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Reverse sweep fins

Does it really matter if fins are swept forward or back? After looking at the pix of the CSXT booster and seeing the reverse sweep fins I've been wondering if there was any technical reason for the shape. Or was it just cosmetic? Since the thing went supersonic I guess the shape could be an aerodynamic aid of some kind. But the fin tip seems to be the least supported part of the structure and a little vibration would be a very big problem at those speeds. Anyone care to clear up this point? Some of my toys are going to go mach+ "soon" and it'd be good to know this stuff towards that time.

Chuck

Reply to
Zathras of the Great Machine
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The CSXT booster didn't have reverse swept fins. I expect you have seen post recovery pictures, such as this one:

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the fin can has become displaced, and is now at the forward end of the booster. Compare with this pre-flight picture:
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Reply to
Darren J Longhorn

The CSTX booster fins were NOT swept forward. They look like that in the recovery photos because the booster impacted terra firma at a velocity sufficient to break all the fin can mounting bolts and allow the fins to move forward. They are on the wrong end of the booster tube.

Reply to
Bill Richardson

That's one hell of a displacement!. Well, at least that solves another problem when seeing the post recovery pic, I thought the memory was going (it is, but at least on this occassion I'm ok)

Chuck

Reply to
Zathras of the Great Machine

Reply to
Zathras of the Great Machine

Just wondering, but was the bodt tubing also the motor casing?

Reply to
Niall Oswald

Good analogy.

It's not the fall that kills you, it's that sudden stop!

Reply to
Jerry Irvine

I read a bit about forward swept fins here:

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Don't know how valid the physics is, but it sure is cool looking.

I've got one of these on its way to me:

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Reply to
Init 6

I haven't seen pics of the CSXT booster, but I use forward-sweeps on my fins. The big difference you'll find is that it moves the CP forward more than you'd expect. :-) The tips also tend to need more reinforcement - being at the 'front' of the airflow, they're more subject to flutter than reverse-swept fins. To help stiffen the tips, I've taken to reinforcing with kevlar - as well as multiple layers of fiberglass.

It's probably not something I'd want to take beyond Mach speeds, but I *have* had comments on how cool they look. :-)

Reply to
Len Lekx

We believe the parachute became detached in the lower atmosphere after re-entry.

The forward three feet of the booster were crushed in the impact. The body was definitely damaged. We had to double-check the structural integrity of the remainder of the booster as we put it on my truck at the impact site before driving it out. We had to traverse muddy dirt roads for about 90 minutes in the dark before we reached pavement, so the booster had to be firmly attached!

The folks who built the rocket (CSXT) estimated from the damage that its impact was at a high subsonic speed.

Some people have been posting links to images on the Stratofox site. But you can see the whole story of the recovery for yourself at

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Reply to
Ian Kluft

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