Physics question

[Rich S.]

There is a (magic) B-17 flying along at 560 mph. The tail gunner is out of
..50 caliber ammo. He sees a Messerschmitt ME-109 crossing behind the B-17,
50 yards away.

He pulls out his trusty .45 Colt auto (muzzle velocity 820 fps) and fires at
the Hun when the ME-109 is directly behind the B-17. He leads the
Messerschmitt by exactly enough to hit the pilot (if he were firing from a
fixed position).

Does the bullet exit the muzzle and fall directly to earth?

Rich "Scratching my head" S.

[RST Engineering]

No, the ME-109 has zero relative velocity in the B-17s flight path...he said
CROSSING 50 yards behind the aircraft.

Jim



"T o d d P a t t i s t" > wrote in message
...
> "Rich S." > wrote:
>
>>Does the bullet exit the muzzle and fall directly to earth?
>
> Yes, aside from the tiny diff between 560 mph and 820 fps,
> assuming he pointed directly backwards and that there was no
> wind. The ME-109 flies into the falling bullets.

[Orval Fairbairn]

In article >,
"Rich S." > wrote:

> There is a (magic) B-17 flying along at 560 mph. The tail gunner is out of
> .50 caliber ammo. He sees a Messerschmitt ME-109 crossing behind the B-17,
> 50 yards away.
>
> He pulls out his trusty .45 Colt auto (muzzle velocity 820 fps) and fires at
> the Hun when the ME-109 is directly behind the B-17. He leads the
> Messerschmitt by exactly enough to hit the pilot (if he were firing from a
> fixed position).
>
> Does the bullet exit the muzzle and fall directly to earth?
>
> Rich "Scratching my head" S.


Yes, but the bullet is traveling at 820 ft/s relative to the B-17. The
bullet will drop straight down, but can still hit the ME, which runs int
the bullet.

[Rich S.]

"T o d d P a t t i s t" > wrote in message
...
> "RST Engineering" > wrote:
>
>>No, the ME-109 has zero relative velocity in the B-17s flight path...he
>>said
>>CROSSING 50 yards behind the aircraft.
>
> True, he said "crossing," but he also said he's leading the
> ME-109, and I specified that he fires straight back, i.e.,
> he leads the ME-109 so that he's aiming at the point where
> the ME-109 crosses the B-17s flight path.
>
> The bullet drops straight down (relative to the ground).
> The ME-109 flies into it before it drops significantly.

Perhaps I wasn't clear. Maybe I can diagram it.

Aiming
point
. <----- ME-109

B-17
|
V

This means that the turret gunner would have a problem in judging trajectory
to a target which passes by either front-to-rear or vice versa. Perhaps the
slower velocity of the bomber (in real life) and the higher velocity of a
..30 cal or .50 cal bullet would minimize the correction necessary. Then too,
that's why they make tracers! :)

Rich "I think I see" S.

[[email protected]]

T o d d P a t t i s t wrote:
> "RST Engineering" > wrote:
>
> >No, the ME-109 has zero relative velocity in the B-17s flight path...he said
> >CROSSING 50 yards behind the aircraft.
>
> True, he said "crossing," but he also said he's leading the
> ME-109, and I specified that he fires straight back, i.e.,
> he leads the ME-109 so that he's aiming at the point where
> the ME-109 crosses the B-17s flight path.

There is "leading" and there is "leading correctly". It makes
no sense to state the former without implying the latter so
the question reduces to whether or not it is *possible*
to hit, since if the gunner leads *correctly* he will
hit by the definition of *leading*.

>
> The bullet drops straight down (relative to the ground).
> The ME-109 flies into it before it drops significantly.

If by crossing we mean the ground tracks are orthogonal and
if it was already behind the B17 when the shot was fired
then without a velocity component parallel to the
flight path of the B17 the Me-109 will always cross the
flight path of the B17 *behind* the point where the shot
was fired. The gunner cannot hit the ME 109 in those
circumstances.

The gunner has to fire (and I got this wrong a minute ago)
at the moment the flight path of the B17 (actually at the
moment the muzzle of his gun) crosses the flight
path of the ME 109 ahead of the Me 109, and at the correct
elevation angle to compensate for differences in altitude,
and rate of climb of the Me-109 relative to the B17, keeping
in mind that the changes in elevation angle will also affect
the horizontal compenants of the bullet's velocity.

--

FF

[[email protected]]

Rich S. wrote:
> "T o d d P a t t i s t" > wrote in message
> ...
> > "RST Engineering" > wrote:
> >
> >>No, the ME-109 has zero relative velocity in the B-17s flight path...he
> >>said
> >>CROSSING 50 yards behind the aircraft.
> >
> > True, he said "crossing," but he also said he's leading the
> > ME-109, and I specified that he fires straight back, i.e.,
> > he leads the ME-109 so that he's aiming at the point where
> > the ME-109 crosses the B-17s flight path.
> >
> > The bullet drops straight down (relative to the ground).
> > The ME-109 flies into it before it drops significantly.
>
> Perhaps I wasn't clear. Maybe I can diagram it.
>
> Aiming
> point
> . <----- ME-109
>
> B-17
> |
> V
>

In your text you said the gunner fies when the ME 109
is directly behind the B17. For orthogonal ground
tracks, he cannot hit the ME 109 if it is *anywhere* behind
the B17 no matter where he aims because the flight
paths of the ME 109 cannot intersect the path
the bullet takes to the ground.


In your illustration, the gunner fires straight back
before the Me-109 is directly behind the B17. He can hit
if he fires at precisely the moment his gun crosses the
flight path of the Me-109.

--

FF

[Rich S.]

> wrote in message
oups.com...

> In your text you said the gunner fies when the ME 109
> is directly behind the B17. For orthogonal ground
> tracks, he cannot hit the ME 109 if it is *anywhere* behind
> the B17 no matter where he aims because the flight
> paths of the ME 109 cannot intersect the path
> the bullet takes to the ground.

That's why, in the text, I also added that he "led" the ME-109 exactly
enough. Did you read the entire sentence? As I said, perhaps I wasn't clear.
He fires directly behind the B-17. The ME-109 is on its way to cross the
flightpath of the B-17.
>
> In your illustration, the gunner fires straight back
> before the Me-109 is directly behind the B17. He can hit
> if he fires at precisely the moment his gun crosses the
> flight path of the Me-109.

Not so. The bullet simply falls to Earth and the ME-109 passes safely 50
yards (or so) behind the B-17.

Rich "Don't use them 3-silable words like 'orthogonal'" S.

[[email protected]]

He misses the ME-109 because the recoil of firing the bullet
accelerates the B-17 just a bit, so that the bullet, travelling at a
little less than the bomber's speed actually briefly follows the bomber
as it falls.

A related question: Haven't there been cases of supersonic
fighters shooting themselves down when they caught up to the shells
they'd fired forward?

Dan

[abripl]

With bullet/plane(s) relative horizontal speed of 820ft/s, the other
plane reaches the bullet position in (50x3)/820 = 0.183 sec (pretty
slow bullet). In that time the bullet falls a vertical distance of 0.5
x 32 x 0.183 x 0.183 ft = 0.536 ft. If the messer plane bottom was at
least 0.537 ft (about 7 inches) below bullet firing vertical position
its gona hit the other plane.

