Estes Astron Explorer Build Thread

Discussion in 'Low Power Rocketry (LPR)' started by sl98, Jul 2, 2018.

  1. Jul 2, 2018 #1

    sl98

    sl98

    sl98

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    I’m surprised there hasn’t been a build thread yet on the Astron Explorer. I will attempt to document my build. Be forewarned...I rarely build a stock kit. There will be a mod or two along the way. Recommended engines are D12-3 and E12-4. Although E qualifies as mid power I'll post in LPR. I won't be flying E12's. I foresee flying this kit on 24/40 hobby reloads.

    Here are a few pictures of the parts:


    IMG_2428.JPG IMG_2429.JPG


    The kit includes 8 nose cones. There are also templates for aligning the body tubes together.

    Thumbing through the instructions, this kit looks very similar to the Trident. The ejection gases will vent from the motor mount tube, through the 3 side tubes and into the top tube.

    Directions have you building motor mount first. I’m going to skip that step and come back to it later. NOTE: See Post 13 below and consider adding a length of coupler above the motor mount to reinforce the bottom tube.

    Next steps are to cut slots in all tubes where ejection gases will vent. I photocopied the templates from the instructions instead of cutting them out of the instruction book. You also get a second copy of instruction in German so you could always cut up that copy if you don’t have a copier handy.

    I used a straight edge and hobby knife for all cuts. The ends align to the ends of the body tubes so you want straight cuts. I tried using scissors but couldn’t get a straight cut.

    IMG_2431.JPG IMG_2432.JPG IMG_2433.JPG
    First up are the 3 BT20 side tubes. One slot is needed in each end. Instructions call for drawing a straight line with a door jamb. Aluminum angle is my substitute for a door jamb.

    IMG_2435.JPG


    The slot cut out template is place on the tube and lined up with the reference line. The slot in the paper does not lay flat and wants to bulge up. I pressed the sides of the slot down with my spare hand and drew traced the slot. I then slid the template to the other end. The slot started to distort when I drew my second slot. I tried using a little strip of tape in the center of the slot to hold the slot together. This didn’t work very well.

    IMG_2438.JPG IMG_2440.JPG IMG_2441.JPG


    I ended up printing out another templates. This time, I put a piece of scotch tape on the slot before I cut it out. This helps keep the edge of the slot from tearing. I was able to trace decent enough lines. I then used the aluminum angle to cut my slots. I inserted used 18mm motors to have something firm to cut against.

    IMG_2446.JPG

    The templates for cutting the slots on the BT-55 tube are not intended to be reused like the BT20 template. I think I will reprint them and not cut out the slots. I will then tape them to the tube and use my aluminum angle to cut the slots.
     
    Last edited: Aug 7, 2018
  2. Jul 2, 2018 #2

    sl98

    sl98

    sl98

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    First slots cut in BT20 side tube. Remember to mark the back reference line before moving the template. The tube alignment templates have reference marks for lining everything up, which will be very handy.

    IMG_2447.JPG IMG_2452.JPG IMG_2453.JPG IMG_2454.JPG
    IMG_2458.JPG
    The three BT20 tubes are done. If you have ever hand cut slots for thru wall fins then you will find this task fairly easy. If you have never hand cut slots it is not that hard. Use a new blade, aluminum angle or other straight edge, and something inside tube such as a used motor or a coupler.

    IMG_2459.JPG

    Next up is to cut slots in BT55 main body tubes.
     
    Last edited: Jul 2, 2018
  3. Jul 2, 2018 #3

    Lugnut56

    Lugnut56

    Lugnut56

    What, me worry?

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    Thanks for taking the time to post your build. I have one of these in these in my "to be built pile" , so I'll be following your thread closely.
     
  4. Jul 2, 2018 #4

    neil_w

    neil_w

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    Thanks for this thread, I've been curious to see how this one goes together!
     
  5. Jul 3, 2018 #5

    sl98

    sl98

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    Time to cut slots in the BT55 tubes. The BT55 templates are not interchangeable and are identified by corresponding tube part number. They also indicate in very small font which end of the template goes flush with the end of the body tube.

