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Paragliding-The Energy Equation

Several months ago I wrote an article about Managing The Risks of paragliding, which spurred a lot of great conversations and comments. Reflecting on that article, one of the items I mentioned was to make sure we understand which side of the energy equation we are flying on.  Several pilots asked great follow up questions wondering what that meant, and how best to apply it.  Therefore, in the spirit of sharing, I thought I would discuss my approach to the energy equation and how it works for me.

2016-09-16-18-48-01Let’s talk ENERGY – It is everywhere, it is in everything, and it is a critical concept not only in paragliding, but in ALL types of aviation.  Learning to manage energy is one of the fundamental principles every pilot should learn.  I say should learn because I do not think many paragliding schools teach it, so it’s up to you!  Energy can be boiled down to basically two kinds, Potential Energy (PE) and Kinetic Energy (KE). Understanding how to balance both is vital to safely flying a paraglider. Today we are going to focus on a portion of Kinetic Energy, or more precisely the moving energy of the air over and around our wing.

What we are really trying to determine with this whole energy discussion, is deciding at any given time what has the energy advantage. Is it the glider, or is it the surrounding air? Let me ask it in a more practical way. On any given flight, if you had to quickly get on the ground, out of this canyon, out of this thermal, or even just get out in front of the ridge….could you? If your answer is yes, then your wing has the energy advantage, and that is what we consider being on the right side of the energy equation. I think we have all had times when we realized the air had the advantage and thus we were on the wrong side. It is scary getting blown backwards over a ridge, or going up at 3000 feet/min in a violent thermal, or being sucked into a canyon…well, it is for me at least. I find it is best to eliminate those scenarios before I decide to fly, and the best way is to survey the energy!

2016-10-12-16-34-14For a little more of a scientific approach, the following is an energy equation I developed that helps me make informed decisions. I do not claim it to be right for everybody, but it works for me. I fly primarily the rougher mountains, and am often alone, so a systematic approach has helped me be less emotional and more calculated in my decisions. The equation is simply:

[Glider Energy] – [Air Energy]
which seems to make sense in that who has the advantage, the glider or the surrounding air?

[Glider Energy] (mph) = Airspeed, which is the actual speed of the air traveling over your wing to keep it flying. This is usually the trim speed of your glider, but can vary depending on how slow or fast you decide to fly. Once you get comfortable using the equation it can help you see why we want to fly faster in turbulent air, and why so often your speed system actually helps stabilize your wing in rough conditions.

[Air Energy] (mph) is a little more difficult to determine as it is the amount of swirling air around you which can possibly disrupt or counteract your airspeed. When airspeed is disrupted too much, you get a collapse. In order to determine the Air Energy, we need to break this out a bit:

[Air Energy] = [Wind]*[Terrain Factor] + [Gust]

[Wind] (mph) is the Base wind you feel sitting on launch (or what you measure while flying).

[Terrain Factor] is a unitless number from 0.0 to 1.0 that measures the roughness of the terrain (0.0 meaning completely featureless and smooth while 1.0 is the roughest mountain terrain possible). Most ridge soaring sites are 0.0-0.4, while most mountain sites are 0.5-1.0. The purpose of a terrain factor has everything to do with how wind and thermals interact with the terrain. In rough terrain it is possible to have the base wind actually reverse back on you in small localized gusts. These can be as small as your wing and only last  a couple of seconds. These small gusts can disrupt the airflow over your wing thus causing potential collapses.  In rough terrain this happens more often, with more force, hence the higher terrain factor.

[Gust] (mph) is the amount of thermal energy you feel while on the ground. This is the gust on top of the base wind that you feel. This thermal energy is from spinning air (thermals are not columns of air going up, they are columns of spinning air with a vertical component). This spinning air can go both ways, and if the spinning air is strong enough it can blow back against the wing, disrupting air flow and thus cause a collapse.

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This is the type of site that would have a terrain factor approaching 1.0

I know this is starting to feel like actual math here, but it is pretty easy and quick, with no pocket protector nor calculator required. Let’s look at a few situations that help put it into action:

Example 1: While sitting on the ground, feeling the steady breeze mixed with thermals rolling up the hill, it is tempting to clip in and go, but should you? You are at your home site, a fairly technical mountain launch with a terrain factor of 0.8. The base wind is about 10 mph blowing straight in. Occasionally you feel about an 8 mph gust on top of the base wind. You fly your glider with an airspeed of about 25 mph, and the stall speed of your glider is about 15 mph.  Let’s do the quick math.