Ignoring air friction, whether the planes are moving or parked on the
ground with same separation it does not matter. It is only the relative
velocity of the bullet to the planes that counts. But with backward
airstream and downward friction the bullet will fall slower down than
in vacuum - so better chance of hitting the plane behind.

Is this your night school physics home assignment and you are cheating
here?

[[email protected]]

Rich S. wrote:
> > wrote in message
> oups.com...
>
> > In your text you said the gunner fies when the ME 109
> > is directly behind the B17. For orthogonal ground
> > tracks, he cannot hit the ME 109 if it is *anywhere* behind
> > the B17 no matter where he aims because the flight
> > paths of the ME 109 cannot intersect the path
> > the bullet takes to the ground.
>
> That's why, in the text, I also added that he "led" the ME-109 exactly
> enough. Did you read the entire sentence?

Yes, you added the condition that he leads by exactly the same
amount he would from a fixed condition to the statement that
he fires when the ME-109 is directly behind the B17.
If he waits to fire until after the B17 has crossed the
flight path of the ME 109 he cannot hit no matter how
he aims. It matters not how he leads.


> As I said, perhaps I wasn't clear.
> He fires directly behind the B-17. The ME-109 is on its way to cross the
> flightpath of the B-17.

This you added in a later post. If, while firing straight back
he still leads as if he were firing from a fixed position he
will miss again because the B17 has already crossed the flight
path of the ME-109 by the time he fires.

No matter the direction, if he fires after the B17 has
crossed the flightt path of the ME-109 he misses.


> >
> > In your illustration, the gunner fires straight back
> > before the Me-109 is directly behind the B17. He can hit
> > if he fires at precisely the moment his gun crosses the
> > flight path of the Me-109.
>
> Not so. The bullet simply falls to Earth and the ME-109 passes safely 50
> yards (or so) behind the B-17.

That is true if he leads the ME109 as he would from a fixed
position, or any way other than the *right* way. But there
is a right way. I *changed* the scenario when I said he
fires at precisely the moment his gun crosses the flight
path of the ME-109.

If he fires stright back at that moment,
and the ME 109 is flying at the same airspeed as
the B-17 then the bullet is *also* 50 yards behind the
B17, when the ME-109 crosses. It will be a half inch or
so lower than the altitude at which it exited the muzzle
if it was fired exactly level.

Firing straight back at the moment the B17 crosses the
flight path of the ME-109 essentially drops the bullet
through the flight path of the ME-109. IF the bullet is
still there when the ME-109 arrives, which it will be
for a range of speeds close the speed of the B17,
the gunner hits.

An the gunner can compensate for the ME-109 flying
at a different speed and altitude by firing up or
down a little, again for some range of speeds and
altitudes.

--

FF

[Montblack]

("Rich S." wrote)
>> In your illustration, the gunner fires straight back
>> before the Me-109 is directly behind the B17. He can hit
>> if he fires at precisely the moment his gun crosses the
>> flight path of the Me-109.

> Not so. The bullet simply falls to Earth and the ME-109 passes safely 50
> yards (or so) behind the B-17.


Agreed.

(For those who don't agree)
Think of a pickup truck driving along at 40 mph. I'm standing in the bed
with a baseball.

When we reach the manhole cover in the middle of the street I let fly out
the back of the truck with my best stuff, which just happens to be a 40 mph
fastball <g>. That ball will not go past the manhole cover.

If you're a batter (or an ME-109) standing at the manhole cover - which
every kid knows is home plate - you won't get hit by my fastball ...or be
able to hit it. (I'm unhittable!!)

Now, if I flip the ball into the air, but a little to the left, and you are
standing in the street when the truck drives by, you will be hit by a 40 mph
ball. Just thought I'd toss that one out there :-)

So long as the ME-109 is not moving (at all) in the same direction as the
"magic" B-17, when it crosses behind the Flying Fortress, it will be safe
from the bullet.. I would think wind drift would not be an issue (with
perpendicular plane paths) since it will drift the B-17 too ... away from
the ME-109.


Montblack ..."car"

[Blueskies]

"abripl" > wrote in message oups.com...
> With bullet/plane(s) relative horizontal speed of 820ft/s, the other
> plane reaches the bullet position in (50x3)/820 = 0.183 sec (pretty
> slow bullet). In that time the bullet falls a vertical distance of 0.5
> x 32 x 0.183 x 0.183 ft = 0.536 ft. If the messer plane bottom was at
> least 0.537 ft (about 7 inches) below bullet firing vertical position
> its gona hit the other plane.
>
> Ignoring air friction, whether the planes are moving or parked on the
> ground with same separation it does not matter. It is only the relative
> velocity of the bullet to the planes that counts. But with backward
> airstream and downward friction the bullet will fall slower down than
> in vacuum - so better chance of hitting the plane behind.
>
> Is this your night school physics home assignment and you are cheating
> here?
>

[Blueskies]

But just imagine, as the bullet falls to earth, it will remain horizontal for a while due to the gyroscopic spin caused
by the rifling...


"Montblack" > wrote in message ...
> ("Rich S." wrote)
>>> In your illustration, the gunner fires straight back
>>> before the Me-109 is directly behind the B17. He can hit
>>> if he fires at precisely the moment his gun crosses the
>>> flight path of the Me-109.
>
>> Not so. The bullet simply falls to Earth and the ME-109 passes safely 50 yards (or so) behind the B-17.
>
>
> Agreed.
>
> (For those who don't agree)
> Think of a pickup truck driving along at 40 mph. I'm standing in the bed with a baseball.
>
> When we reach the manhole cover in the middle of the street I let fly out the back of the truck with my best stuff,
> which just happens to be a 40 mph fastball <g>. That ball will not go past the manhole cover.
>
> If you're a batter (or an ME-109) standing at the manhole cover - which every kid knows is home plate - you won't get
> hit by my fastball ...or be able to hit it. (I'm unhittable!!)
>
> Now, if I flip the ball into the air, but a little to the left, and you are standing in the street when the truck
> drives by, you will be hit by a 40 mph ball. Just thought I'd toss that one out there :-)
>
> So long as the ME-109 is not moving (at all) in the same direction as the "magic" B-17, when it crosses behind the
> Flying Fortress, it will be safe from the bullet.. I would think wind drift would not be an issue (with perpendicular
> plane paths) since it will drift the B-17 too ... away from the ME-109.
>
>
> Montblack ..."car"

[Blueskies]

"abripl" > wrote in message oups.com...
> With bullet/plane(s) relative horizontal speed of 820ft/s, the other
> plane reaches the bullet position in (50x3)/820 = 0.183 sec (pretty
> slow bullet). In that time the bullet falls a vertical distance of 0.5
> x 32 x 0.183 x 0.183 ft = 0.536 ft. If the messer plane bottom was at
> least 0.537 ft (about 7 inches) below bullet firing vertical position
> its gona hit the other plane.
>
> Ignoring air friction, whether the planes are moving or parked on the
> ground with same separation it does not matter. It is only the relative
> velocity of the bullet to the planes that counts. But with backward
> airstream and downward friction the bullet will fall slower down than
> in vacuum - so better chance of hitting the plane behind.
>
> Is this your night school physics home assignment and you are cheating
> here?
>

This would only work if the 109 was ahead of the 17 when the shot was fired.

