🚀 go-pugleaf

In article <YfEm2I600WB24DpYEj@andrew.cmu.edu> lc2b+@andrew.cmu.edu (Lawrence Curcio) writes:
>1) Why is the tank so blunt? Isn't the shuttle a super-sonic vehicle?
>Shouldn't this be sharper, say one of theose secant ogive numbers?

These things are complex compromises.  A more pointed shape would have
lower drag, but also would be heavier for the same internal volume...
and the shuttle does most of its accelerating at extremely high altitude,
where air drag is negligible and weight is all-important.

>2) Why is the tank so rough? Not only is the texture less than smooth,
>but there are a number of grooves near the front as well.

The surface is relatively smooth, but surface smoothness doesn't matter
that much on such a large object, which will inevitably have a turbulent
boundary layer over most of its length anyway.  The grooves you see near
the front are actually ridges, external reinforcements for the intertank
ring; they add some drag but moving them inside or doing without would
add weight.

>3) The struts that hold the shuttle to the tank are apparently naked
>cylenders. Shouldn't these be streamlined in some way?

They're in pretty turbulent air anyway, and it doesn't matter that much.
Again, streamlining would add weight.  Even more conventional supersonic
aircraft have a strong tendency to rely on brute-force engine power rather
than aerodynamic elegance, as a close inspection of most any jet fighter
will reveal!

>4)On the side od each SRB, there is a piece of metal running lengthwise.
>Is this a strap to hold the segments together? 

No, they're held together by pins at the joints themselves.  What you're
seeing is probably the wiring tunnel that runs the length of each SRB,
carrying cables and the linear destruct charge.

>5) Wouldn't the SRB segments mate more reliably if the propellant grain
>from an upper segment extended into the next lower segment? That way,
>the propellant segments wouldn't coincide with the chamber segments and
>the infamous O-rings wouldn't take as direct a blast. No? 

So long as the propellant grain has a joint in it, there's always the
possibility that gas will get through that joint to reach the casing
joint.  It wouldn't help much, and it would complicate handling and
transport.  The post-Challenger joints do have a number of features
to reduce the amount of gas reaching the O-rings.
-- 
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  henry@zoo.toronto.edu  utzoo!henry