Sky Writing in FSX: Steam Edition

By David Smith 

Ever looked up into a deep blue summer’s sky and seen a tiny black dot, high overhead, writing cloud-words in the sky? Sky writing is an amazing way to advertise people, products and events – even if only briefly – to a huge audience on the ground. How difficult would it be to write an advert for PC Aviator in the virtual sky of Flight Sim? David Smith decided to give it a go.

I’ve always loved watching sky writers at work. The little aircraft moves with such precision, ducking and weaving, turning the puffy white smoke on and off at just the right moments to create words in the sky. And as the words drift into incoherence in the gentle breeze, I’m left wondering, “what’s involved – how do they do that?”

As I’ve written before, I find myself flying Flight Sim in one of several different modes. Some days I’m tackling the intricacies of instrument landings, other times I’m trying to land the helicopter  on the oil rig, still other days I just get a buzz out of looking out the window at the amazing – and increasingly realistic – scenery. Today I decided to forget the rules and regulations and try something right out of left field. I knew that Flight Sim had a smoke option so I thought I’d see if it was possible to write some letters in the sky. Here’s how I set about the task.

I had read somewhere that sky writers favoured very maneuverable aircraft, such as crop dusters or aerobatic planes so I chose the Extra 300S that came with Flight Sim X. It’s a superb model with an astonishingly high roll rate and massive power – just the thing for the job!

Airborne Wordsmiths Full Article 9I knew there’d be a fair bit to learn before I’d be able to write words – or even letters – in the sky, so I took the Extra up over our local GA airfield, Moorabbin, for a test flight. I selected the Tower View and there was my little plane poodling along at 5,000 feet. I pressed “I” and – voila! – there was the smoke, but it was lost against the background cloud.

I went to “Weather” and chose a clear sky with no cloud. I also guessed I’d have to have little or no breeze, or my words would be “blowin’ in the wind”. This wasn’t as easy as it seemed because even after setting Clouds to CLEAR and Wind Speed to NONE, I found that, over time, Flight Sim would have the wind pick up speed. The only way around this was to reset wind speed to NONE from time to time. I found that by pressing SHIFT-Z three times I could keep a check on whether the wind was picking up and fix it as required.

Back in the tower, I could now see the smoke from the Extra much more clearly but it was very difficult to fly such a skittish plane using just the tower view. The simple solution was to open a virtual cockpit window on my second monitor and use that to keep my bearings while watching the letters unfold from the tower window.

So how easy would it be to write a single letter – say the letter “O”? I fl ew to a point where the plane was easily visible through the tower window and tried a few maneuvers to see which ones would be most visible from the tower. It’s all very well to fl y a perfect circle to make the letter “O”, but if it’s edge-on to the viewer it’ll look like a straight line – the letter “I”. So I had to learn to alter the plane of my maneuver so the circle would be perpendicular – or as much as possible – to the tower window. This pretty much dictated that I would have to form the letters in the vertical plane, meaning lots of loops would have to be performed.

Fortunately in the Extra this is pretty straightforward. You simply fly level in a straight line, at a minimum altitude of 3,000 feet, increase power to FULL, and pull back on the stick. As you climb over the top it’s very important to ease back on the controls and also reduce power, otherwise you’ll make a very egg-shaped “circle” for your loop. Now things were getting pretty busy, keeping tabs on the instruments and the horizon on one monitor while also checking how the smoke was trailing in the main monitor. I also needed to glance at the indicators in the top left of the screen to be sure the wind was not sneaking up again. Finally I had to hover my ginger over the “I” key to turn smoke on and off.

OK, I tried this a few times with very little success, partly because I wound up having my tower view blocked by parts of the tower’s overhanging roof. I solved that by increasing the magnification of the tower view, although that introduced a new limit, in that although my view of the plane was clearer, it was also closer so now I couldn’t see the whole letters as they formed.

Airborne Wordsmiths Full Article 8This was my plan of attack. I needed to be able to prove to people – such as you dear readers – that I had actually written my words in the sky. The best approach seemed to be to record a flight video which I could then replay in order to select the best shots to submit to our ever patient Editor.

Having recorded my videos, I could play them back, pause them at the appropriate places, use PrtScn to save the image to the clipboard, then paste the image into Paintshop Pro using EDIT>PASTE AS NEW IMAGE.

Lessons to be learned

I learned several things during my first attempts at this process. One was that, even with zero wind, the smoke from the Extra dissipated fairly rapidly for reasons that were not totally repeatable. Sometimes  it was possible to fly a circle, or a loop, and see my own smoke through the windscreen as I came back to the beginning of the circle. Other times the smoke just wasn’t there.

Would I get better smoke at 2,000’ or 10,000’? Flying slow or flying fast? In winter or summer? At dawn, dusk, or midday?

I tried numerous combinations and found that I seemed to get the best effect in daytime, during the summer, at about 5,000 feet. The speed factor was interesting because I seemed to get thicker smoke at higher engine power, but that of course made the radius of my circles that much bigger. Finally I opted for medium power, giving good smoke and reasonably tight turns.

My Flight Plan

Here’s the flight plan I figured out. Real sky writing pilots reading this article will probably have a good chuckle at my approach but, hey, I’m just trying to figure it out for myself.

The second thing was that, during replay of the video, I could turn the smoke on and off to help form the letters for the screenshots. This was very handy, and very different to the situation facing a real-world sky writer, who has to activate the smoke at precise times according to the carefully prepared flight plan.