[Montblack]

(Dan_Thomas_nospam wrote)
> He misses the ME-109 because the recoil of firing the bullet
> accelerates the B-17 just a bit, so that the bullet, travelling at a
> little less than the bomber's speed actually briefly follows the bomber
> as it falls.

Plus there is a constant speed with the B-17. The bullet needs to accelerate
to reach that same speed. <g>


> A related question: Haven't there been cases of supersonic
> fighters shooting themselves down when they caught up to the shells
> they'd fired forward?

'If I drive the speed of light, and turn on the headlights - would anything
happen?' Steven Wright ...and maybe also "The Lazlo Letters" (1977) by Don
Novello.


Montblack

[Rich S.]

"abripl" > wrote in message
oups.com...
> With bullet/plane(s) relative horizontal speed of 820ft/s, the other
> plane reaches the bullet position in (50x3)/820 = 0.183 sec (pretty
> slow bullet). In that time the bullet falls a vertical distance of 0.5
> x 32 x 0.183 x 0.183 ft = 0.536 ft. If the messer plane bottom was at
> least 0.537 ft (about 7 inches) below bullet firing vertical position
> its gona hit the other plane.

Nope. You are assuming "the other plane reaches the bullet position . . .".
It never reaches the bullet's position because it is traveling at 90° to the
flight path of the B-17. If it was following the B-17, it could possibly run
into the bullet, but only at its foward velocity. The bullet has only a
downward component relative to the Earth. (Ignoring minor variations, i. e.
coriolis force & wind velocity.)

> Ignoring air friction, whether the planes are moving or parked on the
> ground with same separation it does not matter. It is only the relative
> velocity of the bullet to the planes that counts. But with backward
> airstream and downward friction the bullet will fall slower down than
> in vacuum - so better chance of hitting the plane behind.
>
> Is this your night school physics home assignment and you are cheating
> here?

Nope. Last physics course I took was at the U of Wash., 47 years ago. I
brought this subject up because I was reading an article in the May 1942
issue of "Flying and Popular Aviation". It was titled "Speedy" and tells the
story of a quiet young fellow named Andy McDonough who dove a new Army
fighter to 620 mph a "few weeks ago". He'd like to try for 700.

The airplane was a new P-39 Airacobra. "After his test, McDonough said he
thought of that now-famous problem: 'I wondered what would have happened if
I could have fired a pistol back over the tail. At that speed would the
bullet have rolled out of the barrel and then fallen back?'".

Well, perhaps that was a famous problem in the spring of 1942. I don't know,
having entered this vale of tears late in 1941. But I thought it would be
fun to toss it up here among all these reasonable, logical, polite folks. :)

Rich S.

[abripl]

> This would only work if the 109 was ahead of the 17 when the shot was fired.

It will work fine as long as the two maintain the relative 50 yards
distance between them. - one following the other. Or is Rich S.
description of the motion muddled? I took "crossing behind the B-17" as
simply crossing the line of sight slightly and not a perpendicular
ground path. Normally a 109 would follow a B-17 to attack.

[[email protected]]

Montblack wrote:
> ("Rich S." wrote)
> >> In your illustration, the gunner fires straight back
> >> before the Me-109 is directly behind the B17. He can hit
> >> if he fires at precisely the moment his gun crosses the
> >> flight path of the Me-109.
>
> > Not so. The bullet simply falls to Earth and the ME-109 passes safely 50
> > yards (or so) behind the B-17.
>
>
> Agreed.
>
> (For those who don't agree)
> Think of a pickup truck driving along at 40 mph. I'm standing in the bed
> with a baseball.
>
> When we reach the manhole cover in the middle of the street I let fly out
> the back of the truck with my best stuff, which just happens to be a 40 mph
> fastball <g>. That ball will not go past the manhole cover.

Won't it drop stairght down toward the manhole cover? (Yes it will.)

>
> If you're a batter (or an ME-109) standing at the manhole cover - which
> every kid knows is home plate - you won't get hit by my fastball ...or be
> able to hit it. (I'm unhittable!!)
>

Evidently you have seen me at bat. But someone else could hit it.

And if I'm running toward the manhole cover at a right angle to
the direction the truck is driving I can catch the ball as I
step accross the manhole cover, right?

(Well, maybe you've seen me field too.)

--

FF

[[email protected]]

Rich S. wrote:
> "abripl" > wrote in message
> oups.com...
> > With bullet/plane(s) relative horizontal speed of 820ft/s, the other
> > plane reaches the bullet position in (50x3)/820 =3D 0.183 sec (pretty
> > slow bullet). In that time the bullet falls a vertical distance of 0.5
> > x 32 x 0.183 x 0.183 ft =3D 0.536 ft. If the messer plane bottom was at
> > least 0.537 ft (about 7 inches) below bullet firing vertical position
> > its gona hit the other plane.

Half a foot at 50 yards? I misrememeberd that a 45 drops half an
inch at 50 yards. How embarassing.

>
> Nope. You are assuming "the other plane reaches the bullet position . . .=
"=2E
> It never reaches the bullet's position because it is traveling at 90=B0 t=
o the
> flight path of the B-17. If it was following the B-17, it could possibly =
run
> into the bullet, but only at its foward velocity. The bullet has only a
> downward component relative to the Earth. (Ignoring minor variations, i. =
e=2E
> coriolis force & wind velocity.)
>

You're still assuming he's leading the ME-109 as if the gunner
were in a fixed location. He's assuming the gunner is actually
trying to hit the plane, and smart enough to figure out how
so that he times his shot *correctly*. You're both assuming
he fires straight back. He can hit the Me-109 by firing straight
back, but ONLY if he fires exactly as B-17 crosses the flight
path of the Me-109, and only if the Me-109 is fast enough or
close enough to get there before the bullet drops out of the
flight path of the Me-109. If the Me-109 is at a range of 50
yards, and no slower than the bullet the bullet will be no
more than 7 inches lower than the muzzle of the gun and will
still hit the Me-109 assuming the two planes are at the same
altitude.

Here is an example:

Both planes are at the same altitude.
The gunner fires straight back and level when the B-17
crosses the flight path ahead of the ME-109. At that
moment, the Me-109 is at a range of 50 yards, e.g. it
is 50 yards directly to the right of the gunner and
flying from right to left, and also flying at 820 ft/s.
If you think that bullet misses, calculate by how much.
Now do that again, assuming the Me-109 is a bit faster,
say, 900 ft/s.

There is a range of realistic speeds and altitudes
for the Me 109 for which it will be hit, and a larger range
of speeds an altitudes for which it can be hit if the gunner
is allowed to aim up or down, larger still if he can aim from
left to right even though in all cases the ME-109 is flying
at 90 degrees to the flight path of the B-17.

