Gliders Launch with 454 Cubic Inches of Pull

By Scott Spangler on June 17th, 2019

Sky SoaringGliders—sailplanes—are engineless flying machines powered by gravity’s conversion of altitude into airspeed. Without a doubt, they are aviation’s purest expression of flying for fun. It is also the most social aeronautical neighborhood, because glider pilots alone cannot pull their craft aloft for a flight’s initial investment of altitude.

I discovered Sky Soaring Glider Club last year, when its Cessna 150 tow plane, with its more robust powerplant, swooped low on its touchdown pass to the club’s 3,000-foot turf strip that is perpendicular to U.S. Highway 20 in Hampshire, Illinois. Imitating an owl’s cranial rotation as we passed, I saw a gaggle of waiting gliders and a covey of humans scurrying around them. With an appointment to keep, I promised that I would return.

Sky SoaringBecause they fly for fun, I figured that the club members would be making the most of a balmy, sunny Saturday. We finally had one of those last weekend. Which was why I was worried by the silence when I rolled into the gravel parking lot. Two men were readying a Schweizer 2-33, but there was no internal combustion buzz. One of the men held the two-place glider’s wing level and, without a word, it leaped forward. After a step or two, he let go.

Around the corner of hangar, sitting under an umbrella covered picnic table, the launch director listened to the glider’s pilot calling out the airspeed and altitude. The speed was a constant 60 mph. The altitude rapidly increased to 2,000 feet above the ground, when he let go of the tow rope that has pulled him aloft.

After the launch director called ATC to file a pilot report of the glider’s release altitude, he explained it’s hard to see the quarter-inch tow rope, and hitting it would not be good. Absent a tow plane, the only launch alternative was a winch, but where was it? Pointing down the runway to the east, “a mile that way.”

Sky SoaringAs I was getting my steps in for the day, a brightly stickered Honda Accord with an unusual red roof rack was slowly driving in the opposite direction, dragging two brightly colored cords, one red, one yellow. This must be the “mule” the picnic table guys were talking about. Coming to the end of the turf strip, a half-mile into the adjoining farmers field was the orange snout of the winch, with a flashing yellow light on top of its cockpit cage.

“Normally we winch from the end of the strip,” said winch driver Don Grillo, “but the farmer hasn’t been able to get his crops in because of the weather, and he let us add another 2,000 feet.” A winch’s launch ratio is roughly 3:1, so the mile-long tow rope would get the Schweizer to 2,000 feet.

Sky SoaringWith the winch at the end of the turf strip instead of out in the farmer’s field, it will pull the 2-33, with its under nose tow hook, to 1,000 feet. The higher performance PZL Krosno KR-03, Puchatek glider pulls a bit higher because the towline attached under its CG, allowing a more acute climb angle. After either glider lets go of the two rope, a ribbon drag chute prevents its freefalling tangle.

Sky SoaringAs the mule pulled the tow ropes back for the next launches, Don explained the winch the club built on the frame of a used box truck. The two-drum Tost winch is from Germany, it’s powered by a “GMC 454-cubic-inch crate engine—same as a Corvette—with the Turbo 400 transmission locked in second gear.” Next to the tachometer is an instrument panel switch labeled N and D.  On the cockpit’s right sidewall is the throttle, and left and right levers either engage each towrope to the transmission or apply the brakes to its rotation.

Sky SoaringDon is one of the club’s four winch drivers, and all three members of the launch crew, which includes the launch director and mule driver, are club certified after successful completion of the training program. “I started driving the winch last year,” said Don. “It’s exhilarating, a lot of fun, but it’s a critical job. You have to pay attention to the glider, which you can’t see at first. You have to talk to the launch director on the radio.”

Getting ready for the next launch, Don dons his David Clark headset. Even with its muffler, the 454 running at 4,500 rpm in second gear is pretty loud. He’s also listening to the launch director and the pilot, who’s calling out the glider’s airspeed. Pull too hard and you’ll overstress the glider. To prevent that, there are several stress-calibrated break links in the towline by the drag chutes.

Sky SoaringWith the winch’s singing silenced by the engine’s effort, the Krosno rises above the horizon, climbs steeply, and disappears. When it releases, the rpm jumps suddenly. Don adjusts the throttle to maintain an even strain on the drag chute. As John Abramski connects the towropes to the mule for the next launches, Don tells me that this launch set a new club record for the Krosno of 3,100 feet AGL. –Scott Spangler, Editor

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One Response to “Gliders Launch with 454 Cubic Inches of Pull”

  1. Bill Palmer Says:

    YAY! Glad to see an article on soaring!
    Soaring is great fun with a little bit of something for every pilot type. You can just soar around the airport enjoying the view within easy reach of landing — testing yourself how long you can stay up, take longer cross country flights (I flew 90 mile out, then back trip last week), enjoy aerobatics, or race other gliders in contests at a wide variety of levels. Soaring with others is great fun and one of the most economical ways to fly. Students as young as 14 can solo, and it is a fantastic way to learn to really fly!
    Take a Sailplane ride today Visit http://www.ssa.org (Soaring Society of America) and look for the FAST (Fly A Sailplane Today) link

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