[Glider Energy] = 25 mph
[Air Energy] = [10 mph * 0.8] + [8 mph] = 16 mph

Therefore, 25 mph – 16 mph = 9 mph. This is the potential worst case airspeed you can expect going over your wing. Is it MORE than the required 15 mph stall speed of your glider? NO! That means you can be sure that the air has the energy advantage in this situation, not your glider. Therefore you can likely expect collapses and other less fun things to happen. Best to stay on the ground for this one.

Example 2: The next day you try again. You hike up to the same technical mountain site with a terrain factor of 0.8. The base wind is 5 mph straight in with a gust of about 5 mph (means the wind goes from 5 mph to 10 mph at the peak). Feels pretty good, should you fly? Let’s do the quick math.

[Glider Energy] = 25 mph
[Air Energy] = [5 mph * 0.8] + [5 mph] = 9 mph

Therefore, 25 mph – 9 mph = 16 mph. This is the potential worst case airspeed going over your wing. Is it MORE than the required 15 mph stall speed of your glider? YES! that means you can be sure that your glider has the energy advantage in this situation, not the air. Therefore you can likely expect little to no collapses and a fun, relatively mellow flight. Time to get in the air.

img_0524This simple mathematical approach is what I have used through the years when trying to assess a flying site. No, it is not perfect, but it has helped me put aside emotion and make better decisions inline with my personal risk tolerance. Hopefully you find this discussion helpful in your flying pursuits.  I would encourage each of you to find your own approach to energy and make a conscious effort to fly on the right side of the equation. Wishing you all safe and happy flying, and I hope to see you up high in the mountain air soon.

 

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Paragliding – Managing the Risks

The other day I found myself on yet another airplane crossing yet another section of the western skies. A younger middle aged man was sitting next to me making small talk, asking the same common questions regarding destinations, home, reasons for traveling, etc.  It didn’t take long before we were talking about paragliding and his curiosity surfaced in a game of 20 questions. As paraglider pilots we are used to these questions and always seem to answer them in a positive tone with a smile on our face. It didn’t take too long to get to the most common question, as he looked over and asked “is it safe?”

Normally, this is an easy question and I have often heard pilots answer something like “it’s really safe…even safer than driving your car to work.” This has been a hot topic in my mind the last 18 months, so I decided to answer his question in a little different way. I said, “it depends on your risk tolerance.” I went on to explain that if you are an avid rock climber, road cyclist, backcountry skier, or sky diver then paragliding will likely be the riskiest thing you will ever do in your life.

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Training teaches you not only how to react, but gives a healthy respect for how quickly things can go wrong.

This pursuit of flying a piece of fabric and string through the sky is risky business.  If we do not already know that, perhaps it is time for a reality check.  The last year or two there have been a rush of accidents and fatalities, which has caused me to pause and explore why. Has it always been this risky? Are pilots making the wrong decisions, or am I just more aware because I am a bit more seasoned? I believe every incident is unique and has its own set of variables and factors, so there is no one clear cut reason.  The one thing that is clear cut, is that severe accidents and fatalities are a reality.

Historically, the best way to determine risk is usually to look at the numbers. I am an engineer by training and with post graduate degrees in applied mathematics, statistical analysis and an unhealthy appreciation for the laws of energy and physics. When things are unclear, I often turn to these scientific baselines for clarification. Let me try and use simple fifth grade mathematics to explain the risks of paragliding.

As of 2015 there were approximately 6,700 registered paraglider pilots in the US. That same year there were at least 8 fatalities that I know of nationally.  Assuming that approximately 2/3 of registered pilots are active pilots (the larger demographic having accidents), simple math equates the annual risk of fatality amongst US paraglider pilots to be approximately 1 in 550.  Keep in mind this is for trained, active pilots and members holding pilot endorsements under our national organization. So, how does this 1 in 550 annual fatality number compare with annually fatality rates of other pursuits? Skiing is 1 in 1,400,000 annually. Bungee Jumping is 1 in 500,000 annually. Road Biking is 1 in 100,000 annually and similarly Skydiving is 1 in 100,000 annually. Racing motorcycles is 1 in 1,000 annually. Climbing in Nepal is 1 in 145 annually. Finally, Base Jumping is 1 in 60 annually.  Paragliding, a pursuit we so often proclaim to be so safe is actually pretty dangerous for us active, rated, and endorsed pilots.

