Bomb hits tailplane on release

On Wed, 23 Jun 2004 17:27:32 +0100, Robert Briggs
wrote:

Ed Rasimus wrote:

Higher speeds mean the store can generate lift (just like any curved
surface.)

IIRC, "curved" is unnecessary here. After all, they do say that, given
enough thrust, a brick will fly, do they not?

Actually, no. Lift is balanced by weight, while thrust opposes drag.
The brick (AKA F-4) would not really "fly", but simply be propelled in
the desired direction. It is the tendency for airflow to accelerate
over a curved surface creating a low pressure area that causes "lift".
The dropped store had better be curved if you want to get lift, since
it isn't supplied with thrust.


Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
Smithsonian Institution Press
ISBN #1-58834-103-8

"Ed Rasimus" wrote in message
...
On Tue, 22 Jun 2004 22:46:32 -0400, "Kevin Brooks"
wrote:


The A3D was not the only member of that family that experienced such a
problem. Knew a guy who flew B-66's (and later EB-66's) who told me that
it
was unnerving to do a bomb drop from the Destroyer because it sometimes
had
a habit of having bombs "bounce" around in the bomb bay after release
before
actually leaving the aircraft (which may explain why its career as a
bomber
was rather short).

Brooks

Early prototypes of the F-105 attempted conventional rigging of the
B-28-RE in the internal bomb-bay. No one anticipated the boundary
layer along the fuselage at 600 knots IAS. When the bombbay opened for
bomb release, shackles opened and bomb dropped a few inches but didn't
come through the high speed airflow. Bombbay doors reclosed with bomb
simply resting on the doors. (Shape--of course, not hot weapon!)

Solution was a "displacing gear"--a roughly six-inch diameter,
pneumatic piston that had about a two foot throw. Charged to a couple
of thousand pounds/sq-inch, the piston was said to either push the
bomb down or the airplane up.

All became moot because the airplane never carried an internal nuke
operationally. Displacing gear was still in place, however.

The boundary layer flow was the reason for the B-66 problem as well, from
what I remember of the gent's explanation. But in his case ISTR he
experienced it when dropping conventional ordnance during a training
evolution; I remember him distinctly mentioning "bombs" (plural) thudding
around, and IIRC he indicated a little pull up on the nose was used to
ensure their eventual departure. I do know he said it was not a pleasant
experience!

Brooks



Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
Smithsonian Institution Press
ISBN #1-58834-103-8

Robert Briggs wrote:
Richard Brooks wrote:
Paul Housley wrote:

A while ago, I saw video footage of a bomb being released from a
fighter-bomber under test conditions. It was on an aviation
documentary. The high speed camera then shows it climb up and
destroy the tailplane. I don't think they quite got their
trajectory calcs right!

This shows up towards the end of a documentary called Dambusters,
which has been seen on UKs Channel 4.

The Lanc may have had guns, but that doesn't make it a fighter-bomber.


I'm sorry, I didn't give enough information. The footage of the American
aircraft disintegrating, being sought was at the end of the hour-long
documentary which included photos with a German officer standing beside a
mine which had not exploded, interviews with one of the tower sentries,
interviews with people who lived near the dams, German and American
variants, etc . It's been the best documentary on the whole bouncing bomb
idea

Richard.

To be 'technically' correct... a wing with camber (curved) can generate
lift at zero angle of attack. A symmetric airfoil (such as a flat brick)
cannot, it must be at a positive angle of attack to generate lift (but the
point is... it CAN). Both generate lift (positive C sub L) but at different
AOA. At 'normal' airspeeds the coefficient of lift may not be sufficient
for a brick to generate enough lift to fly, but then again if the airspeed
was high enough....

Here's some reading on the subject....

"...Almost any relatively flat surface could be made to generate some lift.
In fact, a perfectly flat thin plate will do the job. If you don't believe
that, try out any of a number of simple little balsa-wood hand launched
model gliders. Most of them have flat wing sections, and they fly. The flat
plate, then, is probably the simplest of airfoil sections, as shown in
Figure 5..."

From the following site

http://142.26.194.131/aerodynamics1/Basics/Page4.html

Mark

"Robert Briggs" wrote in message
...
Ed Rasimus wrote:

Higher speeds mean the store can generate lift (just like any curved
surface.)

