Okay, please tell me if I am on track, here.
My Radial Flyer's burnout weight with an M1101 is 10.5#. The max acceleration simmed is 17.8G. Taking a worst case scenario, the maximum separation force on the rocket would be F = MA, or 186.9.
I have a ton of #2-56 nylon screws already, and would prefer to use them. These screws have a shear strength of 30 - 45. If I assume the worst case 30, then 186.9 / 30 = 6.23, meaning I would need roughly six #2-56 pins. In the best case, it comes to 186.9 / 45 = 4.15.
So I am looking at anywhere from four to six #2-56 screws. Am I right so far?
Now, here is another question. My RW X-Celerator has a burnout weight of 13.6 on a J1520. It pulls a max of 25.3G. That gives me an F of 343.1. 343.1 / 45 (best case) is 7.6 shear pins. But I have never used more than two, and never gotten early separation. Since this is a VMAX, that means that I pass through the heaviest G forces during motor burn, and by the time of burnout, the G Force is very low.
So if we say ~40 per #2-56 pin, at two pins, I have 80# of shear strength. Since mass is constant at 13.6, then my G force after burnout must really be about 5.9. Right?
And with that in mind, how many pins do I really need for my Radial Flyer? The M1101W is a longer burn-time motor, so I need to look at my simulations and see what the actual maximum acceleration is after burnout, then use that as my A factor to get the real number of pins.
Make sense?
My Radial Flyer's burnout weight with an M1101 is 10.5#. The max acceleration simmed is 17.8G. Taking a worst case scenario, the maximum separation force on the rocket would be F = MA, or 186.9.
I have a ton of #2-56 nylon screws already, and would prefer to use them. These screws have a shear strength of 30 - 45. If I assume the worst case 30, then 186.9 / 30 = 6.23, meaning I would need roughly six #2-56 pins. In the best case, it comes to 186.9 / 45 = 4.15.
So I am looking at anywhere from four to six #2-56 screws. Am I right so far?
Now, here is another question. My RW X-Celerator has a burnout weight of 13.6 on a J1520. It pulls a max of 25.3G. That gives me an F of 343.1. 343.1 / 45 (best case) is 7.6 shear pins. But I have never used more than two, and never gotten early separation. Since this is a VMAX, that means that I pass through the heaviest G forces during motor burn, and by the time of burnout, the G Force is very low.
So if we say ~40 per #2-56 pin, at two pins, I have 80# of shear strength. Since mass is constant at 13.6, then my G force after burnout must really be about 5.9. Right?
And with that in mind, how many pins do I really need for my Radial Flyer? The M1101W is a longer burn-time motor, so I need to look at my simulations and see what the actual maximum acceleration is after burnout, then use that as my A factor to get the real number of pins.
Make sense?