Taco Posted January 9, 2012 Share Posted January 9, 2012 Great work indeed! Taco. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted January 10, 2012 Author Share Posted January 10, 2012 Thanks Tom ,yeah it will certainly be an impressive sight if I can get it to enough height, hopefully Mark's Wilga will oblige Thanks Barrie, yeah I was looking at pictures of your K18 in bare bones format and the gilders do look splendid. Fitting the servos and their cables is a bit of a a squeeze, the elevator servo that drives the control column will fit in fine, as does the rudder servo and the the cable release. I need to cover the wings after fitting the aileron servo control cables. At the moment I am working on the king post where the wings slot on. This needs strengthening and the dihedral setting for the wing joiner. Thanks Taco, there is still quite a lot of work to do, I have covered the tail feathers, as below. Quote Link to comment Share on other sites More sharing options...
Tom Wright 2 Posted January 10, 2012 Share Posted January 10, 2012 I need to get round to your house for some photography lessons Stuart ,my thread photos are rubbish compared with yours .Glad to see you have mastered the covering technique.lovely job. . Tom. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted January 11, 2012 Author Share Posted January 11, 2012 Hi Tom, yeah you are welcome to pop round. Your photos are not that bad, if you have a camera with a macro (close up) function, use it. The Solartex is antique coloured and very nice, looks like the real deal! Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted January 15, 2012 Author Share Posted January 15, 2012 Hi Taco, do you know where the CG point is on the SG38 wing, I can't find it mentioned on the plans? Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted January 15, 2012 Author Share Posted January 15, 2012 I have decided to use different pulleys as the brass ones were too small and would involve making ply faces both sides to make them the correct size. I picked brass assuming they would be hard wearing but the shaft diameter is only 2mm. I found some 15mm diameter plastic pulleys with a 4mm diameter hole, and so can bush it with some 4mm brass/alum tube and then some 4mm wire which will be stronger. The wire will pass through the fuselage sides/ wooden framework where required and then a pulley pushed onto each end. I need to think about a pulley retaining system to stop them popping off the ends of the shaft, and also to keep the wires/cables from jumping off the pulleys. I will paint these black as all the hardware will be black, i,e. tail struts, rudder bar and clevises, skid metal parts etc.... The rudder pedals have been fitted onto the rudder servo head and a screw through both allow rotation of the pedals as the pilots feet move back and forth. I should be in possession of two pilots this week from AH pilots, a 1/3 scale one for the SG38 and a 1/4 scale pilot for the as yet unstarted 1/4 scale ASK18. My model is not quite 1/3 scale as it's got a 3 metre wingspan and the original has a wingspan of 10.4 metres, so my pilot will be oversize, but of about the equivalent to a man of 6ft two to six foot three inches tall, so should still fit. I have purchased 24 swg wire to make up all the wire bracing for the model, the ends of the wire will have metal clevises on threaded rods soldered to it to alter the tension in the wire and I will use plastic clevises painted black. These are the small variety. Most of the attachment points are on the fuselage, but there are 8 attachment points on the wings and I need to think about making them strong enough so as not to pull out in the case of high loads being put on them. The original SG38 has a metal plate which runs full spar depth and emerges top and bottom of wing to serve as anchor points for the wire bracing system. The wings will have at least 8 or 10 wires running from them and the length of wire needed is 45 feet!!! I am going to stain and waterproof the fuselage with coloured/stained polyurethane which should give a nice finish, although I do have different wood types like balsa and ply together. Did some flying yesterday, the first for some months and was a great and also produced a video for Tom Wright and Pete Fisher of their autogyros which flew very well. Quote Link to comment Share on other sites More sharing options...
