Mach 1 Rocketry Red Shift Build

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Simon Auty

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Just arrived
This will be my first Fibreglass Kit
Any suggestions as I build appreciated
Awaiting arrival of BadAss Rocketry AV Bay and EggFinder Quantum
Not worked out Recovery or Tracking yet
Thinking about a Rocketman Rotating Star Chute - just because I like them and an EggFinder TX

First issue:
Thin walled Motor tube is thinner than expected so motor retainer is quite loose on test fitting
Quick email to Mach 1 and told yes that's correct.
Use JB Weld and slide motor in to centre -remove it and allow to cure
Mach 1 recommend Aeropack 38mm L retainer, but PML HAMR 38mm is a slightly better fit -should I go with that to reduce the play?
 

Theory

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hey there, a few recommendations as you asked:

first, have fun.. yes FG is a little different than cardboard/wood, but do not over think it

second, wash all your parts and keep them clean. i like to keep a can of denatured alcohol and some shop towels around to wipe everything down prior to bonding. also, be careful of the towles than have alcohol on them and be sure to dispose of properly.

third, have fun!!!!

fourth, us the pieces that you believe will work best. if the HAMR fits better, go for it.

if you have questions, just ask.
 

Simon Auty

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Thank you Theory.
I certainly intend to have fun!
I’ll post pictures once I’ve washed all the components this weekend.
 

Theory

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a good read if you havent already done so:


this is the method i use to bond composite components. works VERY well.
 

Simon Auty

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Ok further question Theory:
In the BadAss build video of Mac 1’s other 54mm Rocket they drill holes in the fin roots.
This is to strengthen the joint between the fins and body.
Going by the info in the article, however, this would be cutting the fibres so isn’t recommended.
So what do I do?
Drill the holes or not?
 

dvdsnyd

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Ultimately it's up to you what you decide to do. There are a million opinions on this forum for how to build a rocket properly. The best one is usually the one that you are most comfortable with. The biggest thing with composites that people don't understand is that a chemical bond is ultimately stronger than a mechanical bond. Holes and scratching the fibers = mechanical. Methodically sanding down to expose the fibers yields a chemical bond. That being said, both will most likely work for what we are doing.
 

Theory

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do not see any reason why drilling holes in the fin root would help, and disagree that it would "add a lot of strength"

have never done so, and don't see myself doing it.

wont go so far as to say it is 100% wrong, just, IMHO, not the best idea.
 

rocketman4h

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Badass rocketry has an interesting video on using Kevlar to re-enforce MD fins

I wish I had see this before my carbon fiber Madcow MAMBA build!
 

MidOH

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You can try holes if they're tiny, and use a drill press. You want smooth perfect holes to avoid stress risers.

I simply triple dip my fin roots. It's pretty darn strong. I haven't bothered with holes yet because of how strong these rockets are.

I lightly sand the motor mount parts. Make sure that epoxy gets under the rings, that's why they're loose. Let them float, and carefully rotate the mount as the epoxy dries. They'll self center, dont poke at them more than required to keep them straight. If you're worried about straightness, add more rings.

On my next m1 order, I'm adding extra rings.

I still use a knife to crosshatch my fins gluing surfaces. It doesn't weaken the fins, and it works. Maybe its mechanical, maybe it's more surface to bond with. Dont care. It works.
 

Simon Auty

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So next question:
attaching the rail buttons - just drill appropriate sized hole and screw them in or do I need to epoxy the screws in as well?
 

John_461

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I used the method shown in the videos for mounting the fins in a trough filled with rocketpoxy. It works really well, but seems heavy.
 

MidOH

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I used a CRC aluminum locknuts for my rail buttons on my last build.

On my current build I'm just threading the buttons into the fiberglass with epoxy under the button. I might use a locknut on the front button.

On a rocket as big as yours, you might be able to fit a locknut behind the rear centering ring.

I'm going to use a fly away guide on my 54mm build.
 

Theory

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looks good, time to wash those parts.

on my builds i like to anchor the rail button screw into a wood block or wood centering ring. it is a very solid anchor and doesn't take a ton of effort to fabricate or line anything up.

that said, there are lots of options for backing the rail button, but you do need to do something as it is not adviseable to simply run the screw through the air-frame and leave it.
 

Simon Auty

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This distraction arrived yesterday
More work on Red Shift this weekend
80EECB8D-2771-4A6F-B41D-44C2CB2F6B5A.jpeg
 

David Schwantz

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Backing plates made out of wood with blind nuts to anchor rail buttons is what I like to do. On the Aeropack retainer, you can take some 1/64th ply, cut 3 small pieces, CA to tube it proper place and the JB Weld the retainer on. This will center it and take up the slop. Clean and prep all surfaces, use good glue, sand all inside of ends of tubes. Just lightly, takes the edge off, saves on cuts. I like to bevel all fin edges. Like the sled.
 

tOD

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Mach 1 Thunderbird build video
That's the way I built my Messier65. It hasn't flown yet so I can't say how it holds up. It certainly seems solid. I used strips of balsa and Rocketpoxy.
 

David Schwantz

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What you have there should be fine, I also like to tie a knot and butt it up against the CR to help from pulling through. Rough up glass tube, make sure not to get glue where fins will go.
 

David Schwantz

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I like to make one end of my Av bays non removable with the sled attached to the all thread. This way it all comes out as a unit and goes back in that way. Holes line up perfect every time. So, yes on that end I use loctite. But on the end with wing nut, no. I might also suggest not using the brass casings. I have done that before and had them dig chunks out of my rocket when they did slam together.
 

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Simon Auty

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Thanks David, hadn’t thought about that with the casings, this being my first build of a dual deploy, I’m just following the ‘instructions’ as it were ( not that Mach1Rockets come with instruction!)
 

David Schwantz

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Mach 1 has generic ones on the website, at least Steve did. Ya, it was just a thought when I saw the brass.
 

Simon Auty

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So when checking clearance of fins and recovery harness on the motor mount the tolerance is quite tight.
Not sure how to proceed, but here’s my current thought.
I’ve masked out the space for the recovery harness. This keeps it clear of the fins (just).
If I sand this masked space and epoxy the harness down here then I can get the fins in.
Is that how it’s done or am I missing something?
52F63F16-74C1-4AA4-92DC-ED0E573C5BC3.jpeg
 

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