    I started with the shorter BT55 tube. On this tube you are cutting slots and also marking lines for fins. I used a larger size of angle and a spare coupler to stiffen up the body tube while making cuts. I did not cut out the slots on the template and trace. I placed a small strip of scotch tape over the slot outline to keep the paper from tearing while cutting.

    I rotated the tube in the aluminum angle and alternated cutting slots and drawing fin lines. A few light passes with a sharp blade were enough to cut through the tube. I removed from the angle and cut the small ends of the slots. The instructions also have you trace a line along the bottom of the template around the tube.

    I repeated the process for the longer BT55 tube, cutting slots and marking lines. Time to break out the adhesives and start putting pieces together.

    IMG_2461.JPG IMG_2462.JPG IMG_2463.JPG IMG_2464.JPG
     
  6. Jul 7, 2018 #6

    sl98

    sl98

    sl98

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    If you build this kit, you will see that I deviated from the instructions slightly. The instructions have you cut slots on the short BT55 and then glue in bulkhead and nose cone. You then cut slots in the longer BT55 and glue in bulkhead.

    Returning to shorter BT55. I took a little thin CA on a Q-tip and coated the area between the cut out slots. Don’t get CA above the slots because you will be gluing in a bulkhead and nosecone. I roughed up the base of the nosecone with a little 60 grit sandpaper to assist with adhesion. The instructions call for glue on the bulkhead and plastic cement (i.e. Testors). For LPR, I use Titebond III and instead of plastic cement I use Harbor Freight 5 minute epoxy.

    NOTE: See Post 13 below. You might consider adding a length of coupler above the motor mount to strengthen the lower body tube. You may want to put the coupler in place after gluing the motor mount but before gluing the nose cone & bulkhead in place. Remember not to cover the cutouts with the coupler.

    IMG_2468.JPG

    Next, I assembled the bulkhead assembly that goes into the bottom of the longer BT55 tube. The nosecone on the shorter tube will eventually be fitted in here. I cannot figure out why the purpose of the bulkhead with all the cutouts other that aesthetics. I used a small rat tail file to clean out the burrs in the center hole where the “spacer” (i.e. 1/4” launch lug) fits. I used a scrap of BT55 tube to make sure the two bulkheads were properly centered.

    IMG_2471.JPG IMG_2472.JPG IMG_2475.JPG IMG_2476.JPG

    I was contemplating painting in sections before assembling because this is going to be a pain to spray paint with rattle cans. I abandoned that idea because it will cover all my reference marks that are used with the assembly jigs to line up all of the tubes. You can see in the photos above that I did take a black sharpie marker and color the majority of the inner bulkhead.

    This is also a point where I did a modification. Instead of the Estes rubber shock cord and trifold mount I use 380lb kevlar and cardboard. I also put a length of heat shrink on the kevlar for added protection. The mount was epoxied in before gluing in the bottom bulkhead.

    IMG_2479.JPG IMG_2481.JPG IMG_2483.JPG IMG_2484.JPG IMG_2486.JPG

    Next up is gluing all the body tubes together.
     
    Last edited: Aug 6, 2018
  7. Jul 8, 2018 #7

    sl98

    sl98

    sl98

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    It would be extremely difficult to assemble this kit without the included jigs. Thanks Estes!

    IMG_2502.JPG

    You will also need a long work area for this step (at least 32”). The instructions show you sliding all tubes into the jigs and aligning. What I did was first insert the three BT20 side tubes into jig “O.” “O” is the part number for this jig. I centered the jig between the end of the cut out and end of the tube.

    IMG_2488.JPG

    Next, I placed the end jigs “P” onto each BT55 body tube. I took the shorter BT55 with installed nose cone and inserted into “O.” I did some minor adjustments to get the reference marks on jig lined up with lines on body tube. I then inserted the longer BT55 into the other “O” jig. I then did my final adjustments to get the reference marks lined up.

