Tube Fins in OR

I've been searching for a way to simulate tube fins on Openrocket. I thought Tube fins could be simulated by using 3x the number of tubes you want. i.e, for 6 tubes, I put 18 fins with the profile of the tube. Can anyone confirm this?

I think that is a overly complicated method.

I looked at this a fair amount with Rocksim before they came out with their ability to analyze tube fins. I would compute the surface area and mass of a fin tube. Work through figuring a fin with the same surface area, root length, and mass. Then make 6 of these fins. Should get you close- at least for subsonic.


Mark Koelsch
Sent from my iPhone using Rocketry Forum

I use this approach:

https://www.apogeerockets.com/RockSim/Simulating_tubes_fins_in_RockSim

wfcook said:

I use this approach:

https://www.apogeerockets.com/RockSim/Simulating_tubes_fins_in_RockSim

Click to expand...

I have read many posts saying that OR cannot simulate tube fins. This is the first time I have seen anyone propose this method for approximating the correct results.

Thank you for sharing, and thank you to Apogee and Bruce Levison for another well written and informative article.

Take the size tube you have and but that in as ( 4") sweep and angle as 0 foot and tip core and root cord as 4" hight 8" . You can look at my L3 project SIM and ari 's blue fin tube both 38mm and 75mm and his pipe tube fin but forgot the name of it

codysmith said:

I've been searching for a way to simulate tube fins on Openrocket. I thought Tube fins could be simulated by using 3x the number of tubes you want. i.e, for 6 tubes, I put 18 fins with the profile of the tube. Can anyone confirm this?

Click to expand...

That should work but really only as an approximation, however that should be good enough for launch sims.

Tube fin rockets are very stable in the wind and in calm air as well. They have a rearward center of pressure (usually somewhere down inside the fin can) which allows for a stubby rocket. On the other hand, they cna handle longer body lengths as well. Take a look at Ari's two threads for his "Bluetube Fin" rockets.