Bannerdown News - From January 2012

21st/22nd January

The kit was out on the airfield on Saturday, but it was soon deemed to gusty for flying, as ground handling the K21 was proving problematic.  Thus the kit was put away.  However, there was work ongoing with the K18, Discus and other bits and pieces most of the day.

On Sunday the wind was just as gusty during the morning and early afternoon.  However, in the meantime Jon A., Ali A, Sam A., Ken and myself weighed and rigged the Discus after it’s annual maintenance.  Steve T., Al, Dave O., Bob Brom. and Oscar were busy with the K18 and winch fettling. Over the weekend we managed to get a great deal of work done around the club, sorry if I missed anyone out from the above.

By mid afternoon Sunday the wind had abated a little, it certainly wasn’t as gusty.  Al decided that he was going to take the Faulke for a flight so I grabbed a tow behind him hoping it was going to be waving, although no-one was entirely convinced that it would be, including myself.  After a high tow to just above the unstable layer Al and myself were pleasantly surprised by the conditions.  I returned to Keevil after climbing to 9,500ft in wave as the light was failing.  Al, had the Faulke throttled back with the spoilers open and maintaining height… When I returned to the hanger I found Brian P. hoovering the hanger floor! the hanger floor is now spotless, thanks Brian.

Date posted: January 23, 2012 by admin

Saturday 6th January

Different format for the news this week.  Bob Bromwich has kindly put together the following for our enjoyment, Thanks Bob.

Mild day with west – northwest wind strong enough to just allow ridge flying at Westbury White Horse, and later, with a more northerly and increasing windspeed with height, WAVE at Keevil !!

Several pilots flew the wave above 7000 feet, with Arran Armstrong (ASW27 G1) reaching the best height, 10500 feet, including a short wave cross – country flight!

Bob Bromwich took the following pictures to show just a small part of a very exciting wave flight ….

Here the glider (ASG29) is just above the upwind wave cloud edge, where the wave lift was strongest
after initially contacting and patiently working up the weak wave lift at the lower leading edge cloud wisps :

Soon the glider is climbing in strong lift above the wave edge shown by the cloud, noting a nice wide “wave gap” – that is not closing and shutting off opportunity to descend back down through clear air :

The sun is setting at the end of the day – the glider must be pointed into wind to hold position in the wind, because the windspeed at height was nearly equal the the glider flight speed ! :

The full moon is above the horizon, gliders must be back at Keevil before long …..

You You might all agree that it would be wonderful if more club pilots could benefit from the super flying available – but quite often a wave opportunity is missed !!
If you want to make use of these wave possibilities – like last weekend – the secret is to be prepared :
Always bring warm clothes and optimism to Keevil !!

Assuming you are keen to make the most of your future wave flying chances, here are some hints :
before each flying opportunity, look on RASP to see if there is a possibility of wave.
http://rasp.inn.leedsmet.ac.uk/RASPtable.html

To use this site to obtain an indication of wave is not straight forward, as the calculations cannot be exact enough. Last weekend, for instance, wave was not forecast by the colours and wave bars over the RASP map of the UK in our area, but the atmospheric soundings gave a tip-off to look for wave.
To view the local atmospheric sounding, go to the right hand side of the above linked page, click on “press for full parameter set”, and scroll down to “#11: Larkhill” which is local to our area, and click on this to obtain the sounding. On these soundings, wave is more likely if the wind speed has consistent direction with height (look at the wind direction/speed feathers at the right hand side of the sounding), and increases smoothly in speed with height (look at the green line running up the right hand side of the sounding graph). Note that you can have wave even if the wind is slack or different direction at ground level !!
Here are some general help FAQ’s for the RASP site :
http://rasp.inn.leedsmet.ac.uk/FAQ.pdf

Here is some more wave information
http://www.weatherjackwx.co.uk/tutorials/tut-various/wave/wave.html

When you are at Keevil, keep an eye on the shape of the clouds, if if a “wave edge” shows with a suitable “wave gap”, take an aerotow to just above and in front of the upwind edge of the wave cloud – and wave is nearly guaranteed – its a bit like fishing, and you have to contribute patience and skill to be successful ! If in doubt, tow higher, to give yourself more margin to get “established” in the wave ….
With the hills around Keevil, the most likely wind directions are north westerly (wave from the Welsh mountains) and southerly (wave from the edge of the Salisbury plain) but other wind directions can sometimes produce a surprise !

When the conditions are right, any of the club gliders could do exciting wave sorties – for instance, Ben Dews very, very nearly had his first wave flight in the K18 last weekend, and I am sure that if he had a second go he would succeed…..

 

Date posted: January 10, 2012 by admin