Domed disk on side of body tube

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Amanwhocan

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Hi There, does anyone know an easy way to add round fins/ body item, to a body tube in rocksim? - similar the Starship enterprise - a domed circle?
I don't want to create tube fins - like I did on the DINGLE, or internally as I did in the Bomb, I want to create a circular disk sitting on top of the body tube - at 90 degrees to it - not running alongside. Similar to the main disk on the Starship Enterprise. Should not have called them fins - a lump on the body!
I am not asking anyone to do all the work for me - just to point me in the right direction of how to get started on creating this item?

best regards

Kev
 

jqavins

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I'm not sure I get what you're asking for. I think you're after a disc at the top of the rocket, aligned so that the rocket's long axis is a diameter; is that right? If so, you can use fins.

First, add a fake body tube either above or inside the real one, with a trivial diameter, like 0.001" I.D. and 0.002" O.D. Then attach a fin set to the fake tube, 2 fins, elliptical, span equal to half the root, and thickness whatever you wish.

As I first started reading your question, I thought you were looking for something more like "dalek bumps" on the side of the body tube. Since you mentioned the Enterprise's primary hull I first thought you meant the bump where the bridge is, but I surmise that was wrong. If I was right to begin with and that is what you want, I'm afraid I can't help, and I'm 95% sure you can't do it.

If It's something else you're after that I haven't guessed, please post a sketch.
 

K'Tesh

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Perhaps a drawing of what you are thinking of would help us wrap our heads around what you have in mind.

Based on what you've written, the only way I can think of to do that would be to use one of the developer's versions of OR, or doing a lot of serious playing with phantom body tubes (https://www.rocketryforum.com/threads/offset-wings-fins-in-openrocket.138593/).

1592245157240.png


That said, I'd predict a 0% chance that OR would give flight performance data. It would be very difficult to create a true dome, but with enough layers you might be able to get the shape to appear. Here's another sim that might help you warp (<-Pun Intended) your brain around it.(https://www.rocketryforum.com/threads/kteshs-openrocket-files.123564/page-17#post-1942850).

1592245390354.png
 
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K'Tesh

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Oh my Figure of Speech, how did you do that?!
I did it much like you'd make a diamond... Time and pressure. It takes a lot of time and pressure to force OR to give you a diamond, and not a lump of coal.
 

TSMILLER

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I did it much like you'd make a diamond... Time and pressure. It takes a lot of time and pressure to force OR to give you a diamond, and not a lump of coal.
I admire your prowess with OR. I’ve dabbled with it trying to design my RIM 162. I get frustrated and walk away for a bit. The last time I just decided it would be easier to do a mock up and go from there.
 

jqavins

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I’ve dabbled with it trying to design my RIM 162...
1592398264608.png

This doesn't look hard, just tedious. In RS (and I assume it's be similar in OR) the complex strakes would be built up from five fin sets, each with different shapes and progressive offset angles so they touch. The other circled bit would also be a fin, but a rather thick one. There also appear to be tiny canards. So, in total, that's eight fin sets. Like I said, tedious but not hard.
 

TSMILLER

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View attachment 420779
This doesn't look hard, just tedious. In RS (and I assume it's be similar in OR) the complex strakes would be built up from five fin sets, each with different shapes and progressive offset angles so they touch. The other circled bit would also be a fin, but a rather thick one. There also appear to be tiny canards. So, in total, that's eight fin sets. Like I said, tedious but not hard.
Yes, that was the way I was getting it done. Getting those angles right seemed to be where I kept messing up.
Also that this seems to be pretty "complex" to most "4 fins and a tube" and I am also a complete noob to OR and have not even opened the trial version of RocSim.
Eventually, I will get it done.
 

Nytrunner

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The more overlapping and stepped fins you try and place on a rocket on OR, the less accurate the simulated performance will be.

You may want two copies of the file:
-One with all the aesthetic details
-One with only the relevant surfaces for simulation
 

jqavins

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I was thinking too about the loss of accuracy. But the total area of those strakes is so small that I bet they could safely be ignored altogether, so if they're somewhat inaccurate is shouldn't matter (much).
 

neil_w

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I was thinking too about the loss of accuracy. But the total area of those strakes is so small that I bet they could safely be ignored altogether, so if they're somewhat inaccurate is shouldn't matter (much).
They're small but then so are the fins, so I wouldn't ignore them. I'd include a single fin in the middle of the strakes, just representing the tallest part, for sim purposes.
 

K'Tesh

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View attachment 420779
This doesn't look hard, just tedious. In RS (and I assume it's be similar in OR) the complex strakes would be built up from five fin sets, each with different shapes and progressive offset angles so they touch. The other circled bit would also be a fin, but a rather thick one. There also appear to be tiny canards. So, in total, that's eight fin sets. Like I said, tedious but not hard.
Here's the problem that I can see, at least with OR 15.03, and not one of the developer's versions with pods, if you're trying to create a wedge with a sharp edge... OR limits canting of fins to 15 degrees. With pods it could be done, but there is a question about the ability of OR to properly model it for flight characteristics.
 
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