Danny Fenton Posted December 2, 2011 Share Posted December 2, 2011 Sorry Rich I thought you were scaling up the original design. If its as plan I would do it as plan. My Mamselle tailplane is 18" and as flimsily built as yours, but once covered is fairly (in free flight terms) rigid. But it certainly curled when I covered it, and had to be put in a straight jacket while applying the iron to get it flat again Yep over engineering I reckon..... Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted December 2, 2011 Author Share Posted December 2, 2011 Danny, Yes this a scaled up version, the original size would be more than strong enough I would think. Rich Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 2, 2011 Share Posted December 2, 2011 Ahhh okay, The mamselle uses two pieces of wood for the tips instead of your one, each with the grain at 45 degrees to the span, would that help? I think perhaps just adding an additional spar underneath might make all the difference with minimal weight added. But I am no designer, I just build as the plan tells me CheersDanny Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted December 2, 2011 Share Posted December 2, 2011 I am no designer either.......but .....whilst a lower spar will ad a lot of spanwise strength it won't do much to help the torsional rigidity which I think is what Richard is woriied about....what about adding some extra "ribs" from the spar of rib A to where the TE meets Rib B? This should add a fairbit of rigidity to the structure & look authentically vintage too.... Or maybe make the spar a lot wider....rather than 1/8" square how about 1/4 x 1/8" or even 3/8 x 1/8.....should be a good bit stiffer for very little extra weight.... Quote Link to comment Share on other sites More sharing options...
Erfolg Posted December 2, 2011 Share Posted December 2, 2011 I totally agree with both of you (Steve & Richard). Anyone who has seen the lightweight structures that have been used in the past on floater gliders, will know that even moderate speeds can cause wing flutter. Many of models from this era used multi spar wings, which could be surprisingly strong, if calculated using the idea of the parallel axis theorem, assuming none symmetrical Neutral Axis, due to the wing profile. Today most of us would go for an "I" beam. If not a "D" box leading edge with cap strip rear section, then bracing diagonals add little weight with a massive increase in torsional rigidity. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted December 2, 2011 Author Share Posted December 2, 2011 Well this evening I decided to have a go at one of the tips to see what it turned out like. Soaked some 1/4 grain strips of 1/16" balsa in boiling water for an hour and one by one applied them around my former. Once fully dried they were removed and the results I am pleased with, light but strong. Now I need to make all the others up. Just sticking to the tips like this with everything else as per plan bar for what you guys have suggested regarding a larger spar. I can add other strengthens if needed. Rich Quote Link to comment Share on other sites More sharing options...
Big Bandit Posted December 2, 2011 Share Posted December 2, 2011 Nice job Richard, Did the same with the quiver wing tips in the absence of split cane, worked fine for me. The alternative is to soak the balsa in ammonia, a bit stinky but works very well. It was once suggested to make up a piece of 3 foot rain water pipe with a cap on one end, filled with a 10% mixture of ammonia and water, then soak the wood for 24 hours. It makes it very pliable and will go around very tight curves. Cheers, Chris.Edited By Big Bandit on 02/12/2011 22:26:56 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 2, 2011 Share Posted December 2, 2011 That looks really nice Rich, well worth the extra effort. Its lovely to see things done properly. If I do the larger Mamselle I may have a go at that bending lark Cheers Danny Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted December 3, 2011 Author Share Posted December 3, 2011 Chris, I have heard of using ammonia, but where can we get it from? Danny, It bends round really easy, just a bit time consuming. Looking forward to your Big Mama! Tailplane is almost complete bar for adding the spars. Also had a motor and gearbox waiting for me when I finished work this afternoon. Not really the way I wanted to go originally but I have a cunning plan , of which I will need advice later on in the build Rich Quote Link to comment Share on other sites More sharing options...
Big Bandit Posted December 4, 2011 Share Posted December 4, 2011 Hi Richard, It was used in dyeline printing years ago and some copy shops still have the facility, may be worth giving some of them a try or lab supplies. My missus recons a chemist may be able to supply it, she's going to ask tomorrow. Cheers, Chris. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 4, 2011 Share Posted December 4, 2011 hi Rich i bought a bottle online on ebay, I was surprised because there are new EU rules that restrict it use. If you cant find any let me know and I will try and check my ebay history for the seller Cheers Danny Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted December 4, 2011 Share Posted December 4, 2011 I found a bottle in the local hardware shop not that long ago - 'Kleen Off' branded, £1.40 for 500ml. I dilute it to about 10% in use. I used it to mould some skins for the Eros underside to save planking it, but it would be just as good for laminated tips.If you are a family man, do this well away from the house, the smell of stale pee is a bit overpowering! Edited By Bob Cotsford on 04/12/2011 13:00:36 Quote Link to comment Share on other sites More sharing options...
