How Pilots Avoid Wingtip Vortices While Tanking

Welcome aboard the cockpit of United States Navy E-18G Growler, which is an electronic attack variant of the FAA-18 Foxtrot Super Hornet, with a few modifications. Signature move. No big deal. You may have noticed that we just joined on a Royal Australian Air Force A330 MRTT, or Multi-Role Tanker Transport Aircraft, which is a military derivative of the A330-200 airliner. You can see the tanker off the nose as what we call a chick in tow, or one receiver on the right wing getting gas. Once that Super Hornet is offload complete, it'll be our turn to cross under the tanker and get gas on the right wing. Until then, there's an airwing Super Hornet on my left wing that's trying to get gas before us, so we're just going to hang out in Port Observation while the boom operator directs that Super Hornet to cross under our aircraft and get gas on the left wing. Now it's our turn, so our probe comes out, and we cross under. Time to get gas. But how much gas are we going to get? That's the question we're going to answer today, but I'm not going to answer it in terms of pounds, or gallons, or liters, whatever those are. I'm going to answer it in terms of volume. Volume compared to the average car's gas tank, volume compared to the average size of a six-person hot tub. So the real question is, and I'm sure you're wondering, how many hot tubs full of gas, or how many car gas tanks can this Growler onload when we approach the tanker with just less than a third of a bag of gas? Might be more than you think. Let's find out. All right, so we're established in pre-contact, which is about 20 feet after the drogue. I'm wiggling my fingers and my toes, doing my best to relax. And now it's time for contact. So I'm going to push the probe up towards the drogue at just less than five knots of closure. Here we go. A little forward, a little up, a little left, a little right, right, right, got it. You can see the hose shaking around just a little bit, and now it's starting to stabilize. A couple of things going on in the top left. We've got a counter, and that's the overall time on the hose of us taking gas. Bottom left is how many pounds of JP5 or jet fuel we've taken. So far, we've been on the hose for 11 seconds and taken about 200 pounds. So in order to answer our questions of how many hot tubs full of gas and how many car gas tanks this Growler can take, there's three assumptions we needed to dig into. The first one is that we're going to use the average American gas tank of 15 gallons. The next one is we're going to use a six-person hot tub of around 400 gallons, and the third one is that signature moves either add to nor subtract from the total amount of fuel taken or time on the hose. They're there for pure entertainment value only. If you have any questions about the signature move, be sure not to ask about it in the comments. If you have any questions, however, about refueling techniques, or if you want to see the craziest day, what I call my nightmare behind the tanker, be sure to check out the link in the description and above to see a breakdown of the roughest day I've ever had behind the tanker. Now as we get gas, you see the timer on the top left corner of the screen, it's got a little black bar on top of it that's getting larger and growing in a clockwise rotation. When that bar makes a complete circle at the 12 o'clock position, then our offload is complete. All right, now that we've gotten all out of the way, let's speed it up a bit so we can take that gas. Here we go. Passing the two-minute mark, we've taken about 2,000 pounds worth of gas, which is about 294 gallons or three quarters of a hot tub full of gas. Wait, what's that? Mm-hmm. All right, let's play it safe at regular speed. One question I get asked often in the comments is, how can we fly so close to another airplane without being affected by wake turbulence? For those of you that don't know, wake turbulence is a function of an aircraft producing lift that results in the formation of two counter-rotating vortices that trail behind the aircraft. These vortices circulate outward and upward around the wingtips of the aircraft when viewed from behind. Vortices from larger aircraft, like the tanker you see out the nose, sink at several hundred feet per minute and slowly diminish in strength with time and distance behind the aircraft. So when you look at where we're established in contact, you can see that we're not outboard of the wingtips of the aircraft. So the effects of wake turbulence really don't affect us in this position. Interestingly enough, when you look at military parade positions or the close flying formation position that we commonly fly, you'll see that we generally have about four feet of wingtip separation, with the Dash 2 aircraft slightly stepped down. This position allows plenty of space between the aircraft for the follow-on aircraft to not be affected by the wingtip vortices, or what we call wake turbulence. Okay, let's speed it up. Now as we cross the six minute mark, we've taken on a little more than 6,000 pounds, which is about 892 gallons, or a little more than two hot tubs full of gas. And that just happened. Now that we got that out of the way, you may have noticed that the tanker is yet to turn. And that's because there's two types of refueling areas, what we call tracks and anchors. AR, or aerial refueling, along a designated track is the preferred method for inter-theater refueling. Normally tracks have a designated entry point, initial point, rendezvous control point, and even a designated AR exit point. These are also known as drags, and that's what we're doing here. The tanker never turned because the tanker was taking us into theater. In anchor areas, on the other hand, the tanker flies a racetrack pattern within a defined airspace while waiting for receiver aircraft to arrive. Once joined, the tanker flies an expanded racetrack while refueling occurs. Anchor refueling is normally used for intra-theater operations as opposed to inter-theater operations, where airspace is confined or where receivers need to operate from a central location. This type of refueling is best suited for small, highly maneuverable aircraft like the Growler. Be sure to check out the links in the description for examples of anchored tanking, where I describe tanking at a turn considerations. You'll get to see how weather affects the entire thing, and then you'll get to see the difference between BDA, or boom drogue assembly, also known as iron maiden tanking, as opposed to this soft, fluffy basket that you see off our nose. Okay, let's go back to warp speed. Passing the 10 minute mark, we've taken over 10,000 pounds of gas, or 1,488 gallons, nearly three and a half hot tubs full of gas, or 100 car gas tanks. Let's slow it down for the big finish with the final calculations. As we slowly back out of the drogue, you see the total time taken gas today was 13 minutes and five seconds, and the total on load was 13,200 pounds. When we started tanking, we had 8,200 pounds of gas, and we finished with 19,400 pounds of gas. That's only 11,200 pounds of gas. However, while we were tanking, we were burning about 4,800 pounds of gas per side. Over 13 minutes equals about 2,000 pounds. So 11.2 plus two is 13.2 thousand pounds of gas. Which drum roll? Here we go. Equals about five hot tubs, or 129 car gas tanks full of gas. Now you know. And knowing is half the battle. Well guys, if you enjoyed the jam today, please like, leave a comment, and subscribe. And let me know what you think about the new format with the timer, the how you doing, and the fuel count. Cheers. Welcome to Gravel Jams.