Saturday, January 16, 2010

From the Archives

One of the best features from The Rocketry Planet is a large set of PDF documents from professional and hobby rocketry. The latest document is all about fins used on the Nike sounding rocket. (They are very strong.)

The Archives


The EGE said...

Way cool. I think the Nike has some of the most aesthetically pleasing fins in all of professional rocketry.

R2K said...

I agree that the fins are great looking, I love a thick diamond airfoil.

It is hard to realize just how strong real sounding rocket fins are, but the Stratospheric dreams rocket used modified fins from the Aerobee booster (cut down to size) and they were so strong! They had solid steel bar stock as the root anchor, and used some kind of asbestos phenolic. Each fin was strong enough to hold a cars worth of dynamic forces!

And you know, several major amateur projects failed due to weak fins, most notably a CSXT R rocket that hit the required velocity, about mach 5 at burnout, and then stripped the fins off the airframe. They were pretty solid, something like quarter inch aluminium at the base, but clearly that was not enough and there may have been max Q flutter or wind shear, or maybe even aerodynamic heating that resulted in weakness. (Clearly we have almost zero information on these early CSXT flights, compare that to the info and research done on pro. sounding rockets.)

Perhaps when it comes to fins, overbuilding a bit is a good call.