Carrier Catapault Hold-Back Bar ?

Hi,

Have always been interested in catapults on carriers, but have never been
able to find any good drawings or diagrams showing how the hold-back
mechanisms work.

I remember in the "old days" that they used breakable/frangible bars, but I
doubt that these are used anymore.
Are they ?

Anyone know of any links or pix/diagrams showing details of how they are
constructed, and used, these days ?

Looked pretty exhaustively, but cannot come with any.
Am a retired mechanical engr., and have always been interested in this
component.

Thanks,
Bob

"Robert11" wrote in
:

Hi,

Have always been interested in catapults on carriers, but have never
been able to find any good drawings or diagrams showing how the
hold-back mechanisms work.

I remember in the "old days" that they used breakable/frangible bars,
but I doubt that these are used anymore.
Are they ?

Anyone know of any links or pix/diagrams showing details of how they are
constructed, and used, these days ?

Looked pretty exhaustively, but cannot come with any.
Am a retired mechanical engr., and have always been interested in this
component.

Actually, they are still using the same system. The holdbacks resemble
dogbones or dumbbells in shape, and each aircraft has its own uniquely
shaped and colored item. They are machined to a specific thickness, and
part at a given tension.

There's a pic here of the A-4 setup:
http://www.tpub.com/content/aviation...s/14014_86.htm

Dave in Sandy Eggo

On 20 Jan, 10:27, Dave wrote:
"Robert11" wrote :





Hi,

Have always been interested in catapults on carriers, but have never
been able to find any good drawings or diagrams showing how the
hold-back mechanisms work.

I remember in the "old days" that they used breakable/frangible bars,
but I doubt that these are used anymore.
Are they ?

Anyone know of any links or pix/diagrams showing details of how they are
constructed, and used, these days ?

Looked pretty exhaustively, but cannot come with any.
Am a retired mechanical engr., and have always been interested in this
component.

Actually, they are still using the same system. The holdbacks resemble
dogbones or dumbbells in shape, and each aircraft has its own uniquely
shaped and colored item. They are machined to a specific thickness, and
part at a given tension.

There's a pic here of the A-4 setup:http://www.tpub.com/content/aviation...s/14014_86.htm

Dave in Sandy Eggo

Hard to make anything more reliable than a lump of metal.
Reasonably testable too I would think.

Actually, what we currently use is called "RRHB", (repeatable release
holdback bar).

It is similar to what is talked about in previuos posts, but much more
high tech and reliable to the old plain holdback bar.

In fact, it is high visibility and closely monitored and NDI'd (non
destructive inspection) on a highly controlled schedule.

Go ahead and GOOGLE "RRHB", I'll bet you'll find a drawing of the one
currently in use.


0 On Wed, 23 Jan 2008 05:15:22 -0800 (PST), wrote:

On 20 Jan, 10:27, Dave wrote:
"Robert11" wrote :





Hi,

Have always been interested in catapults on carriers, but have never
been able to find any good drawings or diagrams showing how the
hold-back mechanisms work.

I remember in the "old days" that they used breakable/frangible bars,
but I doubt that these are used anymore.
Are they ?

Anyone know of any links or pix/diagrams showing details of how they are
constructed, and used, these days ?

Looked pretty exhaustively, but cannot come with any.
Am a retired mechanical engr., and have always been interested in this
component.

Actually, they are still using the same system. The holdbacks resemble
dogbones or dumbbells in shape, and each aircraft has its own uniquely
shaped and colored item. They are machined to a specific thickness, and
part at a given tension.

There's a pic here of the A-4 setup:http://www.tpub.com/content/aviation...s/14014_86.htm

Dave in Sandy Eggo

Hard to make anything more reliable than a lump of metal.
Reasonably testable too I would think.