Erfolg Posted December 4, 2011 Share Posted December 4, 2011 I know people have advocated Ammonia in the past. I have always been cautious, just in case I manage to stain anything. This would bring down the wrath of SWMBO, the smell could be enough to be blamed for day following night. I have found that very hot water or boiling water to be enough. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted December 4, 2011 Author Share Posted December 4, 2011 Cheers chaps, I will check out ebay and see what can be found. Or perhaps a trip to the chemist, maybe 'just for men'....not that I need it of course Bar for adding a few bits and pieces and some intense rib breaking sanding the tailplane is all but complete In the end I opted for two 1/8" spars and just tapered them at the tip, seems to be strong enough but with the added strength of the covering should be fine. No elevator as yet as I am thinking of making it all moving to keep with vintage feel, it does have a trim tab that if increased in size should be ok as a rudder. The problem will be hiding the control linkages? I will know more about this option once the fuselage is built. Have to say, though I have only made a small start I am enjoying this! Rich Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 4, 2011 Share Posted December 4, 2011 addictive isn't it? we take on more and more complex models as we progress in the hobby, its so refreshing to stop and reflect. These eliptical wings and tailplanes look wonderful don't they? Cheers Danny Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted December 4, 2011 Share Posted December 4, 2011 Eight ply balsa tips ! Loverly -they'll be the last thing to break .Proper job ! Take note Danny -That is proper building Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 4, 2011 Share Posted December 4, 2011 yep certainly is, and really nicely executed too, but Rich is really good at ths modelling mallarky Cheers Danny Quote Link to comment Share on other sites More sharing options...
Big Bandit Posted December 4, 2011 Share Posted December 4, 2011 That is so smart Richard, a bit of effort, but the results speak for themselves. Cheers, Chris. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted December 4, 2011 Author Share Posted December 4, 2011 It certainly is addictive Danny! There was my daughter playing away on that play station thing for at least 4 hours and me in the shed chopping bits of balsa! I wonder if she will be playing on the PS3 in her 30's? only time will tell. Funny how times change. Thanks for the nice comments chaps, These mass builds are fun and I think we learn a hell of a lot off each other, well I'm certainly learning new things any how Rich Quote Link to comment Share on other sites More sharing options...
Olly P Posted December 4, 2011 Share Posted December 4, 2011 Ammonia can be obtained from boots, they sell it as a cleaning solution, it's about 10% dilute. I have used it to shape wing sheeting, and it works well, I brush it on with a paintbrush. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted December 6, 2011 Author Share Posted December 6, 2011 Another dilemma regarding the tailplane. What do you chaps think? can I get away with throttle and rudder? I have been contemplating making the tailplane all moving as I am reluctant to add an elevator. I was just going to copy my Scarab set up, but on a smaller scale.This has a rudder on the underside with a piano wire loop moving the top rudder giving free play for the pitch alterations of the tailplane. The problem with the Jupiter is its rudder is on the fin so any hidden control would have to have to move with the tailplane. At the moment my only solution that I can think of is to mount a micro servo in between the centre ribs and some how coupling it up to an axle running vertical to the rudder. So much easier if I could just have rudder and throttle, but is this a risk? Rich Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 6, 2011 Share Posted December 6, 2011 Hi Richard, the thought of over control with an all moving tailplane would frighten me, not to mention the zero slop that the system would tolerate IMO. An elevator can be added and still look kind of period Alternatively you could use your all moving tailplane and use closed loop to the rudder attache above the tailplane. If you position guides on the pivot point, but above the tailplane then the angles should mean no rudder deflection change with elevator. The tension in the rudder cable would have to be kept low as to not restrict the elevator though?You do like to engineer stuff CheersDanny Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted December 6, 2011 Share Posted December 6, 2011 I'm with Danny here....I think you would need a very stiff & rigid system to hold the tailplane in exactly the right place & I think this would be difficult to engineer effectively Add simplicity is my motto & I think I would look at maybe modifying the design of the tailplane so you can incorporate an elevator without disturbing the lines of the model too much......take it from me...single channel rudder only is vastly over-rated.... Quote Link to comment Share on other sites More sharing options...
Erfolg Posted December 6, 2011 Share Posted December 6, 2011 All moving tail planes are commonly used on RC gliders. It is not to difficult to make them flutter proof or ensure they are slop free. Yet the Jupiter never had an all moving tailplane or elevator, so both deviate from the original concept. The elevator system of Danny's is more in the spirit of the time. Probably looks far more authentic with respect the era. At the end of the day, it was originally a rubber, semi-duration model. Yours will be an electric RC model. Ensuring that it both flies and looks in line with your aspirations, will be your measure of success, on both accounts compromise of these aspects, relative to one another is inevitable. I personally have a considerable bias to operability. Edited By Erfolg on 06/12/2011 17:28:45 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted December 7, 2011 Author Share Posted December 7, 2011 Thanks for the feedback chaps, must have been a bit of sleep deprivation yesterday on my part. You boys talk sense Must get some more building done rather than trying to ponder over things. Will make a start on the fuselage sides later, heating is on in the shed and the wollie hat is at the ready! Rich Quote Link to comment Share on other sites More sharing options...
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