--=20

FF

[[email protected]]

Rich S. wrote:
>
> Aiming
> point
> . <----- ME-109
>
> B-17
> |
> V
>

The gunner cannot hit the ME-109 given those relative positions
and trajectories no matter where he aims.

If the gunner fires straight back when he is at the aiming point
(e.g. re-lable 'aiming point' to be 'firing point' then the bullet
will drop straight down from that point, right?

Then if the ME-109 is close enough and fast enough the bullet
will be just below the aiming/firing point when the ME-109
gets there and will hit the bullet. Your specified range
of 50 yards (50 yards to the right in this case) is close
enough for normal ME=109 speeds.

If the Me-109 is slower or farther it will pass over the
bullet unless it is also at sufficiently lower altitude.

--

FF

[Rich S.]

> wrote in message
ups.com...

You're still assuming he's leading the ME-109 as if the gunner
were in a fixed location. He's assuming the gunner is actually
trying to hit the plane, and smart enough to figure out how
so that he times his shot *correctly*. You're both assuming
he fires straight back. He can hit the Me-109 by firing straight
back, but ONLY if he fires exactly as B-17 crosses the flight
path of the Me-109, and only if the Me-109 is fast enough or
close enough to get there before the bullet drops out of the
flight path of the Me-109. If the Me-109 is at a range of 50
yards, and no slower than the bullet the bullet will be no
more than 7 inches lower than the muzzle of the gun and will
still hit the Me-109 assuming the two planes are at the same
altitude.

Fred...............

I'll say it again - you misunderstand the question. I have stated it as
clearly as I am able and even drawn a diagram. I don't know how else to
explain it. I'm a pilot. I talk with my hands (hopefully without resorting
to certain gestures).

The B-17 is flying West. The ME-109 is flying South. They are both at the
same altitude. There is no wind. The ME-109 will cross the flight path of
the B-17 and the B-17 will, at that moment, be fifty yards from the ME-109.
The tail gunner fires his weapon straight behind the B-17.

There is no way that he can hit the ME-109, given the stated speed of the
B-17 and the muzzle velocity of the bullet.

The ME-109 will *always* be fifty yards or more away from the bullet.
Always.

Rich S.

[Rich S.]

> wrote in message
ups.com...
>
> The gunner cannot hit the ME-109 given those relative positions
> and trajectories no matter where he aims.

That is the correct answer.

> If the gunner fires straight back when he is at the aiming point
> (e.g. re-lable 'aiming point' to be 'firing point' then the bullet
> will drop straight down from that point, right?

If you change the question you may have any answer you wish.

Rich "So, we agree?" S.

[Dean A. Scott]

Here's a wacky scenario... why can you fire a gun on the equator
in the direction of the setting sun? I mean, the Earth spins at
the equator at around 1,000 miles per hour (24,000 mile circum-
ference divided by 24 hr rotation), so why does the bullet exit
the barrel at the same velocity no matter what direction you
point it in? Hmmm. :-)

I think it's because the atmosphere is rotating at the same speed,
thus no friction to slow it down or keep it inside the barrel.

Yes? No? How does this differ from the first scenario?







Dean A. Scott, mfa
---------------------------------------
School of Visual Art and Design
southern adventist university
---------------------------------------
http://www.southern.edu/~dascott

[Montblack]

wrote)
> Won't it drop stairght down toward the manhole cover? (Yes it will.)


Gads, you're right! Crap, now it's basically T-ball at the manhole cover.
There goes my 1.35 ERA!!


Montblack

[Harry K]

Rich S. wrote:
> > wrote in message
> ups.com...
>
> You're still assuming he's leading the ME-109 as if the gunner
> were in a fixed location. He's assuming the gunner is actually
> trying to hit the plane, and smart enough to figure out how
> so that he times his shot *correctly*. You're both assuming
> he fires straight back. He can hit the Me-109 by firing straight
> back, but ONLY if he fires exactly as B-17 crosses the flight
> path of the Me-109, and only if the Me-109 is fast enough or
> close enough to get there before the bullet drops out of the
> flight path of the Me-109. If the Me-109 is at a range of 50
> yards, and no slower than the bullet the bullet will be no
> more than 7 inches lower than the muzzle of the gun and will
> still hit the Me-109 assuming the two planes are at the same
> altitude.
>
> Fred...............
>
> I'll say it again - you misunderstand the question. I have stated it as
> clearly as I am able and even drawn a diagram. I don't know how else to
> explain it. I'm a pilot. I talk with my hands (hopefully without resorting
> to certain gestures).
>
> The B-17 is flying West. The ME-109 is flying South. They are both at the
> same altitude. There is no wind. The ME-109 will cross the flight path of
> the B-17 and the B-17 will, at that moment, be fifty yards from the ME-109.
> The tail gunner fires his weapon straight behind the B-17.
>
> There is no way that he can hit the ME-109, given the stated speed of the
> B-17 and the muzzle velocity of the bullet.
>
> The ME-109 will *always* be fifty yards or more away from the bullet.
> Always.
>
> Rich S.

The way I see it, you are both in agreement. Fred says to hit the 109
he has to fire at the exact time the 17 croses the 109's path. That is
correct. In effect he says that to fire as per your example he can't
hit it.

Harry K

[Harry K]

wrote:
> He misses the ME-109 because the recoil of firing the bullet
> accelerates the B-17 just a bit, so that the bullet, travelling at a
> little less than the bomber's speed actually briefly follows the bomber
> as it falls.
>
> A related question: Haven't there been cases of supersonic
> fighters shooting themselves down when they caught up to the shells
> they'd fired forward?
>
> Dan

I was hoping someone would answer that. I recall seeing/hearing/reading
somewhat the same thing back when. Best I can recall it involved an
F-86 or equivalent (not supersonic) and happened by firing and then
going into a dive thus flying into the bullet stream. Are 50 cal
bullets supersonic?
If so, the plane would also have to be.

Harry K

[Montblack]

("Dean A. Scott" wrote)
> Here's a wacky scenario... why can you fire a gun on the equator
> in the direction of the setting sun? I mean, the Earth spins at
> the equator at around 1,000 miles per hour (24,000 mile circum-
> ference divided by 24 hr rotation), so why does the bullet exit
> the barrel at the same velocity no matter what direction you
> point it in? Hmmm. :-)


Don't have an answer ...but pointy bullet shaped things + the equator = this
link.

<http://www.qrg.northwestern.edu/projects/vss/docs/Navigation/2-why-launch-from-equator.html>
"Why is it better to launch a spaceship from near the equator?"


Montblack

[Alan Baker]

In article . com>,
"Harry K" > wrote:

> wrote:
> > He misses the ME-109 because the recoil of firing the bullet
> > accelerates the B-17 just a bit, so that the bullet, travelling at a
> > little less than the bomber's speed actually briefly follows the bomber
> > as it falls.
> >
> > A related question: Haven't there been cases of supersonic
> > fighters shooting themselves down when they caught up to the shells
> > they'd fired forward?
> >
> > Dan
>
> I was hoping someone would answer that. I recall seeing/hearing/reading
> somewhat the same thing back when. Best I can recall it involved an
> F-86 or equivalent (not supersonic) and happened by firing and then
> going into a dive thus flying into the bullet stream. Are 50 cal
> bullets supersonic?
> If so, the plane would also have to be.
>
> Harry K

No it wouldn't.

