Estes Pro Series II E2X Mammoth motor selection

Hello,

Someone showed up at our club launch on Saturday with a Mammoth and a pack of F15-8 motors.

I told him that it would be very bad to launch it with that long of a delay time - that it probably would not hit the ground, but that it would arc over at apogee and continue to coast and build up speed for several seconds before ejecting and probably damaging the rocket.

I sold him a pack of F15-4 motors.

He launched it twice. There was very little wind. the 6 foot long steel rod was angled about 5 degrees and the rocket flew virtually straight up. Ejection was at apogee, just as the rocket was arcing over.

Using an F15-8 would be a bad idea. Even if the booster was added with an F15-0 in the first stage, i would use no longer of a delay than an F15-6 in the upper stage as it is very heavy and will not coast for 8 seconds.

https://www.estesrockets.com/rocket...e2x-kits/009708-pro-series-iitm-e2x-mammothtm

Anyone else flown theirs with the F15-6 or F15-8 and/or the booster stage.

By the way, the F15-4 flight was exquisite.

I've launched mine twice on F15-6 (single stage). First flight, I was a bit skeptical of Estes' recommendation of the F15-6 for the first flight motor, but I decided to go with it. The flight was perfect. Ejection was near apogee, maybe a hair past, but not much. Second flight was at NARAM, again with the F15-6, and was also perfect.

So, what do you feel the results would have been if you used the F15-8?

jbuscaglia said:

I've launched mine twice on F15-6 (single stage). First flight, I was a bit skeptical of Estes' recommendation of the F15-6 for the first flight motor, but I decided to go with it. The flight was perfect. Ejection was near apogee, maybe a hair past, but not much. Second flight was at NARAM, again with the F15-6, and was also perfect.

Click to expand...

shreadvector said:

So, what do you feel the results would have been if you used the F15-8?

Click to expand...

Probably would have been a safe recovery, but I'm not sure I'd do it, especially given how well it performed on the F15-6. I don't think it would have been moving so fast it would have shredded the nylon chute, but a potential for a zipper. I built mine with mid-body separation and ditched the plastic shock cord anchor. I'm pretty sure I replaced the stock shock cord with a longer 1/4" elastic one as well, so my mileage probably does vary.