you do this long enough and it's like a machinst can tell just by looking the different between .003 and .005 shim stock. Trained eyeballs. No argument here, buddy! Oth-you have to pay your dues and see a LOT of rockets. Sometimes-it's what's inside the counts (Hallmark Moment Reminder...) Just 'cuz it has fins don't mean it drives like a Cadillac. Old school, that is....Nobody makes an easy answer for you here. 3 fins can be as efficient as 4 depending in your build. When I design a model, I run it through my head if 4 outweighs 3, 5 or 8 fins. I just have to look at my design and make a decision. It has to look aesthetically appealing as well as stable. I'm a little gifted in that I can look at a design and know it's stable. OK, time for all you disbelievers to tap that note.
Next up for discussion ... is it an engine or a motor?
Also 4 fins are easier to align properly then 3 fins.
Nobody makes an easy answer for you here. 3 fins can be as efficient as 4 depending in your build. When I design a model, I run it through my head if 4 outweighs 3, 5 or 8 fins. I just have to look at my design and make a decision. It has to look aesthetically appealing as well as stable. I'm a little gifted in that I can look at a design and know it's stable. OK, time for all you disbelievers to tap that note.
I could not disagree with this any more.
I could not disagree with this any more.
I am building a large mpr so i have a very important question whats better 3 or 4 fins?
I have Open Rocket and my dad helped me to design the fins, so far I am leaning to build three fins. I am building my rocket with G - Cesseroni and I try also to build dual deployment. Any suggestions? I am trying to enter competition, so the hight, look (style) and the flight.
ok, how about 2 fins?
the cp changes dramatically (for the worse) with two fins.
is it possible to build a stable 2 fin rocket?
Read the Apogee Newsletter #220. Two finned rockets are dynamically unstable and will quickly cause the rocket to go unstable. Maybe curved fins will work?
Lots of nose weight and power will help with stability, as will opposed canted motors getting what I call some good "flame fin action." That combo will make an oddroc airplane rocket, basically a 2 finned rocket, fly like a 3 or 4FNC model rocket.
Why? I have always found aligning four fins to be easier to do then aligning three (but then again I don't use a jig -- I just eyeball them).
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