Quick question: what does a plane have that a bullet lacks?

Answer: an engine to maintain its speed.

Bullets start slowing down the moment they leave the muzzle (alright,
just slightly *after* they leave the muzzle), while the aircraft that
fired them can maintain its speed.

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling 4 feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect
if you sit in the bottom of that cupboard."

[Dan, U.S. Air Force, retired]

Rich S. wrote:

> There is a (magic) B-17 flying along at 560 mph. The tail gunner is out of
> .50 caliber ammo. He sees a Messerschmitt ME-109 crossing behind the B-17,
> 50 yards away.
>
> He pulls out his trusty .45 Colt auto (muzzle velocity 820 fps) and fires at
> the Hun when the ME-109 is directly behind the B-17. He leads the
> Messerschmitt by exactly enough to hit the pilot (if he were firing from a
> fixed position).
>
> Does the bullet exit the muzzle and fall directly to earth?
>
> Rich "Scratching my head" S.
>
>
Forgetting turbulence following the B-17 the bullet would still have
a muzzle velocity of 900 FPS, assuming a military load. 50 yards is 50
yards and the Me109 would still be hit assuming proper aim. Whether it
does much more than penetrate the canopy I don't know. Put the trailing
turbulence back into the scenario and all bets are off.

Dan, U.S. Air Force, retired

[Dan, U.S. Air Force, retired]

Blueskies wrote:

> But just imagine, as the bullet falls to earth, it will remain horizontal for a while due to the gyroscopic spin caused
> by the rifling...
>

No, the bullet will start dropping due to gravity immediately upon
exiting the muzzle.

Dan, U.S. Air Force, retired

[Rich S.]

"Dean A. Scott" > wrote in message
news:1126146846.d1f75da4b1eff1487f40a17ade08c409@t eranews...
> Here's a wacky scenario... why can you fire a gun on the equator
> in the direction of the setting sun? I mean, the Earth spins at
> the equator at around 1,000 miles per hour (24,000 mile circum-
> ference divided by 24 hr rotation), so why does the bullet exit
> the barrel at the same velocity no matter what direction you
> point it in? Hmmm. :-)

Imagine that the target is going away from you at the same speed that the
bullet is traveling. It would hit the ground before it reaches the target.
(Actually, it would never catch the target.

Now, turn that around. Imagine the target is standing still and you are
going away from it at bullet speed. Same ting happens, mon. De bullet hits
de ground.

Like incest, it's all relative.

Rich S.

[Rich S.]

"Montblack" > wrote in message
...
> wrote)
>> Won't it drop stairght down toward the manhole cover? (Yes it will.)
>
>
> Gads, you're right! Crap, now it's basically T-ball at the manhole cover.
> There goes my 1.35 ERA!!
>
>
> Montblack

I had a .98 GPA one semester. Only courses I passed were Physics 101 and
ROTC.
Nobody flunked ROTC.

Oh! ERA. Never mind.

Rich S.

[Rich S.]

"Harry K" > wrote in message
oups.com...
>
> The way I see it, you are both in agreement. Fred says to hit the 109
> he has to fire at the exact time the 17 croses the 109's path. That is
> correct. In effect he says that to fire as per your example he can't
> hit it.

We are. Just had to define a few terms and conditions.

Rich S.

[Rich S.]

"Dan, U.S. Air Force, retired" > wrote in message
news:cdOTe.9805$dm.6970@lakeread03...

> Forgetting turbulence following the B-17 the bullet would still have a
> muzzle velocity of 900 FPS, assuming a military load. 50 yards is 50 yards
> and the Me109 would still be hit assuming proper aim. Whether it does much
> more than penetrate the canopy I don't know. Put the trailing turbulence
> back into the scenario and all bets are off.

Remember, the ME-109 is not following the B-17. It is crossing behind the
B-17 at 90° and is fifty yards behind the bomber at the moment their flight
paths cross. The bullet comes out of the muzzle with a velocity of 820 fps
relative to the pistol. The pistol however, is traveling 820 fps in the
opposite direction relative to the ME-109. Therefore the bullet has zero
velocity toward the ME-109 and drops straight down due to gravity.

Rich S.

[Rich S.]

"Dan, U.S. Air Force, retired" > wrote in message
news:MjOTe.9806$dm.4606@lakeread03...
> Blueskies wrote:
>
>> But just imagine, as the bullet falls to earth, it will remain horizontal
>> for a while due to the gyroscopic spin caused by the rifling...
>>
>
> No, the bullet will start dropping due to gravity immediately upon
> exiting the muzzle.

But, it will drop in a horizontal attitude. Pretty much, that is. Since it
begins to accelerate downward, the axis of rotation will diverge due to
gyroscopic precession. Don't ask me in which direction, though.

Rich S.

[Rich S.]

" Blueskies" > wrote in message
...
> But just imagine, as the bullet falls to earth, it will remain horizontal
> for a while due to the gyroscopic spin caused by the rifling...

Quite a while, actually. If you fire it straight up, it will likely land on
it's butt - still spinning. Ever done the math to figure the rpm of a .45
ACP? The twist of the barrel IIRC, is one turn in 9 inches. If it's
traveling at 820 fps at the muzzle, that is 1093 nine inch increments per
second or 65,580 rpm. No wonder the gun twists in your hand during recoil.

Rich S.

[[email protected]]

Rich S. wrote:
> > wrote in message
> ups.com...
>
> You're still assuming he's leading the ME-109 as if the gunner
> were in a fixed location. He's assuming the gunner is actually
> trying to hit the plane, and smart enough to figure out how
> so that he times his shot *correctly*. You're both assuming
> he fires straight back. He can hit the Me-109 by firing straight
> back, but ONLY if he fires exactly as B-17 crosses the flight
> path of the Me-109, and only if the Me-109 is fast enough or
> close enough to get there before the bullet drops out of the
> flight path of the Me-109. If the Me-109 is at a range of 50
> yards, and no slower than the bullet the bullet will be no
> more than 7 inches lower than the muzzle of the gun and will
> still hit the Me-109 assuming the two planes are at the same
> altitude.
>
> Fred...............
>
> I'll say it again - you misunderstand the question.

NO. I understood the question(s) and I answered them. The gunner
cannot hit the ME 109 by aiming and firing the ways you
described. There are an infinite number of ways the gunner
can aim and fire and miss, you picked some of them.

You also stated multiple versions with different
circumstances, not just different wording. It is not clear
that you realize that.

After answering YOUR questions, we then addressed the question
of how the gunner could hit the ME 109. That question was
NOT your question. That is a different question and I
don't see how I can make THAT any clearer to you.

No rule of nettiquette requires that we limit our discussion
to only the case you present. You are not the boss of us!
Courtesy requires that we make it clear when and how we
change the statement of the problem. We have made that
clear. You just don't realize that. We changed the
problem by relaxing the constraint on when the gunner
leaving him free to fire whenever he wants to.