    IMG_2489.JPG IMG_2491.JPG IMG_2496.JPG

    The instructions tell you to put glue around the edge of the cut out on both ends of a BT 20 tube and then rotate into place. Before gluing, I rotated all three tubes and used a flashlight to make sure all the cutouts lined up.

    IMG_2497.JPG

    I used a toothpick to apply a light bead of glue around each cutout. Rotated and aligned. All looks good so far. I will wait for the glue to set and repeat on the other two side tubes. I also have to apply fillets between the tubes at a later step to ensure the tubes stay together and the cutouts are sealed.

    IMG_2499.JPG IMG_2501.JPG

    Time to start prepping motor mount and fins while the glue dries.
     
    Last edited: Jul 8, 2018
  8. Jul 8, 2018 #8

    sl98

    sl98

    sl98

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    I intend to fly this rocket primarily on 18/20 and 24/40 reloads. The only potential issue with reloads is the red ejection charge cap being lodged in the lower body tube. I want to be able to shake out the caps after each flight and the thrust ring and motor hook will make this an impossible task. I am using a Rocketarium retainer. An Estes retainer is too big even with the ridges sanded off. You can visit a LPR/MPR comparison thread I did a while back for a comparison of these retainers.

    If I use D12’s or possibly Estes E12’s then I will simply use masking tape to make a thrust ring. The centering rings provided with the kit includes one that is split so you can still lift the motor hook. I went to my parts bin and substituted the center rings. The paper rings would have been sufficient but I didn’t have a matching paper ring, which is the only reason I’m using these lite ply rings. JB Weld for the retainer. Wood glue for the rings.

    NOTE: See Post 13 below. You might consider adding a length of coupler above the motor mount to strengthen the lower body tube.

    IMG_2505.JPG IMG_2507.JPG

    I slid jigs “O” back and took another look to make sure all cutouts were aligned and I notice light coming through the bulkhead installed at the bottom of the top BT55 tube. I applied a thin bead of glue to seal. I was concerned that ejection gases could leak through.

    IMG_2509.JPG

    I decided to use the jigs to hold the rocket while doing the fillets between the body tubes. I grabbed a couple of wood blocks so the rocket would clear the bench. I used a glue bottle with fine tip to apply glue. I then used a toothpick to poke the glue down and smooth out the fillet.

    IMG_2510.JPG IMG_2512.JPG IMG_2516.JPG

    Fins are ready to go. They received a quick airfoil on leading and trailing edges. I also applied a coat of thin CA.

    IMG_2518.JPG IMG_2517.JPG

    I’m waiting for the first fillets to dry so I can rotate and do the next side.

    Next will be installing motor mount so I can use my fin jig. The final steps include installing fins, launch lugs and the 6 side nose cones. The end is in sight.
     
    Last edited: Aug 6, 2018
  9. Jul 9, 2018 #9

    neil_w

    neil_w

    neil_w

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    Those jigs would have made building a Trident a lot easier back in 1975....

    Nifty build so far.
     
  10. Jul 11, 2018 #10

    sl98

    sl98

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    Launch lugs and fins are on. Started fillets. I'm painting the 6 side nose cones and main nose cone separately. I will epoxy the 6 side nose cones after painting body. Main nose cone was given a kevlar harness because I've had several of the plastic attachment points break in the past.

    I'm not using the tail cone because I'm using the Rocketarium retainer. However, if I want to display with the tail cone I could because I inserted the motor tube far enough forward that the tail cone fits over the threaded portion of the retainer.

    IMG_2522.JPG IMG_2524.JPG IMG_2525.JPG IMG_2526.JPG

    Just need to finish fillets then find time and good weather to paint.
     
  11. Jul 15, 2018 #11

    sl98

    sl98

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    Fillets and first primer coat done. Painting in between side tubes and the middle nose cone is very difficult with rattle cans (at least it is for me).


    IMG_2528.JPG
     
  12. Aug 4, 2018 #12

    sl98

    sl98

    sl98

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    Done. I didn't really like the stock colors so I used colors I had on hand. I painted the six nose cones on the side tubes separately and glued in place after painting the remainder of the rocket. I also didn't use all of the decals because they didn't go with my color scheme. It was a real pain to mask and paint but from a distance it looks okay. Now I just need to get it into the air.



