The day I left London was a bit damp which made for a bit of vapor on departure. I was sitting almost directly over the wing. I couldn’t see in to the inlet but I could see vapor puffs in front of the inlet at lower speeds anyway. As we rotated and climbed out, there was plenty of vapor puffing over the upper surface, aided by climbing through a few patches of cloud. I had the video running the get a view of the moisture and here is what I got.
More shots from a fun shoot a while back. If the wind is coming from the west, evening departures from O’Hare provide plenty of opportunity to get some shots. The heavy departures to Europe leave later in the afternoon and in to the early evening and, as the sun drops down things are getting better and better. The nice thing about this day was that we got a combination of good conditions. Earlier in the afternoon, while the light wasn’t as good, a storm had not long passed through and there was plenty of moisture in the air.
The result was a lot of vapor in the inlets of the jets as they climbed out at high thrust settings. Some of them had clouds sitting in the inlets for long periods of time. Others would just pulse with the vapor as they climbed away. They would also puff up little clouds over the upper surfaces of the wing as they fought to gain height. As the afternoon wore on, the air dried out a bit and the vapor went away. However, the light was then getting better so no reason to go just yet!
Damp conditions are not uncommon in the Bay. Getting some vapor over the wing during a climb out would not be a surprise. Getting it on the approach can also happen but not so often. A FedEx MD-11 was on the approach to Oakland while I was walking along the shore. As it headed away, they were configured for the final approach as some flashes of vapor showed themselves above the wing. I happened to get them this time.
Getting shots of vapor is a popular thing when shooting fast jets. An airliner on a damp day can also result in some clouds being formed. While shooting something special at Oakland, I was getting a few shots to make sure the light metering was working as planned. A Southwest 737 came in and, as it flared for landing, it had a nice cloud of moisture form over the wing. Normally these things pop up further out on the approach and don’t make for a good shot but this one was close at hand.
Moisture in the air is not always what you want when you are out shooting aircraft. However, it does have its benefits if there isn’t so much of it that everything is either obscured or gray. The weather conditions over San Francisco Bay can be very localized and, as the planes come down final approach, they can go through quite a variety. I was out hunting for Air Force One a while back and I got some good examples of this.
The weather at SFO was actually quite nice (although not when Air Force one departed as I have previously written about). The sun was out and the sky was pretty clear. In fact, there was quite a troubling amount of heat haze. However, once you got towards the south end of the bay, there was pretty solid cloud cover. The planes coming in were in full IMC for a good portion of their approach. Somewhere in the region between Coyote Point and the San Mateo Bridge they would break out of the cloud cover. Then, for the next mile or so, they were in the clear but still in very humid conditions.
The result of this humidity was a lot of vapor forming up over the wings. The low speed and high lift configuration made the wings a good place to get cloud formations as the moist air passed over them. Additionally, the trailing vortices were showing up well as a result of the condensing moisture in them too. For quite a while, each aircraft showed similar patterns as it descended. The widebodies seemed to be better for showing this but that might just be a function of them being easier to see further away when the effect was most pronounced. The closer they got to the field, the less the effect until it was pretty much gone when they were on final approach.
Every once in a while you see something and you have no idea what is going on. As a United 767 climbed out from O’Hare, it was streaming something from the fuselage. I saw it through the viewfinder at the time and figured it would be obvious what it was when I looked at the pictures. It turns out I still don’t know what was happening. Anyone reading this that has any ideas, please let me know what you think.
If you want to get some nice vapor from an aircraft, start with a good, humid day. The hours after a storm are perfect since there is plenty of moisture in the air and the ground is wet meaning it will keep feeding the moisture for a while. Now you just need a big jet to climb out at high power settings. Enter an ANA 777-300ER stage left.
The engines were filling with inlet vapor as the beast hauled itself into the sky and the tip vortices were also doing their bit to pull the water from the air. The fact is was late afternoon so the sun was in a good position too meant that the combination was pretty ideal. We got a few like this for a while but eventually the humidity levels dropped and things returned to normal. Still, it was good for a while and there were other benefits to come.
There are some aerodynamic effects that always catch my eye when I am going through images and one of these is vapor forming in engine inlets. The combination of lower airspeed with high thrust settings and moisture can result in puffs of vapor forming in the inlet, either continuously or, more often, as little flashes of cloud. The F-16 can often demonstrate this phenomenon when taking off although the formation is a little way back in the inlet.
On a recent Red Flag, the F-16s were out in force and, since it wasn’t the hottest and driest day that Nellis can provide, they were getting a bit of vapor to show up. Here are a few of the jets squeezing the moisture out of the air (even though it is the opposite of squeezing that makes it happen!).
In going through my archive recently for a piece for Global Aviation Resource, I was searching through old shots of F-4 Phantoms. I noticed one that I hadn’t recalled taking but that seemed pretty cool. Occasionally jets pull ‘g’ when above you and the angle of the sun makes the vapor project a rainbow. This was one of those moments.