Why? Because we're Americans goddamnit we want him
to score a hit. What are you, German?

> clearly as I am able and even drawn a diagram. I don't know how else to
> explain it. I'm a pilot. I talk with my hands (hopefully without resorting
> to certain gestures).
>
> The B-17 is flying West. The ME-109 is flying South. They are both at the
> same altitude. There is no wind. The ME-109 will cross the flight path of
> the B-17 and the B-17 will, at that moment, be fifty yards from the ME-109.
> The tail gunner fires his weapon straight behind the B-17.

In *this* statement of the question, unlike
your first, you do not say WHEN he fires.
Since I WANT him to hit, I'll tell YOU
when he fires.

Got it!

He can hit the ME-109 by firing when the B17 crosses the flight
path of the ME-109. Then the Me-108 is due North of the gunner.
If he waits any longer, the Me-109 passes east of the bullet.
If he fires sooner, the Me-109 passes West of the bullet.

If he fires when the ME 109 is due North the Me-109 either
hits the bullet or passes over it depending on the range and
speed of the Me-109.

You specified that the Me-109 passes fifty yards behind
the B-17. A hit requires that the time
between firing and the time the ME-109 arrives behind the
B-17 is the time it takes the B-17 to travel 50 yards.
OP already calculated that, and also calculated that the
bullet drops 7 inches in that time. You did not
specify the speed of the ME-109 or the range when the
gunner fires, so we are free so vary those as needed.
there are several combinations of speed and range that
allow the ME-109 to be due North when he fires and
cross 50 yards behind. For instance, if the Me-109
is flying at the same speed as the B-17 and it crosses
50 yards behind it, then the Me-109 will also be 50 yards
when it is due North of the B-17 and the gunner can therefor
fire when the B17 is at a range of 50 yards and hit.
What a coincidence!

This time around I did not have to change the problem
because this time around you did not constrain the time
at which the gunner fires.


>
> There is no way that he can hit the ME-109, given the stated speed of the
> B-17 and the muzzle velocity of the bullet.

Wrong. The way is if he fires WHEN the B-17 crosses the flight path
of the Me-109. That drops a bullet in the flight path of the Me-109
and if the Me-109 is 50 yards due North when the gunner fires and
flying at 820 fps the Me-109 and the bullet are *both* 50 yards
behind the B-17 when the Me-109 crosses the flight path of the
B-17. The bullet has only dropped 7 inches, so it hits.

>
> The ME-109 will *always* be fifty yards or more away from the bullet.
> Always.
>

Not if the gunner fires when the B17 crosses the flight path of
the Me-109. That drops the bullet right in the flight path
of the Me-109 and the Me-109 closes on it as it drops.

Here is a hint. If you constrain all of the variables to specific
values the question is 'does', not 'can'. 'Can' implies at least
on variable is unconstrained as in your question above wherein
you left the time at shich the gunner fires free to vary.

--

FF

[Rich S.]

> wrote in message
ups.com...
>
> You also stated multiple versions with different
> circumstances, not just different wording. It is not clear
> that you realize that.

I did phrase the question poorly. I have said that *several* times and
attempted to clarify the wording - not change the intent of the original
question.

Now that that's over, I still find that it is an interesting problem in
relativity and deserved rational discussion.

Rich S.

[Rich S.]

"T o d d P a t t i s t" > wrote in message
...
> If you understood the physics, why did you bother to ask the question?

Is this not a forum for discussion? What may be "obvious" to you, may be of
interest to someone else.

Why do you bother to ask?

R i c h S .

[Rich S.]

"T o d d P a t t i s t" > wrote in message
...
> Because I had a real question - Why did you ask a question
> you knew the answer to? Was it just because you thought it
> was an interesting topic for discussion?

Bingo.

Rich

[Rich S.]

"T o d d P a t t i s t" > wrote in message
...
>
> Then next time, be considerate and tell us that you don't
> have a real question.

You know, I was going to just let this dog go to sleep but this last "bit of
advice" ****es me off. You have been acting like an egotistical pompous ass
throughout the entire discussion, while I have tried my best to be polite.

Stuff it, T o d d!

Rich S.

[Rich S.]

"T o d d P a t t i s t" > wrote in message
...
> It's really not too much to ask that you
> differentiate puzzlers from legitimate requests for help.

Although it was not in my original query, I *did* explain exactly where the
question arose and my purpose in asking it. You must have missed my post of
September 7 @ 6:35 PM in reply to "abripl". I quote:

"I brought this subject up because I was reading an article in the May 1942
issue of "Flying and Popular Aviation". It was titled "Speedy" and tells the
story of a quiet young fellow named Andy McDonough who dove a new Army
fighter to 620 mph a "few weeks ago". He'd like to try for 700."

The airplane was a new P-39 Airacobra. "After his test, McDonough said he
thought of that now-famous problem: 'I wondered what would have happened if
I could have fired a pistol back over the tail. At that speed would the
bullet have rolled out of the barrel and then fallen back?'".

Well, perhaps that was a famous problem in the spring of 1942. I don't know,
having entered this vale of tears late in 1941. But I thought it would be
fun to toss it up here among all these reasonable, logical, polite folks. :)
"

I have already stated that I regret not stating the problem more clearly and
I feel that it has been obvious from the beginning that I wasn't really
asking for help in attempting to shoot down a Hun. My viewpoint.

Now, shall we put this dog to sleep? We both have more serious things to
worry about, I'm sure.

Rich S.

[Dan, U.S. Air Force, retired]

T o d d P a t t i s t wrote:

> "Rich S." > wrote:
>
>
>>> Why did you ask a question
>>>you knew the answer to? Was it just because you thought it
>>>was an interesting topic for discussion?
>>
>>Bingo.
>
>
> Then next time, be considerate and tell us that you don't
> have a real question.
>
>
> T o d d P a t t i s t
> (Remove DONTSPAMME from address to email reply.)

Todd, most of us enjoyed the exercise. Rich reminded many of us
including me how much we have forgotten over the years. My personal
revenge will be to place a dead skunk under the seat of he airplane.

Dan, U.S. Air Force, retired

[Rich S.]

"Dan, U.S. Air Force, retired" > wrote in message
news:MA%Te.10746$dm.4627@lakeread03...
> My personal revenge will be to place a dead skunk under the seat of he
> airplane.

Eeeyew! And how you gonna do it without smelling like the perp? Bathe in
tomato juice and vodka?

Rich S.

[Dan, U.S. Air Force, retired]

Rich S. wrote:

> "Dan, U.S. Air Force, retired" > wrote in message
> news:MA%Te.10746$dm.4627@lakeread03...
>
>>My personal revenge will be to place a dead skunk under the seat of he
>>airplane.
>
>
> Eeeyew! And how you gonna do it without smelling like the perp? Bathe in
> tomato juice and vodka?
>
> Rich S.
>
>
I'll never tell <g>

Dan, U.S. Air Force, retired

[Rich S.]

"T o d d P a t t i s t" > wrote in message
...
>
> Yep - Sorry if I seemed a bit grumpy - It's other things,
> not you - I actually like physics puzzlers.

