Aircraft bomb frag patterns

[Mike D]

Am trying to find some info to help accurize (a somewhat outdated)
Vietnam era flight sim - Janes Fighters Anthology. Can any of you
military folks remember any numbers about the blast frag distances for
various aircraft bombs - 500/750/2000/3000 lb? How about
nape/CBUs/2.75 in FFARs? What would be the safe release heights for
each or any of these before you can expect to be affected by your own
ordnance? I don't have access to an F-105 or F-4 dash 34 manual, but I
bet that would answer my questions.
Thanks,
Mike Druzolowski

[John R Weiss]

"Mike D" > wrote...
> Am trying to find some info to help accurize (a somewhat outdated)
> Vietnam era flight sim - Janes Fighters Anthology. Can any of you
> military folks remember any numbers about the blast frag distances for
> various aircraft bombs - 500/750/2000/3000 lb? How about
> nape/CBUs/2.75 in FFARs? What would be the safe release heights for
> each or any of these before you can expect to be affected by your own
> ordnance? I don't have access to an F-105 or F-4 dash 34 manual, but I
> bet that would answer my questions.

Most of that information is in Confidential Tactical Manuals. It also varies
widely with delivery parameters, fuzes, and other variables.

[Mark]

You are really asking two different questions....

The Fragment Envelope for the weapon (how high, far, fast do fragments
travel) ....

And the safe release height for that weapon....

In level flight you can drop (a single MK-82 for example) from an altitude
lower than the maximum height of the frag pattern (due to your forward
velocity during the time of fall and the time for the fragments to travel
outward). The slower you are the higher you need to drop and vice versa

Then you need to throw in the fuze arming delay, diving deliveries, ripple
deliveries, type of escape maneuver (level, climbing, turning, lateral,
backup) etc....

So if you were going to check out your modeling, and simply looked at
maximum height of the frag pattern to determine if you were a 'mort' or not,
I'd think you'd be given a false view of what's really going on.

FWIW

Mark


"Mike D" > wrote in message
om...
> Am trying to find some info to help accurize (a somewhat outdated)
> Vietnam era flight sim - Janes Fighters Anthology. Can any of you
> military folks remember any numbers about the blast frag distances for
> various aircraft bombs - 500/750/2000/3000 lb? How about
> nape/CBUs/2.75 in FFARs? What would be the safe release heights for
> each or any of these before you can expect to be affected by your own
> ordnance? I don't have access to an F-105 or F-4 dash 34 manual, but I
> bet that would answer my questions.
> Thanks,
> Mike Druzolowski

[Mike D]

Thanks for the responses. I guess what I'm looking for is the minimum
safe release altitude (estimate) where you could release in a dive
then level out right over the target (I know, not recommended) and not
heve to worry about being knocked out of the sky. (I just don't want
to be able to drop a 3000 lb. M118 from 900 feet at 190 knots and fly
away unscathed, because I suspect that this is way too low! The
DuoSoft Toolkit allows creation and/or modification of ordnance used
within the sim, but I don't have any real world info to base some of
the characteristics on.
Thanks again everyone.
Mike D.

[Guy Alcala]

Mike D wrote:

> Am trying to find some info to help accurize (a somewhat outdated)
> Vietnam era flight sim - Janes Fighters Anthology. Can any of you
> military folks remember any numbers about the blast frag distances for
> various aircraft bombs - 500/750/2000/3000 lb? How about
> nape/CBUs/2.75 in FFARs? What would be the safe release heights for
> each or any of these before you can expect to be affected by your own
> ordnance? I don't have access to an F-105 or F-4 dash 34 manual, but I
> bet that would answer my questions.

Safe release heights vary considerably due to speed, angle, clean or
retard, maneuver, etc., and are much too long to list here. If you really
want this stuff you need to invest in a -34. The following info is from
the frag graphs, but realize that each of these shows a pure vertical time
vs. height envelope, as well as a coupel of horizontal time vs. height vs.
distance curves. I'm just giving you the height and max. horizontal
distances.

Max. frag. envelopes from the F-4C-34-1-1:

Mk. 82: Top of frag envelope 2,520 feet vertical @ 9 seconds after
detonation. Max. horizontal spread at ground level +- 3,100 feet 2 13
seconds plus.

Mk. 83: Top 2,820 feet vertical @ 9 sec. after detonation. Max.
horizontal spread @ ground level +- 3,400 feet @ 15 sec. plus

Mk. 84: Top 2,820 feet vertical @ 9 sec. after detonation. Max.
Horizontal spread @ ground level +-3,400 feet @ 15 sec. plus.

M117 (Tritonal filling): Top 2,450 feet vertical @ 7 seconds after
detonation. Max. horizontal spread @ ground level +-2,900 feet @ 13 sec.
plus.

Unfortunately, there's no frag envelope graph for the M118, just safe
escape and safe tables (the other bombs also have these), which would take
far too long to type in.

HTH,

Guy

[BUFDRVR]

>Dropping a slick from level flight below 1000 is dangerous because the
>bomb can bounce back up.

Known as "broaching"(if the weapon actually enters the ground below it, then
"pops back up) or "ricocheting" (if the weapon simply hits the ground and
bounces back up).

>We dropped inert Mk82s at 300 AGL 500K and
>the things were bouncing up level with us. (They were also bouncing
>off the Avon Park range so we had to stop that.)

Walt, surely this was known about in the 60's and 70's no? I find it hard to
believe this is a recently discovered phenomena. It's not a comfortale feeling
to fly "in formation" with your own weapons. As a young co-pilot I watched one
of our Mk-82 AIRs fly up in front of the wing, then off to the side. Obviously
the AIR didn't function.


BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

[Walt BJ]

For BUFDRVR - bouncing bombs were known about in WW2 - skip-bombing.
Very effective against ships (Bismarck Sea). Was also used against
tanks. (And big dams) We just didn't expect to see it at Avon Park
that day in 1968. It was a low ceiling, under 1000 AGL, and we
couldn't dive bomb. Our IP had big ones and gave us the choice of
dropping or aborting to fly the mission again on a better day. We
wanted to drop so he led us around the pattern. About the third time
around the Range Officer called a halt as the bouncers were going off
the south end of the tactical range and that was it for the day. We
formed up and got another thirty minute of wing weather time going
home. We did get an actual road cut - one of the bombs hit the
thin-layer asphalt-on-sand road around the end of the tac range and
cratered it nicely. (500# concrete filled M82 dropped at 450 KIAS) I
suppose that would be a major incident these days. Back then it was
just worth a chuckle or two. Sigh. Skip bombing went out of favor just
before/during SEA - flak. We used to bet on range scores - hits 'on
the fly' were all that counted in operational outfits, dropping blue
bombs (BDU33) in level flight at 50' agl and 450 against a 10x20 cloth
target. Going below the range tower's sight line - about 40') was a
foul - no score.
Walt BJ