Peter Miller Posted May 27, 2013 Share Posted May 27, 2013 Many years ago one of our club member's son had a Tutor, it was never over stressed and failed in the same way. The replacement from Ripmax failed in the same way on the first flight, again, not over stressed. The spars had the consistancy of foam plastic.. The member asked for and got a proper kit so he knew that the new model would properly built. Quote Link to comment Share on other sites More sharing options...
Rick Tee Posted August 12, 2013 Share Posted August 12, 2013 I've flown many Tutors 1's and 2's currently teaching 4 new members all flying Tutor 2's. 4 wing bands is not enough, you need 6 and after a couple of outings at least 2 of those will need to be stretched across the fuselage before pulling them over the wing. The recommended 6" bands are too long, when you buy new bands get 5" ones, then you won't have to stretch them across the fuselage. I always put bands on 2 each side parallel to the fuselage and two crossed over to prevent the others sliding off. Crossing them all can allow the wing to rock under stress, try it. The additional stress caused by flying in high winds vs light winds is negligible compared to an emergency pull up or even a reasonably tight loop. Quote Link to comment Share on other sites More sharing options...
dlonrar Posted August 12, 2013 Author Share Posted August 12, 2013 Rick Tee, Yes, after many flights with the Tutor 2 I have found that 6 bands give the best result arranged in the way you have used. I did consider trying some 5" bands, so I wilI give them a go. Thanks for your post. Quote Link to comment Share on other sites More sharing options...
Rich too Posted August 12, 2013 Share Posted August 12, 2013 Nothing wrong with bands - in the old days they were common, and I never had one issue. However, I agree that four is not enough in any conditions, I would use at least six. Rich Quote Link to comment Share on other sites More sharing options...
Ian Jones Posted August 12, 2013 Share Posted August 12, 2013 Posted by Rick Tee on 12/08/2013 08:18:28: I've flown many Tutors 1's and 2's currently teaching 4 new members all flying Tutor 2's. 4 wing bands is not enough, you need 6 and after a couple of outings at least 2 of those will need to be stretched across the fuselage before pulling them over the wing. The recommended 6" bands are too long, when you buy new bands get 5" ones, then you won't have to stretch them across the fuselage. I always put bands on 2 each side parallel to the fuselage and two crossed over to prevent the others sliding off. Crossing them all can allow the wing to rock under stress, try it. The additional stress caused by flying in high winds vs light winds is negligible compared to an emergency pull up or even a reasonably tight loop. Yep, insuffient banding will allow the wing to lift. This not only gives some very tricky flying characteristics it also puts a tremendous strain on the wing & spars especially when the wing bangs back down again. I can think of two different branded models with a wing that lifted and ended up with spar failures. The models got the blame but I think it was the movement that did it. Quote Link to comment Share on other sites More sharing options...
graeme jones Posted August 12, 2013 Share Posted August 12, 2013 There is a simple way of checking. When you have fitted the bands, pick the aircraft up with one hand on each wing, fingers under, thumbs on top. Shake the aircraft up and down as hard as you can. If the wing lifts from the fuselage, add two more bands and check again. Graeme Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted August 12, 2013 Share Posted August 12, 2013 In my view 6 are the minimum - under any weather conditions! The above is right, the moment of greatest stress on the wing is going to be when your instructor has to achieve the near possible in an effort to save your model for you! and usually does! BEB Quote Link to comment Share on other sites More sharing options...
Shaunie Posted August 12, 2013 Share Posted August 12, 2013 Perhaps I go OTT but, waaay back in the day my Hi-boy was flown with about 8 bands and I now do the same with a TT OBL 40 trainer I use for others to have a go. I suspect six would be okay but never less than that. I've always thought banded on wings were a waste of space in the respect of saving damage on a rough arrival as using sufficent bands to avoid movement in flight will also prevent movement on a hard landing. I was also taught to give the plane a shake to see the wing was firmly fixed. Bands don't hold the wing down onto the fuselage, they hold the fuselage up underneath the wing! Remember that the centre of pressure is not midway along the chord but much towards the front (20-30%, I'm sure BEB will correct me ...) so it will almost certainly be the front that lifts causing a sudden increase in AoA and likewise a sudden and dramatic increase in generated lift. This will stress the main spar in anything, surely? I'm sure in my early days I heard a plane (not mine) make a sort of "clap" noise and an experienced modeller immediately gave an instruction for the plane to be landed as he thought there were not enough wing bands and it had lifted and dropped sharply back down on its seat. Sure enough there were very few bands on the wing. Shaunie Quote Link to comment Share on other sites More sharing options...
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