- Ok, which is it: "gliding" or "soaring"? And what IS soaring?
- How does a glider fly?
- So how does a glider stay up without an engine?
- How does a glider get up in the air in the first place?
- What kinds of gliders are there?
- Where is the best place to fly?
- Is soaring only done in the summer?
- Can a sailplane do aerobatics?
- What happens if you can't make it back to the airport?
- Is soaring safe?
- This must be an expensive sport.
- Who can be a pilot?
The preferred term is "soaring," since this is what all sailplane pilots seek to do. Technically, soaring is the act of maintaining or gaining altitude in unpowered flight (aided by rising currents of air). It's interesting to note that gliding is always occurring even while soaring — the pilot is going up in air rising faster than the plane is gliding down.
For the aircraft themselves, the situation is somewhat reversed. The common term is "glider" (even for sailplanes, which are considered the higher-performance end of the spectrum).
Paradoxically, by using gravity.
From an aerodynamic standpoint a glider flies exactly the same way all heavier-than-air aircraft do. The wings of a glider turn (deflect) the air through which they're moving, producing the reactive force of lift which supports the glider. (Huh? It's not like that, you say? Actually it is…and many popular theories about lift are incorrect. But the devil is in the details, and exactly how turning occurs is a contentious subject even today.)
The paradox is that the glider needs to keep moving to produce lift, and this movement is provided by gravity. In effect the glider is continually "falling" forward; this falling creates airflow over the wings which produce lift, and the glider stays airborne.
It's an irony of soaring that the same force pulling the glider down is also responsible for keeping it aloft.
By using rising currents of air in the atmosphere, called lift (not to be confused with the lift produced by a glider's wings). These invisible currents are typically generated by three mechanisms:
- Thermal lift. Solar heating of the ground warms the air above it, which then rises in bubbles or columns called thermals. The tops of thermals are often marked by puffy cumulus clouds, a reliable sign to the glider pilot that lift is active.
- Ridge lift. Wind blowing perpendicular to a slope is deflected upward, which the glider can use to stay aloft. Flights of hundreds of miles along the Appalachians are made in this manner.
- Wave lift. Wind blowing over mountains sometimes results in "ripples" in the atmosphere, as the wind compresses and rebounds after passing over them. These ripples, or waves, can extend high into the atmosphere. Flights over 20,000 feet in wave lift are not uncommon.
Thermals are the most ubiquitous type of lift, and make soaring possible almost anywhere in the world. This is the type of flying done in Michigan.
The same way every other airplane does — it flies off the ground! The difference, of course, is how this is achieved:
- Aero tow. The glider is towed into the air behind another airplane. This is the most common method of launch, and is the type used most often at Sandhill. (Aero tow is also formation flying, giving "bragging rights" to the sailplane pilot so inclined.)
- Winch launch. The glider is rapidly pulled into the air on a long cable by a winch. Not as common as aero tow in the US, but widely used in other countries due to lower costs.
- Self-launch. For sailplanes with an auxiliary engine (motorgliders) it doesn't get any easier. This class of soaring aircraft is becoming increasingly popular for just this reason.
There are other methods for getting a glider airborne (towing behind a vehicle, for example, once a standard method of training pilots), but these are rarely seen today.
About as many varieties as there are people who design them. A glider is technically defined as an aircraft that does not depend principally on an engine; in practice, a glider is also defined by its high glide ratio (the ability to travel forward a relatively long distance for an amount of altitude lost). Within that framework categorization depends on the features of interest, but for someone new to the sport, some useful definitions might be:
- Recreational/training gliders. The ability to fly predictably and at slower speeds make these excellent for recreational soaring. May have one or two seats and be constructed from a variety of materials.
- Sailplanes. The "high performance" class of glider. Typically single-seat and manufactured from composite materials. Wings are long, thin and use an advanced airfoil design.
- Open Class. Actually a class defined for competition by the FAI (Fédération Aéronautique Internationale), this can be read as "anything goes." The most advanced sailplanes fall in this category, with glide ratios approaching 60:1, and are not likely to be seen at your local airport. (The eta is a prime example.)
