SpiderMax Too - The Return

[frogglicker]

Part 1:

Hey everyone. Thanks for stopping by.

Introduction:


This is the build thread for my 2nd iteration of the SpiderMax rocket. Last May, I started working on the SpiderMax project, a scratch-built, 3-in Big Red Max clone. There were things that I really liked about that first attempt and some things that were less than ideal, the project was about learning to build rockets, prep for my L1, and have a rocket that didn't require a bunch of bits and bobs to launch. It had a 29mm MMT, allowing me still launch at my host club, CRASH, without adaptors. A simple, easy, fun rocket. I feel like SpiderMax was a huge accomplishment, as was the Hobgoblin, a 3-in Goblin scratch clone that doesn't suck. Unfortunately, on my 3rd flight with SpiderMax, I didn't have an H-motor for which it was still set up for. Instead, I used a G74 and the CG was off. This provided for a spectacular display of skywriting and a week of repairs. Looking back, I believe the landing sans parachute weakened one of the fins. The forth, and final flight, SpiderMax Redemption, was a huge success with a successful flight. However, we discovered that one fin was broken upon arriving at home. I have had hopes that I would be able to salvage the rocket but I built the MMT like a brickhouse and the fin can was a loss.

SpiderMax and SpiderMax Too Liveries

“Failure is simply the opportunity to begin again, this time more intelligently” - Henry Ford

Last month, I decided to build on what I learned from SpiderMax and my other projects and improve on the engineering. This build thread will discuss those points while I move through the build, focusing those topics toward building yet another Max rocket design. My intention was simply to replace the one I had build last year but that got out of hand quickly. I decided to redo the graphics for the new one based on the Spider-Man 2 Game release.

(continues with Part 2)

 

[frogglicker]

(Part 2)

Specifications:
All printed parts were printed on the Comgrow T300 FDM printer with Elegoo Rapid PETG, at 0.2 resolution, 100% infill, and an extruder temperature of 250 degree Celsius. Various brims, rafts and supports, as needed.

Originally, this design was taken from a Der Red Max Open Rocket file that I found last year, where I then upscaled it using software that I wrote in conjunction with TinkerCAD and OnShape CAD. I have subsequently modified the fins using Fusion 360. The retainer ring/cap and ebay were also designed in Fusion 360.

For full disclosure, The threaded ebay design isn't mine. I couldn't get mine to work or look very good until I saw Jonathan's from Inverted Pursuits Labs' version. His is on point and my design is a derivative of his. If you look at both, you will clearly see where I made changes to suit my specific needs, but I don’t want anyone, including Jonathan, to think that I am passing the design off as my own. He gets the accolades, I just adapted the idea for my own evil porpoises. We'll get into the details of my design updates/changes down the road a bit.

Here are the parts for the rocket: I will add to this as I get/add other things:

Fins (3x):	90g
Retainer Ring:	12.2g
Retainer Cap:	32.2
Body Tube (Office Depot 3-in:	113.1g
MMT Carriage:	121.5g
38mm MMT:	21.5g
Nose Cone:	204.5
Coupler:	74.4
Ebay (with electronics and hardware):	156.3
Rail guide (2x):	4.4
Camera mount	TBD
Parachute	TBD
Fire blanket	TBD
Shock cord	TBD
MMT Eyehook	TBD
Parachute Quicklink	TBD

SpiderMax Too Build Plate


Total print time for all three plates:
23h13m (this took longer)
307meters and 915.27grams of filament (This took much more)

There were several iterations of the coupler and nosecone, MMT carriage, fins, and the tube slotting jig. It was worth it in the end. The kit is dry assembled and looks great. Primary assembly will begin in a couple days.



(Continues with Part 3)

 

[Hobie1dog]

Thanks for the pictures

 

[cwbullet]

Great design. I could probably print them all on on sheet.

 

[frogglicker]

Part 3 - Component Details

Fins 3x: I printed these face down on the print bed as opposed to my previous method of printing with the root edge down. I did this primarily for strength, with the layers running laterally though the fin. Spider-Max was retired because one of the fins broke were the layer line was weak. The compromise is aesthetics since printing the fin flat will result in garbage airfoils. My current thinking is that any fin smaller than this will be generally fine without airfoils and anything bigger will probably require different material that will allow for airfoil shaping (if I need it). This rocket will not be coming close to Mach and I'm not trying to break any records. With some modification to the tab, this could be modified to accept CF or Glass fins that could be airfoiled. That is not the focus for me on this build, so I'm not concerned with that.


