Little John prototype fin flutter hypothesis

[SolarYellow]

My TLAR meter really likes the Little John prototype version fins, but I have a hypothesis about them. I haven't seen any good reason for the masses or strakes that are seen in some of the prototypes. They don't seem to serve any functional purpose such as lighting or instrumentation. The only thing I can think of is that they were trying mass dampers. My intuition and experience suggests the single mounting point at a pivot at the thickest point of the root would tend to promote flex in both torsion and bending. There are examples of LJ with what appear to be reinforcing pucks/doublers on either side of the pivot point on the fin. Attaching the fin at additional points closer to the leading and trailing edges would be far more efficient structurally than a significant amount of reinforcing of the central pivot point. But presumably, there was some functional reason that was not viable.

So anyway, my hypothesis is that the TE strakes were an experiment in mass damping and the root pivot doublers were an attempt at structural reinforcement, both to counter flutter. The second part of the hypothesis is that these and any other measures taken were ultimately unsuccessful, which led to the development of the deployed system with much smaller fins and the launcher that spun the airframe to ~200 rpm or whatever prior to launch.

Just wondering if anyone out there has more knowledge about the development program and in particular the details I mentioned above. I would be happy to learn more, whether it supports the hypothesis or not.

 

[PeterAlway]

If you mean what I think you mean by "TE strakes" I am going to guess that they are fairings for tracking flares that trailed behind the fins. I've seen a few rockets (Asp, Pogo Hi) that had tracking flares. It make sense that these might be useful for test flightes with the prototype design, but not needed for the operational missile. But this is also just a guess.