Wing tips on fins in RockSim

[stealth6]

I'm trying to figure out how to do something in RockSim that I'm not sure is possible.

Basically I'm trying to add small wingtips onto some fins. The problem is that the tip chord of these fins are not parallel to the centerline of the rocket. It seems that I can add a pod to the tip of the tip chord of the fin, but only if that chord is in line with the body tube. Is this correct? Anyone know a way around this?

And yes, I understand that I will be adding a fair amount of drag - this is about style, not performance.

thanks in advance for any help, s6

 

[GrossApproximator]

Maybe just make your fin really thick and override the component's mass. The sim wouldn't perform exactly like the real thing, but it might be good enough.

 

[brianc]

This Peak of Flight newsletter may help
https://www.apogeerockets.com/education/downloads/Newsletter232.pdf

Winglets are simply 90 degree polyhedral wings, right?

 

[stealth6]

This Peak of Flight newsletter may help
https://www.apogeerockets.com/education/downloads/Newsletter232.pdf

Winglets are simply 90 degree polyhedral wings, right?

I thought this might be the ticket at first - but nope. I actually already know how to do what's shown in this article, and that's not quite what I'm after. That is an example of how to use fins that aren't perpendicular to the centerline - what I want is a pod that's not parallel.

However, the picture of the Lexxjet on the cover of that issue might help to illustrate what I'm trying to do. That rocket has wingtips similiar to what I want. However, that's easy to do because the tip chords (the outer edge) of those wings are parallel with the centerline of the rocket. (this is also true about the winglet on top of the tailfin). What I want to do is to have THAT edge be angled, and to attach my pod to it.

Another way to explain it maybe is that I want to add canted pods.

Again, I suspect RockSim will not allow me to do this. But I'm hoping that someone knows how to do it who will prove me wrong.

thanks, s6

 

[Pat_B]

I don't think RS can do that unless there is some complex work around.

I mentored a TARC team who built their rocket at the max weight for TARC and needed to find a way to lower the altitude. I had them glue popsicle sticks on top of the leading edge of their fins to increase the drag. I had instruct them to make the fins thicker in order to simulate the frontal section of the sticks.

I had called Apogee and talked to Michelle who talked to Tim in the background and he recommend using the pod feature. But I noticed, like you, that it appears that pods have to be parallel to the body tube.

 

[SteveA]

Are you trying to achieve an arrangement similar to Squirrel Works' JX rocket? If so, I hope that you can find a solution to this because I have wanted to design something along a similar line, but only bigger. I've also wanted to design a fin that curves similar to those you would see in the old 50s and 60s sci-fi book covers. I'm following this with great interest.

Steve

 

[stealth6]

Are you trying to achieve an arrangement similar to Squirrel Works' JX rocket? If so, I hope that you can find a solution to this because I have wanted to design something along a similar line, but only bigger. I've also wanted to design a fin that curves similar to those you would see in the old 50s and 60s sci-fi book covers. I'm following this with great interest.

Steve

That's not really what I'm after.

That said, reproducing something like that in RockSim would be pretty straightforward. The tubes in the fins (and consequently the outer tip of the fins) could simply be done as pods. And although you can't REALLY do curved edges to your fins in RockSim, you can simply add enough points (when doing full custom fins) to make a close enough simulation.

s6

 

[SteveA]

Oh, Hmmm, well, It was shot.

I'll give the extra points a shot. I kinda wondered if that wasn't what you would need to do, but I was wanting to see if there was a more direct method. Thanks for your input though!

Steve

 

[Rex R]

one could do it the easy way(curved fins) by importing from image(freeform fins/shape), then scale them to the right size. nice to be able to draw a shape with your fav tool then import it. thanks folks.
rex

 

[SMR]

Are you just trying to add winglets to fins, Jayhawk style, but with the fin tip not being parallel to the body? if so, have you tried making your fin in two parts? i.e., do a fin with a straight tip chord, parallel to the body, add the pod, add your winglets to that, and then add the curved tip of the original fin to the pod? This should work, as long as you intend the winglets to be edge-on into the airstream as the rocket ascends.

However, if you wanted the winglets to have an angle-of-attack, the pod does have to be canted and I have no idea if that is possible or not. Looking forward to your progress. Good luck.

 

[stealth6]

one could do it the easy way(curved fins) by importing from image(freeform fins/shape), then scale them to the right size. nice to be able to draw a shape with your fav tool then import it. thanks folks.
rex

This is not pertaining to the original question - but I'm intrigued anyway. Not sure how exactly to do this - can you explain a bit more? Thanks!

However, if you wanted the winglets to have an angle-of-attack, the pod does have to be canted and I have no idea if that is possible or not. Looking forward to your progress. Good luck.

Yep, this is exactly what I'm trying to achieve. But I fear it's not actually possible.

s6