Model Rocket Building Blog 
Model Rocket Building Posts
Rocketry Product: Estes - Thor Agena-B {Kit} (28) [1966-1971]
Estes Thor Agena Build Part 1 Parts (2012-06-11)
Here's the parts I had on hand before the build. Parts of interest are the: TA-52-60 balsa adapter BT-52 (3.938" long) BNC-52G nose cone The instructions are at Jim Z's. You might recognize some ... [Read More]
Estes Thor Agena Build Part 2 Nozzle Fit (2012-06-12)The nozzle was traced and redrawn in Corel Draw. The re-draw was needed because the SP-28 PDF print was a little big and the lines were grainy. The upper shroud shows the print from the ... [Read More]
Estes Thor Agena Build Part 3 Engine Mount (2012-06-12)Glue was applied to the edges of the JT-60C coupler. The RA-2060 rings were set on the edge and turned. This evens out the glue ring into a smoother internal fillet. After it is thoroughly dried, ... [Read More]
Estes Thor Agena Build Part 4 Engine Mount Fine Points (2012-06-13)Figure 3 of the original instructions show the glue tab formed so it is a raised "step". This would make the outside of the shroud edge smoother. One way to do this is with finger pressure. ... [Read More]
Estes Thor Agena Build Part 5 Engine Mount Fine Points (2012-06-13)After the CA coat dries, sand the flat exposed side of the ring flush with the BT-20J motor mount tube. This is the ring about halfway through the sanding. I had to take it down a bit, ... [Read More]
Estes Thor Agena Build Part 6 Engine Mount Fine Points (2012-06-14)TIP: That inside glue tab can distort the final "round" of the nozzle shroud. Sometimes you can sand a small flat spot on the ring that fits the raised tab better. You won't have to sand off ... [Read More]
Estes Thor Agena Build Part 7 Engine Mount Fine Points (2012-06-14)The instructions showed a fillet applied after the engine mount / nozzle is slid in place. I felt too much glue would have to be applied for a complete seal. Also, trying to smooth that fillet ... [Read More]
Estes Thor Agena Build Part 8 Vernier Shrouds (2012-06-15)The instructions originally had the Vernier Shroud made out of balsa. To save time and grain filling, I'll make them out of basswood. The stock is 1/4" wide by 7/32" high. You'll find it easier ... [Read More]
Estes Thor Agena Build Part 9 Vernier Shrouds (2012-06-15)To start the notch, my 2' machine square was set down the length of the stick. This gave me an accurate 90 degree to rest my razor blade against. The rounded top was scored and the notch cut with ... [Read More]
Estes Thor Agena Build Part 10 Vernier Shrouds (2012-06-16)The sides are slightly tapered to the center. Mark and sand with 220 grit on a block. The small end is hard to see when shaping. I darkened the end with ... [Read More]
Estes Thor Agena Build Part 11 Vernier Shrouds (2012-06-16)This is all four with the small ends facing you. I've looked at a few pictures of the real vernier shrouds. It's hard to see the actual shape. This is the shape shown on the Estes i ... [Read More]
Estes Thor Agena Build Part 12 Vernier Nozzles (2012-06-17)The Vernier nozzles are small! Small cones are made from 1" square pieces of copy paper. I pre-rolled the squares with a small dowel. To get the glue "tab" under the outside edge, a razor blade ... [Read More]
Estes Thor Agena Build Part 13 Vernier Nozzles (2012-06-17)1/8" of the paper tip is cut off with a razor blade. Because the holes I drilled are probably deeper than needed, I cut the nozzles a little longer than the 1/8" length. ... [Read More]
Estes Thor Agena Build Part 14 Half Round Fairings (2012-06-19)The instructions say to make the half-round tunnels from balsa. It's easier to form, sand and seal these if made from hardwood dowels. A 1/8" X 48" long dowel was cut into fourths for easier ... [Read More]
Estes Thor Agena Build Part 15 Half Round Fairings (2012-06-19)The ends of the fairing tunnels are rounded and tapered. The silhouette of the tunnel end isn't perfectly round, but more like the top of an egg or short elliptical shape. Start by rounding ... [Read More]
