My time to get slammed.....
just do your sim. I've never swing tested anything, nor am I ever going to.
Far from a slam, but, well, a partial disagreement!
First of all: LPR kits are designed to fly with the motors they state. I'm pretty certain I'm not smarter then Estes, so I'm just gonna build and fly it.
Second;y: I've RSO'd probably hundreds if not thousands of rockets If I identify the kit, I'm certainly NOT going to ask you for CP and CG. That's not just low power, either. Wander up to me with a Quark, Wildman JR, Super DX3. I already know it's ok as long as it's stock-built. I bet most other RSO's are the same (but I"m sure the exceptions to the rule will point out the error of my statement.)
Thirdly: I don't know everyone, and if I don't know you and you wander up talking about swing tests, it will just cross my eyes. If I don't know you, I have no idea you can either do the test corretly and/or are able to correctly interpret the test while you do it
I agree with the above statements 100%.
Unless the kit is pretty heavily modified, she's gonna fly safely. Aside from a rather large set of fins glued to the nosecone, most kits have a safety margin that will cover a multitude of sins, intentional or otherwise.
To the third point, there is some nuance involved in conducting a proper swing test. Failure to understand these things can cause "false readings", but the failure mode is almost always to indicate instability in what is actually a stable rocket rather than vice versa.
The old Estes technical report on stability outlines the proper methods to achieve accurate results. Here is a link to it on
Ninfinger's site.
Fourth: It's 2022 not 1970. Most computers can do 150-200 million operations per second. that's way fast enough to run these amazing computer programs with way more precision then my eyes have. Why regress to the tests of our grandparents? Do you communicate with telegraphs? Move into this century, it's way more accurate. If you're really worried about it, skip directly to the front of the line, RS-Pro, with it's 6 degrees of freedom analysis.....or go to the middle, Rocksim, open rocket or RS Aero.....
This is where we differ a wee bit...
You know, I have never been one to toss out old tools just because something newer or better comes along. I have a Dremel and an even smaller micro drill/rotary tool thing, but I also still have an old hand drill and a pin vise in my collection. Sometimes the finesse achievable with the hand drill or pin vise is much more appropriate to the task at hand.
I like to sim everything I can, and I find it to be a modern miracle compared to the old days of longhand Barrowman equations, but a lot of my builds involve odd shapes and configurations that are beyond the capabilities of most sim programs to model accurately, and sim programs that will model them are beyond the capabilities of my wallet. Time to break out the hand drill...
Things like the one in the pic below are fairly easy to swing test and, provided the test is done properly, will provide a reasonable expectation of a safe flight. I couldn't begin to build a sim model of this in either RO or RS...
Now, where'd I put that roll of string???
As much as I like my truck, some jobs just require a horse!
Mike