October 30, 2024
Description
Introduction:
Inspired by the 4-in Crayon Bank Rocket, this rocket was designed from the ground up to be a park flier and/or show-stopper at your next club event.
The Extreme Series of Builders Kits were designed for easy printing, assembly, and flying. These rockets can be flown on lower-powered motors in a park, or with higher-powered 24/29mm motors. Typically, an Estes E15 can loft these rockets to nearly 1000 ft, thus the name Extreme.
The construction is simple. Included is a one-piece fincan with the fins attached. The inside diameter of the fincan was designed to be lined with a 29mm motor tube. Between this tube and the fin can is a small channel for a piece of kevlar kite string (~1mm thick). This should also be epoxied in.
The motor retention ring will slip onto the end of the motor tube and be glued with epoxy. The nose cone includes a screw-in plug. It will accept a 1/8-inch eyebolt and also incorporates two holes for venting altimeters and e-matches for electronic deployment.
I have included motors simulations in the OpenRocket design. All pre-populated motors SHOULD fly fine. The rocket has been stabilized to fly any of these motors, but it is absolutely your responsibility to verify the rocket's stability and safety on each one of your flights.
If you print and enjoy this model, please consider clicking the LIKE (Heart) button and posting a Make. It really helps me and I would love to see other models made from this.
NOTE: I have not flown this model yet. It is very similar to the other Extreme kits, and I will post more pictures and the results post-flight, but please keep in mind that this is an untested model.
Models Included:
Additional Files:
Materials Needed:
Please note that the ebay or plug in the Extreme Accessories Kit are not compatible with this model's nosecone
Printing Guide:
These parts work well with PETG, though PLA+ will work too. I printed mine with 4 walls at 0.2 resolution @ 100% infill for durability. This will make it heavy, but strong. You could get away with 2-3 walls and 15-30% infill, but you probably want to use a stronger infill like Cubic or 3D Honeycomb. Your field conditions will need to be a consideration. You can print the fincan lighter and the nosecone heavier to help with stability. Let me know how you configured yours.
Building Guide:
Starting with the fin can, your motor tube (MMT) should be as long as the fin can plus the retaining ring. I suggest using a longer tube, and after the MMT and ring are glued, trim the excess off at the ring. Dry fit your MMT into the fin can. If you encounter moderate resistance, either sand the inside of the fin can or sand/peel the top layer of the motor tube until you can slide the tube in without kinking it. If you kink the tube, the motor will not insert easily and can become jammed after flight.
Once the dry fit is complete, run one end of your shock cord down from the forward end until about 25mm (1 in) is extending out the back. Apply a thin coat of epoxy to the aft end of the MMT and slide it in from the forward end until about 15mm sticks out the aft section. You must align the shock cord in the internal channel that was modeled to accommodate it. Take your retention ring and slide it onto the end of the tube and push it up until the ring is seated on the aft end of the fin can, pinching the shock cord. Make sure everything is aligned and seated then set aside to dry. Clean any excess epoxy from the fin can, retention ring, or inside of the MMT with Rubbing Alcohol.
Next, you will need ~ 9-in (228mm) of Estes BT60 body tubing. Use the body tube cutter in the Accessories folder to trim it to the desired length. You can cut the tube back to the desired length after assembly. Apply a film of epoxy to the inside aft end of the tube and slip it into the fin can. Give the tube a little twist to make sure there's good coverage. Make sure to feed the shock cord through. Apply a little epoxy to the aft end of the motor tube and slide the retaining ring on until it bottoms out. Your fincan is now complete.
Safety Police Disclaimer:
Rocketry is a safe and rewarding hobby. With knowledge and experience, you can experience the excitement of yeeting a rocket thousands of feet into the sky. There is nothing else like it.
Having said that, you are responsible for the rockets you fly. If you build and fly one of these rockets, you should understand the NAR Safety Code and the potential risks involved with launching any rocket, especially these. They were not designed to be toys. They are real rockets that can potentially go very high and carry significant energy. This rocket is intended to be built and flown by experienced rocketeers who understand the risks and can mitigate potential issues through experience. By printing and flying this model, you do so at your own risk. You are solely liable for any unexpected results and you agree to hold me and any manufacturer harmless of any liability. I recommend you join NAR or Tripoli, join a club, and ask lots of questions. Launching a rocket as a NAR/TRA member at a sanctioned event provides you with insurance you don't get at the park. </end of Safety Rant>
License:
Creative Commons — Attribution — Noncommercial
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David Frey
