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Yea, I think with the sub-mach stuff and good motor data, Rocksim does fine. Its Mach plus where it breaks down, largely due to the Datcom methodology imo. I noticed no diff in sims between v7 and v8 and even…   Read more»

Warren,When you get those files cleaned up, post them. We’d all be very grateful. That is one hell of a daunting task. Most would probably pay you for them. Sell them on the Internet. SpaceCAD uses the same .eng files…   Read more»

I paid for 7 and the upgrade to 8. I use 7 for most of my stuff because 8 seems to be over optimistic all around on sims. 7 seems to be right on vis a vis optimal weight simulation,…   Read more»

I actually use Rocksim V4.0, which is ancient. “Dance with who brung ‘ya”, as the old adage goes. V4.0 is the first/last version I’ve ever used….

I’m one of 40 circumstances. Two flights at Hartsel BB were dead on with RockSim. The first was projected to 1800′, actual was 1776. The second was 3000′, actual was 2980.Both flights were the first using an RRC2.kp

Pretty sure Apogee has been doing it all along. I can’t say anything about older versions, or reminisce about the good old days with building size computers less capable than my calculator ( ), but I love V8 (actually…   Read more»

SpaceCAD comes within two hundred feet for a 4k flight, which is 5%. You know, guys, I think the extra $50 bucks, compared to SpaceCAD’s $49+, for RockSIM is worth it. I’m sold. Both use the same eng.dat files, I…   Read more»

Yes – I’ve been amazed by rocksim before. My Black Brant at mile high mayhem was my closest to simmed yet – it got 5120′ out of a projected 5137. I can only hope it’s as accurate on my SSS…   Read more»

To clarify — I think Rocksim is dead on (in genera)l. That said, I think the G80 file, at least the OLD G80, is way, way, way, way off. The new one seems to be potentially even worse, and in…   Read more»

Yeah – I’ve had that feeling before As for mine – it looks great on the sims – way above what I ever expected for the contest – but we’ll have to see how close it actually comes to the…   Read more»

1.2 is great, Chris. You’re on your way. However, with all this talk, I picked my rocket up to take a look at it… and noticed I’d set it next to something that ate into the paint. This really isn’t…   Read more»

Actually I just did. It currently is hovering around 1.2 calibers (with noseweight), and the CG is pretty much central (the noseweight balances out the motor weight). As for mach – I break it, but not by much, 818mph is…   Read more»

Absolutely, J! I remember an IBM 360 that took up a house, and you had to punch the program on cards! But that was then… 🙂 I worked out Barrowman’s CP calc in Excel. Doesn’t agree with modern CP calculators…   Read more»

Now, John, if Chris wants to fly lighter than he seem right. ….In regard to weight, I’m just not getting good, sound results with SpaceCAD. I needed to add 2 oz. at one point, and that’s fine, but it has…   Read more»

Chris, I’d really like to see you win this. I’ve already blown, most likely, with two bad judgements that I can’t undo without starting over–and that’s not gonna happen, this year. I haven’t worked on altitude optimization since 1969, and…   Read more»

Mine is intentionally coming in as light as possible, and I will add weight with lead shot as needed. My thought is that I can always make it heavier if need be, but not lighter, so I will bump it…   Read more»

chris can certainly speak for himself as he’s a rocksim maven and knows where to find the optimal mass button.personally i like to distribute the weight as small fins and heavy nose may be statically stable but dynamically underdamped so…   Read more»

Now, John, if Chris wants to fly lighter than he should, he has every right to… You said something earlier about sims having undependable, not right, screwy, etc. engine data for the G80T. Even though I use something other…   Read more»

Ahh yes I have said and belive this my very self in several places and times. It comes down to trying to throw a feather or throw a rock for distance in essance. People forget alot abot the coast time…   Read more»

Cross section, i.e. diameter is very important — smaller is better (duh). That said, optimal mass is extremely important as well. I’ve been profoundly amazed at Rocksim and it’s ability to predict optimal mass — at least with White Lightning,…   Read more»