Taco Posted January 16, 2012 Share Posted January 16, 2012 Posted by Stuart Eggerton on 15/01/2012 09:05:35:Hi Taco, do you know where the CG point is on the SG38 wing, I can't find it mentioned on the plans? From the original i can say this: CG can be measured from the leading edge of the wing, and should Iie between 400 and 480mm with the pilot in the seat. I think this will help? Taco Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted February 4, 2012 Author Share Posted February 4, 2012 Hi everyone, latest on the SG-38, not done a terrific amount of building due to other commitments. Taco, thanks for the CG recommendations, that will be very useful when it comes time to fly her. First of all I finally got my pilot from AH designs, will look the part in the SG38! I have covered the wings in the antique solartex, very nice but I have encountered a small problem, I painted the bare balsa wood with a wood stain so that once covered it would look like the leading edge and wing tip panels were made from a different wood, as per the original SG38, but the glue of the solaretx has only stuck to certain parts and left a patchy appearance. This may be OK as the glider is supposed to be vintage but I could paint on top of the solartex, will have to see. The rear of the fuselage has been covered I have painted the seven pulleys required Here are the rudder pedals and rudder bar. Glued on the skid front tonight, just needs shaping / tapering a bit at the front etc... Rudder servo has been glued in place (on rails) and you can see the tow release mechanism and wire too. Tow release servo to be fitted. The steel bars to which the pulleys attach to have been added at various points. The wire wing joiners have been fitted and the wings easily slide onto them and are true (thank goodness!) So all in all it's progressing nicely. Looks like going to be snowed in tomorrow so some more work to be done!! Quote Link to comment Share on other sites More sharing options...
Barrie Dav 2 Posted February 5, 2012 Share Posted February 5, 2012 First class job Stuart. Good workmanship. Don't worry about your paint problem. If you saw some of the old gliders at the gliding clubs you would see that there are very few in pristine condition. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted February 8, 2012 Author Share Posted February 8, 2012 Thanks for the praise Barrie it will be the oldest glider at our local field. Over the past 3 days i have painted the fuselage and finished fitting the ski (looks good ) and also fitted the pulleys and am in the process of making the various closed loop wire systems to actuate the rudder and the elevator. The seat has now been made and painted so the pilot has something to sit on, might be a bit hard though! needs a cushion for him! I have just glued in the elevator servo and the control stick that the elevator servo drives. Trouble is getting glue down to the servo rails, so have wicked in some cyano and hopefully it will hold the servo in place. I may add a servo rail on top of the servo case and glue to the servo case to ensure the servo does not move. Will keep everyone posted with pics in the near future. I have next week off work, yay, so ill have a chance to finish the model (fingers crossed) and do a test glide. Also will be able to start my ASK 18!. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted February 15, 2012 Author Share Posted February 15, 2012 Hi Taco, I am currently balancing the SG38 on your recommended CG position of 400 - 480mm from leading edge (full size). The full size SG38 wing chord is 1600mm, therefore I get a forward limit of 25 percent of wing chord and aft limit of CG is thirty percent of wing chord. Translating this to my model I get a forward CG limit of 119mm and an aft limit of 143mm (both measured back from the leading edge. I will start with the CG in the middle of this range i.e. 27.5 percent of wing chord which translates to 131mm. I hope to give the SG38 a test glide tomorrow from a small hill, and will report success or not (hopefully success!). Regards Stuart Quote Link to comment Share on other sites More sharing options...
Taco Posted February 15, 2012 Share Posted February 15, 2012 Stuart, i hope this will work out right for you!! Taco. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted February 15, 2012 Author Share Posted February 15, 2012 Thanks Taco, fingers crossed! Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted February 20, 2012 Author Share Posted February 20, 2012 Well I have had a few test glides with the SG-38, the first set was on Friday and the wind was about 12 mph and I launched off a small slope, the plane had a tendency to pitch downwards and so I took some nose weight out and the glider performed well. However a heavy landing meant that the tail boom came away from the main body, I repaired this overnight and on Saturday morning had a few more test glides, this time from my local field. All was going well (even managed to get some video!) until I hit a very small sapling tree which caused the plane to land on a wing and has broken the wing joiner assembley but she is now in the workshop and I am making the joiners better and stronger. I may add a power pod to enable the SG-38 to climb to altitude! Video to follow ! Quote Link to comment Share on other sites More sharing options...
