Scratch built I'm calling Rings-N-Things

[Back_at_it]

First time posting in the scratch built section. I've designed and built a large number of scratch builds, clones etc. but haven't really ever shared them. This one I think is interesting enough to share.

I've always had an interest in tube fin rockets. I like the look and I like the fact that they tend to be a bit draggy so I can use larger motors and they don't tend to fly that high as I generally have limited space to recover. For this build I'm going to have fins, tubs and rings incorporated into the same design.

Major Parts List.
- BT55 Main body tube. Main tube is 18 inches. Payload tube is 4 inches.
- Outer rings. Not sure the part number but they are 1.88 OD and purchased from ERockets.
- Tube fins. 3 of them, all BT20, 3.25 inches long.
- Main outer ring. 3.5 inch OD cut 1.75 inches wide.
- BT50 motor tube.
- BT50 Centering rings.
- Fins cut from 3/32 Balsa.
- Choice of nose cones. I have two shown as I haven't figured out which one I wan to use.



Starting with the motor mount. I marked the lower ring location at 3/8 of an inch from the end of the tube. Once assembled the motor tube will be exposed by 3/8 of an inch. The upper ring is 1/8 inch plywood, the lower ring is fiber. A motor block was also installed.



Here is the finished motor mount. I did notch out a small section of the upper ring for the Kevlar shock cord to pass through.



Once dry I attached a section of 300# Kevlar to the upper ring then gave it a small amount of added protection with some heat shrink wrap.



Using TBII wood glue, the motor mount was inserted into the main body tube until the lower centering ring was flush with the end of the tube.




I'm stopped here to let this dry over night. I'm going to be working on marking the main tube and installing the three main fins this evening.

More to come

 

[neil_w]

Hmm, looks interesting.

 

[Back_at_it]

With the body tube marked I began attaching the first of the main fins. These were tacked in place with a drop of CA at the tail and another at the tip. I will go back and add fillets to make them permanent.

Two fins attached. These attach even with the bottom of the body tube.



All three of the main fins attached. It was also at this time that I realized that the angle of my motor tube cut was not straight. I'll need to square that up at some point.



Next up was attaching the smaller fins. These also attach even with the bottom of the body tube. These will be used to hold the tube fins in place.



Next up it's time to install the tube fins. The BT20 tubes were attached to the outer edge of the smaller fins. The launch lug was also attached at this time.



Before going any further, I'm going to go back and do fillets on all of the joints. Due to this being very thin balsa, I'm going to do the fillets and coat the fins using thinned T-88 epoxy to add some rigidity.

So far this is going together pretty well.

 

[ljwilley]

Awesome! Are those ultra high performance super turbo power ion pulse thrusters?

 

[jqavins]

First time posting in the scratch built section. I've designed and built a large number of scratch builds, clones etc. but haven't really ever shared them.

This one I think is interesting enough to share.

If this is any indication of your design and building skills, please post more!

 

[jqavins]

As for the choice of nose cone, you've got a six inch conical and a five inch conical. Flip a coin. Or think ahead to what would fit a future scale upscale/downscale or clone build, and use the other one. Just my 2¢, of course.

 

[jmasterj]

As for the choice of nose cone, you've got a six inch conical and a five inch conical. Flip a coin. Or think ahead to what would fit a future scale upscale/downscale or clone build, and use the other one. Just my 2¢, of course.

Nah, one's conical and the other is a secant ogive.

 

[neil_w]

Nah, one's conical and the other is a secant ogive.

That's a great 4-pack of nose cones from Estes. I got good mileage out of mine.

Anyway, now that construction seems to be mostly complete, put up a picture with each of the nose cones for comparison and we'll provide our incredibly useful input.

 

[jqavins]

Intrigued, he looked more carefully, using straight line visual aids. "Son of a gun, so it is!" he said.

It still looks like a pretty minor difference, so my 2¢ answer remains the same.

 

[Back_at_it]

That's a great 4-pack of nose cones from Estes. I got good mileage out of mine.

Anyway, now that construction seems to be mostly complete, put up a picture with each of the nose cones for comparison and we'll provide our incredibly useful input.

