gangster Posted December 28, 2018 Share Posted December 28, 2018 Guys Any thoughts about removing the twist in a glass fus. Way back last century I bought a glass fus for a classic aerobatic model, Might be one of the lightenings. I will post it on here for identification. Anyway this winter I will build a model with it as I have a nice vintage redshift 61 longing for a bit of nostalgia. The problem, and I suspect the reason it was sold is because the Fus is twisted leaving the top of the fin about 1" out of vertical. Now whilst it would probably make no difference the way I fly as well as a good talking point down the field I really want to build it true. So any thoughts, assuming it could not have been moulded that way on how to straighten it, would heat work? Should I leave it that way and correct the tailplane position so that is level and cut the fin off and replace with a balsa one or even glass the old one back on straight Or going for splitting somewhere retwisting and glassing back?. What would you do? Quote Link to comment Share on other sites More sharing options...
Colin Carpenter Posted December 28, 2018 Share Posted December 28, 2018 I used to design and mould fast electric hulls for racing , in polyester grp . Quite often , although the mould was flat , the running part of the hulls would develop a hook . Using carbon tows would help a bit. Nothing would remove them apart from filling / sanding. So , my guess would be to remove the fin or a slit in the rear fuselage and re glass when straight ! Hope this helps . Colin Quote Link to comment Share on other sites More sharing options...
Dave Hess Posted December 28, 2018 Share Posted December 28, 2018 I don't think there's anything you can do now that the fibreglass is fully cured, other than cut and repair it. It most likely got like that due to improper handling or storage in the days after it was moulded, before it was fully cured. Quote Link to comment Share on other sites More sharing options...
Don Fry Posted December 28, 2018 Share Posted December 28, 2018 Dave is right, it's set like that. Is it possible to cut the fin off, glue some reinforcement across the cut, and glue it back on, straight. Then sand and fill the damage caused by the cut. I assume is was going to be painted, wot will lose the signs it's been recreated. Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted December 28, 2018 Share Posted December 28, 2018 Posted by gangster on 28/12/2018 11:34:59: Should I leave it that way and correct the tailplane position so that is level and cut the fin off and replace with a balsa one or even glass the old one back on straight What would you do? As above . Quote Link to comment Share on other sites More sharing options...
Don Fry Posted December 28, 2018 Share Posted December 28, 2018 And I would disagree you won't notice, an inch out is a lot. And a couple of hours will sort it out. And if you didn't care, you wound have asked. Conscience speaking. For wound, read wouldn't. Edited By Don Fry on 28/12/2018 17:32:25 Quote Link to comment Share on other sites More sharing options...
gangster Posted December 28, 2018 Author Share Posted December 28, 2018 Posted by Don Fry on 28/12/2018 17:31:11: And I would disagree you won't notice, an inch out is a lot. And a couple of hours will sort it out. And if you didn't care, you wound have asked. Conscience speaking. For wound, read wouldn't. Edited By Don Fry on 28/12/2018 17:32:25 Quite so Don, it was a tongue in cheek comment. Quote Link to comment Share on other sites More sharing options...
gangster Posted December 28, 2018 Author Share Posted December 28, 2018 Thanks for the advice everybody Looks like surgery it is then which as Don said should only be a couple of hours work Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted December 28, 2018 Share Posted December 28, 2018 A 'banana shaped fuselage' is usually scrap but what you have is a twisted fuselage. If the tailplane seat is at 90 degrees to the fin you may be able to pack up one side of the wing seat but much depends on the cross sectional shape of the fuselage (it may still look odd). If the fuselage cross section is round then you might also be able to cut the fuselage and rotate it a few degrees and rejoin but you will need to be able to epoxy/glass the join from the inside ideally. That may not be possible. A couple of photographs is worth a thousand words! Good luck ganster with your un-twisting project at any rate. Quote Link to comment Share on other sites More sharing options...
brokenenglish Posted December 28, 2018 Share Posted December 28, 2018 You could try just cutting the side towards which the fin is leaning. That should allow you to pull the fin back to upright, and then fill the gap created with some kind of GRP wedge. Even just epoxy would work if you hold the fin upright while it's hardening. Quote Link to comment Share on other sites More sharing options...
