Questions on catapult officer

[micro]

Burner you do your homework dont you. However, the dogbone has been phased out of current carrier ops. Whats used now is called a Repeatable Realease Holdback Bar. The best way to describe it without seeing it is a cork being pulled out of a wine bottle. The cork is the holdback bar and the bottle is the scissor link on the nose gear. The math geniuses figured out how much forward force (thrust) each aircraft can produce, then they made it so the "cork" only comes out of the bottle when more force is created (the catapult pulling the jet). This way nothing breaks, and more importantly..... no FOD.

[SpazSinbad]

Burner & Microbrewst: This was all news to me also, apparently there are two versions of this 'new' catapult system. See PDF zipped here made from a USN LSO briefing PPT (76Mbs). You can see why there are many pages on one page in zipped PDF to give a sense of what is happening (at under the 1Mb file size limit here). Unfortunately the link to the original PPT file is not available. I'll keep looking. [Pages became scrambled making this sub 1Mb PDF so bear with me - you'll figure it out.]

[burner12]

Burner you do your homework dont you. However, the dogbone has been phased out of current carrier ops. Whats used now is called a Repeatable Realease Holdback Bar. The best way to describe it without seeing it is a cork being pulled out of a wine bottle. The cork is the holdback bar and the bottle is the scissor link on the nose gear. The math geniuses figured out how much forward force (thrust) each aircraft can produce, then they made it so the "cork" only comes out of the bottle when more force is created (the catapult pulling the jet). This way nothing breaks, and more importantly..... no FOD.

Yeah here is info on it along w/ a diagram, but it's still the same priciple. 1/2 stays w/ the aircraft the other on the holdback


http://www.freepatentsonline.com/4101099.pdf

[micro]

Actually, the whole thing stays intact and nothing goes along with the aircraft. The point of it was to prevent anything from breaking. It's all based on pressurized release.

[SpazSinbad]

From another NATOPS: NAVAIR 00-80T-120 'CV Flight/Hangar Deck NATOPS Manual' June 2005

"4.3.3 Determination of Gross Weights
It is essential that the Catapult Officer know the correct gross weight of every aircraft being launched. In order to
minimize any chance of error, the gross weight shall be computed by squadron line personnel/pilot, and shall be
checked by the Catapult Officer against information available on the status board in Flight Deck Control.
4.3.3.1 Weight Chits
1. No later than 45 minutes prior to a launch, each squadron shall furnish the Catapult Officer with a weight chit
listing the computed weight of each aircraft scheduled.
2. Weight chits shall be locally prepared and shall contain the following information:
a. Squadron
b. Date
c. Launch event number or time of scheduled launch
d. Aircraft side number
e. Basic weight
f. Fuel weight
g. Ordnance/external store weight
h. Gross weight
i. Signature of person filling out chit
j. Flap setting for E-2/C-2
k. CRT/MRT for F-14/F/A-18"
&
4.4.2 Confirming Aircraft Gross Weight
As each aircraft approaches the catapult, the Weight Board Operator shall show the pilot/NFO the computed gross
weight of the aircraft. The pilot/NFO shall verify and confirm the gross weight by giving a thumbs-up signal (day)
or a circular motion with a flashlight (night). A thumbs-down or negative signal shall not be used to indicate
disagreement with the weight. If the pilot/NFO does not agree with the gross weight, he shall signal as follows:
1. Day
a. To raise gross weight, hold hand flat with palm up and move in a vertical direction, emphasizing the upward
motion.
b. To lower gross weight, hold hand flat with palm down and move in a horizontal direction.
2. Night
a. To raise gross weight, move flashlight in a vertical direction, emphasizing the upward motion.
b. To lower gross weight, move flashlight in a horizontal direction.
Note
The weight board shall be changed in 500- or 1,000-pound increments in
accordance with applicable launch bulletins.
3. When more than two corrective steps are required on the weight board or any difficulty is experienced in
confirming the gross weight, the aircraft shall not be launched until positive determination can be made by the
Air Officer and confirmed by the pilot and Catapult Officer.
4. Once the weight of the aircraft is confirmed by the pilot/NFO, the Weight Board Operator shall show the weight
board to the Catapult Officer, Centerdeck Operator, and Deckedge Operator (JBD Operator for ICCS).
a. The Centerdeck Operator, Deckedge Operator, or JBD Operator shall in turn relay this weight to the Console
Operator/CCP Operator and Recorder.
b. The Console Operator/CCP Operator shall use this weight in confirming the Catapult Officer’s desired CSV
setting using applicable launch charts.
5. The Weight Board Operator shall display the weight board to the Catapult Officer until he receives a positive
acknowledgement that the weight has been noted.
Note
One weight board is required per catapult. Once the aircraft weight is
confirmed, the weight board operator shall not change the weight displayed
until the aircraft is off the catapult.

