FWAL Posted August 23, 2011 Share Posted August 23, 2011 Very little wind today so decided to test the OCD (flying wing). Started off with too much reflex and too little nose weight. After seven or so test throws she was gliding much better but I couldn't stop her from porpoising. Q. What is the cause and more importantly how do you eliminate it Thanks Mark Quote Link to comment Share on other sites More sharing options...
PatMc Posted August 23, 2011 Share Posted August 23, 2011 More nose weight or less reflex. It's just a question of balance between the two. Quote Link to comment Share on other sites More sharing options...
Devon Flyer Posted August 23, 2011 Share Posted August 23, 2011 Surely, if it's porpoising after getting up speed in a glide, then it's probably nose heavy and has too much reflex in to compensate? Moving the balance point back (ie. less nose weight) and reducing the reflex would help.............wouldn't it? Quote Link to comment Share on other sites More sharing options...
PatMc Posted August 23, 2011 Share Posted August 23, 2011 Porpoising is usually caused by over control due to the elevators being too sensitive. Some flying wings & models with small tailplanes tend to have less range of cg between oversensitive tail heaviness & inefficient nose heaviness. Quote Link to comment Share on other sites More sharing options...
stephen wenban Posted August 23, 2011 Share Posted August 23, 2011 Its actually known as hyperstall and yes a few thing can contribute to the problem Nose heavy requiring excessive reflex to overcome ,combined with elevator throws being to large 6. to 7.0mm max throws up and down is all thats required . So move your balance point rearward and reduce your reflex and your elevator throws. Ailerons can be as much as you feel comfortable with Edited By stephen wenban on 23/08/2011 21:03:06Edited By stephen wenban on 23/08/2011 21:03:26 Quote Link to comment Share on other sites More sharing options...
stephen wenban Posted August 23, 2011 Share Posted August 23, 2011 P.S another good check for your balance point is the good old dive test get some height point the nose into a shallow dive let the stick go if it pulls out its nose heavy ,if it tucks under its tail heavy . I prefer my balance point netural meaning put into a dive its stays there some prefer it slightly positive so it pulls out very slowly .but that just personal preference Quote Link to comment Share on other sites More sharing options...
Conwy Soarer Posted August 23, 2011 Share Posted August 23, 2011 Your elevator throw needs to be about 30% of the aileron thow, also try using expo if you have it. If the rain holds off will probably be at Hunts Bay 4ish tomorrow, will text you in the morning. As Steve says make sure your balance is right with a dive test - planks can be notoriously difficult to balance. Jon Quote Link to comment Share on other sites More sharing options...
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