Adrian Law
Mar 26, 2003, 01:00 AM
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<P align=justify>Welcome once again to my corner of The Lift Zone. Over the past 2 installments of Darkside we have looked at the basic theory, and I have tried to give you some pointers how to get started on your first DS outing. If anything I have said has helped you or you have some questions, drop me a line and I will do my best to sort you out. If there is enough interest, or I get a lot of the same questions, I will do a Q&A here next time.<BR><BR>This month I am going to try to broaden the sites you think of as DS sites. Maybe you don't have a site similar to what I have shown you. Or even maybe you don't have any slope sites at all, then I may be able to help you. <BR><BR>I covered DSing technique to an extent in the last article and little of it changes for the more interesting DS site. All you need to remember is; windy air passing over a sharp edge creating dead air. No slope lift is needed, just that nice sharp boundary between the 2 air masses, and<BR>enough room in the dead air to get your chosen model around.<BR><BR>Due to the nature of some of these smaller sites (µDS) the only model worth thinking about is a small light foamy. Zagi THL, and other light combat foamies are among the best. These sites normally have a much sharper edge to them, with very little room in the dead air, so light wing loading for tight turns with lower drag is more important than momentum.</P>
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<DIV align=justify><BR>The above picture is of one of my local slope sites. On top of the hill is an Iron Age hill fort. The defences are still there to some extent. This makes a tight and challenging site for us µDSers. The ditch is approximately 5ft deep, and 15ft front to back. This doesn't give a lot of room, and its more about getting round the circuit in one piece rather than going fast. The model needed for this size of site is a foamy, anything crunchy is suicidal. It needs to be light, so it can turn sharply at low angles of attack and relatively low drag. A heavy model needs more angle of attack to create the greater lift needed to turn at the same radius. A zagi THL or similar is a good example. <BR><BR>The following video is in a similar site. The backside is a small quarry at the top of a slope. On this day, the conditions could not have been better. The boundary was high and the dead air was truly dead, so I decided to drop my discus launch glider in. Jim Burton was there too, and kindly took this video and set it to me. You will need the divx codecs (<A href="http://www.divx.com/">www.divx.com</A>) to view the video, this makes the videos smaller for the same quality.<BR><BR><A href="http://www.liftzone.com/~ade/vids/dlgds.avi">http://www.liftzone.com/~ade/vids/dlgds.avi</A><BR><BR>Another site I fly is similar to the one above. Again, it is on top of a slope but a row of bushes at the front edge of the hill provide the<BR>sharp edge to make the air break away from the ground. In this case, it gives us a lot more room to play with. On some days, a large molded model will pick up a fair bit of speed, on others not even a foamy will get round. <BR><BR>These examples involved using slope lift to gain a bit of height for the initial entry speed. There are people out there who are flying DS miles from the nearest slope lift. HOW I hear you ask?! Andreas Herrig has provided the answer. The following video explains everything!<BR><BR><A href="http://studweb.studserv.uni-stuttgart.de/studweb/users/lrt/lrt28575/DS_zdo.mpg">http://studweb.studserv.uni-stuttgart.de/studweb/users/lrt/lrt28575/DS_zdo.mpg</A><BR><BR>The video shows Andreas bungee (hi-start) launching an Xtrem 3, 1.5 m (60") span, and weighing about 1.3 kg. The site consists of a 15 m, 30° slope at a river bank, with trees about 10 m high at the top of the slope, The backside is close to being flat. The wind was about 50 km/h (14 m/s) and is near a village Called Penig (20 km west of hemnitz/Saxony). His website is in German, but google does a pretty good job of translating it.<BR><BR><A href="http://studweb.studserv.uni-stuttgart.de/studweb/users/lrt/lrt28575/DS.htm">http://studweb.studserv.uni-stuttgart.de/studweb/users/lrt/lrt28575/DS.htm</A><BR><BR>In the video, the wind is coming over the top of the trees towards us, and the bungee is in the dead air almost across wind. As soon he is off the line, he half loops over the top and drops down behind the trees. He then punches up back into the wind, and after a few circuits, you can see that this model is really shifting!<BR><BR>So now you have no excuse. You guys in mid America (and anywhere else flat), find yourself some trees and get on with it!<BR><BR>Now last month you may have noticed a lack of Video. This month there is no shortage! Again make sure you have the divx codec (<A href="http://www.divx.com/">www.divx.com</A>).<BR><BR>This video is thanks to Alex McMeekin. This is me DSing my Acacia F3F at crooks peak in western England. The wind was blowing about 12mph over the front. The Boundary was very wide, which meant I had to fly much bigger circuits than I normally would do. This reduces the speed available. Watch for the wiggles!