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Questions on catapult officer

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vuong:

--- Quote from: burner12 on December 17, 2009, 03:08:32 am ---
--- Quote from: microbrewst on December 17, 2009, 02:50:12 am ---Once the catapult fires, the hold-back breaks free as the shuttle moves rapidly forward

--- End quote ---

I'm just curious how the hold back break free, is it some kind of shear pin? Just wondering how the mechanism work.
Jimmy
--- End quote ---

SpazSinbad:
vuong, this online downloadable PDF has most up to date USN deck equipment information: http://www.hnsa.org/doc/pdf/aviationboatswainsmateH.pdf (6.4Mb)

Sadly in this instance it concentrates on the other launch aspects with the holdback not getting much of a mention. However a lot of procedures about deck crew catapulting are explained therein. More later on the holdback details.
______________

From the 'LSO reference manual' PDF: http://server2.simulacion-esp.com/Janes%20FA18/Documentacion/?download=Landing_Signals_Officer.pdf (5.5Mb)


There is this info: "Preparing Aircraft for Launch. The aircraft is spotted just aft of the shuttle at the battery position. After the holdback is installed the aircraft is attached to the shuttle, the bridle tensioner is actuated applying pressure against the grab and moving the shuttle forward to tension the aircraft.
Firing the Catapult. After tensioning, the catapult is fired by opening the launching values and permitting steam to surge into the cylinders. The force of the steam pushes the piston in the cylinder breaking the tension bar. The steam then forces the piston forward, towing the shuttle and aircraft at an ever
increasing speed."
____________________

As you can probably gather I'm more interested in the OLDE SkYhawke so it is easy to reference that info at: http://www.skyhawk.org/specials/html/holdback.htm for HOLDBACK info. I'll look for HORNET specific later.

SpazSinbad:
Looks like the catapult system has changed and changed again:

http://en.wikipedia.org/wiki/Aircraft_catapult

"At launch, a release bar holds the aircraft in place as steam pressure builds up, then breaks (or "releases"; older models used a pin that sheared), freeing the piston to pull the aircraft along the deck at high speed. Within about four seconds, aircraft velocity plus apparent wind speed (ship's speed plus "natural" wind) will be sufficient to allow an aircraft to fly away, even after losing one engine."

burner12:
Vuong the answer to your question is a dog bone. The holdback bar has a piece of steel that connects to the back of the landing gear. it's the size of a small dog treat. Half of it is put into the holdback bar and the other half into the landign gear connecting them. Then when the cat fires due to physics the steel breaks straight down the middle of the dog bone, 1/2 staying inside the holdback the other goes along for a wild ride on the planes landing gear.

Watch this video he gives good insight on cat ops, 

if you are really anxious then go to 5:12

vuong:
Thank you  very much gentlemen.
Jimmy

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