Rocsim Tubes and Fins

I'm just getting started but am stuck.

I have attached a very basic, design in progress and cannot get what I need.

Right now I have the NC, the BT and an inner tube along with three centering rings.

First problem: The Inner Stop CR (forwardmost) is "owned" by the BT20 tube. It should be owned by the BT5 inner tube but it seems like that is not an option unless I want it to fit inside the BT5. Is that correct?

Second problem: I want to put a second BT20 around the after end of the BT5. RS will not let me. I have tried doing this as a "ring fin" but apparently, inner tubes are not allowed to have fins.

Third problem: related to 2nd, I want to add fins to the BT5. RS will not allow.

To make sense of this, what is shown is a piston in the extended position. When the ejection charge goes off, it should blow the piston back to where it is shown. The BT5 is not yet trimmed to length. That length will be determined by where the CG ends up.

Where am I going wrong?

View attachment Mini Magnus.rkt

I think you are running into the same problem I posted on yesterday. The BT5 is an inner tube for part of its length but is just a plain body tube where exposed. Rocksim doesn't seem to be designed to deal with the tube having two functions (inner tube and body tube). Inner tubes can't have fins.

The solution I found yesterday is to break the BT5 up into two parts (from a logical perspective in Rocksim, not actually cutting your tubes!). The part that is actually inside the other tube should be an inner tube of appropriate length. The part that is actually outside becomes its own separate length part as a Body Tube part. Just make sure the two lengths together add up to the ACTUAL PHYSICAL length of the tube.

I've been able to own CRs that are bigger than the owning part... not sure what's up there, but I'm in a rush so hopefully someone else can solve that part. Good luck and please post your eventual resolution.

Marc

PS: I'm a novice hack at Rocksim, there may be a better way to do the inner tube / body tube thing, but I haven't found it. See my staggered tubes thread.

John, did you ever sort this out?

I apologize. I did see this but it was at work and I didn't have time to respond.

I understand your solution but have not tried it yet. I've gotten bogged down in other matters.

I am VERY new to Rocsim. I am in my 2nd week. I have reluctantly come to the conclusion that it will not handle the cases in which I have the most interest. I still like it but it doesn't seem like it will be as "useful" as I had hoped.

Here's a potential solution, assuming I understood your criteria. The only real trick was with the fins. They're still parented to the outer body tube but the location is adjusted way past the end.

Doug

View attachment Mini Magnus2.rkt

Centerng rings are owned by the outside tube. Often you can cut and paste parts to be children of others. Fair warning. SAVE your work often. Copying, cutting, and deleting parts is the easiest way to crash rocksim. Save early and often

duckhead said:

Here's a potential solution, assuming I understood your criteria. The only real trick was with the fins. They're still parented to the outer body tube but the location is adjusted way past the end.

Doug

Click to expand...

Thanks for the contribution. I hope to take a look at it when I get home from work tonight. Things have been so busy that I haven't been checking in too often or thoroughly.

gdjsky01 said:

Centerng rings are owned by the outside tube. Often you can cut and paste parts to be children of others. Fair warning. SAVE your work often. Copying, cutting, and deleting parts is the easiest way to crash rocksim. Save early and often

Click to expand...

Thanks for the info and advice.

The advice is something I have taken to heart ever since I typed my master's thesis a total of 5 times after getting 90% through each time.

Saving and backing up is now a part of life.