Most serious of all was that, even when the sim was paused, the smoke trail would continue to dissipate. This was quite unexpected and added yet another dimension to the challenge. Now I had to watch the flight video, select the best magnification to show off the letters without getting the tower structures in the way, turn the smoke on at the appropriate time to create and finish a letter, then pause the simulation at just the right moment while rapidly pressing PrtScn to capture the image. As the screenshots show, even on a dead calm day and with the sim paused, the smoke dissipates really fast, so you need your wits about you.

After several hours of messing about I started getting serious. I really wanted to write “PC Aviator” in the sky. Then I started thinking about the way Flight Sim might handle smoke in the atmosphere. What would be the best conditions to achieve clea defined letters, well contrasted against the sky and persistent e  to complete the word?

I drew up the letters “PCA” and then began to figure out how best to complete them. I wanted to optimize the maneuvers in order to complete the letters in minimum time so they wouldn’t drift away.

Let’s imagine in the first case that the letters are to be laid out horizontally and that they are to be read from the west by people on the ground. I’ve set this up over Moorabbin airport (YMMB) near Melbourne so I can use Runway 35R as a visual guide. Moorabbin just happens to be the busiest GA airfield in the Southern Hemisphere.


Airborne Wordsmiths Full Article 3Once I’m on bearing 170° I start the smoke again briefly to form the cross-bar of the letter “A”. I then complete a slow right turn (6 in Fig 8) until I straighten onto bearing 115° with smoke on for the same time as I flew the vertical of the letter “P” – about 50 seconds. Finally, I complete a tight left turn to 235° (7 in Fig 8) which I maintain with smoke on to complete the “A” (8 in Fig 8).

If the plane of the writing had to be vertical, then all of the turns described would be loops and the whole exercise would be far more difficult. Perhaps more importantly, if there was any wind at all, its strength and direction would have to be vectored into my flight plan and the whole exercise would be far more complex and demanding.

So how did I do?

The first point to make is that I was not able to make more than one simple letter. Ever. This is due to the rapid dissipation of smoke in Flight Sim.

From the START (1 in Fig 8) I fly at 3,000 feet AGL, IAS 120 kts on bearing 170° until I cross the perimeter of the airfield. I turn the smoke on and then complete a steep left turn through 180 degrees. As I leave the airfield, I turn the smoke off and immediately commence  a second steep turn to the right. This turn is continued until I reach a heading of 260° at which point I turn on the smoke and maintain the heading to complete the straight vertical of the letter “P”.

Using Flight Sim’s Flight Analysis system and my area chart of the airfield, I found that my smoking left turn described a half circle about 0.7 nm in diameter. This means the height of each letter will be about 1.4nm. Therefore I maintain the course of 260 for 46 seconds then turn off the smoke and commence a left turn onto 170 degrees.

Now for the letter “C”. After a couple of minutes I make a left turn and fly 80° until I cross the axis of Runway 35R. At that point  I commence a 30 degree turn to the left, then turn on the smoke. I maintain this turn until I’m on bearing 200 degrees, then bank right until I’m once again in line with Runway 35R.

Having convinced myself to not being able to write “PC Aviator”, or even “PCA”, I still wanted to discover how difficult it would be to fly my Flight Plan for the letters “PCA”.

I used my recorded Flight Video to help work out the times of each segment, then saw the result in Flight Analysis.

If nothing else, this graphic shows clearly how difficult I found the whole exercise. It would take me a great deal of practice to master just the first three letters of “PC Aviator” and I imagine the level of skill and concentration required to write the whole word would be enormous.

Overall, I have to say there was far more to this exercise than I had ever imagined. How complex would it be for a real sky writer pilot?

In a real sky writing exercise, the entire sequence has to be mapped out precisely, allowing for the desired size of the letters, the plane

of optimum visibility from the target audience and the prevailing weather. So, just as in an aerobatic competition, the flight plan will  be totally structured so that the aircraft can complete the maneuvers in the minimum time, thereby minimizing dissipation and hopefully allowing the word or words to all be visible at once. In fact the letters are placed about 15,000 feet AGL which means they can be read within a circle of than 30 nm.

In my first attempt the letter P didn’t work well at all. My right turn was too shallow so I crossed the earlier smoke trail without leaving room for the loop of the “P”.

The circle for the “C” was way too small but otherwise would have worked, and the “A” wasn’t too bad at all – the cross bar wasn’t quite long enough before I began the right turn.

Second attempt

Airborne Wordsmiths Full Article 4My second attempt was, overall, a little better with a nicely formed “P” and “C” and a reasonable “A”, although again the right turn in the “A” was executed too soon.

One relatively recent technique is to squirt the smoke as a series of dots rather than a continuous stream.

Typically a single aircraft can produce words about five or six letters long. Longer words are possible, requiring up to seven aircraft flying in formation and delivering smoke under computer control in a fashion analogous to a dot matrix printer (see and

Fairly obviously this requires a very high degree of precision control of the aircraft, bearing in mind that the pilot can’t ever see all the letters as they’re being completed and must turn the smoke system on and off precisely in order to make neat and legible letters.


As you can see from my screenshots, there’s no way I could write “PC Aviator” in the sky. In fact unless there’s a way to alter the smoke persistence in the sky within Flight Sim, I doubt that anyone ever will. After many hours of trying I did manage to write a nice letter “O” and I did manage to create a kind of letter “P” and also an “X”. Doesn’t sound like much, I know, but if you give it a try you’ll soon discover how difficult it is. If you do manage to write “PC Aviator” in the sky, send us a screenshot. Don’t cheat like the Paintshop Pro version here but see how far you can get. The flight plan I came up with would have worked had it not been for the problem of rapid smoke dissipation, but I came away having learned many new aspects of this amazing simulator. I also gained a very healthy respect for real-world pilots who do sky writing for a living. And along the way I had a lot of fun. I hope you do too!

FSX Admin

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