Wave flying at Dartmoor Gliding - a personal view

After Malcolm's post about wave flying over Mount Cook in New Zealand, I thought that I would review some photos from my library showing wave flying from Brentor. Some of these are published here

So how do we know when the wave is working at Brentor? The wind needs to have an easterly component but the wind at the west end launch point can be misleading. On a good wave day the wind can be almost calm as the rotor opposes the easterly wind. Sometimes the wind can be strong enough to make you question your sanity.

If the sky is "blue" i.e. no clouds, then the only way to know if the wave is there is to take a launch. Often though the clouds give us clues. The following photos are some of my favourite ground based ones.

Looking east showing a cap cloud over the higher tors.
A good indicator that the wave is working

This photo taken at the same time as the previous shows obvious wave bars near the airfield.
Notice the windsock hanging almost vertically.Don't be fooled.
This was anything but a gentle day with 30+knot winds at flying heights,
strong lift and sink and character forming rotors

Another wave bar over the runway

This wave bar photo was taken well to the south of the airfield.
I like the curved shape and the scale of it

A wave bar out towards Dartmoor

And this was taken late in the afternoon, Awesome.

So we've decided to give it a go. What happens next. Well the preparations should be thorough. At height it can be very cold; the temperature reduces by 2 degrees for every 1000 ft. So warm clothing is a must. Pay particular attention to the straps; these need to be TIGHT; wave rotors can be very lively. 

The early part of the winch launch is usually fairly normal but from about 400 ft upwards the rotor may make itself known often requiring large inputs from the pilot to keep the glider pointing the right way. Don't panic, this is normal. At the top of the launch, after release, you may well find yourself in more rotor, ride it out while heading towards the east. You may well be climbing in this turbulent air  but be careful. The sinking air in and around wave systems can exceed 10 knots down so from 1000 feet you may be less than a minute from the ground. 

If you are lucky enough to contact the wave the air will suddenly smooth out. Turn across the wind and commence following the wave. Because the wave forms parallel to the hills that triggers it, the beat Brentor is often North  - South. If there are clouds, the lift will be under or in front of the upwind cloud edge. This feels ( and looks ) very much like ridge soaring. If there are no clouds then "feel" for the strongest lift and adjust your track accordingly. If following the wave bar does not work very well, maybe try circling in a strong bit; if the wind is very strong maybe some figures of eight across the wind in  the strongest lift,

Tracking along the cloud ( wind is from the right)

Approaching the top of the cloud.

Tracking along the wave slot ( wind still from the right)

Well above the cloud tops

Just couldn't resist this view approaching another wave slot.
Wind is from the right. Best lift somewhere between centre and left hand side of slot

Now a word of warning. If you are above the cloud keep a very careful eye on the gaps. At the first sign of the gaps closing, descend immediately; you do not want to end up "stranded" above a solid cloud sheet.

Roger Greens Astir panel showing 11000 feet above Brentor.

Plymouth from 13,000 feet

The South Devon coast from 14,000 feet

All too soon it will be time to go back. Be very careful during your descent. Keep a good lookout. Soon enough it will be time for the circuit. Start your circuit with a lot of excess height. At Brentor when the wave is working the circuit is often in rotor. Stay high you may well need the extra energy to fly faster to maintain good control. Final turn should be high and the approach needs to be fast enough to maintain good control in the rotors. Normally the last 20 feet or so smooths out but don't relax, keep flying until the glider has stopped.

Wave flying at Brentor can be epic. It is not for inexperienced pilots but there is also great fun to be had flying with the instructors in a 2 seater.

This picture was taken by me from the backseat of K13 G-CHPX
while moving downwind to share that wave bar with K13 G-DDMX
crossing left to right in front of us

K13 G-DDMX at 10,500 feet.

Steve