Model Forum / General / Rockets / September 2005

I consider the fincan the "rocket".  Replace that, and it's a new bird.

What if it were a car? If you replaced a just 1 fender, a door, the
windshield, a rim, etc. is it the same car?

Maybe it comes down to a percentage. Some of it is, some of it isn't. It's a
little of both.

Randy
www.vernarockets.com

What I do, just for my own preference, is say that it's the same rocket
if I replace less than 50% of the original weight. On most rockets, the
fin can/motor mount is usually close to 50% of the weight of the rocket.
Bottom line, it's your rocket, call it what you want.

I look at it this way -

("I hold in my hand George Washington's hatchet.  Well, the handle
cracked a few years ago so I had to replace it.  Then the head got very
rusted, so I replaced it, too.  But it occupies the same space.")

Isn't it the same with rockets?

I guess thats why I modularize my rockets back home... I built a fincan, put
a couplar there, then a tube, then payload (if any) then nosecone. That way
if the thing should zipper, I can replace the tube without having to cut it
or anything. Plus I could like mix and match and get all kinds of crazy
configs (and color schemes)

There is a theory regarding the transmigration of rocket sould, so that
by preserving a component of the original rocket, its essence will be
present in the rebuilt rocket.  The components are but a shell, a
vessel for the essence of the rocket.

If you believe that, I have some prime real estate in southern
Louisiana for sale.

Bill Sullivan

"For every complex problem there is an answer that is clear, simple,
and wrong."
H. L. Mencken

To me, it would depend on the extent of repairs at each stage, and
whether or not the rocket still maintains any original parts.

If you've replaced everything, it's not the original rocket anymore.

If you replace more than 50% at one time, it's not the original rocket
anymore.

-Kevin

Absolutely. It is a rocket with _history_.  Rocket WhatsItsName with n
flights and x, y, and z repairs. As long as it is less than 100% per repair,
and a flight is executed, then the new parts are as integral as the former
and are permanent proxy.

What about a rocket that has interchangeable fin cans based on payload?

What about a rocket with changeable motor mount?

What about removeable fins?

Rockets have no permanent "skeleton" per se. They are rather a system of
parts making up a whole, each with a different task.

I have a rocket (an Estes ARV) that does not use a fin can. It instead has
twin gliders that act as fins until separation at apogee. I have replaced
just about everthing on one glider or the other due to happy young fingers
breaking them when they to go to retrieve them or throw them around, or one
glider goes missing. I have had to repair both body tubes and all glider
mount points. I have upgraded the mount points so they do not break as often
(they actually have not broke since). But it is still the same rocket, and
is always the highlight of any launch with young people.

For these and other reasons, I feel that rockets are more like a company:
employees come and go, owners, shareholders, or CEO may change, locations an
equipment may change, but it is the same company, with _history_.

For those who are more into the "science" of rocketry, it may feel
appropriate to add a letter or designator, but for me it is still just
_history_; the extra designator doesn't add anything with out the knowledge
of the history that designator represents.

~ Duane Phillips.