soc.history.war.world-war-ii

Bombardier wrote:

>We had a top speed of about 300mph.But we had to cruise at 180mph to
>reach our targets. Even if we coild cruise at 250 IAS so what?. The
>fighter after us were working at well over 300 mph often near 400
>mph.,That increase in our speed would hardly effect the fighters
>attacking us or the tracking of the Germaan 88's.

Consider the difference between
catching a 250 MPH plane
and a 180 MPH plane with a
300 MPH interceptor (I).

Let's assume the target plane
(T) is on a return leg, and is 100
miles from the edge of the
defended zone when detected by
the ground observers.

The observers relay the detection
to ground control, which then
vectors I to intercept. Let's
assume that I is in the air, 50
miles back along the return course
and 100 miles to one side.

|
|
T--(50 M)--+--(50 M)--->|
| |
| |
(100 M)
|
|
I

(If this diagram is garbled, clip
it out and paste it into Notepad
or some other editor with monospaced
text.)

If T is moving at 180 MPH, I intercepts
at 39 miles (13 minutes) from the edge.

If T is moving at 250 MPH, I intercepts
at 10 miles (2 minutes) from the edge.

In this second case (T flying 250 MPH),
if there is some delay in the relay
from observer to controller and from
controller to interceptor, or the
intercept vector is not exact and the
interceptor must visually locate T,
T may well evade interception.

In the first case, T is in much
greater danger.

Now let's consider flak. T, flying
at 25,000 feet, passes over a flak
battery. The battery's guns can easily
reach 25,000 feet; their arc of fire
is up to 30 degrees off of vertical.
At 25,000 feet, 29,000 feet of the
bomber's course is in the fire cone.

If T is flying at 180 MPH, it will be
in the fire cone for 118 seconds; if
T is flying at 250 MPH it will be in
the cone for 78 seconds. That reduces
the battery's opportunity to hit T
by over 1/3.

Also, the flight time of a shell from
ground to 25,000 feet, assuming a
muzzle velocity of 2,700 fps (typical
of an 88mm Flak 37) would be 9 seconds.

At 180 MPH, T moves about 2,400 feet in 9 sec.
At 250 MPH, T moves about 3,300 feet in 9 sec.

That's a substantially greater "lead" to
calculate and match. If the estimated target
course is 2 degrees off, the shell would
miss by 84 feet at 180 MPH, but 115 feet at
250 MPH. The effectiveness of the burst should
be about proportional to the square of the
distance, so the second shell would be half
as effective.
--
| People say "There's a Stradivarius for sale for a |
| million," and you say "Oh, really? What's wrong |
| with it?" - Yitzhak Perlman |