Modified Mach 2 Kit

[David Schwantz]

with a K2050, nope. Do NOT use just glue. Screw them on.

 

[Buckeye]

I've heard flyaway rail guides go with the rocket and can be single-use, and I'm using a Slimline retainer so tower launches could be funky. The plan is to 3D print some glue-on rail guides.

For the non-threaded closures, what is your plan for harness attachment?

When you are ready to go "commando," you can tie the harness to the forward closure with a knot.

https://www.rocketryforum.com/threads/wildman-mach2-hed-recovery-gear.165178/post-2167821

 

[Buckeye]

This is your second HPR flight, a minimum diameter, your first reload, and extreme thrust motor. I agree with @rfjustin. Pump the brakes.

 

[briewillcox]

with a K2050, nope. Do NOT use just glue. Screw them on.

It's an MD rocket, so I can't put hardware through the airframe like that. I was told elsewhere to glue them on because apparently flyaway rail guides can suck and my rocket might not launch straight out of a tower with the motor retainer I'm using.

 

[briewillcox]

For the non-threaded closures, what is your plan for harness attachment?

When you are ready to go "commando," you can tie the harness to the forward closure with a knot.

https://www.rocketryforum.com/threads/wildman-mach2-hed-recovery-gear.165178/post-2167821

I'm going to attach an eye bolt to a bulkhead, maybe 2 stacked bulkheads just in case. It's G10, thoughts?

 

[briewillcox]

The plan for the bulkhead eye bolt is use a ton of epoxy to secure the bulkhead(s) into a short section of coupler, and then radial bolt the coupler into the rocket just above the motor section.

 

[user 30299]

What should I use to bond them? Do the instructions include that? This will be my first reload.

This is the glue for AT motor bonding. You can find the bonding instructions on the AT website.



You may want to try a simpler reload if this is your first.

The bonding will just complicate your learning curve.

Don't risk a CATO on your first launch.

 

[Buckeye]

The plan for the bulkhead eye bolt is use a ton of epoxy to secure the bulkhead(s) into a short section of coupler, and then radial bolt the coupler into the rocket just above the motor section.

That works.

 

[StreuB1]

For rail guides on minimum/sub-minimum diameter rockets, you have 2 choices.

• Fly-away rail guides (investment)
• Conformal rail guides that get glued onto the airframe

The conformal guides are cheap, work well, and look quite nice.

https://giantleaprocketry.com/products/acme-rail-guide-3-00in

 

[StreuB1]

If you want to do your L2 on an M2 (lol), and you want to stay safe. A J180T is a nice motor, longish burn, proven propellant that generally causes no dramas, won't go crazy high but will definitely go high (8k).

 

[mrwalsh85]

I would, but I'll end up flying some motors without threaded forward closures and I want to keep this thing somewhere in the middle of high-performance and versatile.

If you're flying 38/29mm motors you can build the recovery harness anchor into your adapter, no issue there.

The M2 is a performance bird. THe questions you're asking

I'm considering just buying some rail buttons and standoffs. Will they hold if I attach them with epoxy or CA glue?

I think maybe it's time to pump the brakes a little bit. I understand your enthusiasm.... But you should have a pretty solid understanding of building high power rockets and what will or will not work, without relying on TRF to answer all of your questions. Further, you don't seem too interested in the advice that others are offering - except advice you want to hear to advocate for your discussion points.

 

[David Schwantz]

I screw rail buttons on MD rockets all the time. Use a blind nut, grind out a small hollow spot at location of button. Insert button through hole, apply small amount of epoxy to hold in place. Screw button on with screw that does not stick into motor.

I also use flyaway guides, mine work great.

 

[rfjustin]

What should I use to bond them? Do the instructions include that? This will be my first reload.

Old video, but concept remains...

 

[tim cubbedge]

What should I use to bond them?

AT recommends Elmers Glue All Max. It should be in the instructions. I think others have used some form of Gorilla glue.

 

[UPscaler]

Yeah, that was the plan. I don't mind a little extra drag for a motor retention system I have a little more faith in, lol

I friction fit a 98mm N motor case, and we needed a come along to get it out

Braden

 

[briewillcox]

For rail guides on minimum/sub-minimum diameter rockets, you have 2 choices.

• Fly-away rail guides (investment)
• Conformal rail guides that get glued onto the airframe

The conformal guides are cheap, work well, and look quite nice.

https://giantleaprocketry.com/products/acme-rail-guide-3-00in

I think conformal rail guides are a good option, but I need to space my rail guides out from the tube a couple mm because of my motor retainer. Are there rail guides for that out there? or should I just 3D print spacers or my own guides or something?