IIRC, "curved" is unnecessary here. After all, they do say that, given
enough thrust, a brick will fly, do they not?

"Pete" wrote:

ISTR an F-111 film of that, too.

The store (or tank) separated, floated in the slipstream for a second or
two, then went straight back and cleaned off the right stab.

That is what I remember as well. Wasn't a chase plane also caught up in the
mishap?

-- Charlie Springer

Ed Rasimus wrote:
Robert Briggs wrote:
Ed Rasimus wrote:

Higher speeds mean the store can generate lift (just like any curved
surface.)

IIRC, "curved" is unnecessary here. After all, they do say that, given
enough thrust, a brick will fly, do they not?

Actually, no. Lift is balanced by weight, while thrust opposes drag.

This assumes more than I wrote.

Can you say "Harrier", for example?

Okay, I didn't have that aeroplane in mind, but I *was* careful not to
specify any particular angle of attack - after all, an "inverted" pass
at an air display is not *exactly* inverted, with the aerofoil acting
against you (in the case of "ordinary" aeroplanes, at any rate).

The brick (AKA F-4) would not really "fly", but simply be propelled in
the desired direction. It is the tendency for airflow to accelerate
over a curved surface creating a low pressure area that causes "lift".
The dropped store had better be curved if you want to get lift, since
it isn't supplied with thrust.

I was also careful to omit any assertion about the aerodynamic stability
of the brick.

In article ,
Ed Rasimus wrote:

On Wed, 23 Jun 2004 17:27:32 +0100, Robert Briggs
wrote:

Ed Rasimus wrote:

Higher speeds mean the store can generate lift (just like any
curved surface.)

IIRC, "curved" is unnecessary here. After all, they do say that,
given enough thrust, a brick will fly, do they not?

Actually, no. Lift is balanced by weight, while thrust opposes drag.
The brick (AKA F-4) would not really "fly", but simply be propelled in
the desired direction. It is the tendency for airflow to accelerate
over a curved surface creating a low pressure area that causes "lift".
The dropped store had better be curved if you want to get lift, since
it isn't supplied with thrust.

....except when you're looking at something like the B-70 "waverider"
technique, where the underside of the plane provides compression lift,
without providing classical Bernoulli-type lift.

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

"Paul Housley" wrote in message
om...
Perhaps a bit of a random question for this newsgroup.

A while ago, I saw video footage of a bomb being released from a
fighter-bomber under test conditions. It was on an aviation
documentary. The high speed camera then shows it climb up and destroy
the tailplane. I don't think they quite got their trajectory calcs
right!

Has anyone seen this video? Does anyone know where I could get a copy.
Stills from it would be fine. It's for a uni project in case you were
wondering.

If not, anyone able to point me in the right direction of where to
ask?

Thanks for your help.

Paul.

We have a compilation video at work of "Store Release gone WRONG!" Makes
interesting viewing before we start doing release and jettison work.
Unfortunately it would be too large to email out of the office (and I don't
think the security people would like it too much!)

Its made up mainly of Edwards/Eglin/Pax River stuff, but a few things from
RAF/RN are in it as well.....

The store (or tank) separated, floated in the slipstream for a second or
two, then went straight back and cleaned off the right stab.

That is what I remember as well. Wasn't a chase plane also caught up in the
mishap?

Are you thinking of the F/A Teen test where a Mk 82 plus the pylon detaches and
wipes out the TA-4 chase plane? Some of the nastiest video I have seen - you
can almost hear the Scooter pilot yelling, "What the hell did you doooooooo!!!"
just as he flinches into the path of the oncoming bomb. Bonus points for the
crew, staying in their flaming torch for the first 6-7 fiery tumbles, then
ejecting just before the debris rains down next to the range observation boat.
A++ video clip (cuz no one got kilt).

v/r
Gordon


====(A+C====
USN SAR

Its always better to lose -an- engine, not -the- engine.

"Ian" wrote

We have a compilation video at work of "Store Release gone WRONG!" Makes
interesting viewing before we start doing release and jettison work.
Unfortunately it would be too large to email out of the office (and I
don't
think the security people would like it too much!)

Its made up mainly of Edwards/Eglin/Pax River stuff, but a few things from
RAF/RN are in it as well.....

As an ex-weapons troop, I'd *love* to see that.

Pete