Within our local community here in the Rockies, which is one of the most active in the country, I have noticed through the years a rate of about 10 serious accidents for every one fatality.  A serious accident usually involves a broken back, broken legs or major trauma to the body thus landing oneself in the hospital for an extended stay. Mathematically, this leads to yet another statistical probability that as active, rated and endorsed paraglider pilots our chance of landing in the hospital with major trauma is 1 in 55 annually. That means I am 3 times more likely to break my back this year paragliding than die climbing in Nepal. I do not want to break my body any more than I want to meet my end on this earth, so 1 in 55 becomes an unacceptable number to me.

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Too many friends from this historic picture have since been broken while paragliding…and it’s only 3 years old.

They say knowledge is power, and power creates change. Knowing now the statistical risks stacked against us as paraglider pilots does this then change the way we approach flying? It does for me.  Free flight is a miracle, a pursuit that rivals only dreams and once you experience this new dimension of the world, it is difficult to give up.  I would argue that we do not have to give up on free flight, but rather use the knowledge to manage the risks.  How to manage those risks has been a healthy conversation the last 12 months amongst several of my mountain flying companions.

I will be the first to admit I am just a student of free flight, not a teacher. I do not pretend to know everything. I am also keenly aware I have made bad decisions in the past, decisions that required luck to be on my side. Unfortunately, I am sure to make some in the future. That being said, I thought I would share a few thoughts on how me, and a few of my fellow pilots do our best at managing some of those risks:

  1. Get SIV training. Although vital to ones development of skills many think of it as just a way to learn to get out of situations when things go wrong. The most important thing I learned from my first SIV training was that I NEVER wanted to have to do that stuff in the real world. It was a good reminder to make good decisions long before I ever had to call upon those skills.
  2. Never stop flying! Many pilots put their gear away for the winter, then dust it off in the spring and think they are still good, sharp pilots.  News flash, you’re not!  Spring is the most demanding and dangerous air of the year, and thus the time we see many accidents occur.  You need to keep flying all the time in order to stay fresh and sharp. Besides, winter air will teach you more about how your wing flies than any other time of the year.
  3. Determine your risk tolerance. Everyone has a different tolerance to risk based on life status, responsibilities, age, health, goals, etc. Find out what your tolerance is and chose a group of like minded pilots who share that same tolerance level. Then use that group to hold each other accountable when making decisions. This has been very helpful to me learning and listening to my friends!
  4. Survey the conditions of the air and always understand which side of the energy equation you are flying on. If you do not understand how to properly survey the energy, talk to someone who does. In my mind, this is the most important assessment you can make before flying. Talking with many of my friends who have been injured, in almost all cases, they were on the wrong side of the equation. I have flown on the wrong side too many times in the past and am making a conscious effort not to do it again.
  5. Never feel bad walking down or choosing not to fly. That is one of the great things I have noticed about the mountain flying community. When you decide not to fly for whatever reason, nobody questions or mocks your decision. If you ever get that feeling you shouldn’t fly, then trust your gut and don’t.

20140802_10I explained to the middle aged man seated next to me on the plane, that although paragliding appears risky, if you make good decisions, chose the right group of pilots and approach it more like aviation rather than sport, those risks can be managed. I shared a few photographs, stories and it didn’t take long for him to see this magic that paragliding offers. I still feel so lucky to have been touched by paragliding, by free flight and the experiences, friendships, and perspectives of this world it has offered. As we launch into another year of spectacular adventures, may we all work towards managing the risks both individually and as a community. Knowledge is power, and power creates change.  See you in the sky, hopefully somewhere high above the mountains.

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Life in Color

As autumn comes to an abrupt end, and the snow begins to fall, it is a good time to reflect.  Life can often be very mundane; the same schedule day in and day out.  At times it has felt like my life is filled with only the drab, the relentless grind, the longing for wishing, wanting, and working toward a future day.  As I briefly pause and look back over the last few months I realize how much color is actually in my life.  Color shining forth not necessarily in specific adventures, but the friends along the way that embody the color of life.  Paragliding, although beautiful and breathtaking, is a lonesome pursuit once you are in the air.  However, whilst on the ground, this pursuit often presents a colorful collection of personalities.  It is this collection of close knit friends, family, and fellow adventurers that bring so much color to my life.  My feet dangling thousands of feet over the mountains, circling with eagles and touching the clouds…well, that is just a bonus.