SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  N07-015 (Navy)
Title:  Improved Catapult Performance Monitoring Through Advanced Cylinder Elongation Measurement Techniques
Research & Technical Areas:  Materials/Processes

Acquisition Program:  
  Objective:  Develop an innovative means of monitoring the average catapult cylinder temperature through indirect measurement techniques.
  Description:  When launching aircraft from the flight deck of a carrier, several variables are involved in calculating the energy required to set the catapult prior to launch. One variable is the temperature of the catapult cylinders. This is currently derived from the cylinder elongation reading, which is an indirect way of measuring the temperature of the power cylinders. The cylinder elongation is currently determined by reading the through-deck pointers mounted on the power cylinders. These pointers move relative to scales mounted in the deck plates and the scales are calibrated in inches. The catapult should be elongated to a pre-determined range before the aircraft can be launched. This window of elongation is to be maintained during operations. Elongation of the catapult is brought about by steam preheat (a set of finned steam pipes located in the trough) and maintained through aircraft launches and the steam preheat system. This system has an inherent flaw in that the scales used for measuring the cylinder elongation also grow (to a smaller degree) with the increasing temperatures during operation. Currently, the bow safety observer leaves the catwalk and goes out onto the flight deck to read the elongation when requested during operations (periodicity can vary). This topic seeks to provide the Fleet with real-time (deck temperature corrected) elongation readings of the catapult for every launch. This will remove the bow safety observer from the dangers associated with taking readings during flight operations, improve catapult performance monitoring, and allow for more accurate catapult settings that will yield more consistent catapult performance. The system will provide a readout of the elongation in a location other than on the flight deck. The current C13-2 catapult has a nominal power stroke of 309.7 feet. Power cylinder material is MPR2 steel. The length can grow up to 10 inches due to temperature expansion during normal operations, so a sensor will need to indicate a range of 0- to 10-inch expansion at a resolution of 5/100th of an inch. Any sensor will need to survive the harsh environment: steam temperatures up to 550 degrees F, humidity approximately 100 percent, shock loads up to 1000 Gs, salt spray/water and exposure to various lubricants. Proposals that will investigate multiple solutions (both contact and non-contact) in order to determine an optimum solution will be given more consideration.

  PHASE I: Determine the feasibility of the concept(s) by developing a conceptual design and addressing all technical issues either through analysis or limited lab demonstrations. Develop a concept of operations, and provide defendable estimates for cost and reliability and maintainability.
  PHASE II: Develop a prototype and demonstrate. The final demonstration will be in an environment representative of a shipboard catapult (such as a NAVAIR Lakehurst test catapult). During a final demonstration, the system should provide system health monitoring, fault detection/isolation, and a method of visual verification of elongation position (in the event the system fails). The system will be tested for a number of catapult shots (precise number to be determined) with and without intentional faults injected.

  PHASE III: Further develop a prototype for robustness, shock, vibration, environmental and electromagnetic interference (EMI) testing (as applicable). Produce units for delivery to carrier Fleet and shore sites. PRIVATE SECTOR COMMERCIAL POTENTIAL/

  DUAL-USE APPLICATIONS: The proposed system will have commercialization potential with the Foreign Military Service (such as the French and potentially the British). The technology used to develop the sensor for this application will have potential industrial commercialization in applications that require high precision measurement with tight tolerances in harsh environments.

  References:  

Keywords:  Non-Contact Sensors; Health Monitoring; Fault Isolation; Catapults; Elongation; Indirect Measurement

Additional Information, Corrections, References, etc:
AFT Looking FWD.jpg
Elong Scales.JPG
N07-015FAQ.doc
FWD Looking AFT.pdf
Trough Cross Section.pdf
Trough Side View.pdf
AFT Looking FWD.jpg
Elong Scales.JPG
N07-015FAQ.doc
FWD Looking AFT.pdf
Trough Cross Section.pdf
Trough Side View.pdf

Questions and Answers:
Q: Could you please provide a reference about the C13-2 catapult, preferably including a picture of its installation on the deck?
A: At this time we are unable to post any reference documents pertaining to the catapult installation. Hopefully the following images will help to clarify. Also, please find the FAQ page as promised. The following is a brief description of the files that are being made available.

AFT Looking FWD.jpg - Standing at the Aft end of the catapult (fixed point for the cylinders) looking forward, down the catapult. Note the Steel partition (near top of image) which blocks the direct line-of-sight down the length of the catapult.

Elong Scales.jpg - Shows through deck pointers of current system and the scales which are attached to the water brake cover.

FWD Looking AFT.jpg - Demonstrates the small clearances between the equipment in a fully assembled catapult. Note the elongation pointers directly adjacent to the cables running down the center of the image.
Their mounting arm is attached to the forward end of the catapult cylinders, which telescopes over water brakes to allow for thermal expansion.

Trough Cross Section.pdf - Cross section of catapult trough, including wing voids. Note, the wing voids are not present in our test site catapult. Also, the colored dots indicate likelihood of direct, full-length line-of-sight down the catapult. Red = None, Yellow = Limited, Green = Fairly Clear/Minor Obstructions.

Trough Side View.pdf - Shows forward end of the power cylinders and water brakes. Illustrates the telescoping arrangement of the two and the position of the elongation pointers.
Q: Usually, how long does the preheating last?
A: The pre-heat system is usually brought up the day before operations are to begin and remains on during operations. It is only secured if the operational tempo is sufficient to maintain cylinder elongation or if the catapults are being downed for maintenance.
Q: Could you please provide a reference about the C13-2 catapult, preferably including a picture of its installation on the deck?
A: At this time we are unable to post any reference documents pertaining to the catapult installation. Hopefully the following images will help to clarify. Also, please find the FAQ page as promised. The following is a brief description of the files that are being made available.

AFT Looking FWD.jpg - Standing at the Aft end of the catapult (fixed point for the cylinders) looking forward, down the catapult. Note the Steel partition (near top of image) which blocks the direct line-of-sight down the length of the catapult.

Elong Scales.jpg - Shows through deck pointers of current system and the scales which are attached to the water brake cover.

FWD Looking AFT.jpg - Demonstrates the small clearances between the equipment in a fully assembled catapult. Note the elongation pointers directly adjacent to the cables running down the center of the image.
Their mounting arm is attached to the forward end of the catapult cylinders, which telescopes over water brakes to allow for thermal expansion.

Trough Cross Section.pdf - Cross section of catapult trough, including wing voids. Note, the wing voids are not present in our test site catapult. Also, the colored dots indicate likelihood of direct, full-length line-of-sight down the catapult. Red = None, Yellow = Limited, Green = Fairly Clear/Minor Obstructions.

Trough Side View.pdf - Shows forward end of the power cylinders and water brakes. Illustrates the telescoping arrangement of the two and the position of the elongation pointers.
Q: Usually, how long does the preheating last?
A: The pre-heat system is usually brought up the day before operations are to begin and remains on during operations. It is only secured if the operational tempo is sufficient to maintain cylinder elongation or if the catapults are being downed for maintenance.

Record: of