38mm Mega Der Red Max clone

Discussion in 'High Power Rocketry (HPR)' started by Nick Hutton, Aug 2, 2019.

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  1. Aug 2, 2019 #1

    Nick Hutton

    Nick Hutton

    Nick Hutton

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    Another of my clone kits from Toby. This will be my first 38mm build. He’s pretty much supplied me with everything save glue and paint. Being in Australia, decals were going to be a problem, but Toby convinced me that Stickershock had fast turnaround and indeed I ordered them and had them sent to Toby and they arrived in a couple of days to be included in my package.

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    The kit had 4 sets of the fins, I’ve only displayed one as I forgot to take a before photo prior to flying the fin sandwich.

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    Planning to do most of the build with Titebond III again. One question for all those who have already completed this kit. I’m not going to bevel the fins. I want this to be a low flying, high drag rocket. Do I need to reinforce the leading edge? I’m planning to sand it smooth, but in a couple of spots the glue clearly hasn’t come right to the edge. I was thinking of wicking Cyanoacrylate into the 3 fin edges as a minimum, but also wondered about a fold over of fibreglass.
     
  2. Aug 3, 2019 #2

    Nick Hutton

    Nick Hutton

    Nick Hutton

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    More building today. I’m really loving this kit and can’t believe Toby had to convince me on the 38mm mount. Having been through the sims a few times, it doesn’t go far on G motors!

    I ended up running a line of titebond around the edges of the fins and reclamping them. Left them for a few hrs whilst I did some LPR scratch building with my son and started to teach him how to use open rocket.

    I sanded down the shiny layer on the motor tube and glued on the top and middle CRS after measuring up with the fins. It’s all very tight tolerances, so Toby’s laser must be well calibrated.

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    I wasn’t sure quite where to put the rail buttons and have read extensively on it. Looks like there is still no consensus. Our local expert told me to put the top one on the CP, which I marked but it just seemed to close to the lower one. So I’ve preglued some ply onto the upper ring and will drill into that later on.

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    Glued the motor tube in and almost immediately did the fins as we’ll give they all lock into place fairly securely. Loving pre cut fin jigs again

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    I sanded off the glassine around the fin slots as well. Will be using Titebond so figured being able to soak into the cardboard more easily will add strength.

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    Last job for the day was the nose cone mod. I initially thought I’d been provided with one that was way too small as I was expecting to lodge in front of the shoulder as I had done previously. However this one was cut to sit inside the shoulder, so require a bit of marking out to get it right, then some 5 min epoxy to secure it in place followed by some 15 min to put a good fillet in behind the bulkhead

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    Question for anyone who’s made one. I used the supplied shock cord on a smaller build, a Star Orbiter. Ive purchased 100ft of 1000pd Kevlar ford. How long do I need?
     
  3. Aug 3, 2019 #3

    Jozef

    Jozef

    Jozef

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    Who is Toby?
     
  4. Aug 3, 2019 #4

    OKTurbo

    OKTurbo

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    I just ordered the same kit. Toby is on the Facebook ‘Model Rocketry BST’ page....buy sell trade. He makes up clone kits of discontinued mid powered designs. He’s probably on here too, but I’ll let him chime in.
     
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  5. Aug 3, 2019 #5

    Jozef

    Jozef

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    I got my L1 on an MDRM with a CTI H123 (29mm). The design begs for a 38mm mount... more options. Just round the leading edges. It is not a speed demon...no need to bevel anything. Apply some thin CA to the all fin edges to toughen them. I glassed my fins with 3/4 ounce cloth and finishing resin for finishing purposes. Not needed for strength. I use a 3/4 inch wide x 20 foot nylon harness with a kevlar sheath to protect from ejection charges. Your kevlar will be fine, but suggest layering some duct tape at the point it exits the airframe to deter any chance of zippering. Use of a Jolly Logic Chute release is highly recommended. I have had several very late delays and swear the JLCR has saved the airframe. Mine has ten flights over the years... would fly more if I could fly it on 38's. BTW, my flying weight is 3.2 pounds. Has always flown on CTI 29mm H motors. Best off luck with yours. Its a fun rocket. Id love to build a 38 version...use my existing nosecone...
     
