I'd like to respond to your question about buying more than you need in terms of motors and hardware, so you have extra if/when there is a backorder. As someone who flies both personally (both model and HPR) and competitively (TARC, Battle of the Rockets, and Nasa Student Launch), I think I've got a somewhat different perspective than a lot of the purely personal fliers. For a competition, we can't order motors 2 years in advance - we don't know what the rocket and payload requirements are going to be until that year! Furthermore, our funding often comes in on a per school year basis, and not until the beginning of said school year, at the earliest. That means the earliest we could even conceivably order motors is September (which I've always tried to do), and for a lot of those competitions, you have to be flying before winter break. That's not a lot of time to design, build, test, and fly a rocket, especially a complicated HPR project like Battle of the Rockets or Student Launch tend to be. After 6 years of flying TARC, even I could tell what the motor of choice was going to be as soon as the rules were released. If it was a two egg year, the F39 was going to be impossible to find come December or January. If it was one egg, the E28 was going to vanish (ok TBH I'm clueless on this new 3 egg thing they're doing this year!). For the other competitions, the motor requirements are a lot more varied, since it depends a lot more on the exact design of the rocket and payload, but again, we have to order at most 2-3 months in advance because of the structure of those competitions. I'm only going to briefly mention the logistical nightmare of trying to get a vendor approved to order from, so when our usual sources don't have motors, it can really put a lot of these teams in a bind. For example, last year, we had to switch from the I600 to the J500 for Battle of the Rockets, because both our rocket and payload ended up heavier than initially anticipated (the rocket was my fault - grossly underestimated the weight difference between a phenolic and paper motor mount tube, and the then necessary epoxy). However, by the time we figured this out, it was mid-January, and we had 3 months until competition. Of our approved vendors, only one of them had J500's in stock, and he only had one. We bought that one, and backordered 5 more. Those didn't arrive until this summer. Luckily, we were able to compete because I had one personally (one of my favorite J motors), and was able to order a couple more from a vendor we haven't been able to get on the approved vendor list yet (if you're reading this, thanks so much for the speedy delivery!) and just get reimbursed in kind when the backorder eventually came in. As a personal flier, yes, I can buy a motor a year or two years in advance of when I'm going to use it, or just wait the 6 months to fly that project I've spent the last year and a half working on. As a competitive flier, that's simply not an option, either in time or money.
