Funny you should bring this up. I was just looking around for some stuff for some projects I'm working on for this year. I don't believe, but could be wrong, that's it's not necessarily, just a long motor issue. It is for "high" mach flights. What's high mach? I'm not sure. I've posted the following a few times. Over the years I've seen a bunch of high altitude record attempts. Not all of them go as planned. Usuallly it's a rocket where the fins spans are one caliber and the rockets have around one caliber of stability. Sometimes these rockets work. Most of the times they don't. I call these types of rockets glass slippers. It does not take much for then to "break". For a few years now, I've flying min dia rockets I refer to as AeroPac Sport Flyers. They're not going to break many records. The design is pretty simple, Fin spans of 1.1 calibers and staic margins of 2.5 or more. 3(?) years ago I had a flight mishap where I lost one side of the exit cone on my nozzle. Most rockets would have been toast once this happens. Mine was able to "recover" and still flew to 24K (?). Sorry for all the ?, but I'm on a new laptop and don't have all my notes.
One of the threads I was rereading tonight was on this subject starts here https://www.rocketryforum.com/showt...ion-98mm-Minimum-Diameter&p=574080#post574080
In my mind I sort of think it of it like.....searching for words...two force (that work against each other) that get a running start and take some time to stop the momentum. (I'm not sure if it's the right way to think of) and your rocket needs to have enough stability built in to over come these two (additional) forces.
As for the TRF search: try typing in your search in front of the following site:https://www.rocketryforum.com
such as glass slipper site:https://www.rocketryforum.com
works pretty good
Hopefully this was helpful.