shooting yourself down - more physics?

Smitty Two wrote:
In article t,
Dave S wrote:

Smitty Two wrote:

1. I didn't stipulate a vacuum. My engine and wing don't work very well
without air. I said, to simplify calculations, ignore the effects of
friction on the projectile. We are flying above the earth.

You said discounting air friction. This is key to the problem. No air
friction would be the physical equivalent of being in a vacuum.

If there were no air friction, the projectile would continue ahead with
a forward speed of 1500 mph - its own 500 mph from its spent propellant
charge, and the 1000 mph imparted to it from the airframe.

...

So... are we or are we not including air friction? If we are, I am not
going to hazard a guess.. my math gland atrophied long ago after I
passed calculus. If we are not, then the problem is unsolvable in level
flight on earth.



Neglecting airfriction, the trajectory relative to the aircraft,
of the bullets fired from that aricraft will be the same
as the trajectory of bullets fired from a fixed position,
relative to that fixed position. As OP noted, the gunner hits
his own aircraft by firing staight up.

No Calculus required to reach that conclusion.


It's a hypothetical question, of course. I think I stated it fairly
clearly. Bill has already answered it correctly, with a second from
Alex. My calculus skills have also eroded over the years, which is one
reason I wanted to discount friction. But, I'd be curious to learn what
the real world answer would be, including friction, which of course is
dependent on a whole host of factors. (Of course, by the time the plane
caught up with the bullet in the real world, the friction would likely
have reduced its speed to something *relatively* harmless.)

That all depends on the relative velocity. If he fires upward and
forward and then does a low yo-yo to intercept I expect the bullets
could come down hard enough to hurt.


--

FF

(snip)
... my math gland atrophied long ago after I passed calculus.
(snip)

That calculus was *nasty* stuff ...
and matrix algebra was *worse*

I haven't recovered either, after 35+ years!

Peter

Peter Dohm wrote:
(snip)
... my math gland atrophied long ago after I passed calculus.
(snip)

That calculus was *nasty* stuff ...
and matrix algebra was *worse*

I haven't recovered either, after 35+ years!

Peter


Geeze, a buncha light weights. The calculus series and linear
algebra you guys took were rough? Differential equations? Hah! Take a
course in imaginary variables.

Dan, U.S. Air Force, retired

I remember reading of a F-104 Starfighter pilot who shoot himself down.
He tested his guns, then accelerated, nose down and ran into his own
shells.

On Sat, 10 Sep 2005 12:21:29 -0400, Smitty Two
wrote:

If you guys aren't tired of arithmetic, I'm wondering if any fighter
pilots have shot themselves down. Probably not, but imagine you're
flying straight and level at 1000 mph and fire a 500 mph projectile at
an enemy that's directly ahead but at a higher altitude. You miss him;
the bullet follows a parabolic path, returning to your altitude just as
you overtake it. Discounting air friction, at what angle was the bullet
fired?

(extra credit question -- how many rivets could you have installed in
the time you wasted thinking about this question?)

--
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"Smitty Two" wrote in message
news
If you guys aren't tired of arithmetic, I'm wondering if any fighter
pilots have shot themselves down. Probably not, but imagine you're

I know a guy who got shot down by his own waist gunner in a B-24, does that
count?

(The gun mount broke and the gunner didn't let go of the trigger as he (and
the gun) fell backwards...)

--
Geoff
the sea hawk at wow way d0t com
remove spaces and make the obvious substitutions to reply by mail
Spell checking is left as an excercise for the reader.

Has nothing to do with physics, but it is possible for a helicopter to shoot
himself down in several different ways. Fire a pair of 2.75" rockets at the
same time with proximity fuses while doing running fire and it could get
ugly.

Running fire while shooting the gun (or rockets) at close ranges could
easily produce ricochets that could hit the helicopter. I have seen the 50
caliber machine gun on an OH-58D blow out the copilot chin bubble before.

Another good way to shoot yourself down is for one helicopter to remote
LASER designate for another helicopter firing a Hellfire missile while you
are inside a certain fan in front of the firing helicopter. The Hellfire
can lock on to the laser designating source rather than the target.

Jeff
recently retired Army CW4 Master Army Aviator

"Smitty Two" wrote in message
news
If you guys aren't tired of arithmetic, I'm wondering if any fighter
pilots have shot themselves down. Probably not, but imagine you're
flying straight and level at 1000 mph and fire a 500 mph projectile at
an enemy that's directly ahead but at a higher altitude. You miss him;
the bullet follows a parabolic path, returning to your altitude just as
you overtake it. Discounting air friction, at what angle was the bullet
fired?

(extra credit question -- how many rivets could you have installed in
the time you wasted thinking about this question?)

Jeff wrote:
Has nothing to do with physics, but it is possible for a helicopter to shoot
himself down in several different ways. Fire a pair of 2.75" rockets at the
same time with proximity fuses while doing running fire and it could get
ugly.

Running fire while shooting the gun (or rockets) at close ranges could
easily produce ricochets that could hit the helicopter. I have seen the 50
caliber machine gun on an OH-58D blow out the copilot chin bubble before.

Another good way to shoot yourself down is for one helicopter to remote
LASER designate for another helicopter firing a Hellfire missile while you
are inside a certain fan in front of the firing helicopter. The Hellfire
can lock on to the laser designating source rather than the target.

Jeff
recently retired Army CW4 Master Army Aviator

During WW2 P-51s shot them selvesdown when making low level passes
and debris got scooped into the oil cooler.

Dan, U.S. Air Force, retired

Jeff wrote:

The Hellfire
can lock on to the laser designating source rather than the target.

This is what the post-accident investigators refer to as "a very bad
thing" (TM).

Dave

Smitty Two wrote:

If you guys aren't tired of arithmetic, I'm wondering if any fighter
pilots have shot themselves down. Probably not, but imagine you're
flying straight and level at 1000 mph and fire a 500 mph projectile at
an enemy that's directly ahead but at a higher altitude. You miss him;
the bullet follows a parabolic path, returning to your altitude just as
you overtake it. Discounting air friction, at what angle was the bullet
fired?

(extra credit question -- how many rivets could you have installed in
the time you wasted thinking about this question?)

What kind of gun do *you* have with a muzzle velocity of only 733 fps ?

....Ken

..22 shooting CB caps.