OpenRocket 3" vs 2.6" ???

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I suspect that you downloaded Madcow's rkt file and read it into free-ware OpenRocket. Do so at your own risk. OR conversion errors can occur.

As for the "raging mess", are you confirming the Madcow design files in native Rocksim or converting to OpenRocket?

When I first BAR'd last year, my mentor loaned me a laptop with RS on it. I learned RS. When he moved away, the laptop went with him. Since I didn't want to purchase RS, I went OR. EVERYTHING that I had made in RS converted to OR without a single translation error. The only things that didn't translate were the launch/flight data. Since OR doesn't support things like pods or tube fins the way that RS does, those never translate. While I have encountered SOME errors, they're few and far between.

When I've downloaded and opened files that have fin and centering ring thicknesses that are off (too thick or too thin), fin locations as much as an inch off, structural components not even represented but present in the kit, and nose cone weights WAY off....I stand by my comment. I get it, they're free, and not a part of their core business or business model. Caveat Emptor.

Other manufacturers that post RS or OR files have a better track record of more complete and more accurate representations of their kits, and I don't have translation errors that I would deem substantive.

I don't care if you're using their native RS/OR or translating them into OR/RS, I have found that the sims provided for free are a loose starting point, no better, and require close scrutiny, regardless of manufacturer. YMMV
 
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Agree. I loaded this particular Madcow DX3 rkt file into OR, and it looks like the translation occurred with no issues. WYSIWYG. The OP did a number of changes not included in Madcow's file.

I would like to trust the OEM's design file to include at least everything in the bag and in nominal position. That's the least they could do before posting the file. Looks like that doesn't happen. It would be great if the OEM also included mass override on every piece in the bag, since the material databases in RS and OR are far from exact. Any design file from an individual gets the stink eye from me. In either case, you are correct. All files need close scrutiny.

In most threads like these, responses are quick to suggest aerodynamic theory and optimum mass, but the answers are usually far more simple. That is why thrustcurve is a good starting point. There are only 4 or 5 inputs, and they are hard to screw up.
 
MadCow files are a raging mess. Often weights are WAY off (especially for the nose cones), centering ring thickness is often off, and parts fit and sometimes actual location is often off, too. I LOVE their rockets, but their sim files are no better than a good starting point. I've emailed them corrected ones for several that I've bought and built, but they've never been put up on the web pages.

There's correcting it somewhat in build for planning, but once you have the form factor correct, overriding the actual weight and CG gets things right.

If anyone wants to send me samples of some MC rockets, I'd be happy to do a .ork file for them. Trust me... They'd be a lot more accurate than most files you see out there.
 
Madcow has at least the half dozen or so that I did for my own rockets and then sent them. Several DX3 sizes, cowabunga, and fg tomach.
 
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I have seen a few RS files that were strange (mostly odd shock cords), the bit that I dislike is finding a cg over ride for the 'stage'.
Rex
 
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