A quick review came up with several possible causes:
- You can't trust software. Possibly, but I've never seen a sim that far off.
- You can't trust RASP motor files. Also possible, but it seems OK based on my other F15-powered rockets and their associated sims.
- Poopy clay. You have to be on the rocketry forums to appreciate this term. The nozzle on the booster looked fine so scratch this one off.
- Cruddy rail. It was a bit rough, but it's hard to believe it was THAT bad.
- The rack bowed under thrust, causing the buttons of bind. And a cruddy rail might contribute to this one too. No real way to tell.
I have rebuilt the rocket with the following changes:
- I ditched the 4th F and the need for an uber long launch rail.
- In the interest of using a 4' 1/4" rod, I needed more thrust...thus the '2Ds' part of the name. I'm going to bond two D12's to the first booster.
- These boosters required that two of the rack supports be moved upward.
Here is the rocket with dry fit and used motors just to show what it will look like:
And, here is a close up of the butt end:
I really put some blood, sweat and tears into this rocket. Well, at least the blood part..
(I really need a better name for this one.)