[burner12]

Actually, the whole thing stays intact and nothing goes along with the aircraft. The point of it was to prevent anything from breaking. It's all based on pressurized release.

Then why in that diagrahm do they show it being split , like a dogbone? Can you tell me the basic way it works? Does it still connect into the back of the LG, and are different bars used for different aircraft?

[wilycoyote4]

Actually, the whole thing stays intact and nothing goes along with the aircraft. The point of it was to prevent anything from breaking. It's all based on pressurized release.

I've seen this in video I have at home on dvd but don't know of youtube showing it but there must be a youtube video so I'll look and hope someone finds it before me, lol.

[SpazSinbad]

Perhaps these 'catapult tensioner' graphics from the LSO Catapult briefing PDF explain? Last graphic (4th) is a screenshot from:

"Nuclear Aircraft Carrier Charles de Gaulle (CDG). Focus on the Steam Catapults used to launch the jets. The Steam Catapults technology is originally from Great-Britain but is only operated by USA, France and Brasil (on the Sao Paulo). French catapults are also US tech as the CDG builders thought it would be cheaper to buy the American system instead of developping their own that would do the same job. This vid is about this system and how it works."

[burner12]

So your explanation is that the t shaped end fits into the back of the gear then whe launched just falls down and the LG is empty it doesn't break, correct? Are there differetn sizes for different planes or is it universal?

[micro]

The “split” is just a standard schematic drawing technique. It’s used to show that a section of the bar has been removed for the drawing in order to make the schematic fit on the page. In the PDF of the patent, under “Background of the Invention”, read about the 5th paragraph down: “Other holdback bars utilize……”.

If you look it Spaz’s last picture, you can see the holdback in place. The part on the right of the drawing in the PDF is attached to the deck. You can then see the bar is actually much longer than it is in the schematic. The part on the left of the schematic is the part that connects to the back of the nose gear, called the holdback link.

This is kind of what they look like from the top-down.


The sleeve (which is spring loaded to the forward position) is slid back, and the fitting is placed in the holdback link on the nose gear. The sleeve is then released allowing it to slide forward, holding everything together. When the right amount of pressure is applied, the bar releases the link. Each aircraft does have its own hold back. The sleeves are color coded for each jet.

Spaz, the pictures that you have there are for something a little different. That is referring to taking up the slack in the shuttle once the launch bar is inside of it. Anyone confused yet?

[burner12]

No I'm not confused, it seems after seeing holdback bars on the deck they leave the holdback link inside that bar so all they have to do is just slide it to fit into the nose gear. But from the pic you put up of the nose gear what does the end of the holdback link (the part that attaches to the plane) look like? To me from the pic it looks like a T that fits inside that slot on the LG, then when fired just drops down. Am I not correct?


Question where are you finding these pictures, i did a search and found nothing but that PDF file.

[micro]

The holdback link itself is part of the plane, the nosegear to be more accurate. It is the little thing in the first pic that sticks out from the back of the nose gear. It kind of looks like a giant electrical plug, or clamp.

[SpazSinbad]

microbrewst, definitely I had no idea about this new arrangement for catapulting. No wonder I'm confused.   It helps to have / use the new correct terminology as indicated. That will help searching for info on the net. Thanks for the illustrations - they really help get the picture.

[burner12]

The holdback link itself is part of the plane, the nosegear to be more accurate. It is the little thing in the first pic that sticks out from the back of the nose gear. It kind of looks like a giant electrical plug, or clamp.

You know from seeing this image it seems that the clamp on the back end of the gear is put inside the holdback link and then when fired the link drops down and the LG is released from the plane.

And why do they need to have the ability to slide it, if they use different ones for different planes? When would a plane be at a different elevation?

[micro]

You know from seeing this image it seems that the clamp on the back end of the gear is put inside the holdback link and then when fired the link drops down and the LG is released from the plane.

Dont confuse the terminology. The holdback BAR and the holback LINK are two completely separate things. The clamp IS the holdback LINK. It is part of the nose gear and is what they connect the holdback BAR to. The holdback bar then connects to the deck and keeps the jet in place.

As for the sleeve, think about a jigsaw puzzle piece. Because of the shape, the only way to fit one piece into another piece is to lay it over top and push down on it. That is the same way the bar is connected to the link. If the sleeve couldn't retract, you couldn't put the fitting from the bar into the link. Then the sleeve goes over the connection to hold it all together.