NTP2
Well-Known Member
If I try and copy this in open rocket will it give accurate results or nonsense?
Ps I’m referring to the rotation on the fin section.
Ps I’m referring to the rotation on the fin section.
Openrocket question
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I doubt OR will SIM that correctly,, but a phantom fin set could be added, to adjust results.
Was that an "oops" or did you intentionally can't the fins? What is the angle? Are they all canted the same way (induced spind) or are 2 on one side opposite direction 2 on other side (offset spin, but cause "side slip" from trajectory)?
I'll look into the SIMs for various arrangements, and how predicted apogee changes.
Was that an "oops" or did you intentionally can't the fins? What is the angle? Are they all canted the same way (induced spind) or are 2 on one side opposite direction 2 on other side (offset spin, but cause "side slip" from trajectory)?
I'll look into the SIMs for various arrangements, and how predicted apogee changes.
For reasons not entirely clear to me, OR doesn't support canted tube fins. However, if you just enter them as regular tube fins, you should get a sim that's pretty close. The cant isn't that steep.
NTP2
Well-Known Member
It was a big oops!
Sorry to hear that, but we've all been there to some extent or another...(myself many times.)
My "gut feel" is it's not a big deal. With tube fins I think you still have plenty of stability, so no problem there... It will give the rocket some "spin" (or) "slip" depending on how many are angled, and in which directions relative to each other.
Just make sure you get a good bond as there must be some gaps along the contact points somewhere. A little extra glue will be good, but don't go crazy.
It will look worse to you, than anyone else. Out on the launch rail it won't be seen. And most people waking by will not notice, unless they stop and look close.
Because I was happy to just get straight tubes fixed!
It won't model the rotation caused by the cant; my guess, like others, is it won't be that big a deal unless you get some roll coupling going that causes coning.
NTP2
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Can you say that again? I’m completely lost.
NTP2
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Titan II
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boatgeek
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You’re looking at this all wrong. The canted fins won’t make a difference in performance (flat fins canted 10 degrees only shave a couple of percent off of altitude). You’re experimenting with canted tube fins since OR doesn’t handle that.
It’s not an error, it’s science!
NTP2
Well-Known Member
As programers say “it’s not a bug! It’s a feature!”You’re looking at this all wrong. The canted fins won’t make a difference in performance (flat fins canted 10 degrees only shave a couple of percent off of altitude). You’re experimenting with canted tube fins since OR doesn’t handle that.
It’s not an error, it’s science!
NTP2
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That was a little helpful, I found out what coning is still confused about roll coupling (it sounds like some sort of Bering)
boatgeek
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My (very limited) understanding is that roll coupling happens when an object starts off rotating about one axis and then due to the magic of 6-degree-of-freedom dynamics transitions into rotating about other axes. AFAIK, that's typically only an issue in hobby rocketry on either very high (say >50K feet) or very high performance (say >Mach 2-3) flights.
NTP2
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Well then I’ll ignore it then as a cyclotron is not what you’d call a performance rocket.
THANK YOU FOR ALL YOUR WORK. I know the Tubefins, were a hiccup when at the 11th hour it fell apart somewhere in the rewrite process a few versions ago.
IT SEEMS TO BE WORKING VERY WELL NOW. I'll be testing some of its limits this summer. (Hopefully)
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