iawnski Posted July 2, 2009 Share Posted July 2, 2009 well now ive got your attention here we go ,my friend al the destroyer has just purchased a aggressor glider from the states all epp, 1 mtr w/span,2 mini servos,small electric motorpusher, 2 cell lipo ,the prob is its hellish unstable in the air it ROCKS with no power on like mad, right wing tip to left wing tip,then no chance of controlling it what u boffs gotta say to this one why does she rock wildly and i mean wildly ,????????????????????? Quote Link to comment Share on other sites More sharing options...
Gemma Jane Posted July 2, 2009 Share Posted July 2, 2009 Well that would be 'dutch roll'. Check the usual stuff CofG, no warps or misallignments, also as it is often triggered by rudder movements that the throws are correct (assuming it has a rudder) and it isn't set-up 'crossed controls' i.e. it hasn't been trimmed with the rudder cancelling out the ailerons. I'm not that into glilders so maybe somebody else has more insight for you, but that is what I would start with. And before anyone says it, no dutch roll isn't only a feature of swept wings, my PZ Corsair demonstrates it at times! Quote Link to comment Share on other sites More sharing options...
iawnski Posted July 2, 2009 Author Share Posted July 2, 2009 hi gemma forgot to mention its a flying wing ,no rudder,done all the usual checks and still dont no whats going on thanks for your input Quote Link to comment Share on other sites More sharing options...
Matthew Lloyd Posted July 2, 2009 Share Posted July 2, 2009 I think the main problem is that this 'glider' ISN'T a glider Chuck out the lipo and motor and go find a hill. If it smacks into the valley floor then best leave it there - it sounds awful! Yours, The Oracle Quote Link to comment Share on other sites More sharing options...
Gemma Jane Posted July 2, 2009 Share Posted July 2, 2009 There, see Matthew had the answer Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 2, 2009 Share Posted July 2, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 2, 2009 Share Posted July 2, 2009 You can hide, but I know where you live remember kev.... it sounds to me like either a control surface issue such as loose control horns, slipped servo outputs etc, or even more likely a COG issue TBH. Flying wings are notoriously sensitive to incorrect balance point, and one model I had ( great Planes Slinger ) was a complet pig if the COG was shifted by just a few mm. Quote Link to comment Share on other sites More sharing options...
iawnski Posted July 2, 2009 Author Share Posted July 2, 2009 timbo u could be right mate we have gone for and aft with the cg and still the same its a beast ,,this is aileron movement 1mil. elev 2 mil.and its till a beast ,polli u ok now mate ?,its a new model from the states and has yet to visit the rock ,dont no if it ever will as al the destroyer has promised if it dont go right next time out its dead ,gee he means it and he aint flown it yet,come on guys help some more we dont want a bonfire yet lol Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 2, 2009 Share Posted July 2, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 2, 2009 Share Posted July 2, 2009 I assume Al has balanced it laterally too? PS tell him to bring along anyway and we will have a look..sure we can sort it on site. Quote Link to comment Share on other sites More sharing options...
iawnski Posted July 2, 2009 Author Share Posted July 2, 2009 ok timbo will do, polli will try to get a photo off al for you to have a look at Quote Link to comment Share on other sites More sharing options...
Slopetrashuk Posted July 2, 2009 Share Posted July 2, 2009 Assuming that the cg and control throws are correct as per instructions it sounds as though there is not enough fin area on the model. Having a swept wing means that the drag off the wings as the leading edges swing back and forth varies to try and keep it stable just like the B2 bomber (with no fins). Of course the B2 has a good number of computers to keep it straight and not a set of thumbs. Consider the swing where the left wing tip slides forwards and the right rearwards to the direction of flight. The leading edge of the left wing may be square on to the airstream over it while the regressing right wing will have reduced drag. the left wing will now get dragged backwards as the right wing comes forwards. The aircraft is trying to equalise drag on each wing but will find it hard to achieve equilibrium without rocking from side to side in the manner you describe. Try an experiment with a central fin on just the upper side only - perhaps hanging back off the wing trailing edge like a halfpipe or larger fins at the tips if it already has them. A comment on your control throws too - it is more usual to have more aileron than elevator on a pitch critical model. Too much elevator will stall the control surfaces and cause the aircraft to flick. Of course all this is quite hard to ascertain without a picture mate! Andy Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 2, 2009 Share Posted July 2, 2009 Ah yes of course...the winglets or whatever things are fitted to it! I wonder if there are any Quote Link to comment Share on other sites More sharing options...
iawnski Posted July 2, 2009 Author Share Posted July 2, 2009 timbo and slopetrash there are no winglets, they seem to fly ok in the states there is a vid of them ,just waiting for al to get them to me so i can post for you guys to have a scan Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 2, 2009 Share Posted July 2, 2009 Quote Link to comment Share on other sites More sharing options...
paul (dig-it-up) Posted July 2, 2009 Share Posted July 2, 2009 going to stick my oar in now .kev the glider is called the assassin not the aggressor combat wing Edited By paul (digitup) on 02/07/2009 21:45:36 Quote Link to comment Share on other sites More sharing options...
paul (dig-it-up) Posted July 2, 2009 Share Posted July 2, 2009 heres the link www.utahflyers.org/ Quote Link to comment Share on other sites More sharing options...
Slopetrashuk Posted July 2, 2009 Share Posted July 2, 2009 Extracted from the instructions..... 28. Aligning winglets is done by taping the elevons in place and placing the trailing edge of the elevons against a straight edge or wall. Using a 90 degree square draw a line at each wing tip of the EPP foam making sure both wings are the same length. The winglets should be mounted with the front of each winglet toed in towards the center 1/4 inch. This stabilizes the yaw of the plane. Use an exacto knife to carefully cut the foam I guess this solves your problem..... Andy Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 2, 2009 Share Posted July 2, 2009 Doh....no wonder I couldnt find it ...thanks kev Quote Link to comment Share on other sites More sharing options...
G Posted July 3, 2009 Share Posted July 3, 2009 A lot of flying wings rock slightly. I find you need quite a bit of reflex to launch any flying wing, but if you leave that reflex in place for normal flight, the wing rocks. So you need a launch mode (with both elevons up say 3mm) and a flight mode (with both elevons up say 1mm). Or reflex on a switch or something. (Reflex is having both elevons slightly upwards, all flying wings I'm aware of need it, but too much causes that distinctive oscillating). Quote Link to comment Share on other sites More sharing options...
iawnski Posted July 3, 2009 Author Share Posted July 3, 2009 errrrrrrrr im sure webby told me it was aggressor ? .....but its really an ASSASIN that got you all going eh,,,,, de dum de dum de dum ,,,gonna have to watch that digitup s-a-t-r-e Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 4, 2009 Share Posted July 4, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
iawnski Posted July 4, 2009 Author Share Posted July 4, 2009 hi eric cheers for input, if you have a scan at the link ,it shows you them flying ,amazing really ,cheers iawnski Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.