<BR><BR><A href="http://www.liftzone.com/~ade/vids/crooks_quickish.avi">http://www.liftzone.com/~ade/vids/crooks_quickish.avi</A><BR><BR>The next is again supplied by Alex, Same place as the last on the same day. Slower than the first video, but it really shows what the conditions were like. Note the really nasty wiggle round the last bottom turn. <BR><BR><A href="http://www.liftzone.com/~ade/vids/crooks_wiggle.avi">http://www.liftzone.com/~ade/vids/crooks_wiggle.avi</A><BR><BR>Now to a couple of foamies. Both of these models belong to Jim Burton who also supplied the video.<BR><BR>Firstly we have an Sblitz, A 2 piece 60" wing designed for the UK EPP pylon league. It did very well, and looks set to dominate next years league too. (<A href="http://www.geocities.com/superronik_models/">http://www.geocities.com/superronik_models/</A>) Jim has modified his slightly by putting some carbon tows in the bottom of the slots for the spars. This seems to help a lot with the stiffness of the model compared to standard version. The conditions were about 20mph, but the boundary was a little wider than it has been in the past. Having said that, it's not slow by any means!<BR><BR><A href="http://www.liftzone.com/~ade/vids/sblitz.avi">http://www.liftzone.com/~ade/vids/sblitz.avi</A><BR><BR>Love them or hate them, Zagis are here to stay. Some versions are better than others. The Zagi LE in the following video was really struggling. The video doesn't show it very well, but it spent quite a lot of this day at whumpcrump fluttering its little elevons! What this video does prove is that you really don't need anything special to go DSing.<BR><BR><A href="http://www.liftzone.com/~ade/vids/Zagi2.avi">http://www.liftzone.com/~ade/vids/Zagi2.avi</A><BR><BR>Lastly, back to Crooks peak. This day was really quite dismal. For a time, the mist came down and showed the boundary quite well!<BR><BR><A href="http://www.liftzone.com/~ade/vids/mist.avi">http://www.liftzone.com/~ade/vids/mist.avi</A><BR><BR>Once again I have filled my slot. Thanks for reading, and see you next month when I hope to give you a look at some of the special DS models for when conditions are just too fast or turbulent for anything else. This doesn't happen very often, but when it does, the big molded ships and your average slope model might as well be made of tissue and dope. If you are flying one of these specialist models, I want to hear from you with your thoughts on it. Until then, be safe and have fun.<BR></DIV></BLOCKQUOTE>
<P align=justify>Welcome once again to my corner of The Lift Zone. Over the past 2 installments of Darkside we have looked at the basic theory, and I have tried to give you some pointers how to get started on your first DS outing. If anything I have said has helped you or you have some questions, drop me a line and I will do my best to sort you out. If there is enough interest, or I get a lot of the same questions, I will do a Q&A here next time.<BR><BR>This month I am going to try to broaden the sites you think of as DS sites. Maybe you don't have a site similar to what I have shown you. Or even maybe you don't have any slope sites at all, then I may be able to help you. <BR><BR>I covered DSing technique to an extent in the last article and little of it changes for the more interesting DS site. All you need to remember is; windy air passing over a sharp edge creating dead air. No slope lift is needed, just that nice sharp boundary between the 2 air masses, and<BR>enough room in the dead air to get your chosen model around.<BR><BR>Due to the nature of some of these smaller sites (µDS) the only model worth thinking about is a small light foamy. Zagi THL, and other light combat foamies are among the best. These sites normally have a much sharper edge to them, with very little room in the dead air, so light wing loading for tight turns with lower drag is more important than momentum.</P>
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<TD align=middle width="50%"><A href="/articles/liftzone/2003/mar/darkside/dark1.jpg"><IMG height=150 src="http://static.rcgroups.com/articles/liftzone/2003/mar/darkside/dark1_t.jpg" width=200></A></TD></TR></TBODY></TABLE></DIV>
<DIV align=justify><BR>The above picture is of one of my local slope sites. On top of the hill is an Iron Age hill fort. The defences are still there to some extent. This makes a tight and challenging site for us µDSers. The ditch is approximately 5ft deep, and 15ft front to back. This doesn't give a lot of room, and its more about getting round the circuit in one piece rather than going fast. The model needed for this size of site is a foamy, anything crunchy is suicidal. It needs to be light, so it can turn sharply at low angles of attack and relatively low drag. A heavy model needs more angle of attack to create the greater lift needed to turn at the same radius. A zagi THL or similar is a good example. <BR><BR>The following video is in a similar site. The backside is a small quarry at the top of a slope. On this day, the conditions could not have been better. The boundary was high and the dead air was truly dead, so I decided to drop my discus launch glider in. Jim Burton was there too, and kindly took this video and set it to me. You will need the divx codecs (<A href="http://www.divx.com/">www.divx.com</A>) to view the video, this makes the videos smaller for the same quality.