Estes Thor Agena Build Part 16 Antennas (2012-06-20)Antennas are shown on the Exploded View and looked on as optional. I don't know why the instruction drawings weren't full size templates, they are just slightly larger than the finished ... [Read More]
Estes Thor Agena Build Part 17 Antennas (2012-06-20)After tapering the end to a wedge, the stick was set on the drawn template and the angled top trimmed off. Here I've started the cut for the root edge. I'm cutting a little outside (to the ... [Read More]
Estes Thor Agena Build Part 18 Long Adapter Fill TIP (2012-06-21)The long transition has a an angled "step" about two-thirds the way up. I wanted to keep the edge fairly sharp. To help keep the edge straight, the side of a pencil tip was rubbed over the ... [Read More]
Estes Thor Agena Build Part 19 Turbine Exhaust (2012-06-21)The turbine exhaust is made from a 3/4" long piece of 1/8" diameter launch lug. Step 12 of the instructions has you cut and glue the turbine exhaust (lug piece) in place before the super ... [Read More]
Estes Thor Agena Build Part 20 Turbine Exhaust (2012-06-24)I tried to use the small gussets from my print of the SP-28 pattern sheet. The line thickness was pretty thick. The gussets I'd cut out were inconsistent in size. I decided to redraw them ... [Read More]
Estes Thor Agena Build Part 21 Turbine Exhaust (2012-06-25)Press the square corner of the gusset into the joint of the flange base and launch lug. Be sure the base edge of the gusset is on the line. The side of the gusset should go straight up the lug. ... [Read More]
Estes Thor Agena Build Part 22 Turbine Exhaust Wires (2012-06-25)Here's the start of the bend of the modified "V" piece from Step 17. I've already made the first bend on the right side. The center is a 1/8" flat area that rests against the turbine ... [Read More]
Estes Thor Agena B Build Part 23 Removable Fin Unit (2012-06-26)The Estes kit had clear fins "glued" to a clear coupler wrapped around the body tube. After my experience with the 260 Booster's clear fins breaking off on landing, I wanted to try something ... [Read More]
Estes Thor Agena B Build Part 24 Open Rocket File (2012-06-27)I've prepared an Open Rocket (.ork) file for the Thor Agena B. This file has the small Delta shaped fins, not the old style clear fins. I wasn't able to add the removable fin unit (body tube ... [Read More]
Estes Thor Agena Build Part 25 Tunnel Sealing (2012-06-27)All the basswood pieces - tunnels, antennas and vernier nozzle housings - get sealed with clear varnish. You could use sanding sealer or dope. I don't get too fancy with this, most all of it gets ... [Read More]
Estes Thor Agena Build Part 26 The Real Thor Agena B (2012-06-28)Brian Coyle and Chas Russell sent me some great pictures of the Thor Agena B. These pictures give a better idea of what the back end looked like. The nozzle is a bell shape, not the straight ... [Read More]
Estes Thor Agena B Build Part 27 Priming TIPS (2012-06-28)TIP: I'm using the base of my thumb as a "bumper" to prevent the body tube edge from being rounded or sanded off. The base of my thumb raises and stops the sandpaper from rolling over the ... [Read More]
Estes Thor Agena B Build Part 28 Tunnels (2012-06-29)You should extend the tunnel lines over the lip of the lower BT-60 body tube. This will give you a centering tick mark at the end of the half round. When the half round is glued down, ... [Read More]
Estes Thor Agena B Build Part 29 Tunnels (2012-06-29)Use your aluminum angle to be sure the tunnels are glued on straight. On the lower right, the section of body tube from the removable fin can was taped in place. The tunnel ends were butted up ... [Read More]
Estes Thor Agena B Build Part 30 Tunnels (2012-06-30)Use your aluminum angle again to insure the upper tunnel is straight down the body tube. The front end of the tunnel is glued .20" from the front end of the BT-52 tube. Figure 11 of the Estes ... [Read More]
Estes Thor Agena B Build Part 31 Fillet TIPS (2012-06-30)The lower tunnels are 5 1/2" long, much longer than a root edge of a fin. If you were to lay a bead of glue down the joint and smooth it with a finger, you would have a lot of (drying) glue to ... [Read More]
