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The CfdOF workbench in FreeCAD includes the density-based compressible solver, HiSA, developed for transonic and supersonic flows. I am not experienced in compressible flow CFD, so I am learning as I go. The documentation discusses two validation test cases, the Army-Navy Basic Finner (ANF)...

I think I bought a genuine 80/20 20 Series rail from Grainger: https://www.grainger.com/product/80-20-INC-T-Slot-Framing-System-20-Series-804TA2 The Mini Buttons from rail-buttons.com seem to fit correctly. However, I am having trouble with T-nuts. I bought these from Amazon, and they are...

The Base Drag Hack is one of those legends on TRF that gets repeated over and over and assumed to be true. Here are 3 reasons why this technique should be abandoned. 1. The origin of the technique is from Bruce Levison in the Apogee Reak of Flight newsletters Simulating Short, Wide Rockets...

I put my Fat Boy CFD model to the test with a center of pressure analysis for this short, stubby design. Since we have 3D discretized numerical solution, we can easily integrate over the rocket area and define CP per the classic NASA Beginners Guide. Since the CFD includes viscous effects, I...

I started looking for an OpenFOAM UI freeware a few months ago. FreeCAD with the CfdOF workbench seemed ideal. Coincidently, David Carter made a nice presentation at NARCON 2024 2 weeks ago on this very software. I built up a simple test case of the Estes Fatboy design using the parametric...

I am designing a MPR/HPR booster stage to deploy a parachute via motor ejection. RockSim indicates that after stage separation, the booster coasts for several more seconds before reaching its apogee. When observing real world 2-stage flights (granted, I have not seen many nor paid close...

This thread will document my build of a mid-power 2-stage rocket. I will probably need some help along the way. These are my goals/key points: Learn 2-stage with 29mm motors, maybe 24mm in the sustainer. 29/180 is probably the longest I would ever use. 2500 feet or so altitude to start so...

https://www.nar.org/message-from-the-president/ Once again, the NAR Prez offers scant details about an incident at a NAR launch. This time, an insurance payout was made to a farmer whose cattle "ended up expiring" from model rockets that "were not well-received." What the hell does that word...

I know the answer to this question is simulate, simulate, simulate. However, I will ask anyway, since I am a total noob at electronic staging. Is there a good rule of thumb for the length of the booster airframe or ratio of sustainer to booster? Just enough to fit your motor and recovery...

I think I know the answer to this, but I want to double check with other Raven users. I am planning my first electronically staged flight with a Raven 4 to control all the events. Output 4 will be the sustainer motor igniter. For extra safety, the igniter will have a switch. The end of my...

This app was mentioned on the Missileworks T3 product page and is fairly new (2021). I haven't seen it mentioned on the forum previously. GPS Connector It is a basic app that reads the NMEA data stream from the receiver unit into your Android device via BlueTooth. It prominently displays...

I am planning my first 2-stage HPR build and learning. I want to use a 4-channel Raven in the sustainer payload to control all the events: separation charge, sustainer motor ignition, sustainer drogue, sustainer main. When the sustainer drogue fires, the wires to the separation charge and...

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This is a pretty old reload. 29mm F52 Blue Thunder. The grain looks like it contracted over time, pinching the slot closed. In addition, the grain is also sloppy loose in the liner tube. Safe to fly as is, or does it need some remediation? I was thinking to at least wrap some tape around...

I have a couple baffles from Apogee, up to 66mm, for MPR. At first glance, I don't like the design - too many holes - and easy for hot particles to pass through. I may stuff a pot scrubber inside the baffle coupler for added protection, ala the Aerotech baffle, which works well. Any thoughts...

I may get permission to launch from a farm field. The property size looks suitable for Class 2 High Power Rockets. This site would be for personal launches with a few friends. Right now, another friend is the intermediary between me and the landowner, but we are trying to set up a...

I built this contraption over my Christmas vacation. I am not an electronics guy, so I spent several days researching previous posts and sourcing parts. Then, several more days of design, testing and construction. This project was a tremendous time suck, but it was fun and I learned a few...

Shown is the progression of primer>paint>clear I applied to a scrap piece of fiberglass airframe. All directions were followed and wait times observed. All was good until I applied the clear. Within seconds of a light second coat of the clear, the wrinkles formed. This is my first experience...

I would like to touch up my RocketPoxy fillets with Bondo, as others have mentioned - fill in depressions, pock marks, and get nicely sculpted fore and aft end points. What is the method? Do you pull another complete Bondo fillet with your radius tool, or just apply the Bondo where it is...

Garmin GPS units have a nice feature (called "Sight N Go") to sight in a bearing line, and then you can navigate yourself along that line. The Garmin will tell you how much you deviate from that line so you can correct yourself. This is very handy if you see the rocket land in a vast sea of...