  6. Aug 3, 2019 #6

    Jozef

    Jozef

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    IMG_3387.JPG ....oops...here it is...
     
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  7. Aug 23, 2019 #7

    OKTurbo

    OKTurbo

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    I’ve been making progress on mine too. Are you going with altimeter deploy at apogee? What’s your plan on the static port location for the barometric altimeter?

    I’m trying to get the static port further down the body tube using as much nose cone shoulder as I can. I made a tunnel into the e-bay and will drill the static port after i make a ‘key’ so the cone goes in the same position every time. Hoping this will give a better static pressure for the altimeter and still protect it from the ejection charge.

    Thoughts?

    1CDB0684-0269-43F1-9BE3-D7FE248745DC.jpeg 08ADB084-5286-4236-8BA1-4142CDA06E23.jpeg 4D22FC31-9FE4-49BA-B0B2-89F41E0C2BC6.jpeg
     
  8. Aug 23, 2019 #8

    swatkat

    swatkat

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    Mine is through the side wall of the cone and body tube.
     
  9. Aug 23, 2019 #9

    Charles_McG

    Charles_McG

    Charles_McG

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    2x the height of the trees where you fly.
     
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  10. Aug 23, 2019 #10

    swatkat

    swatkat

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    I try to do 4x the body tube for MOST rockets. For MRDM being short and squat I used 12'. That being said, I'm still finishing mine, so can't say how it works out, but for other similar kits (Pihrana, Batray) 10-12" has been plenty.
     
  11. Aug 23, 2019 #11

    swatkat

    swatkat

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    10-12 FEET... not inches.
     
  12. Aug 24, 2019 #12

    Nick Hutton

    Nick Hutton

    Nick Hutton

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    Update to follow
     
    Last edited: Aug 24, 2019
  13. Aug 24, 2019 #13

    Nick Hutton

    Nick Hutton

    Nick Hutton

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    Ok, time I did a follow up post. It’s completed and flew well last week. I just got busy and didn’t add to the build thread.



    I left off the rear CR and did internal fillets and external with TB3. One issue with using it over epoxy is the drying time and resulting 48 hr build period it takes so do all the fillets. Plus with the shrinking I did two layers of external fillets.

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    Paint wise I experimented with a new brand for me MTN 94, based on a recommendation on the Australian forum. Awesome selection of colours, I just chose the wrong ones for this rocket!

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    They are both matt and the body is not nearly bright red enough. As a result I intend to repaint it before I put the sticker shock stickers on. But as we had a launch last weekend I was eager to fly it.



    I also purchased a sewing machine and taught myself to make spherical parachutes based on threads in the forum as well as some nomes chute.

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    Toby supplies the kit with a perfectly good red PSII parasheet, but I was keen to go bigger.



    The 3D printed retainer went on easy and seems very solid. After one flight there is absolutely no signs of injury

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    Maiden flight was on a 38mm Aerotech H100W DMS. Flew to 1200ft according to my Altimteter 3. I haven’t put vent holes in it yet, so my graph looks odd. I think I will, but want to make sure they don’t interfere with the stickers, so need to measure up. Motor eject with a 6 second delay and Jolly Logic chute release at 400ft. It landed about 100ft from the pad.

    IMG_1431.JPG




    All up a great project. I’m really happy with the two kits from Toby so far. Once I get through my build pile I will be keen to see what else he has come up with.



    In the meantime I plan to go for my Level 2. I’m going to quick build a PML 1/4 patriot using a 3D printed fin can developed by some guys in NZ rocketry and also an Ausrocketry 75mm Katana dual deploy (which looks like a clone of a Wild,an darkstar). Will give me 2 chances at a successful J motor flight at Havoc in the Paddock in NZ in February.
     
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  14. Aug 24, 2019 #14

    Tobor

    Tobor

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    Congrats on the build and maiden flight.
     
  15. Aug 24, 2019 #15

    OKTurbo

    OKTurbo

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    Excellent! The slow motion launch is too cool. Flies great.
     

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