Using OpenRocket with Square or Triangular rockets?

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mcderek

Free Flight Rocketeer
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Has anybody used OPenRocket to simulate flights with square or triangular bodied rockets? Any thoughts on how to go about it? ie. A matching round rocket with the same frontal area with adjustment for increased drag from the for corners? Would there be increased drag due to the corners?

I have a large supply of surplus foamcore and would like to build rockets with it. Any previous links dealing with this? Thanks for any thoughts or ideas.
 
Cross section area is correct I think. I wouldn't worry about the corners, the flats ought to about balance out. Nobody usually calcs fillet drag anyhoo.
 
Has anybody used OPenRocket to simulate flights with square or triangular bodied rockets? Any thoughts on how to go about it? ie. A matching round rocket with the same frontal area with adjustment for increased drag from the for corners? Would there be increased drag due to the corners?

I have a large supply of surplus foamcore and would like to build rockets with it. Any previous links dealing with this? Thanks for any thoughts or ideas.

I was thinking about that very idea this weekend. Then I heard that they are no longer being produced.

The only way to simulate flat sided rockets is with fins... You would need to make the width of the fins the width of the rocket's side, your height would be the thickness of the material. OR is going to give you merry hell with the warnings (Thick fins are not supported). There's no way to do the graphics work on them with the current version of OR.

slab sided.jpg

Using a developer's version, I could create the look of the rockets, but the flight characteristics will be highly suspect.

The nosecone would have to be done much the same way. I could do it, but it's 4:21am, and I'm out of steam.


If anyone has one of those flat sided models (like the goblin) they don't need, I'd be interested in scoring it from you. I'm also looking for decals, instructions, and fins templates (with rulers for scale as appropriate).
 

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  • slab sided.ork
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I used equal cross section area for my 4" square rocket (https://www.rocketryforum.com/showt...don-A-square-rocket-that-doesn-t-quite-fit-in). For a little extra stability margin, I put the fins on the corners (further from centerline) but modeled them as if they were on the OD of the tube. A CFD analysis for stability and flight results are "pretty close". I wouldn't want to run it at 1.05 calibers of stability, but that wasn't an issue given the actual weights I had. OR file attached, but no decals or anything. I'm boring like that. :)

View attachment Dimetrodon Small.ork
 
Thanks for the files guys. I appreciate it! I have a design in mind and hope to build the prototype in the next couple of weeks. It will have a 29mm motor tube. The hope is to build a large level 3 capable Square-tube rocket in the future. One nice feature to a square body tube is the the fins can be extensions of the sides and made removable. Important for storage and transport.
 
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