Originally Posted by
Tengah Type
BEagle
The problems at Scampton were not caused by the wing mounted AAR pods but by the ground clearance below the Underwing Fuel Tanks on the K2. The pods were head high, whereas the clearance below the tanks was only about 18 inches. So low that they were likely to hit any snow depth warning indicators next to taxiways. At Paine Field (Washinton State,USA) my Nav Rad and Crew Chief had to navigate us about 2 miles, on foot, over these as we taxied in to the parking area for an airshow. One other snag at Scampton was the "lumpy" nature of the runway construction which would have had severe consequences for the Victor fatigue life. This together with the need to remove concrete kerbs and refuelling pipes at all the dispersals was too expensive to rectify for the, then, proposed life of the Victor K2.
The choice of using the wing pods or centre line HDU was also a function of the flow rate of the various receiver types. The Mk 20 pod on the Victor, which had an integral 1000lbs fuel tank, had a flow rate of 1500lbs/min whereas the HDU was 4000lbs /min. With aircraft such as the Lightning and Jaguar, which took fuel at 1100 lbs/min, it was quicker to refuel a pair on the pods rather than sequentially on the HDU. The F4 took fuel at 4000lbs/min, so would empty the pod fuel tank fairly quickly, which would not pass any more fuel until it had filled to half fuel again. Hence it was quicker to refuel a pair of F4s one at a time, with continuous fuel flow, on the HDU.
The VC10 had the Mk 32 pod, which did not have an internal tank, and gave a fuel flow of 2800lbs/min, however the VC10 fuel system only allowed 2200lbs/min if both pods were in use together. The HDU was the same on both types. So, again it could be quicker to use the HDU for a pair of F4s than to use the wing pods.
All of the above figures are from memory of 30+ years ago, so anybody with the reference books can challenge me without me getting upset or descending to personal abuse.
Thank you Tengah, I was not aware of all of the differences in flow rates between the types, very informative. Curious about keeping the Mk 20 pod "topped off" when it was actively dispensing fuel. Sounds like it could be drained pretty quickly (especially by the Phantom), so did you have the pumps going to the pod tank continuously? Gravity? Automatic shut off when the pod tank is full?