Completing a wave task in the Arcus M
Saturday was a poor day for solo flight at Denbigh because of the significant cross-wind. So instead, I decided to go and do a navigation task around the north of Wales in the Arcus M with my instructor.
The aircraft I typically fly is a trainer glider called the Twin II Acro. 50 knots is slow flight for that glider, and 80 knots is fast.
If the Twin II Acro is a Kia Picanto of gliders, then the Arcus M is something like a Porsche Boxter. It is a nimble, fast aircraft. It is capable of a range of different speeds depending on the flap settings.
The first task was to get to the actual start of the wave bar. This was a 15 minute flight from base, being towed behind the tow plane:
After the long tow out, the instructor handed the controls to me and we started flying along the wave. As the wind blows over the mountains, it gets pushed up. This creates a long bar of air, many kilometers in length, that is being pushed up higher in to the atmosphere. If you fly at right-angles to the wind, this allows the glider to steal energy from the atmosphere and use it either to climb or to accelerate and maintain a higher speed across the ground. The wave is usually marked by clouds just downwind of the area with the best lift. The clouds form as the moisture in the rising air condenses.
I was flying at 110 knots through one portion of the task, which is about the cruise speed of my PA28. Despite flying this fast, the glider was still climbing, such was the power of the wave. I still find this fact about gliding utterly bonkers. The fact that you can fly as fast or perhaps even faster than a powered aircraft while still maintaining a decent climb.
The mountain ridge runs all the way to the coast so if you follow the wave down you end up popping out over the ocean.
At the end of this section the instructor took control and did a chandelle to turn us around and head back towards base. Watch the video below for that bit of hooliganism!
The flight back involved going down the wave bar in the opposite direction. We tried to go to the next wave bar downwind of the mountains but found the lift was much weaker. We darted back through a gap in the clouds over to the wave bar we’d just been on:
Then it was just a question of riding the wave back home. With the wind behind us we achieved a mind-blowing 147 knots across the ground, which is about 170 miles an hour! Once again, you can’t help but be staggered by that. 170 miles an hour across the ground and you don’t have an engine running. The tow out took a good 15 minutes, but the flight back from the wave bar was about 6 minutes.
Then there was nothing left to do but for the instructor to land.
The landing was pretty smooth considering the amount of crosswind we had.
With our mission complete, I opened the canopy and hopped out of the plane. I can’t wait to do a task like that myself some day. What an adventure!
