Wildman mongoose rocket fins

[Bender222]

I have noticed that many of the high performance 3fnc have a very similar fin shape (as seen with the mongoose,blackhawk, and shadowaero blackbird) I have done alot of research to try to find the reason for this shape and why it would be chosen over other shapes and I have been unable to ubderstand it. I read a piece in an apogee components book but it gave me no specific reason on why that shape would perform better than a swept parallelogram.

 

[jj94]

I think it's because that, now forgive me here because I have no clue if I'm right or wrong, the reduced angle of the leading edge proposes a more aerodynamic shape. It won't cause as much turbulence and drag as a trapezoid would, which conventionally stick out of a rocket. And cause it looks sleek and fast.

 

[blackjack2564]

Low drag, smoother mach transition, long root for more area to glue and fillet to the airframe. The later being extremely important on minimum diameter rockets.

Like high performance cars, sooner or later as form follows function.....they all begin to resemble one another.

 

[madmax]

I think part of the answer is avoiding landing damage. Sure a swept parallelogram may be better but with our reusable rockets it's much easier to break off a fin if they hang below the airframe. Patriot and Iris fins also probably work great but again more easily damaged then the slightly forward swept trailing edge of the style you described.

 

[Ethan]

I'm not 100% sure but I read somewhere that a swept delta fin shape produces less drag than the clipped delta but because of the highly swept shape the aft edges of the fins are prone to fin flutter.

Ethan

 

[hardinlw]

Low aspect ratio, highly tapered fins are less prone to flutter. This shape packs in a lot of area, hence stability, while keeping the risk of flutter down. A delta would work, but the tip really isn't doing much for you aerodynamically.

 

[dixontj93060]

Yes, it's flutter. Get yourself a copy of AeroFinSim and see for yourself. It is invaluable when you have Mach+ flights in the works.

Low aspect ratio, highly tapered fins are less prone to flutter.