 

[David Schwantz]

Sometimes I am really glad I fly in MN

 

[StreuB1]

I think conformal rail guides are a good option, but I need to space my rail guides out from the tube a couple mm because of my motor retainer. Are there rail guides for that out there? or should I just 3D print spacers or my own guides or something?

Motor retainer on a M2??

Why not just install a removable bulkhead at the head end of where your motor will extend to and bolt the motor to that?

There are other options as well, I can post when I get home of what I do with mine.

I flew to 21k in my M2 on a K270W with no motor retention, just friction fit tape.....

.....laundry was attached to the head of the motor though. The motor was essentially floating though with only tape holding it in place.

You don't need to get complicated. Did you also see my motor adapters that I posted on the prior page? They will also give you more flexibility for flying on smaller motors, the M2 can fly on G's to L's.

 

[briewillcox]

Motor retainer on a M2??

Why not just install a removable bulkhead at the head end of where your motor will extend to and bolt the motor to that?

There are other options as well, I can post when I get home of what I do with mine.

I flew to 21k in my M2 on a K270W with no motor retention, just friction fit tape.....

.....laundry was attached to the head of the motor though. The motor was essentially floating though with only tape holding it in place.

You don't need to get complicated. Did you also see my motor adapters that I posted on the prior page? They will also give you more flexibility for flying on smaller motors, the M2 can fly on G's to L's.

I considered that but I was worried about using different, longer motors and ending up with a bunch of bolt holes in my airframe.

 

[StreuB1]

A radial bolt pattern beyond the longest motor that you can use, would not mean you have a bunch of holes in your airframe. It just means you need to plan a little, which can be a pain if you don't have the hardware to plan around or the means to design or draw things up.

I can tell you though, the stock M2 can be built with a forward bulkhead that will accept the longest AT case, with the extended smoke bulkhead and a means to attach the laundry. All without needing any means of motor retention.

Take your time, plan things out, then execute. Or, since the M2 is pretty cost effective, build one, then build another. I have 2 and one thats still unbuilt.

Enjoy the process, there are launches all the time around our parts. No need to rush, unless thats what you enjoy.

Lots of us in the area to lean on for advise as well.

 

[briewillcox]

A radial bolt pattern beyond the longest motor that you can use, would not mean you have a bunch of holes in your airframe. It just means you need to plan a little, which can be a pain if you don't have the hardware to plan around or the means to design or draw things up.

I can tell you though, the stock M2 can be built with a forward bulkhead that will accept the longest AT case, with the extended smoke bulkhead and a means to attach the laundry. All without needing any means of motor retention.

Take your time, plan things out, then execute. Or, since the M2 is pretty cost effective, build one, then build another. I have 2 and one thats still unbuilt.

Enjoy the process, there are launches all the time around our parts. No need to rush, unless thats what you enjoy.

Lots of us in the area to lean on for advise as well.

Would a bulkhead with an eye bolt offset from the center to make room for a threaded rod with a nut on either side of the bulkhead work? I guess I'd need different lengths of threaded rod and I'd still need to find a solution for smaller motors that doesn't involve tape. I'm just not comfortable with it.

 

[StreuB1]

The eyebolt can go right through the bulkhead and attach to the motor. Or, the recovery loop can go through the hole in the bulkhead and through the eye in the top of the motor. Tape retains the motor, it is far more secure than most newer people realize. It is not going anywhere. For shorter motors, or the rocket I flew at Airfest that used tape, can still use the eyebolt and a threaded rod extension to hold the motor in place with a threaded forward closure.

One thing about tape retention. Tape only needs to hold the motor in one time, ejection. Well, assuming the motor is tied to the recovery! LOL

Tape (friction fit) requires pressure over time in order to move. Ejection charges act so quickly that there is not enough time to overcome the breakaway friction long enough to spit the motor out. Small little Estes motors or composite motors, maybe. Long motors with multiple tape bands, not likely. Ultimately though, you need to do what you want and makes you happy and comfortable. Though, the best way to become comfortable with something, is to get experience and how do you get experience? Doing it.

 

[rfjustin]

Would a bulkhead with an eye bolt offset from the center to make room for a threaded rod with a nut on either side of the bulkhead work? I guess I'd need different lengths of threaded rod and I'd still need to find a solution for smaller motors that doesn't involve tape. I'm just not comfortable with it.

How are you tracking for your flight at MWP?

 

[briewillcox]

How are you tracking for your flight at MWP?

I'm using an Eggfinder with the bluetooth receiver.

 

[briewillcox]

The flight was perfect! Everything but the Eggfinder worked as intended, but I suspect it wasn't the Eggfinder's fault; there might've been an issue with the power connector. Fortunately, the rocket landed closeby. It reached an apogee of 11,099 ft. Because I only had a barometric altimeter the velocity and acceleration readings are unreliable, but I estimate it hit ~mach 1.3 and around 70-80g of acceleration.