- Motorgliders. The exception to the rule. As the name suggests, these gliders carry a small engine which can be used for takeoff (self-launch) or prolonging flight in minimal lift.
It depends. Are you interested in thermal soaring? Then head to the southwest, where sunny days and warm temperatures create thermals that can top out at 15,000 feet. Has ridge soaring captured your interest? Pennsylvania and the Appalachians are a mecca for the modern breed of "ridge runner." Or perhaps wave soaring, with visions of jetliners passing far below? The mountain states are your goal, with future visits to New Zealand and South America.
For the rest us with job and family responsibilities, however, the best place to fly is "at home." Soaring is done in all 50 states; most individuals can find a club or organization to join within an easy drive. And don't think you're missing out by staying in your backyard — the challenges to be found 20 miles from home can be greater than those 2,000 miles away! (And we'd be remiss if we didn't suggest Sandhill as the best place to fly, either.)
No, it's a year-round activity. For some types of soaring (wave in particular), conditions actually improve in the winter. That being said, you're far more likely to see activity during the summer in the northern half of the country. Thermals are much stronger due to longer days and higher sun angles, and good flying weather is much more frequent. (Pilots also appreciate the ability to wear Panamas instead of parkas.)
With proper training and using a glider certified for this type of flying (and further not confusing can with should), yes, aerobatics are entirely possible in a sailplane. Many commercial operations offer this type of instruction.
As an interesting footnote: gliders are typically stronger than other types of aircraft. The FAA (Federal Aviation Administration) recognizes three ascending strength categories for aircraft of "Normal," "Utility" and "Aerobatic." All gliders are at least Utility — without an engine and related components, it's easier to create a stronger airframe.
The old saw of "what goes up must come down" applies equally well to gliders. Eventually the flight must end…sometimes when you don't want it to! While not a problem for students and sightseeing rides that stay close to the airport, every experienced sailplane pilot has "landed out" at some point.
Luckily, gliders are designed with just this event in mind. Light, strong and able to fly slowly, almost any open field will serve as a landing strip when the lift just up and quits. Wings are designed to be removed with just a few bolts and pins, and the glider can be carried home on a trailer behind even a small car. The biggest problem for the pilot is usually how to fill his time waiting for the retrieval crew.
Nothing in life is 100% risk-free, and neither is soaring. Accidents can and do occur, though thankfully on an infrequent basis. Soaring in general compares well against other aviation activities (light aircraft and hangliding).
The soaring pilot is often in a better position when problems do occur, because of the light weight and slow flying capabilities of the aircraft. Accidents that could severely damage the sailplane often result in the pilot walking away unharmed. Additionally, glider pilots are highly-trained in energy management and situational awareness, factors that translate very well into making them safer powered aircraft pilots as well.
With that in mind, even one accident is one too many. Many organizations continue to work with the soaring community to make an already safe sport even safer.
No more than a dedicated game of golf, actually, if you join a club. Soaring by itself is the least-expensive of the many types of general aviation; joining a club further spreads costs among members and can be very economical indeed. In addition, many clubs charge little or no fees for use of equipment and instruction (Sandhill included).
Once you strike out on your own things begin to change, though soaring is still well within the reach of most. Older model gliders can be purchased for less than $10,000, and insurance, maintenance, and storage costs are much lower than for a comparable powered aircraft. (Got a few more dollars to spend, you say? Then grab a Stemme S-10 — the world's most expensive motorized sailplane at a mere $340,000.)
Just about anyone! The requirements to operate a glider are less than that for powered aircraft, and the FAA allows individuals as young as 14 to fly as solo students. Additionally, medical certification is not needed to become a glider pilot. It's safe to say if you can drive a car, you can probably fly a glider.
With that in mind, no, you can't take your first ride on Saturday and walk off with your license on Sunday. Proper instruction is required, as is passing a written FAA exam and demonstration of piloting skills to an FAA examiner. A certain amount of solo time is also required before a pilot certificate is received. Most people find they can easily get to the solo stage of training in a summer of weekend flying, while dedicated individuals can go from novice to licensed pilot in the same season.