In February 2020, AeroClub Albatross hosted a seminar series about ridge soaring. Below is the YouTube link to a talk by Karl Striedieck entitled “Good Ridge Gone Bad” and a summary of the key takeaways.
Good Ridge Gone Bad – Karl Striedieck
Karl Striedieck highlighted several risks of ridge soaring:
- Know your rough air speed.
- Gliders are very robust. Generally, the risk over-stressing them is low. Most robust: short wing span, light fuselage, water in wings (e.g. ASW20). Least robust: long wingspan, heavy fuselage (e.g. 2-seater with engine), no water in wings.
- Flutter could be concern but practically not likely at low altitudes.
- A good harness is essential to avoid hitting the canopy hard with the head. Best are 5-point harnesses. Never wear a hat with a button on top. You will break the canopy if you hit it hard.
- No loose items in the cockpit.
- Don’t hold the stick on top to prevent accidental stick movements in turbulence. Rest arms on legs and hold stick low.
- Use water ballast, it dampens the ride. Don’t put water in the tail, flying nose heavy is good when ridge flying. Watch for freezing temperatures – see below under “Cold”.
2) Poor Visibility
- Beware low clouds, rain, and snow-showers
- Snow does not degrade performance of the glider but rain does.
- Rain provides the illusion of flying faster than actual. This is risk because performance is degraded and flying faster is necessary. Pay close attention to air speed in rain.
- Do not fly through a snow shower unless you can see through to the other side.
- Beware the angle of the sun late in the day.
- If visibility is poor for whatever reason, keep more distance from the ground.
3) Closeness of the Terrain
- Best lift is usually at ridge top level, and 1 wing span in front of the ridge.
- Trim the glider such that you always have to push the stick forward to stay low. If you accidentally let go of the stick, the plane should rise up a little, not drop down.
- If you look away for a moment, remember to always check terrain ahead to not hit anything.
- Faster is safer because the plane is more controllable at higher speeds and you have additional energy to avoid obstacles if necessary.
- When climbing off the ridge in thermal: pull off in bump, keep going straight till end of bump, turn into the wind (i.e. away from the ridge), and continue into wind to test if this is a thermal street perpendicular to the ridge. When lift weakens, turn back and decide right away if you can make a turn or if you should do a figure 8. In general, do not turn until you are 200-300 feet higher than the top of the ridge. When turning, drop the nose to increase speed for the turn close to to the ridge, only pull up once nose points away from the ridge again. Always expect the possibility of a stall and one wing dropping. Keep your airspeed up.
4) Wave Suppression
Be mindful of the possibility of wave suppression if there is another ridge upwind. Wave suppression is invisible – you’ll notice it if the ridge no longer works (i.e. if you have to slow down to maintain altitude.)
- Prepare for the flight and know where they are. Be mindful that cell towers etc often have guy-lines anchoring them to the ground. Give towers a wide berth so you don’t hit a guy line.
- In Europe beware of cables from (often small private) cable cars that may not be on a map. Talk to locals about cables in your flight area.
- In freezing temps, never put water in the tail tank.
- The wing tanks won’t easily freeze, but the valves might. This could make it impossible to dump water, or the water only dumps on one side. When dumping, always check that both tanks sides are dumping. Do not dump if in doubt. Better to land with water. Add alcohol to the water ballast to prevent freezing.
- Beware of canopy shrinkage in cold temps, especially for large canopies. Shrinking canopies will increase noise and you will lose insulation (cold feet!).
- Main dangers are other gliders and birds.
- Turkey vultures will get out of the way and eagles usually as well.
- Be careful with (red tail) hawks. In particular, never fly below a hawk. Hawks are fixated on their prey on the ground and will not see you. If they spot prey, they will dive. If you happen to fly underneath at that point, they will hit you.
- If you fly with birds, make sure you don’t fixate on the bird but watch the terrain!
- When climbing up into wave, make sure you always have an out to the ground within easy glide range (within a 10:1 glide ratio or closer).
- If trapped above the clouds: if you must descend through clouds, let go of the stick, open the spoilers fully, and wait until you come out below. Very dangerous when cloud base is low to the ground.
9) Ridge Weakening
Always watch your airspeed. As long as you can fly at ridge top level with more than 80 knots you have some extra energy. If you have to slow down to stay at ridge top level: danger! You must always have a land-able field in glide when you can’t maintain high speeds along the ridge.