Originally Posted By: lubricatosaurus
Originally Posted By: lubricatosaurus
Astro, refueling on the hose-drogue, did you hit wingtip vortices?
Asked that on Astro's F-14 thread too. Seems like it would be a problem, yet its been that way forever.
Qouted from another Navy flier, but wondering what is involved in vortex flight there:
Originally Posted By: USNBandit
"KC-135s have been doing drogue and probe tanking for a long time. They used to use a short hose and a really hard basket. The receiver had to bend the short hose to open two knuckle joints. In the late 90’s a wing mounted long hose/reel pod was introduced. Much easier to keep the fuel flowing, but depending on the aircraft you sometimes end up flying in the wingtip vortex.---14 posted on 5/22/2014, 11:21:58 PM by USNBandit (sarcasm engaged at all times)"
You do hit the wingtip vortex.
The worst was the UK VC-10, which had the wing refueling pod near the tip....putting the receiver right in the middle of the vortex.
Vortex could be mildly annoying...or downright rough with severe roll. Once you're in the basket, you can move out of the way. It you've got to get in first. And it's not easy. You fly the airplane in formation with the tanker, and the probe has to be aligned vertically and horizontally as you close at 2-3 KTS with the basket.
Now, that [censored] basket moves in response to tanker movement, or turbulence, or in the bow wave off the Tomcat's nose. And it isn't always predicable. And from the pilot's seat, the probe is off to the right, like a passenger side mirror, but you have to look forward at the tanker to keep your position, so it's a pain to see the probe and basket out of the corner of your eye. A good RIO is very helpful here...
Sweetest tanker was the KC-10. Nice big basket in the smooth air beneath the jet...and lots and lots of off-load....
The KC-135 was a PITA. Tanked hundreds of time during desert storm...still hated it. The basket, or either knuckle, was a jet breaker. Mis-contact the basket and it could hit the jet with anything from mild to severe damage. You had to put a kink in the 9 foot hose connecting the basket to the boom. That meant perfect alignment, then move the basket forward about a foot. Less, you might disconnect, more, you get an unmanageable loop.
I generally took the basket down and left, to keep the loop in the hose up and to the right of the probe...away from the nose, and canopy, of my airplane.
We had to use AB to plug in the -A model because of all the drag with added weapons. Also, an engine feature called MCB, mid-compression bypass, opened with probe extension. By dumping 7th stage bleed air, the engine stall margin was improved, at the cost of 3,000# of thrust per engine.
The probe created turbulence down the right side of the airplane that could cause engine issues. Actually, it was mostly the probe door that caused it. You'll often see F-14s with the doors removed, but that's because the KC-135 was so unforgiving, that doors were often damaged, and you don't want door bits going down the engine.
Even with MCB open, TF-30 engine stalls were not uncommon...and it was always the starboard engine...always...because it was operating in AB, the throttles were constantly moving to maintain position, and it was eating turbulent flow from the probe door...