Mach One “Alien Interceptor” build

Discussion in 'Mid Power Rocketry (MPR)' started by downhill_D, Sep 3, 2018.

  1. Sep 3, 2018 #1

    downhill_D

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    I am going to post my first fiberglass build on MPR but might fly it on a small HPR motor later. I heard of this company from the rocketry show podcast and liked the sound of the quality of the kits so I went and bought one. I just finished a loc graduator for my L1 flight next month and can relax a bit and enjoy the challenge of building a new kit. I was interested in fiberglass kits for a while but stayed away due to weight. This kit will likely not fly anything other than a baby H but looked to be a clean kit and I liked that it was one of the few without radical split fins. I also liked the motor diameter to body tube (29/38mm)

    I will post the kit contents tonight-it appears so far from everyone else who has purchased one that these kits are very nice to build.

    As time allows I might try to post a few pics of my loc graduator L1 build but for now this kit has my attention-says it can use up to an “I” so we will see-the site said through “H” but the package says “I”. I am not sure why but it would be nice for Mach One Rocketry to offer the final built weight on the website-Ill be translating it to rocksim anyway but it would be nice to know ahead of time. (After speaking with the owner tonight the rocksim files are already available)

    As a side note-these kits do not offer a parachute BUT when I ordered the cheaper of what they offered they were unfortunately (fortunately) out and substituted for a rocketman parachute at no additional cost! Great customer service guys! Keep it up! Really looking forward to this build.

    I typically with quality cardboard rockets (Loc etc) will use 30 min epoxy and make another CR and sometimes 2 part foam around a motor mount if its gonna get kicked hard. This kit will be a bit different but I am still planning on using the 30 min Epoxy for all assembly and fillets. I notice lots of people using huge amounts of rocketpoxy and even J B weld for fillets-is this really necessary? I have never lost a fin to 30 min epoxy but my HPR experience is limited at this time. I typically leave the aft ring off during the build so I can access the MMT and fins for internal fillets. Any thoughts/ideas are welcome in my build thread.

    Pics of kit tonight!
    Thanks!
     
    Last edited: Sep 17, 2018
  2. Sep 3, 2018 #2

    Wallace

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    Odds are you'll be fine using what you have. Don't overthink it, just enjoy building..
     
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  3. Sep 4, 2018 #3

    downhill_D

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    The kit- “Alien Interceptor” almost complete (motor mount is missing from the photo-29mm MMT). I dry installed the fins so you can see the rocket profile-pretty awesome! I am really happy with this kit. Oh and the”Rocketman” chute is top notch! They also include a “micro” rail button set which I will use on a smaller rocket. The club I launch with uses 1010 so I will be using 1010 buttons or guides for this rocket.

    The kit comes dual deploy capable which was an unexpected bonus! These parts fit clean and tight. This is gonna be a fun build! I preinstalled the coupler so you can see how thin the tubes are. Incredible and strong. Time to play with Dawn soap, Rocksim and the scale.

    Overall-this is a nice way to get introduced to fiberglass rockets without breaking the bank. I didn't want to spend over $100 on a fiberglass rocket which is typical for much larger fiberglass birds. This is a very nice kit that reminds me of my Loc Park Flier Hyperloc (also a really nice kit) only much taller.
     

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    Last edited: Sep 4, 2018
  4. Sep 4, 2018 #4

    downhill_D

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    I appreciate the keep it simple attitude-Ill stick to my 30 min guns :)
     
  5. Sep 4, 2018 #5

    downhill_D

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    For a visual comparison-Loc Precision Graduator next to the Mach One Alien Interceptor. Just a guess but I would say this alien interceptor is gonna be able to take a kicky motor! (Graduator is still not done being painted)
     

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  6. Sep 4, 2018 #6

    Eric

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    That's a good looking kit. I am happy with my Mach 1 kits. What was the weight of your kit before assembly?

    I think it would be hard for a kit manufacturer to give a really good final build weight. As they offer different motor mount sizes, and everyone builds a little different. Even the recovery gear you choose for a rocket this size will make a difference.

    My BT-60 Black Hole started at 12oz. And is looking to come in at 19oz without a motor. But I cut 3-4 oz due to different build / prep techniques on this one.

    Good luck, I'll be following the build.
     
  7. Sep 4, 2018 #7

    downhill_D

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    All the parts minus decals weigh 15.1 ounces. Stellar! This is a pretty long rocket for the diameter-not the craziest I have seen but this will be perfect for a good range of motors-G77RL is sounding good-for a night flight :)

    I forgot: this does not include the 29mm motor mount tube weight-it is being shipped separately.
     