<BR><BR><A href="http://www.liftzone.com/~ade/vids/dlgds.avi">http://www.liftzone.com/~ade/vids/dlgds.avi</A><BR><BR>Another site I fly is similar to the one above. Again, it is on top of a slope but a row of bushes at the front edge of the hill provide the<BR>sharp edge to make the air break away from the ground. In this case, it gives us a lot more room to play with. On some days, a large molded model will pick up a fair bit of speed, on others not even a foamy will get round. <BR><BR>These examples involved using slope lift to gain a bit of height for the initial entry speed. There are people out there who are flying DS miles from the nearest slope lift. HOW I hear you ask?! Andreas Herrig has provided the answer. The following video explains everything!<BR><BR><A href="http://studweb.studserv.uni-stuttgart.de/studweb/users/lrt/lrt28575/DS_zdo.mpg">http://studweb.studserv.uni-stuttgart.de/studweb/users/lrt/lrt28575/DS_zdo.mpg</A><BR><BR>The video shows Andreas bungee (hi-start) launching an Xtrem 3, 1.5 m (60") span, and weighing about 1.3 kg. The site consists of a 15 m, 30° slope at a river bank, with trees about 10 m high at the top of the slope, The backside is close to being flat. The wind was about 50 km/h (14 m/s) and is near a village Called Penig (20 km west of hemnitz/Saxony). His website is in German, but google does a pretty good job of translating it.<BR><BR><A href="http://studweb.studserv.uni-stuttgart.de/studweb/users/lrt/lrt28575/DS.htm">http://studweb.studserv.uni-stuttgart.de/studweb/users/lrt/lrt28575/DS.htm</A><BR><BR>In the video, the wind is coming over the top of the trees towards us, and the bungee is in the dead air almost across wind. As soon he is off the line, he half loops over the top and drops down behind the trees. He then punches up back into the wind, and after a few circuits, you can see that this model is really shifting!<BR><BR>So now you have no excuse. You guys in mid America (and anywhere else flat), find yourself some trees and get on with it!<BR><BR>Now last month you may have noticed a lack of Video. This month there is no shortage! Again make sure you have the divx codec (<A href="http://www.divx.com/">www.divx.com</A>).<BR><BR>This video is thanks to Alex McMeekin. This is me DSing my Acacia F3F at crooks peak in western England. The wind was blowing about 12mph over the front. The Boundary was very wide, which meant I had to fly much bigger circuits than I normally would do. This reduces the speed available. Watch for the wiggles!<BR><BR><A href="http://www.liftzone.com/~ade/vids/crooks_quickish.avi">http://www.liftzone.com/~ade/vids/crooks_quickish.avi</A><BR><BR>The next is again supplied by Alex, Same place as the last on the same day. Slower than the first video, but it really shows what the conditions were like. Note the really nasty wiggle round the last bottom turn. <BR><BR><A href="http://www.liftzone.com/~ade/vids/crooks_wiggle.avi">http://www.liftzone.com/~ade/vids/crooks_wiggle.avi</A><BR><BR>Now to a couple of foamies. Both of these models belong to Jim Burton who also supplied the video.<BR><BR>Firstly we have an Sblitz, A 2 piece 60" wing designed for the UK EPP pylon league. It did very well, and looks set to dominate next years league too. (<A href="http://www.geocities.com/superronik_models/">http://www.geocities.com/superronik_models/</A>) Jim has modified his slightly by putting some carbon tows in the bottom of the slots for the spars. This seems to help a lot with the stiffness of the model compared to standard version. The conditions were about 20mph, but the boundary was a little wider than it has been in the past. Having said that, it's not slow by any means!<BR><BR><A href="http://www.liftzone.com/~ade/vids/sblitz.avi">http://www.liftzone.com/~ade/vids/sblitz.avi</A><BR><BR>Love them or hate them, Zagis are here to stay. Some versions are better than others. The Zagi LE in the following video was really struggling. The video doesn't show it very well, but it spent quite a lot of this day at whumpcrump fluttering its little elevons! What this video does prove is that you really don't need anything special to go DSing.<BR><BR><A href="http://www.liftzone.com/~ade/vids/Zagi2.avi">http://www.liftzone.com/~ade/vids/Zagi2.avi</A><BR><BR>Lastly, back to Crooks peak. This day was really quite dismal. For a time, the mist came down and showed the boundary quite well!<BR><BR><A href="http://www.liftzone.com/~ade/vids/mist.avi">http://www.liftzone.com/~ade/vids/mist.avi</A><BR><BR>Once again I have filled my slot. Thanks for reading, and see you next month when I hope to give you a look at some of the special DS models for when conditions are just too fast or turbulent for anything else. This doesn't happen very often, but when it does, the big molded ships and your average slope model might as well be made of tissue and dope. If you are flying one of these specialist models, I want to hear from you with your thoughts on it. Until then, be safe and have fun.<BR></DIV></BLOCKQUOTE>