Martin Gay Posted December 28, 2018 Share Posted December 28, 2018 Had a Fox glider fuselage where the fin leaned to one side by an inch.I cut through the join on the front of the fin and re-fixed it with the fin vertical. Simples! Quote Link to comment Share on other sites More sharing options...
Don Fry Posted December 28, 2018 Share Posted December 28, 2018 Might work. Quote Link to comment Share on other sites More sharing options...
Former Member Posted December 29, 2018 Share Posted December 29, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
gangster Posted December 29, 2018 Author Share Posted December 29, 2018 Piers you are quite right I did describe it badly it is not banana shaped at all it is in fact a twist. Very hard to determine where it starts. The markings for the tail plane slot is within 1.5mm so not too much to worry about there that cannot be compensated for. I think as so many of you have suggested it’s a slit and reclassify but it is still a rescission where. I will post a couple of picture in a bit and may start an identification thread. Oh an as for the control line idea. Suspect it will be for clockwise flights Quote Link to comment Share on other sites More sharing options...
gangster Posted December 29, 2018 Author Share Posted December 29, 2018 Quote Link to comment Share on other sites More sharing options...
gangster Posted December 29, 2018 Author Share Posted December 29, 2018 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted December 29, 2018 Share Posted December 29, 2018 Posted by gangster on 29/12/2018 15:11:22: Looking at that I reckon the advice others have given ie: slit it along the seem and reposition to straight ahead would work fine . Check what type of resin has been used in manufacture . Re-fix with the same type of resin epoxy to epoxy or polyester to polyester Dont mix the two as they will eventually come apart. Quote Link to comment Share on other sites More sharing options...
gangster Posted December 29, 2018 Author Share Posted December 29, 2018 Well the deed is done. Looking at the picture on a bigger screen I realise it looks like it was twisted in a manner to simulate left rudder. In reality the fin was leaning to the right. I cut a vertical slot immediately at the leading edge where it joins the fuselage and then a cut along the length o f the base of the the fin from the back to the vertical cut Opening the lengthways cut to about 3mm has restored the fin to upright. There is possibly a tiny twist in the other plane which I may deal with later. The first stroke of the saw confirmed the resin as poyester, The first tacks of glass have now gone on and have set so its time to try and get a layer of glass inside, that will be fun. Thanks to all for your advice Quote Link to comment Share on other sites More sharing options...
PatMc Posted December 29, 2018 Share Posted December 29, 2018 I think I know the model but just can't remember the name. In fact I think I have an identical fuselage, except that mine's white, in the loft. The original kit model had a balsa built up fus with a clear canopy & swept veneered foam wings. IIRC it was designed for a 40 but there may have been 2 sizes available. If it is the one I'm thinking of, it dates back to the late 70's - early 80's so the resin will most likely be polyester. Dunno if mine has a twist, I'll check it at the next opportunity. Edited By PatMc on 29/12/2018 18:47:25 Quote Link to comment Share on other sites More sharing options...
gangster Posted December 29, 2018 Author Share Posted December 29, 2018 Hi PatMc I am told that it is a Dave Hardacre Lightning and I think that is pretty well confirmed by Google. There is no way that it was designed for a 40 and is definitely 60 sized. I would say your estimate of age is spot on. Hopefully yours wont have a twist. I am hoping to fit a contemporary motor in it , a Fisher Redshift with an ED quiet pipe, if that doesnt work well tough it will have to put up with an SC 61. From what I see on the web it was origionally a wooden model. I have a set of wings from an unknown model which I am sure will work Quote Link to comment Share on other sites More sharing options...
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