We're still a little ways from complete but I should have some mock up pics of the completed rocket tomorrow.

 

[jmasterj]

I'm looking forward to a picture with the outer ring!

 

[Back_at_it]

For a scratch build, this thing is going together rather quickly but I did find that I made a mistake when building the design and I didn't catch it until last night.

After letting everything cure I started test fitting the outer rings. It was there that I notice that the outer ring fit perfectly around the main fins but the tube fins did not stick out far enough to touch the ring. The solution was to cut small strips of balsa and attach them to the outer edge of the tube fins.




Once the strips were in place I was able to test fit all of the outer rings. The main ring sits flush with the tip edge of the main fins. The larger of the two upper rings was slid until it touched the leading edge of the main fin. Upper ring was then slid in place with 1/4" gap between the upper and lower rings.

After looking at the mock up, I decided on the conical nose cone as I feel it fits the design a bit better.


Next up comes primer and paint. This one will need to be painted in pieces as there isn't really a way to get in there after the rings go on.

 

[DigBaddy]

Love it! That looks great already!

 

[jqavins]

After letting everything cure I started test fitting the outer rings. It was there that I notice that the outer ring fit perfectly around the main fins but the tube fins did not stick out far enough to touch the ring. The solution was to cut small strips of balsa and attach them to the outer edge of the tube fins.

I'm actually relieved. From the pictures, at some angles, I was afraid the tubes would stick out too far, which would have been a bunch harder to deal with.

Nice job adapting, and it's a beautiful rocket.

 

[Back_at_it]

I managed to get everything into primer and some filler applied and sanded yesterday.



Next up will be painting this which might take me a few days to complete.

 

[BABAR]

I definitely like the rings. Ya know, however, it actually looks pretty cool without them!

 

[Back_at_it]

Weather played nice long enough for me to get the first color sprayed in. A couple of coats of gloss white were applied to the tube fins.

 

[Back_at_it]

Getting close to wrapping this one up. I managed to get everything painted over the weekend and I'm letting the parts cure before final assembly. There will be a couple of areas where I'll need to scrap paint off the mating surfaces.

Main body is painted in Krylon Blue Foil. Tube fins are painted in Krylon Gloss White and the fins are painted with Tamiya Gloss Red. The rings and cone were shot with Duplicolor Gloss Black. Still need to do some detail around the tube fins but that will come later with the vinyl.

 

[BABAR]

Love the paint scheme.

 

[Back_at_it]

After letting everything cure, Paint was removed at the attachment points and the rings were slid into place. All rings fit fairly snug so I chose use CA on the upper rings but went with epoxy on the large rear ring. Still need to check CG and add some vinyl but we're getting close to completion on this one.

 

[PDawg]

Is "Rings and Things" the official name? This is way out of my league but I got an idea for some fins from this.

 

[Back_at_it]

Is "Rings and Things" the official name? This is way out of my league but I got an idea for some fins from this.

Yeah I think I’m going with rings-n-things as I’m not creative when it comes to naming rockets.

Maybe the next one, I’ll ask for suggestions from the group to name it.

 

[BABAR]

Yeah I think I’m going with rings-n-things as I’m not creative when it comes to naming rockets.

Maybe the next one, I’ll ask for suggestions from the group to name it.

Going out on a limb here…..”Things-and-Rings”?

 

[Back_at_it]

Finally got the bench cleaned up enough to do some vinyl. I spent a little time on Sunday and came up with what you see below. I'm happy with the results and looking forward to getting this one in the air in the spring.



Last part of the build was to attach the nose cone to the main body with some 200# Kevlar.

This one is done and ready to fly.

 

[lakeroadster]

Finally got the bench cleaned up enough to do some vinyl. I spent a little time on Sunday and came up with what you see below. I'm happy with the results and looking forward to getting this one in the air in the spring.

View attachment 625494View attachment 625495View attachment 625496

Last part of the build was to attach the nose cone to the main body with some 200# Kevlar.

This one is done and ready to fly.

View attachment 625493

Truly a fine locking rocket. Well done, Sir.​