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The Downside of Big Ears

We've all been there. We've all done it. We've all wanted or needed to get down, preferably 5 minutes ago, for any number of imaginable reasons and an equally vast number of unimaginable ones. We have all, at some point in our time as pilots, thought "If I make my glider the size of a marmot pelt, I should pick up a few extra miles per hour and get down faster!" The logic works doesn't it? Smaller surface area, increased wing loading, speed increases with wing loading...just what we were looking for! We all remember that stuff from our training...Right? As an added bonus our gliders feel more stable in turbulence and we don't have to worry about the bumps! This is the part where you should hear a little voice that sounds suspiciously like Scooby-Do saying "RUH-ROH!"

To understand the problems, and why big-ears are so commonly used in inappropriate circumstances we have to understand the up-side to big-ears and what happens while they're installed. Increased descent rate without compromising speed? Check. We can see it on our instruments and it's quantifiable. This is, after all, the primary reason we use big-ears. Increased wing loading? Check. Make your glider smaller and you're suspending the same weight from a smaller wing. We could measure it with the right instruments but we shouldn't need to. Increased angle of attack? Absolutely, and like an increase in wing loading, it's a byproduct of big-ears. You can't have one without the other. Without increasing your horizontal speed the angle at which the air is intersecting the chord increases. It's debatable as to whether the angle increases to a dangerous level, but it does happen to some degree and could, in some conditions, be an important factor.

But how do we get ourselves into trouble with such a common, useful, and if used properly, safe maneuver? Unfortunately it often goes all the way back to our training, where we learned that increasing the wing loading, however we choose to do it, increases all our speeds, makes our glider less susceptible to deflations, and that big-ears is one way of increasing our wing loading. It's an explanation that leaves out a myriad of variables. As eager students we instantly deduce that big-ears are the perfect method for getting into tight landing zones, dealing with turbulence that makes us uncomfortable, often on approach to a landing zone, or escaping "park-out" where our ground speed is 0 or negative. We like to think of big-ears positively. "What can they do for me?" rather than "What does it cost me?"

The reality is that using big-ears to descend lower on a windy ridge may put us in a position with less wind and thus increase our ground speed, but no matter how much we wish they did, big-ears do not increase our airspeed. The extra drag from all that limp fabric flapping in the breeze conveniently negates any increase in speed we would have gained through higher wing loading. Some high performance gliders may actually lose air-speed while in big-ears. Using speed-bar in conjunction with big-ears (big-ears first, then speed-bar) would clearly help our penetration and decrease our angle of attack, but using an appreciable amount of speed-bar close to the ground isn't recommended. I wouldn't want to give anyone the impression that descending below 500 feet AGL with speed-bar applied in turbulent conditions is a good idea. It's most definitely not.

What about getting into tight landing zones or dealing with turbulence? Tight landing zones are often tight because they're surrounded by trees, buildings, and an assortment of other turbulence inducing nuisances. By using big-ears to descend steeply into a landing zone you are gambling that the amount of turbulence behind the obstacles will be less than the turbulence required to disfigure your glider in its highly loaded state. Remember that you already have a higher angle of attack and while holding onto the outside A-lines it's utterly impossible to be an active pilot. For those unfamiliar with the term active piloting, it's what we do when we sense the glider through the brake toggles and harness, and translate those senses into properly timed inputs that keep the glider flying the way we want it to. With big-ears installed you have no surge control or feedback from the glider through the brake lines not to mention diminished directional control. It's like driving a 4WD road with both hands on the dashboard. One should always be an active pilot, but of all the times to be especially vigilant, flight close to the ground should rank high. To add to the complexity of landing, if you did suffer an unexpected glider disfigurement or surge while in big ears and you released the outside A-lines to apply brake, you're now dealing with high wing loading, an increased stall speed and a bunch of brake to stop the surge. Messy.

Very, very tiny big ears don't solve the problem! By using very small ears you gain none of the advantages and all of the disadvantages. Your descent rate wont increase much, your hands are occupied with something other than active piloting, and you don't gain any real increase in stability through wing loading. You'd be better off yelling to someone on the ground to throw you a rope or some lead bricks.

Wouldn't the turbulence required to disfigure a glider in big-ears be greater than the turbulence required to disfigure a glider without big-ears? Not if you're being an active pilot. Be a pilot! Fly the glider and take command of your aircraft. Active piloting is much better at preventing glider disfigurement than passively hoping that big-ears will. Remember, big-ears are a descent maneuver, not a deflation prevention maneuver. By using big-ears as a band-aid for poor planning, fear, lack of skill, or lack of knowledge, you are taking yourself out of the equation and placing your fate in the hands of your environment. Planet earth is hard, and the atmosphere has no pity. If you have the altitude for it, and you no longer want to be involved in piloting your aircraft, come up with another descent maneuver. I'm a big fan of B-Line stalls and spirals. In a B-Line stall your glider is no longer flying and is significantly less likely to require inputs from you. As with most maneuvers, get training at a maneuvers course before doing a B-line stall. Once you've descended to within 500-1000 feet of the ground, exit your descent maneuver of choice and actively pilot your glider to the ground. Obviously any horizontal wind component will be a deciding factor since in a B-Line stall or spiral you will drift downwind at at whatever rate the wind speed happens to be.

So why do we bother learning how to do big-ears? Is there any appropriate place to use them? Absolutely! We learn how to do them because they're a handy tool for escaping clouds or descending at a moderate speed in reasonably smooth air (your bump tolerance may vary). Big-ears is also the only descent method that doesn't compromise our progress toward a goal. You can install ears and still be zipping along at or at least near trim speed which make it a great method for escaping cloud suck or getting down to 1000ft AGL over a buoyant landing zone. When nearing cloud-base, and think you may be unable to make it to the edge before whiting out, toss in big-ears, pick a direction and make a quick exit. It's a band-aid for poor planning but is still better than illegally entering a cloud. If the cloud suck is extremely strong, use a faster descent method, lose some altitude, then go back to big-ears.
Used in the right situations big-ears can be a safe and useful descent method. Used inappropriately it's a sloppy band-aid for poor planning, or fear, and is significantly riskier than actively piloting your glider.

© Christopher Grantham