Know what you mean. They said my back surgery would last ten years. It's
been nine and the Vicodin count is rising rapidly. I am also sorry for
yelling.

Rich S.

[John Ammeter]

Oh come on you guys.... don't get serious now... that would ruin your
reputations on USENET.

John (I learned to like Rum and Cokes from Rich S) Ammeter

( I ALSO learned to dread his almost daily reports on his bowel
movements... I learned to NEVER take another road trip with Rich)

T o d d P a t t i s t wrote:
> "Rich S." > wrote:
>
>
>>You know, I was going to just let this dog go to sleep but this last "bit of
>>advice" ****es me off. You have been acting like an egotistical pompous ass
>>throughout the entire discussion, while I have tried my best to be polite.
>
>
> Interesting. I thought I was trying to be polite too. If I
> gave offense, it was unintentional, and I apologize. (I can
> hear the Usenet gasps - an apology! - coming through my
> network connection :-) From my point of view, someone asked
> for help, I spent time trying to give it, then I found out
> that it was a trick question, somewhat poorly expressed at
> that. It's really not too much to ask that you
> differentiate puzzlers from legitimate requests for help.
>
> T o d d P a t t i s t
> (Remove DONTSPAMME from address to email reply.)
> ___
> Make a commitment to learn something from every flight.
> Share what you learn.

[John]

T o d d P a t t i s t wrote:

> "Rich S." > wrote:
>
>>Know what you mean. They said my back surgery would last ten years. It's
>>been nine and the Vicodin count is rising rapidly. I am also sorry for
>>yelling.
>
>
> I've been out of flying twice this year with a back problem.
> While I was out, a developer signed a contract to buy our
> airport (N82) and the current airport manager is destined to
> be his partner. The town offered to buy the airport for
> more money than the developer, but the executrix of the
> estate and heir to the airport property sold it to the
> developer instead. (Two of the 4 heirs fought the
> executrix, as they love the airport, but one recently died
> of appendicitis, and the other is being evicted from her
> family home on the airport property.)
>
> The town doesn't want to lose the airport. The pilots were
> told if they spoke at the town meeting against the developer
> they'd be kicked off the airport.
There are laws against coersion I'd have my lawyer suit for enough for you
to take over the airport for payment! ;-)
John
I put developers in the same catagory as doctors (especially FAA!) and
lawyers.

[BRO]

You've made an irrelevant assumption here.


The answer is "It's all a matter of relativity"
With the correct lead, it does not matter what speed relative to the ground
the bullet is travelling, relative to the two aircraft is what is important.
remember the bullet is spinning so also maintains some gyroscopic stability.

All bullets fall to earth at 9.8 m/s^2 regardless of their path over the
surface of the earth.

With the correct lead the bullet and the ME-109 colide, at which point the
tragectory of the bullet is drasticaly altered such that it, and teh ME-109
all fall/fly to earth as one mass.

If the case is simplified such that the bullet is simply fired backwards but
at nothing, then it will accelarate to earth, only with a 0 lateral velocity
relative to the ground.


Rgds,

"Rich S." > wrote in message
...
> There is a (magic) B-17 flying along at 560 mph. The tail gunner is out of
> .50 caliber ammo. He sees a Messerschmitt ME-109 crossing behind the B-17,
> 50 yards away.
>
> He pulls out his trusty .45 Colt auto (muzzle velocity 820 fps) and fires
> at the Hun when the ME-109 is directly behind the B-17. He leads the
> Messerschmitt by exactly enough to hit the pilot (if he were firing from a
> fixed position).
>
> Does the bullet exit the muzzle and fall directly to earth?
>
> Rich "Scratching my head" S.
>

[[email protected]]

Quick question: what does a plane have that a bullet lacks?


>Answer: an engine to maintain its speed.


>Bullets start slowing down the moment they leave the muzzle (alright,
>just slightly *after* they leave the muzzle), while the aircraft that
>fired them can maintain its speed.

But in this case there is no air friction to "slow" the bullet.
It leaves the gun into still air, and so if the bomber is accelerated a
bit by the gun's recoil, its muzzle velocity is a bit less than the
airplane's velocity and so will move "forward" a little as it falls.


Dan

[RST Engineering]

Several people, most of whom have at least had physics, and at least one
with a degree in physics have stated that you are wrong and why. Suggest
you read the thread before you post.

Jim



"BRO" > wrote in message
...



>
> With the correct lead the bullet and the ME-109 colide, at which point the
> tragectory of the bullet is drasticaly altered such that it, and teh
> ME-109 all fall/fly to earth as one mass.
>

[Alan Baker]

In article . com>,
wrote:

> Quick question: what does a plane have that a bullet lacks?
>
>
> >Answer: an engine to maintain its speed.
>
>
> >Bullets start slowing down the moment they leave the muzzle (alright,
> >just slightly *after* they leave the muzzle), while the aircraft that
> >fired them can maintain its speed.
>
> But in this case there is no air friction to "slow" the bullet.
> It leaves the gun into still air, and so if the bomber is accelerated a
> bit by the gun's recoil, its muzzle velocity is a bit less than the
> airplane's velocity and so will move "forward" a little as it falls.
>
>
> Dan

Read the question I answered...

> > > > A related question: Haven't there been cases of supersonic
> > > > fighters shooting themselves down when they caught up to the shells
> > > > they'd fired forward?
> > > >
> > > > Dan
> > >
> > > I was hoping someone would answer that. I recall seeing/hearing/reading
> > > somewhat the same thing back when. Best I can recall it involved an
> > > F-86 or equivalent (not supersonic) and happened by firing and then
> > > going into a dive thus flying into the bullet stream. Are 50 cal
> > > bullets supersonic?
> > > If so, the plane would also have to be.
>

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling 4 feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect
if you sit in the bottom of that cupboard."

[Morgans]

"John" > wrote

> There are laws against coersion I'd have my lawyer suit for enough for you
> to take over the airport for payment! ;-)
> John
> I put developers in the same catagory as doctors (especially FAA!) and
> lawyers.

I'm with you, on that. He should be able to get a lawyer to take the case,
for a percentage of the settlement, and still clean up, and get to keep the
airport.

I would sue each of the members of the council, and the one who delivered
the threat, and whoever ordered the threat given, and the town as a whole,
and the developer.

Don't go quietly on this on, Todd. You can win this one, hands down. You
will find plenty of support for you, too, I'll bet. Oh, and call AOPA, and
get them involved. I'll bet they would be salivating, to get ahold of this!
--
Jim in NC

[Morgans]

"T o d d P a t t i s t" > wrote
>
> The AOPA was at the town meeting where I stood up and said
> we'd all been threatened. So far three pilots have been
> ejected. I think the stink has stopped the process, but the
> pilots have agreed to all stand up and oppose the developer
> next meeting.

Good.

The more I think about this, the more ****ed (and I don't mean intoxicated)
I get.

In case it isn't possible to do things the nice way in the end, document,
document, document.

If they are still refusing you tow, I would fly in, ask for a tow, and if
refused, as for the refuser to sign a statement, or even better, wear a tape
recorder.

