Out of curiosity a few years back, I flew the Bonanza down to Seminole Lake Gliderport (6FL0), about 25 miles west of Orlando, to inquire about soaring lessons. Flying a glider was something that intrigued me for a number of years after getting my pilots license. I wanted to see if I was truly capable of being towed into the air by another aircraft, flying and then successfully landing a sailplane all without the benefit of an engine. Seminole Lake is a beautiful facility, with a groomed 3000 foot grass runway, oriented north/south. I took the demo ride and was hooked!
If you hold a private pilot’s license or higher, a glider rating can be added-on in as little as 10 hours of flight instruction. Successfully passing this check ride counts as an FAA Flight Review, good for two years.
When transitioning from powered to non-powered flight, there is a fair amount of book work. The student glider pilot is much more immersed than a private pilot in the in-depth study of weather, temperature inversions, thermals, cloud streets, and their effects on aircraft performance. Knowing this information is critical to passing the oral part of the check ride.
The nose of a glider is attached to the tail of the tow plane with a 200 foot rope. The tow rope has a metal “weak link”, designed to break if you accidentally create too much tension on it. The tow rope is normally released by the pilot of the glider at a pre-determined altitude.
The tow plane pilot can easily tell he is towing a newbie because, once airborne, you are literally pulling him all over the sky, much like an overweight water skier pulling around an underpowered boat. I have found that tow pilots are a pretty patient group. Flying a glider takes a deft touch.
A typical glider has minimal instruments; the two primary being an altimeter and a variometer. The variometer lets the pilot know if he (or she) is in an area of rising air, called “lift” or sinking air, called “sink”. The variometer indicates, in knots, the rate of climb or descent. It is much more sensitive than a typical VSI, found in powered aircraft. The variometer is used to help locate even the subtlest areas of lift, and it can indicate climbs rates of as little as 1 knot.
In order to stay aloft for as long as possible, or to fly cross-country, the glider pilot seeks out these areas of lift, known as thermals. The act of circling in these rising columns of air is known as “thermalling”. Sink is to be avoided at all costs, unless you want to “land out”, or off field. Landing-out is a major PITA, because you must to disassemble the ship, so it can be loaded on a long trailer for the humiliating road trip back to base.
Another important flight instrument is the yaw string, a simple 3 inch piece of yarn taped to the outside front of the Plexiglas canopy, directly in the pilot’s line of sight. This functions like a poor-man’s turn coordinator. The yaw string helps the pilot maintain coordinated flight. In uncoordinated flight, the yaw string will not line up with the longitudinal axis of the glider, so the pilot must use rudder to get the aircraft again coordinated.
My training and check ride was in the sleek Grob 103 (pictured below), a high-performance, two seat composite craft with a 38:1 lift over drag ratio (L/D). The L/D ratio indicates how many feet forward this particular model will cover, while losing just 1 foot of altitude, in still air. The greater the L/D, the longer a glider will be able to stay aloft in the absence of lift. By comparison, my Bonanza has a L/D of about 7:1, power off, so you can see how efficient these sailplanes really are.
Initially, the most challenging aspect of learning to fly a sailplane was remaining in the correct position behind the tow plane, a powerful single-engine Piper Pawnee. You learn visual aides, such as positioning the tow planes landing gear on the horizon to stay out of the prop blast and maintain the smoothest ride on climb out.
One of the first things I learned in training is “boxing the wake”. This procedure teaches you how to explore the 4 corners of the tow plane’s wake, which is a combination of prop blast and vortices created as a byproduct of lift. You also learn the proper positioning for a “high-tow” and a “low-tow”.
Seminole Lake has an instructor and FAA Designated Pilot Examiner on site. When you are signed off by your instructor, you take your oral exam and check ride in the same aircraft and at the same field with the Examiner. I passed my check ride, which included a simulated tow line break on departure, landing with failed wing slats and spot landings, in the minimum ten hours required. At that point I was able to take up passengers in the Grob, and give them an experience they never would have imagined.
On a typical soaring day in Florida, you will be towed to, and release at, 2000 feet AGL. After pulling the tow release in the cockpit, the tow plane will immediately bank left, and the glider banks right. Your airspeed will settle in around 50-55 knots indicated, and because there is no engine, the only noise you hear is the quiet hiss of airflow over the sleek fuselage. There is no vibration in a glider, and the canopy allows you a full 360 degree view of the earth and sky.
On a clear day with lots of lift, you can easily climb the Grob to 5000 feet AGL. From that altitude, you can see the Disney complex, downtown Orlando and maybe even the skyline of Tampa. We don’t have any mountains in Florida, so there are no mountain waves or orograhphic lift like they have out west. By comparson, sailplanes up to 30,000 feet or higher are not uncommon in the Western mountains.
Once aloft, there is nothing like finding and circling a strong thermal, and sharing it with a lone hawk or bald eagle. The newcomer “big giant bird” does not intimidate them; in fact they seem a bit curious at my presence. These beautiful birds of prey don’t seem to mind a game of chase, or sharing their airspace one bit.