The PROPELLER INFLATER

Link: http://prepaplsanglais.canalblog.com/archives/2008/08/21/10293158.html

A KC-10 Extender refuels a Royal Air Force Tornado GR-4 so that it can sustain airborne operations in support of Operation Iraqi Freedom. The KC-10 is with the 908th Expeditionary Air Refueling Wing. (U.S. Air Force Photo/Master Sgt. Ruby Zarzyczny)

INTRODUCTION

1. Mission description. The mission or objective of Air-to-Air Refuelling (AAR) is to enhance mission effectiveness by extending the range, payload or endurance of receiver aircraft by the in-flight transfer of fuel between the tanker and receiver aircraft. ATP-56(A) or AJP 3.3.4.2 is the AAR document used by NATO forces. Non-NATO air forces seeking more detailed information than is contained in this chapter should refer to ATP-56(A) or AJP 3.3.4.2 for guidance.

2. There are two basic AAR systems. These systems are not compatible and are quite distinct.

a. Boom and Receptacle System. The boom is basically a telescoping pipe that extends from the aft portion of some tanker aircraft. The end of the pipe is configured with a nozzle that couples into the receptacle of suitably equipped receiver aircraft. The nozzle end of the pipe is equipped with two air foils which allow the operator to “fly” the nozzle end of the pipe into the receptacle of the receiver. The nozzle is then latched into place. Once the nozzle is latched into the receptacle, the tanker crew can begin the fuel offload process. This system permits offloads in excess of 6000lbs of fuel per minute. The actual offload rate is adjusted to accommodate the receivers optimum onload rate.

b. Probe and Drogue. There are two types of drogue systems. The Hose and Reel system and the Boom / Drogue Adapter (BDA). The probe coupling is contained within the cone-shaped drogue. The position of the drogue cannot be directed by the tanker crew. It is therefore incumbent upon the receiver crew to fly to the drogue and make the contact. Contact is made by the receiver crew flying the probe into the cone-shaped drogue and maintaining forward pressure on the drogue to sustain the contact. Generally, the maximum possible offload rate with this system is approximately 4,800lbs of fuel per minute.

(1). The Hose And Reel System. This system consists of a soft collapsible drogue that is fitted on the end of a flexible hose. The hose is attached to a reel system that takes-up any slack in the hose. This keeps the hose to the optimum length.

(2). The BDA System. This system consists of a length of hose (with a hard non-collapsible drogue attached) that is fitted to the telescoping portion of the boom. The telescoping portion of the boom is kept fully extended while the BDA is in use. This system has no excess hose “take up” feature. This means that the receiver aircraft have to continually adjust their position to ensure proper flow of fuel. Refueler_drogue_maintenance

Tech. Sgt. Christopher Walls (left) and Staff Sgt. Chris Wietecha use a breakaway force tester March 25 on a KC-135 Stratotanker aerial refueling drogue. The sergeants are with the 452nd Maintenance Squadron's aircraft pneudraulics systems shop at March Air Reserve Base, Calif. March ARB, located in Southern California, is home to the largest air mobility wing in the Air Force Reserve Command. (U.S. Air Force photo/Val Gempis)

AAR FUNCTIONS

3. AAR can serve three main functions as a force extender, a force multiplier and/or a force requirement.

a. As a force extender, AAR can add significantly to the overall effectiveness and flexibility of operations by the extension of range, endurance or payload, allowing long range / endurance missions and enhancing the deployment of Forces.

b. AAR can act as a force multiplier by allowing the air commander to accomplish many missions with fewer assets(i.e., aircrews, aircraft, logistic effort). For defensive air operations, which are reactive in nature, AAR allows a sustained airborne alert posture, enhancing the capability to react quickly to the unforeseen development of critical situations. This immediate, sustainable availability of defensive assets can markedly reduce reaction time and enhance the air commander’s flexibility for the employment of the available assets.

c. Range from base to target or combat air patrol position, or takeoff weight restrictions, can make AAR a force requirement. Similarly, AAR for air transport support can become a force requirement to allow maximum payload, avoid intermediate refuelling stop-overs, and allow routing around sensitive areas. Furthermore, a requirement exists for AAR of scarce command and control, intelligence and reconnaissance assets.

Thanks to LTC Rene SONNTAG (Luftwaffe LNO for the French AF Academy) who provided this part of a public-release Nato document) and thanks to Air Force Link: www.af.mil