Be prepared to have things go badly. Assume they will. Be happy if they
don't. Did I say document, document, document? <g>
--
Jim in NC

[Blueskies]

"Dan, U.S. Air Force, retired" > wrote in message news:MjOTe.9806$dm.4606@lakeread03...
> Blueskies wrote:
>
>> But just imagine, as the bullet falls to earth, it will remain horizontal for a while due to the gyroscopic spin
>> caused by the rifling...
>>
>
> No, the bullet will start dropping due to gravity immediately upon exiting the muzzle.
>
> Dan, U.S. Air Force, retired


Exactly, but in a horizonal attitude...assuming the gun was fired straight back...

[Blueskies]

"Rich S." > wrote in message ...
> There is a (magic) B-17 flying along at 560 mph. The tail gunner is out of .50 caliber ammo. He sees a Messerschmitt
> ME-109 crossing behind the B-17, 50 yards away.
>
> He pulls out his trusty .45 Colt auto (muzzle velocity 820 fps) and fires at the Hun when the ME-109 is directly
> behind the B-17. He leads the Messerschmitt by exactly enough to hit the pilot (if he were firing from a fixed
> position).
>
> Does the bullet exit the muzzle and fall directly to earth?
>
> Rich "Scratching my head" S.
>

OK, more questions. What was the muzzle velocity of the .50 machine guns used as tail guns? What kind of gun was
installed in the stinger on a B-58?

[Dan, U.S. Air Force, retired]

Blueskies wrote:

> "Rich S." > wrote in message ...
>
>>There is a (magic) B-17 flying along at 560 mph. The tail gunner is out of .50 caliber ammo. He sees a Messerschmitt
>>ME-109 crossing behind the B-17, 50 yards away.
>>
>>He pulls out his trusty .45 Colt auto (muzzle velocity 820 fps) and fires at the Hun when the ME-109 is directly
>>behind the B-17. He leads the Messerschmitt by exactly enough to hit the pilot (if he were firing from a fixed
>>position).
>>
>>Does the bullet exit the muzzle and fall directly to earth?
>>
>>Rich "Scratching my head" S.
>>
>
>
> OK, more questions. What was the muzzle velocity of the .50 machine guns used as tail guns? What kind of gun was
> installed in the stinger on a B-58?
>
>
I don't recall the actual velocity of the 50, but it was supersonic.
The B-58 tail gun was the M-61A1 20mm cannon.

Dan, U.S. Air Force, retired

[Rich S.]

" Blueskies" > wrote in message
...
>
> OK, more questions. What was the muzzle velocity of the .50 machine guns
> used as tail guns?

Try 2912 fps or 1747 knots. Real B-17's cruised about 145 knots from the IP
to the drop point, IIRC.

This means the bullet, fired directly aft, will still have a ground speed of
1602 knots.

Rich S.

[Blueskies]

"Dan, U.S. Air Force, retired" > wrote in message news:hWBUe.10909$dm.6874@lakeread03...
> Blueskies wrote:
>
>> "Rich S." > wrote in message ...
>>
>>>There is a (magic) B-17 flying along at 560 mph. The tail gunner is out of .50 caliber ammo. He sees a Messerschmitt
>>>ME-109 crossing behind the B-17, 50 yards away.
>>>
>>>He pulls out his trusty .45 Colt auto (muzzle velocity 820 fps) and fires at the Hun when the ME-109 is directly
>>>behind the B-17. He leads the Messerschmitt by exactly enough to hit the pilot (if he were firing from a fixed
>>>position).
>>>
>>>Does the bullet exit the muzzle and fall directly to earth?
>>>
>>>Rich "Scratching my head" S.
>>>
>>
>>
>> OK, more questions. What was the muzzle velocity of the .50 machine guns used as tail guns? What kind of gun was
>> installed in the stinger on a B-58?
> I don't recall the actual velocity of the 50, but it was supersonic.
> The B-58 tail gun was the M-61A1 20mm cannon.
>
> Dan, U.S. Air Force, retired
>

The B-58 was mach 1.6 or so, right? Any idea what the muzzle velocity is for the M-61A1? I read somewhere that the radar
for the gun tracked targets in a 30° cone behind the plane...

[[email protected]]

Rich S. wrote:
> > wrote in message
> ups.com...
> >
> > You also stated multiple versions with different
> > circumstances, not just different wording. It is not clear
> > that you realize that.
>
> I did phrase the question poorly. I have said that *several* times and
> attempted to clarify the wording - not change the intent of the original
> question.
>
> Now that that's over, I still find that it is an interesting problem in
> relativity and deserved rational discussion.
>

Ah, if you want a problem in relativity, have the gunner shine a
flashlight on the Me-109.

This was interesting and a lot of fun. It's fun to consider
alternatives.

--

FF

[[email protected]]

Harry K wrote:
> wrote:
> > He misses the ME-109 because the recoil of firing the bullet
> > accelerates the B-17 just a bit, so that the bullet, travelling at a
> > little less than the bomber's speed actually briefly follows the bomber
> > as it falls.
> >
> > A related question: Haven't there been cases of supersonic
> > fighters shooting themselves down when they caught up to the shells
> > they'd fired forward?
> >
> > Dan
>
> I was hoping someone would answer that. I recall seeing/hearing/reading
> somewhat the same thing back when. Best I can recall it involved an
> F-86 or equivalent (not supersonic) and happened by firing and then
> going into a dive thus flying into the bullet stream. Are 50 cal
> bullets supersonic?
> If so, the plane would also have to be.

I don't know the muzzle velocity of 50 caliber ammo but even it
is supersonic, it is balistic whereas the plane is powered so
it could (maybe) dive and catch the bullets as they slowed.

--

FF

[[email protected]]

RST Engineering wrote:
> Several people, most of whom have at least had physics, and at least one
> with a degree in physics have stated that you are wrong and why. Suggest
> you read the thread before you post.
> ...
>
>
> "BRO" > wrote in message
> ...
>
>
>
> >
> > With the correct lead the bullet and the ME-109 colide, at which point the
> > tragectory of the bullet is drasticaly altered such that it, and teh
> > ME-109 all fall/fly to earth as one mass.
> >

No. With the _correct_ lead he can hit.

The _correct_ lead is different from how he would lead if
he was firing from a fixed position.

The _correct_ lead is incompatible with firing when the ME-109 is
directly behind the B-17. He cannot correctly lead the Me-109
AND fire when the Me-109 is directly behind the B-17. But he
CAN correctly lead AND fire straight back.

In fact, he correct lead if the ME is at a range of 50 yards,
when the B17 crosses the flight path of the ME-109,
is to fire straight back. Then he will hit when the Me-109
is fifty yards behind the B-17.

The problem is not with what he said, but with what he did
not say. He didn't say what part of the original problem
he was changing in order to introduce his new condiditon,
_correctly_ leading he Me-109. Maybe he didn't realize
there was an incompatibility, or mybe he thought it
would be obvious which statement he was dropping.

Which just serves to demonstrate the conventional wisdom
about assumptions.

--

FF

[CB]

All 'a dem Fokkers wuz Messerschmits!