PRO-38

[Chris LaPanse]

That was a relatively quick and dirty sim.

It may be a bit on the high side, as it is claiming 8300 for K550. The 660 is quite a bit bigger, so I have no doubt it’ll go >2 miles, 13k might be a bit optimistic…

How heavy is the fiberglass one – I could make the sim quite a bit more accurate with a good weight…

[Bruce R. Schaefer]

How heavy is the fiberglass one – I could make the sim quite a bit more accurate with a good weight…

Don’t know, my SpaceCAD hit the dirt after Microsoft threw in an XP update. I hate it when they do that! I lose my sound card and other things go splat…
RockSim gives options on airframe materials, doesn’t it? SpaceCAD has more than I’ve ever seen used. It has G-10 and spiral wound fiberglass, a big difference in weight. I’ve been trying to get SpaceCAD up and running, with the help of the author, for over a week. I need to work on my L3, and it’s driving me nuts… or nuts-er. 🙂 And, you’re right about the altitude being greater since it’s heavier a bit with SW FBG. At LEAST, 10K, if not more. 8)

[Chris LaPanse]

Yeah it has material options, but to get an accurate weight that way, I have to know things like wall thickness, and I have to sim EVERYTHING. It’s a heck of a lot easier to just get the shape right and do a mass override if all you need is a fast sim.

[Bruce R. Schaefer]

Yeah it has material options, but to get an accurate weight that way, I have to know things like wall thickness, and I have to sim EVERYTHING. It’s a heck of a lot easier to just get the shape right and do a mass override if all you need is a fast sim.

Chris, if it’s the same as the Thunderbolt 38, and I bet it is, it’s 1/16″.

[Chris LaPanse]

OK – I’ll try to put together a more accurate sim in a couple minutes then.

[Chris LaPanse]

Interesting – it must be really close to the optimal mass for the K660…

It is now saying 7350 for the K550 in an updated sim, at just shy of mach, but the K660 still gets 13100. A bit slower, at 810mph, but what it lacks in speed it makes up for in extra coast time…

Basically, with the shape I have, any mass from 2 to 12 pounds keeps it well over 12k, and any mass between 5 and 11 pounds keeps it at 13k or higher. Optimal mass appears to be about 8 pounds even without motor (14061 feet, 860mph).

So, it looks like it should be right in the 13k zone, assuming a smooth finish and a straight flight…

Oh – and an L730 sims right at 15K and 900mph

The Cd of the rocket sims quite low, with a smooth finish. Rocksim says about 0.4 for subsonic, 0.75 transonic, and right at 0.7 supersonic (~M1.75 and up).

[Bruce R. Schaefer]

Only time and a flight will tell, Chris. There’s a really good guy, who I certed L2 earlier this year, Jason C., who shot his VA on a K660, I believe, and lost it ath their new launch site in Pueblo, no events heard or seen… I hope he foiund it, but if the altitude is what you say… who knows? Good job! Hope Jason finds his VA! I love that GLR rocket, and I WILL get in in FBG sometime next year.

[Jason Chamberlin]

I launched my VA on a PRO 54 K530SS. It was an amazing boost but I have not yet found the rocket. I may have to look into that fiberglass VA, that is after I get a tracking system.

[Chris LaPanse]

Only time and a flight will tell, Chris. There’s a really good guy, who I certed L2 earlier this year, Jason C., who shot his VA on a K660, I believe, and lost it ath their new launch site in Pueblo, no events heard or seen… I hope he foiund it, but if the altitude is what you say… who knows? Good job! Hope Jason finds his VA! I love that GLR rocket, and I WILL get in in FBG sometime next year.

We’ll have to see…

I’m looking forward to seeing the flight, that’s for sure.

Oh – and that K530SS should be a pretty nice motor. I’ll be using two of them in my Deuce at MHM, so we’ll see how they perform. With any luck, it’ll break 3k this time 😆 🙄

[Anonymous]

8) As a side note, I have picked up an all glass Vertical Assault that I am going to fly at MHM on an Pro 54 K660. This is a showstopper load. A full K at 2437ns. with a 3.7 burn time. (It makes a max. 245lb. thrust.) I saw one launched over in Utah. What a motor!! I will add tracking, should get way up there. Bruce, what does your simm say? 8)

Hey Tim, I was going to fly that load at MHM as well. Drag race? 😆

[Author]

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