Printed Fin at 4.7mm thick


Retainer Ring and Cap: This is a retainer for a 38mm MMT that I designed for the Menace 3D challenge. There is a recessed area at the top to accomodate an Aerotech RMS motor case and a disk for motor adaptors. I did not test this with Cesaroni cases because I don't have any, but if someone wants to donate, I will be happy to test and adjust. I only just received a 38mm DMS motor and haven't tested the fitment yet, so I may have to make adjustments.


38mm Retainer Ring and Cap

38mm MMT Carriage: I designed one of these for Spider-Max and I really liked it. It helps grab the fin and provide additional gluing surface, making the whole fin can very solid at the expense of weight. The fins for this rocket are 1.65mm thinner than on Spider-Max, and I wanted to make sure they didn't move once glued. It's probably overkill but the fincan should be a tank when completed. This was made specifically for this model which will fit inside a LOC 3" body tube and will accept a LOC 38mm MMT. It could be used for other models. The fin tab diagram above along with 4.7mm thickness would be the only constraints. I don't anticipate getting rowdy with this rocket so I included only one 6.35mm hole for a 1/4-20 eyebolt.


38mm MMT Carriage


Nosecone: I really struggled with this component. I have several ogive designs that would work, but I really like the look of the original Red Max nose cone. I spent a lot of time trying to recreate it in Fusion 360, Importing and tracing, using Dave The Rocket Guy's nosecone plugin for Fusion360, magic fairy rocket dust... nothing got me where I wanted to be. I finally pushed everything aside and opened up TinkerCAD and used the Der Great Red Max nosecone designed by Arogen67 on Thingiverse (https://www.thingiverse.com/thing:5454175), upscaling it:

• 79.8 x 79.8mm x 323mm
• Removed the threads on the inside/base of the nosecone

3-in Nosecone

Nosecone Coupler/Ebay 76mm x 76mm x 93.6mm (~ 5mm thick): As I mentioned earlier, I designed my ebay sled around the Jonathan's (Inverted Pursuit Labs) design. To integrate this, I need a shoulder for the ring with threads to mount to. Since I was now back in the TinkerCAD world, I created a simple coupler, then attached the threaded ring within it. I then aligned the nosecone 58mm above the coupler, put the nosecone in "hole" mode, then joined them. This carves out a shoulder in the coupler. When printed, the coupler slides into the nosecone for a perfect fit. These will be epoxied together during assembly. The shoulder fits nicely in the tube.


Nosecone coupler

(Continues in Part 4)

 

[frogglicker]

Part 4 - Finishing up the Specifications

Ebay Sled and Threaded Ring:

These are my derivative of the IPL version. I have resized it to fit 3-in tubes, since that what I fly the most. The sled plate has channels cut out to reduce weight and to allow for zip ties/Velcro straps. I also added hex holes to accommodate nylon standoffs sized to accept an Eggtimer Quantum Flight Computer.

The ring can be printed separately and used by gluing into the bottom of an existing nosecone. You just have to lop to bottom off and size the external diameter to accommodate. I did this with my Mega Red Max and it worked really well. For this build, I have integrated the ring into the coupler. The sled securely threads into the coupler and then has a 1/4-in x 20 hole on the bottom and top. The top one is for the nosecone adjustable weight system (which I may employ with this build... we'll see). The bottom is the same dimensions for accepting an eyebolt. There are two mating holes on either side of center for routing e-matches and venting for the flight computer. I have used this on several rockets and I include it as stock for most of my designs. It's epic. You can download the STL from IPL on Printables or buy many common sized from their web store.


3-in Nosecone Ebay Sled and Threaded Ring

Conformal 1010 Rail Guides for 3-in tube - Designed in TinkerCAD - I designed these originally for my Cookie Monster Doorknob builder's kit. I got the idea from RocketyWorks rail guides that had holes in the base for the epoxy to flow up. It looks cool and should be more than strong enough since it will be chemically boded to the body tube. I have used these on my 4-in Mega Red Max

Body Tube: 440mm paper tube from Office Depot - I was shocked when I bought these tubes and discovered that they accommodated my LOC 3-in designs. They are pretty reasonable and feel solid. I would rather go with LOC tubes, but I'm already down the road. This might be a point of foreshadowing. We'll see.

MMT: LOC 38mm ~ 9-in long - Nothing special about this other than its a tank. I'm loving these for MMT/

(Continues in Part 5 - Dry Fit and Assembly Prep)