    Last edited: Sep 4, 2018
  8. Sep 4, 2018 #8

    downhill_D

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    What different build technique did you use to drop weight? I figure after I aero the fins the weight will go down a tiny bit-they weigh about 119grams by themselves (total for all 3). I keep it thin on paint jobs (krylon fusion) because I have to repaint them at some point anyway. I use about two coats, sanding the first.
     
  9. Sep 4, 2018 #9

    Eric

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    Yes, the 29mm MMT, rings weigh about 2.5oz. I removed those and the fin tabs for the 38mm stuffer. Saving 1.5oz.

    Fillets were done smaller then my normal, and sanded down smooth to take of more weight.

    My coupler end caps will only use a kevlar loop instead of eyebolts. Along with through the wall charge wires instead of terminals, saved me another 2 oz.

    The avionics sled was printed with a honeycomb core. Saving at least an ounce over a commercial sled or what I would have built with a fiberglass sled.

    Paint is being kept thin and light. And is being sanded down smooth between coats. It will be wetsanded and polished with a very smooth finish.

    Sims show that a really smooth paint job has a better effect on altitude then saving an ounce with less paint.

    Also, a little more weight savings with motor retention being removed in exchange for friction fit.
     
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  10. Sep 4, 2018 #10

    swatkat

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    I did the same as Eric for my Mach 1 BT-60 build. Nice small fillets and light paint. Came in just 3 Oz. above the dry weight with parachute and recovery/paint/1010 buttons. No Decals. Haven't flown it yet, but I suspect it'll be just fine on anything from an E up to an H...
     
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  11. Sep 5, 2018 #11

    Scott_650

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    Ordered one of Mach One’s LPR kits today - BT55 Blackbird. OR sims show it, using the Mach One .ORK file, performing well on an Estes E12 so it should fly nicely on any 24mm motor with the same impulse or higher. This will be my first fiberglass build so I’ll be watching this thread for sure!
     
  12. Sep 6, 2018 #12

    downhill_D

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    I built my kit in rocksim yesterday to the best of my ability and all flights are stable but anyone know why I cant get the little parachute to show a perfect flight? I know the 2D flight profile is what is important with rocksim for simulation but it would be nice to get “perfect flights”. I have tried getting the ideal delays and most flights are deployed at a relatively low speed.
     

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  13. Sep 6, 2018 #13

    crossfire

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    R
     
  14. Sep 6, 2018 #14

    crossfire

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    I had no idea Rocketman makes chutes in small sizes?
     
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  15. Sep 6, 2018 #15

    downhill_D

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    I was surprised but it is a high quality chute-I have never owned one until now but I may never use anyone elses again-these are really nice! This one will play the drogue chute for the higher flights-I am so impressed at the quality of the chute-a very good match for the Mach One kit-both great quality. I have worked in the bicycle industry with Carbon for a while now and can safely say, for fiberglass-this stuff is impressive.
    As with just about any purchase of mine I also like to encourage those not sure about fiberglass to start with a cheaper kit like me-the value in it will be worth it in the end I have found. These airframes when built correctly (build to follow these posts once I have the motor mount Friday) will withstand a great deal of kick from a motor. I am however interested in how much “kick” Eric’s Mach One kit will get away with without through wall mounting. I have seen surface mounted wooden fins withstand quite a bit so fiberglass should be a greater exception! I would consider my next kit to be minimum diameter like his but for now I am just getting back into the hobby. I practice great patience in the learning process. Although I THINK I know building from back in the day (1998) I know I have already learned a great deal of new information from those around me, including here! That is why I encourage anyone to offer suggestions through this build. I will first layout my build plan and then do the build.
     
    Last edited: Sep 6, 2018
  16. Sep 6, 2018 #16

    downhill_D

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    Alien Interceptor tubing all washed up. I used a magnet reach tool and a papertowel as a tube brush. Made sure to keep the ID and OD bulkheads separated for ease of identification. There, drying out on your wifes favorite towel-just kidding-this one has bleach stains. I will scour the areas tomorrow that will get epoxy. I only needed one paper towel for the whole process. I rinsed the tubing with fresh water after using soap and then carefully dried the tubes with a lint free towel (microfiber in my case). I let these all dry for 24 hours, fiberglass is a bonded glass fiber so although water probably doesnt saturate it too much it is best to really make sure it is gone before scuffing and bonding. I have planned in advance to wash these items now as I am not starting any bonding until Friday and live in a very dry region. This gives plenty of time to dry out (including inside the nose cone!). The way I figure if these parts have been in a fiberglass manufacturers warehouse everything has fiberglass dust, parts have the mold release. It is best to just be sure everything is clean. I might even wash the parachute.
     

