Is n't a bit of knowledge a dangerous thing? The HDU is the centre hose on the VC10 and the 135 no direct equivalent. I take it STH means the wing hoses of the MPRS equipped ac. The availability of said assets has f*** all to do with sets rather the no of ac that have been modded. The set no problems is that on the KC10. All types of the FJs in theatre in GW2 used the MPRS but I cant say whether the RTS' still allow this.
BEags -just read your crit on tanker types. The Mk 20 pod gave a low fuel flow whatever the Victor fuel state which is why out of choice we refuelled F4s on the HDU rather than in pairs on the wings. I cant believe the lash up on the Vulcan was any better that the Victor HDU.