描述： 前美国空军加油机飞行员Mike Little 所分析的歼-8D战机通过与轰油-6不同的空中加油方式所能达到的1200KM，1500KM与1800KM任务半径。
文章作者为前美国空军加油机飞行员Mike Little。Mike Little在KC-135加油机上积累了超过4000小时的飞行经验。
Two variants of the H-6 tanker have been noted: the HU-6 (or H-6U) PLAAF version, and the PLANAF's HU-6D (or H-6DU). These designations are uncertain, but for clarity we'll call them HU-6 and HU-6D. They can be distinguished by the HU-6 having a "solid" nose radome and the HU-6D retaining a "glass" nose with a chin radome. Observed serials for the HU-6 include 43595, 43698 and 43499. Ten HU-6s are thought to be assigned to the 8th Air Division (or possibly the 48th) at Leiyang Airbase in Guangzhou Military Region. The number and location of the HU-6Ds is uncertain but some sources mention them operating out of Lingshui (where the EP-3 landed in 2001!) on Hainan Island.
Turning to modifications, the "solid" nose and the removal of the chin radome in the PLAAF model appear to be related. The original '50s technology NAS-1 bomb-nav system with the old RBP-4 ground-mapping radar was replaced by a lighter, more modern navigation suite featuring dual INS, two "TACAN" (or possibly RSBN), and a weather radar in the nose. Besides saving weight this probably reduced drag somewhat and the weather radar - even without 360 degree coverage - could almost certainly be used in a ground mapping mode to aid navigation. Removing the PV-23 defensive fire control system would result in substantial weight savings, since the guns by themselves weigh 43kg apiece, never mind the turrets, sights, computer and attendant radar. One substantial difference from the Russian Tu-16 tankers is that while these employed either a unique wingtip-to-wingtip system or a single drogue from a hose-drum-unit in the bomb bay, the HU-6 tankers have two underwing pods. These were developed by the China Research Institute of Aero Accessories, and are common to both the PLAAF and PLANAF aircraft.
Although the guns have been removed it's been reported that a radar warning system and chaff/flare dispensers have been retained. This is an intelligent decision that should increase the aircraft's survivability in actual combat operations. As force multipliers tankers have long been high value assets - and thus high value targets - but provision for self protection by individual airplanes (beyond a coat of camouflage paint) have been slow in coming, at least in the USAF.
Removal of the fire control system would appear to render gunners superfluous, however it is likely that the gun positions in the aft fuselage are still manned by scanners to monitor the refueling. This is common practice in other air forces; for example, the Canadians add a scanner to the crew of their CC-130H(T)s for refueling sorties (required crew for such missions is pilot, copilot, navigator, flight engineer, loadmaster, and scanner). This supposition is supported by one photo of an HU-6D tanker that appears to show the silhouette of a crewmember in the tail gunner's position, and another that shows a line of HU-6s with six crewmen running towards each aircraft. Extrapolating from the bomber versions, these are probably pilot, copilot, navigator, weapon systems officer (WSO – but literally “navigator-gunner” in Russian), radio operator, and scanner (it is likely that one of the last three is also tasked with operating the defensive systems). It also appears that the WSO has retained his dorsal bubble behind the cockpit. If the PLAAF and PLANAF still employ celestial navigation to back up the aircraft's electronic systems, the WSO is most likely the crewmember responsible for taking the navigator's sextant shots from that bubble.
Radio and light signals are reportedly available for the refueling itself, although it isn't clear precisely what these consist of. In photographs the signal lights on the A/R pods aren't visible, and since the photos were taken under bright day/VFR conditions other lighting isn't apparent, either. On most Western pods of this type the lights are red, yellow and green, and are often located behind a transparent panel below the opening for the drogue. However, at least one photo of a J-8D refueling simulator shows something above the pods that may be a light housing. Besides signal lights there is probably a system to illuminate portions of the airframe to give the receiver pilot a visual reference for A/R under low light conditions. The refueling-specific "radio signal" is something of a mystery, but may refer to a system whereby the receiver(s) can talk to the tanker crew "radio silent" (over the tanker's intercom) once plugged in to the drogue. For communications in general the aircraft is reported to have two VHF and two "frequency-hopping" (probably UHF) radios.
From examining open sources it appears that the only mode of operation observed to date has been "buddy" or escort-type refueling. However, the HU-6 is equipped with an air-to-air Tacan-like system (based on Russian RSBN) that provides "mutual detection" (apparently azimuth and range information) between tanker and receiver within 200 km and is obviously intended to facilitate rendezvous. These are likely to be by timing (what the USAF terms an "enroute" rendezvous), and it's possible that something similar to an anchor-type refueling - which is, in essence, refueling in a holding pattern - is planned for some situations.
According to some reports PLAAF H-6 pilots (presumably including the crews of the tanker versions) only get 80 flying hours a year.  Flying hours by themselves are not necessarily a good guide to the level of training. They are really used for higher-level planning purposes and relate to funds allotted for such things as fuel, oil, maintenance on the airframe, and other expenses, which are generally computed by flying hour. If you've ever rented an airplane you may recall you paid by the hour, same kind of thing. That said, 80 hours seems very low. This amount of time would only allow for one three-hour training sortie (which I would expect to be the shortest duration of flight that would allow the crew to meet minimum training requirements) every two weeks. For comparison, in the early 1990s (and it probably hasn't changed very much since then) KC-135 pilots, copilots, navigators and boom operators (who operate the refueling systems on the KC-135) might expect to fly around 250 hours per year. 
SAC KC-135 crews were also required to conduct thus-and-so-many takeoffs, landings, instrument approaches, rendezvous, air refuelings, navigation training legs, contacts (physical connection of the refueling boom to the receiver aircraft's receptacle), and so forth during these sorties. Some training - especially emergency procedures - could be done in a simulator, and the PLA's lack of available flying time may be why there is such emphasis in open-source Chinese literature on the use of simulators. It also implies extensive use of part-task trainers and other training devices to help keep aircrew current in their mission specialties without having to actually go fly. Using standard Russian practice as a guide, the crew probably plans the sortie, runs through all the planned events and any likely contingencies in a simulator and/or part-task trainer, flies the mission, then debriefs it exhaustively. This also suggests that Chinese unit commanders and flight instructors are under a lot of pressure to wring all possible benefit from every moment in the air!
* Edited by xinhui on Oct. 18 2002,09:50
Revised by Mike Little, August 2009
中国军网8月7日电 邓建波 何群光 特约通讯员高宏伟摄影报道：8月3日，在南海上空南航、北航协同成功实施了远海空中实战演练。中国海军航空兵再次在南海上空成功实现空中对接，并形成了较大规模的空中加受油能力。
广空航空兵某师坚持以科学发展观指导训练，不断挖掘战机性能，通过南海纵深战斗巡逻中实施空中加受油课目，创造出二代战机远海方向最远航程记录，部队遂行空中进攻作战能力进一步增强。 中国军事图片中心 罗培武 摄 （责任编辑：孙礼）