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    Last edited: Sep 6, 2018
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  17. Sep 7, 2018 #17

    downhill_D

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    Motor Mount showed up today with extra centering rings and extra stickers. Thank you Mach 1 Rocketry!
    I will begin building the rocket tomorrow or Saturday. No instructions come with the rocket so this leaves a bit of room for customization. I will build this kit like most others I build: I start with the motor mount without the aft centering ring installed to leave access to the fins for internal fillets. Since I was given extra centering rings with this kit and usually make new aircraft plywood ones with my cardboard kits I may opt to use 3 centering rings total-two forward spaced about an inch apart and one aft with room for a motor retainer. It may be overkill so I will have to check CG as I go along. I posted my rocksim file in the electronics forum if anyone is savvy and can help with getting the parachute in the simulation to go green with no arrows (if you own rocksim you know what I mean)...I cannot get the delays exactly right and must be missing something.
     
  18. Sep 7, 2018 #18

    matthew

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    This is a long rocket. Adding one extra centering ring the size of a rubber band will have a negligible effect on your CG. Unless you decide to braze it in with lead, of course. :)
     
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  19. Sep 7, 2018 #19

    RFMan

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    I took advantage of the sale I ordered one of these also. It will be my first foray into fiberglass rocketry (aside from some G10 fins I played with a long time ago).
     
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  20. Sep 8, 2018 #20

    downhill_D

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    Nice! I will be posting some pictures tomorrow of my fin prep and tube/coupler prep, sand and paint the nose cone and attach the coupler.
     
    Last edited: Sep 8, 2018
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  21. Sep 8, 2018 #21

    downhill_D

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    Ok. Hit the hardware store and since I will eventually need dual deploy and tracking prepared myself with some fittings. I purchased the skinniest allthread I could find, 6/32 and some matching washers and nylon locknuts. I also picked up some machine thread eyebolts but didnt bother getting the forged version. This is a small rocket and wont be very heavy and I typically use a flexible line between forward and aft sections of kevlar with cardboard but with this rocket I will keep everything kevlar for the shockcord since this is fiberglass. Will just need to keep an eye on the edge. these fiberglass tubes are fairly stiff so they do have rigid and thin edges.
     

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    Last edited: Sep 9, 2018
  22. Sep 8, 2018 #22

    downhill_D

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    After putting a mask on and wearing gloves I sandwiched the sanded (I am just using 400 grit and 90%alcohol for piece prep) ID and OD bulkhead pieces together with epoxy.

    *** I emphasize gloves and a mask because I know we all kind of assume we are careful ourselves but I know there are some people who have not worked with fiberglass or carbon or epoxy before. the items should not be inhaled, ingested and preferrably not touched as some people are allergic to the resins and sometimes the fiber and dust.***

    That said, my first fiberglass build kit begins: in the pictures you can see the inner diameter (ID) and outer diameter (OD) sandwiched so you will have a little step that will fit inside the coupler and the outer will be the same diameter as the outside of the coupler. I recommend drilling the bulkhead finished pieces in order to keep alignment of the hole(s) in your bulkhead center. If you drill them separately at the center punch you will likely get misaligned holes. Guess how I know. :)
     

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    Last edited: Sep 9, 2018
  23. Sep 8, 2018 #23

    downhill_D

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    After the epoxy has cured and I have installed the eyebolt I will check the fit both in the coupler and within the lower body tube. Mine is a really good fit. This is where it will separate on mine for deployment for now so the bottom half of my coupler (at the eyebolt/shockcord) must have proper fit for separation of the lower body tube.

    Make sure the eyebolt is installed in case you push it into the tube too far (past the bulkhead cap) it wont be difficult to remove during your test fit.
     

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  24. Sep 9, 2018 #24

    downhill_D

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    My next Satruday project (after mowing the lawn) was to prep my fins for installation. I will be roughing the surface of the root of the fins with 400 grit just until the gloss is gone and wipe with a clean dry cloth then clean with alcohol. I then mark all fins (both sides) for my attempt at airfoiling if I expect it to go really fast...this one will. I use a Mr. Pen brand engineering ruler (easy to hold still) a sharpie and about 3/32” space to mark my foil-this is how I am doing it on this size rocket- a larger fin would dictate a slightly wider airfoil possibly. I use a dremel with a regular sanding drum attached for knocking down the heavy material and then smooth and finish the fine edges with 400 grit.
     