    IMG_4945.jpg IMG_4944.jpg IMG_4943.jpg
     
  13. Aug 4, 2018 #13

    sl98

    sl98

    sl98

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    Maiden flight on D12-3. Low and slow with apogee estimated around 400 feet. I used an 18" semi- hemispherical in lieu of the 18" plastic chute. D12-3 was perfect delay and rocket came down very slow with what appeared to be a gentle landing. I was surprised to see the body tube above the fins buckled a little. If you build this kit you might consider adding a length of coupler above the motor mount to reinforce. I'm just going to fly it unless/until the buckle makes it unsafe to fly. I will just hack off the fin can, add a coupler and clue back together.

    Nice kit. Fun build. The build was not as hard as I was expecting given the included templates for gluing. The rocket is very long making it easy to watch as it slowly climbs into the sky.



    IMG_4965.jpg IMG_4966.jpg IMG_4963.jpg IMG_4964.jpg
     
    Last edited: Aug 4, 2018
  14. Aug 4, 2018 #14

    Scott_650

    Scott_650

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    Really wasn’t thinking of buying one of these but seeing your paint scheme has me thinking otherwise. I like longish, slow and low flying rockets.
     
  15. Aug 6, 2018 #15

    sl98

    sl98

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    I had a rare opportunity to fly again today. I use an AT E11-3J (actually a 4 second delay per packaging). Nice slow boost and estimated 700-800 foot apogee. I used a larger 24" nylon chute this time because there was virtually no wind today (approx 2 mph). It took forever for the rocket to land with the 24" chute. As the rocket was coming down it was apparent the shock cord was fouled because the chute was not very far above the rocket. You can see from the following pictures how the nose cone fouled behind one of the side pod nose cones. Fortunately no damage to the side pod. With the 24" chute the rocket softly touched down. However, it appears the buckle from the prior landing is a little more pronounced.

    The E11-3 is a perfect motor but I wouldn't recommend it if there was much wind.

    IMG_4976.jpg IMG_4977.jpg IMG_4978.jpg
     
    Last edited: Aug 6, 2018
  16. Aug 6, 2018 #16

    neil_w

    neil_w

    neil_w

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    I was not in love with this design, but after seeing your paint job I might be changing my mind. Looks fantastic.

    Did you use any special tricks or techniques to get the paint all through the innards? (I ask this question of everyone...)
     
  17. Aug 7, 2018 #17

    sl98

    sl98

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    First trick is don't glue the 6 side pod nose cones in place. Paint the 6 nose cones separately and paint the body. You can see in post 11 above a picture of rocket after primer was applied without side nose cones. It would be impossible to paint the area behind the nose cones after glued in place. Only glue side nose cones in place after all painting is done.

    Second trick is I used Krylon Shimmer Metallic paint. My experience has been the shimmer paint does not have as much a tendency to run as compared to regular spray paint.

    I painted the red first then masked to paint the black. I used the ends of the side pods as a reference to mask. I also used the ends of the BT-55 tubes as the other reference to mask.

    To paint the innards, I tried to spray at an angle to get behind the side pods. Even with this angle it coated the inner nose cone. I had to keep reminding myself to spray just a little and keep rotating the rocket to get even coverage. If you were to look close, you will see small areas where it was impossible to get paint. If you want/need prefect coverage then I think you would have to use an airbrush.
     
    Last edited: Aug 7, 2018
  18. Sep 12, 2018 #18

    Ryan weeks

    Ryan weeks

    Ryan weeks

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    What did you use for a fun jig. I have the two angled boards set up for my fin jig but won’t work due to middle body tubes. Wondering what you used to line up. Thanks
     
  19. Sep 12, 2018 #19

    sl98

    sl98

    sl98

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    Ultimate Rocket Fin Guide

    https://www.rocketryforum.com/index.php?posts/1407171/

    but he is out of business. There are other similar jigs out there and several threads with homemade versions using wood and aluminum angle.
     

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