PML Black Brant VB on an F40-4W RMS: This rocket flew it's second flight
yesterday afternoon on an F40-4W and pranged. For some reason the ejection
charge didn't fire until the rocket was only about 5 feet above the ground
coming straight down ballistically. The nose cone came off and the chute
made it out and unfolded enough to have the body tube cut half moons in two
of the panels. The piston was still inside the body tube. The only damage
appears to be a flexure dent in the body tube just below the upper launch
lug, and two small longitudinal cracks about two inches apart in the QT on
either side of the dent. The flexure was enough to pop off the upper launch
lug epoxy and all. The paint cracked a little on the fin fillets, but no
apparent damage to the fin joints which still feel solid. The rocket
apparently flexed then popped back to original shape. I used 30 minute
epoxy everywhere. My questions are the following:
1. Is there a way visually to tell if the delay element was a 4 or 7. The
package said 4, and it had the little maroon spacer.
2. Could too much masking tape on top of the RMS F40 fuel element have
caused late ignition of the delay charge? I was following AT instructions
to put a small amount of masking tape there so that the igniter stops at the
top of the fuel element and does not go all the way to the delay element.
What else may have caused a slower than normal delay?
3. Is my rocket safe to continue flying?
4. If not, what repairs should be done to restore this rocket to full
5. I assume I should epoxy on a new launch lug as the detached one already
has solid fillets around it and I would just be gluing a rounded epoxy
surface to the QT body tube?