ve been waiting to reveal for weeks: There is a WHOLE OTHER BODY TUBE that I’ve kept hidden all this time! Here is what the thing will look like when it’s fully assembled, and the final bits epoxied together and cured.

 

[smstachwick]

Star Orbiter Update 14:

With the big reveal out of the way, now I can share what exactly I did.

Photo 1: The kit comes with a motor retention system, a set of screw threads that are epoxied onto the end of the motor mount. A removable screw-on cap prevents the motor from ejecting itself backwards (this is called “positive motor retention”) but allows the exhaust to pass through and produce thrust.

It also comes with a coupler, a red ring that glues into the inside of the ends of the two tubes and holds them together.



Photo 2: The free end of the shock cord is tied to the nose with a simple overhand knot.



Photo 3: The parachute, proudly displaying the kit manufacturer’s logo and location, as well as the date of manufacture. This one waited a long time for somebody (me) to put it together.



Photo 4: The parachute is tied to the shock cord by its shroud lines. The instructions say to tie it to the nose, but this way a failure partway up the shock cord gives the main portion of the airframe at least a chance of an arrested descent. Noses are much easier to replace should they get lost or damaged, as they can be swapped out much quicker than a new airframe can be built.



Photo 5: The parachute is packed in the upper body tube and the nose inserted.



Photo 6: The upper body tube is mounted onto the coupler. It wasn’t epoxied when I took the photo but it is now.



The airframe is complete, and the Star Orbiter will fly at Holtville this Saturday. If it survives at least one flight on each of the recommended motors, it will earn its paint.

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The Star Orbiter ended up flying eight times at Tripoli San Diego’s October 2021 launch, earning itself the nicest paint and decal job I could apply. It also flew twice more at ROCstock. I’m now waiting for my Aerotech E16-4W and E16-7W reloads to show up, and they’re not scheduled to arrive for at least 11 weeks, possibly as many as 15. Once they do, the Star Orbiter shall fly again!

 

[DabCat]

Great job on the construction and documentation! Great build thread! The star orbiter is a great kit by estes and easily one of my favorites. I've flown mine a few times past 3k on G76s and plan to do a full send on one of the longer 29mm Hs at the next ROCstock. Maybe we can drag race...

 

[smstachwick]

Great job on the construction and documentation! Great build thread! The star orbiter is a great kit by estes and easily one of my favorites. I've flown mine a few times past 3k on G76s and plan to do a full send on one of the longer 29mm Hs at the next ROCstock. Maybe we can drag race...

I'll have to give you a rain check on that one, I've got a bunch of loads in the E and F range I want to try before pushing it into G and H territory. This is my favorite bird that I have right now and I'm really trying to baby it. At least for a while.

But yes, I do plan to continue flying with ROC when logistics and scheduling allow. I recently discovered that my Goblin and my Hi-Flier XL are both ceiling busters with the motors I have and Tripoli San Diego is having some site difficulties, so I'd love to bring those out to fly with you guys again.