Estes Thor Agena B Build Part 32 Nose Weight (2012-07-01)My Open Rocket simulation showed I'd need 1/4 oz. of nose weight to be more stable. The original kit was stable with three larger clear fins. This version has a smaller four fin removable ... [Read More]
Estes Thor Agena B Build Part 33 Fin Can & Lug (2012-07-02)A scrap piece of BT-60 was marked for four fins. The sliced segment was wrapped around the marked tube to transfer the fin positions onto it. I wanted to be sure the fins would be evenly ... [Read More]
Estes Thor Agena B Build Part 34 Antenna (2012-07-03)The small antennas were made from basswood in an earlier post. They were sealed and sanded smooth before gluing onto the body tube. They will be glued to the side of the tunnels on the lower ... [Read More]
Estes Thor Agena B Build Part 35 First Color Coat (2012-07-04)The area around the small gussets was rough, even more noticeable after some white was sprayed on. The is no way to sand between the small gussets. Before the paint was totally dry, some of ... [Read More]
Estes Thor Agena B Build Part 36 Fillet Bubbles! (2012-07-04)After the first white color coats had dried I found bubbles down the tunnel joints! I though the fit of the tunnels was good enough that fillet bubbles wouldn't be a problem. After two fillet ... [Read More]
Estes Thor Agena B Build Part 37 Details (2012-07-05)According to the directions, the turbine exhaust and vernier nozzles are painted aluminum or silver. After looking at pictures of the real Thor Agena B, these looked to be more of an aluminum ... [Read More]
Estes Thor Agena B Build Part 38 Details Finish (2012-07-05)After gluing the nozzles into the vernier housing, a sharpened dowel was lightly spun in the inside wall to make it a rounder shape. This sharp dowel also helps seat the point of the ... [Read More]
Estes Thor Agena B Build Part 39 Detail Gluing (2012-07-06)The engine mount was glued in with 15 minute epoxy. This gives some extra time to be sure of positioning. Epoxy won't allow the mount to freeze up in the wrong place like some white glues can. Here ... [Read More]
Estes Thor Agena B Build Part 40 Decals! (2012-07-06)I'm leaving for another Alaska cruise this morning, be back on July 14. If I miss posting it's because the ship couldn't get an internet signal. I couldn't find any K-28 decals online. I'd ... [Read More]
Estes Thor Agena B Build Part 41 Decals Available (2012-07-07)I've made the corrections and the Thor Agena B decals are available as a PDF to print your own. On the lower half is a 1" square to check your print sizing. On the lower half I've added some NASA ... [Read More]
Estes Thor Agena B Build Part 42 Decals (2012-07-07)I thought I'd printed enough of the straight black bands, but started to run out! TIP: Anytime you print up decals for a rocket, you probably won't be filling the entire sheet. Print extras and ... [Read More]
Estes Thor Agena B Build Part 43 Nozzle Details (2012-07-08)The V shaped turbine wire was too long to fit like the illustration. The sides were cut to 1 3/16" long as the instructions directed. But, to fit down the back of the turbine exhaust I had to cut ... [Read More]
Estes Thor Agena B Build Part 44 Decals (2012-07-08)This diagonal band was hard to get straight. Be careful with home printed decals, if you stretch them the ink will crack under the clear coat! The Estes instruction illustrations show the bands ... [Read More]
Estes Thor Agena B Build Part 45 Nozzle Details (2012-07-09)I drilled a small hole for the bottom of the turbine oil discharge wire. This small of a piece would need a little more support than just be glued beside the turbine exhaust lug. I bent and ... [Read More]
Estes Thor Agena B Finished! (2012-07-10)I know - the nose cone needs the upper 2/3rds painted black! It'll happen, I just needed a break from this build. It seemed to go one entirely too long! ... [Read More]
Estes Thor Agena B Build Part 46 Finishing Up (2012-07-23)I finally got around to finishing up the Thor Agena B. The nose cone was masked and painted black. I used the scotch tape strip cut in an arc to fit the contour of the nose cone. The ... [Read More]
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