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  25. Sep 9, 2018 #25

    downhill_D

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    Okay fins are mostly beveled for airfoiling and I merely used a dremel sanding wheel to lightly scuff the root edges. After soaping them up-if you scuffed correctly the surface of the roughed root edge will not feel slick and will even sort of grab your finger as your rinsing soap and fiberglass dust off into the water. Here are the washed fins:
     

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  26. Sep 9, 2018 #26

    downhill_D

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    Next up, shaping the fins, scuffing the tubes and after a quick conversation with Eric I will either rivet the coupler to the forward tube (payload section) or friction fit as I will be using single deployment. I may consider a long home fashioned ebay tube from some 50% lighter than regular aircraft ply I picked up from SIG about a month ago for backup fin stock. I have built centering rings with it and now maybe an etube or something. The payload section is huge so I have a LOT of payload room to use if I choose too.
     
    Last edited: Sep 9, 2018
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  27. Sep 11, 2018 #27

    downhill_D

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    So an ebay it was-I am filling a payload area on this rocket that would normally be innaccessible unless a friction fit is used so the coupler can be pulled out for access. I decided to build an ebay above the coupler that can slide out the top at the nose cone. I purchasd cheap 50% lighter than normal aircraft ply 1/4” and traced a circle of the tube it is going in. I used a japanese razor saw, a dremel and a sanding block-here is 40 min worth of work. I used a design similar to the ones sold at apogee.
     

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    Last edited: Sep 12, 2018
  28. Sep 14, 2018 #28

    downhill_D

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    So the rocket was shipped without a MMT and the one I received as replacement is too big for a 29mm motor so this build is on a stall for a few days. I was reassured by Steve a replacement will be on the way as soon as the next round of MMT's gets made. Kind of a bummer but Steve is taking very good care of their customers and is sending me something to help make up for the motor mount. I have a month still before it could fly so I have time. I did spend some time masking and painting the Graduator I am using for my Level 1 in October. I will put a build post up a separate post for the LOC Graduator on Sunday, it is currently ready for a gloss coat now and doesn't look how I wanted but still pretty good coats for krylon.
    As soon as I have the motor mount I will continue this thread-I will be making a longer E-bay as well so this Mach 1 rocket has both two small E-bays like the one I just built with a little room left over and also one long E-bay for simplicity and uninterrupted GPS. I am thinking "modular" fitting smaller E-bays together with some sort of fitting instead of all-thread as GPS would be hindered by the steel all threads. I like the wooden E-bays because they can be modified and designed around what payload I want to have running inexpensively. The 2ft x 3ft 1/4" aircraft play cost me about $12-$15 or so and I have used a tiny amount with plenty left over. I should mention I also chose the 1/4" light ply for this project over 1/8" because care must be taken cutting it. It will splay and tear out on the backside easily if you dont clamp it close to the edge of the cut-I just use a sturdy box and my hand (wearing leather utility gloves). I use a Japanese razor saw I bought on amazon for about $20 and it is still sharp as ever after cutting fins for 6 rockets out of 1/8" ply and an E-bay out of 1/4" ply. I am sold on wood for electronics compartments - $32 and I didn't need a 3d printer-just my imagination and I can make tons of stuff. A 3d printer would be cool though-I see a lot of cool projects, fins, Ebays here using them. The wood from sig "lite ply", is very light-about 50% less than normal stuff. It might be a good way to lower aft weight with kits that have standard ply if you wanted your CG forward.
     
    Last edited: Sep 18, 2018
  29. Sep 17, 2018 #29

    downhill_D

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    Finally finished the longer e-bay-it weighs at 34g with a bit of wood filler but exactly what i need. I drilled tiny 1/8” holes for kevlar pull cords to remove. I can completely customize this to hold electronics, weight etc. with the smaller one I made earlier there is still room for an egg-finder...however I like Erics nosebay for the egg finder so i might do that-going metallic paint so i would have to paint plain color (non metallic) on the nose cone.
     

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    Last edited: Sep 17, 2018
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  30. Sep 17, 2018 #30

    Normzilla

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    Very nice. Picked this kit up Saturday after catching up on my Rocketry Podcast; right on time as it was the last one!

    Really excited for the build.

    Thanks!
     
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