Fly the littoral zone—Slope Soaring on small hills
by Dave Garwood
dave.garwood.518@gmail.com
Eight years ago, in the February 2008 issue of Model Aviation, my column covered flying in slope lift created at a 3-foot Armco barrier at the edge of a beach parking lot. Thank you to Dave Sanders for showing how it can be done.
He demonstrated the method with one of his EPP foam warbirds, and everyone I know who has tried it since then is amazed that it can be done, and pleased that he or she can do it.
Now RC pilots can fly in slope lift generated over an 18-inch bump. In one Cape Cod Slope Soaring day, four flying buddies flew from 12-foot hills, 6-foot hills, and an 18-inch slope on the beach just above the high-water line. On this day, we flew from Head of the Meadow Beach, near North Truro, Massachusetts. I thought that there must be other locations all across the country with similar topography and wind.
The area where the land meets the sea is called the intertidal zone, also known as the littoral zone. It’s the area that is above water at low tide and under water at high tide. Use of the term littoral zone can be limited to the wet sand area, or it can be considered to include a larger zone.
For Cape Cod Slope Soaring, I generally climb the hills beside the parking lots and fly from 80- to 200-foot hills. This time, merely for variety, I flew from 12-foot dunes. The sailplanes that my fellow pilots and I flew included Alulas, Sabres, Weasels, and Zulu delta wings, 48-inch wingspan EPP foam warbirds, 60-inch wingspan and 2-meter wingspan Magnum Models Duster ODR racers, and Dave’s Aircraft Works (DAW) Schweizer 1-26s.
After some time on the small dunes, we decided to try flying over a slightly raised part of the beach that appeared to be approximately 5 to 6 feet above the water level. There was more big fun with the Alula, Sabre, and Zulu deltas, and 48-inch DAW Kawafomiae-61 warbirds.
We were pleased with ourselves
for flying from a 6-foot hill. It was at roughly that time that Soaring philosopher Jan Carstangen noted, “Helmut Lelke used to stand down by the waves and fly.” We took it as a challenge and marched down to the wet sand part of the beach and launched Alulas. Amazingly, there was plenty of lift to not only stay up, but to climb to approximately 20 feet above the water. The experience was amazing, rewarding, and confidence-inspiring for Slope glider pilots of all skill levels.
Note that in order to fly in these tiny hill conditions, the wind must be nearly perfect. On our memorable flying day, wind speed was a steady 15 mph, and wind direction was dead-on straight in.
The topography is critical to success, and it helps to have a well-trimmed sailplane. Although we fly a lot of short-wingspan sailplanes, other small-hill Slope seekers favor longer-wingspan sailplanes. Bill Kuhl is one of them. Bill has flown a large number of sailplane flights on small hills and has documented them on his website. He mentions trying small RTF foam gliders such as an E-flite UMX ASK-21 or E-flite UMX Radian.
Pilots spend a lot of time and effort getting to big hills, which have more possibilities for long flights, high flights, racing, and aerobatics. Small hills, however, offer a greater number of Slope flying sites. You might find that they present their own excitement—not the least of which is discovering what minimal topography and how little lift you actually need to fly and have a good time.
Keep these things in mind when searching for new Slope Soaring spots. Hills of any height work best when turbulence-creating upwind obstructions are minimized, and having an ocean, lake, or river out front creates smoother air coming into the slope. Smooth wind improves flying on any hill, but it’s more noticeable when flying from small hills. It’s a good idea to seek out flying spots that are unobstructed by upwind turbulence makers.
The US has 12,383 miles of coastline. Twenty-four states have ocean coastline, while eight states share 4,851 miles of Great Lakes shoreline. It boggles the mind to think about how many small-hill Slope Soaring sites could be found along those 17,000 miles of coastline and shoreline.
Did I just identify 17,000 potential Slope Soaring sites? You decide after you try flying over a 1- or 2-foot-high bump of wet sand.
(Editor’s note: Make sure to check with proper authorities to ensure you have permission to fly within parks or public areas.)
SOURCES:
Model Aviation Digital Library
http://library.modelaviation.com/ma/2008/2
“Small Slope RC Soaring” by Bill Kuhl
www.ideas-inspire.com/small-slope-rc-soaring
League of Silent Flight (LSF)
www.silentflight.org
