THIS DESIGN HAS BEEN REPLACED. SEE THIS THING...https://www.thingiverse.com/thing:3113350 ...FOR THE UPDATED DESIGN.
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NOTE: I've made enough changes to this design that I will be releasing it as a separate thing on thingiverse. Basically every part has been changed. I've also designed parts more in scale to the original Ramjet so that you will be able to make a 2x scale Ramjet (ok, closer to 196% larger than original, so not quite 2x). It is with this 2x scale Ramjet design that I will also post the new parts for the new fat ramjet.
This design DOES work, so there's no reason to take it down. Just don't strap a camera to the outside like I did. Being a short rocket, it needs a lot of weight added to the nose to make it stable and adding the camera's wind resistance to the outside pushed it over the edge, so it flew into the woods and collided with a tree (and I lost the camera). But it flew fine on a C6-3 just prior to the launch it died on. It doesn't go more than a few hundred feet on a C6-3 though.
Stay tuned for the re-design. I should have that posted before months end.
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This is a remix of ellipticaloptician's model rocket kit allowing you to make an upscale version of Estes RamJet rocket using BT-55 and BT-80 body tubes. You don't have to make a stubby one like I did, I did that because I only had one short piece of BT-80 to work with (and I thought it'd be funny).
The Mid and Top pieces may need to be printed a little larger than normal to fit, like 101 or 102% or so. I printed them at 100% then sanded them to fit. You might have better luck. Don't glue them to the BT-55 center tube until you're sure you have them where you want them.
You'll have to print a nose cone and retainer ring from ellipticaloptician's original designs. And adapter rings if you want to use a C size motor.
It's up to you to figure out how you want to mount a shock cord and what to use for recovery. You should also know something about making rockets stable. The one I made has not yet been tested for stability, but I printed the nose hollow and can (and probably will) add weight as necessary to produce a stable rocket.
The fins are designed to go through the BT-80 tube and mount along the tops of three of the inner fins. The three to use have a base they can glue to. You'll have to figure out where to put these slots and cut them yourself.
NOTE: If you build this kit, be sure to sand the body tubes where you glue the pieces and fins. Body tubes come shiny, and glue doesn't adhere well to shiny. Make them not shiny before gluing.
8/23/2018 Edit: I haven't been able to get motors yet, but figured out that a D12-5 weighs the same as 18 pennies (providing they're made after 1982) so I made a dummy weight and did a swing test. I had to add a lot of weight to the nose but was able to make it stable. Even so, I doubt I'd get much height out of a C6-5 in this one. It'll probably only fly good on D's.
8/24/2018 Edit: Added a two part nose cone that is in the middle between the regular and stubby nose cone from the original source. This nose cone allows you to easily add weight to the nose if necessary. Some sanding and shaping may be necessary to get the base to fit into the nose cone.
8/26/2018 Edit: Added the decal sheets for the original Ramjet and for the Fat Ramjet. I don't know of the original Ramjet decals are still copyrighted by Estes. I found them on-line and the kit has been out of production since the early 80's so I'm pretty sure I'm safe. But if someone complains, I'll have to take those down. Otherwise, print them on clear decal paper with your inkjet, follow the instructions with that paper, and you'll be all set.
9/1/2018 Edit: Alas, the Fat Ramjet died. I launched it on a C6-3 and it flew fine, though not very high. Then I launched it on a D12-5 with an 808 camera attached to the top outside body tube. Sadly this proved to be too much aerodynamically and the rocket canted badly just after take off. It achieved stability, but at a near horizontal condition. It flew off into the woods where it apparently impacted a tree. We found the rocket, but never found the camera. I will build another, and I'll build an upscale of the original. But first I need to redesign the parts based on some observations of the wreckage.
9/2/2018 Edit: Reworking the design based on things noticed from the destruction of the fat ramjet. The fins will be thicker but can be printed with infill. Everything will have rounded edges. The lugs will be made for maxi launch rods. I won't be publishing these parts until I get the tubes I need to make sure everything is right.
10/1/2018 Edit: While I do encourage anyone to check out the newer design listed at the top of this text, I did manage to rebuild this rocket after the crash using the new mid coupler version posted with this thing. I've included a photo of the rebuilt rocket.
10/21/2018 Edit: Flew the rebuilt rocket on a D12-3 today. Everything was perfect until the nosecone separated at apogee. The nosecone and chute are in a tree somewhere. The body tumbled down nicely and survived the fall. I'll print a new nosecone for it and get a better shock cord. But the flight was nice and straight.