Tom Wright 2 Posted February 23, 2012 Share Posted February 23, 2012 Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted February 24, 2012 Author Share Posted February 24, 2012 Thanks Tom for posting the video of the SG-38 test glides. Repair work is going well, although not had much time to do it to be honest. I have re-attached the tail boom to the fuzelage and used more screws and some good old carbon (with screws for added strength). The wing joiners are next on the agenda and I will glue them in place and slot the wings on so that the joiners dry in the correct position. Tom (Tom Wright2) is going to fit a motor to the SG-38 and we will see how she peforms. We noticed on the test glides that the model suffered a bit from adverse yaw and so coupling the rudder and ailerons seems like a good idea for the next round of flights Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted February 25, 2012 Author Share Posted February 25, 2012 Well I have just re-glued the wing joiners and the ply plates that they fit into, these have been increased in size, so looking good Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted February 26, 2012 Author Share Posted February 26, 2012 Tom has made a pod for an electric motor for the SG-38, it sits high up on the A-frame and will not detract from the lovely lines of the model. The motor will swing a 16 x 6 prop! wooden of course. I will work more on the model on monday and Tuesday and get her flight ready hopefully one day next week so excited about that. Tom has helped me make some adjustments, so thanks Tom. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted February 29, 2012 Author Share Posted February 29, 2012 Well today is a successful day for the SG-38. Last night Tom Wright 2 helped me get her ready for test flights with the power pod. We had to tweak the elevator controls/linkages/wires to get more elevator movement and did a test of the power of the motor on the watt meter. I think about 500 - 600 watts. We tested 3 and 4 cell batteries and both were deemed suitable to fly the GS-38. This evening around 5pm I rigged up the SG-38 and Tom lent me a 3700mah 3 cell lipo, the cg looked ok so I launched the model why Tom flew her as conditions were nearly flat calm. The model flew away nicely, with a bit of a tendenct to nose down in the climb, we need to increase the amount of up thrust a tad. Once at height Tom passed me the controls and I got the feel of the craft. She needs alot of rudder together with the ailerons to get coordinated turns, but they can be done, the glide was sweet and fairly flat and I got a two minute glide from a few hunderd feet, which is reasonable. There is a bit of adverse yaw going on. The SG-38 flies very stable and the scale pilot could be seen enjoying the ride!. The landings that were done, I think 3 in total needed a bit more speed on the approach as I think I ran out of elevator authority on a couple of occasions, resulting in not a heavy, but not as light landings as one would have hoped. I need to adjust the ailerons to give more differential aileron movement and also the elevator to get more up elevator A few of the lads got video of the SG-38 in action and I will post as soon as I get the video from them and make a video Edited By Stuart Eggerton on 29/02/2012 20:05:26 Quote Link to comment Share on other sites More sharing options...
Tom Wright 2 Posted March 1, 2012 Share Posted March 1, 2012 Stuart It was a great pleasure to be of assistance The S-38 is an iconic glider ,and your interpretation from the full size plans and subsequent build is to be commended. All the lads at the field and the on looker from a pennies r/c club (sorry I did not get your name) really enjoyed watching the several flights achieved before sunset. Tom. Quote Link to comment Share on other sites More sharing options...
Taco Posted March 1, 2012 Share Posted March 1, 2012 Nice it flies so well. Next you will go to the coast or another soaring site? Taco. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted March 1, 2012 Author Share Posted March 1, 2012 Hi Tom, thanks so much for all your help We flew the SG-38 again today and success again. The model is fairly slow and needs a good deal of control input yet has a grace and beauty all of it's own. I am currently saving a video of todays action and will upload to you tube tonight and then post the link in due course Taco, the SG-38 flies vey well, I have no plans to go slope soaring with her at the moment as the power pod will allow the model to gain several hundred feet. In fact we are sure that based upon the performance at the field the model should thermal well We will have to wait and see what happens when the thermals arrive Edited By Stuart Eggerton on 01/03/2012 20:40:52 Quote Link to comment Share on other sites More sharing options...
Tom Wright 2 Posted March 2, 2012 Share Posted March 2, 2012 Stuart:s EP SG-38 takes to the air powered by a modest 3.7A three cell lipo , Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted March 5, 2012 Author Share Posted March 5, 2012 Edited By Stuart Eggerton on 05/03/2012 23:36:00 Edited By Stuart Eggerton on 05/03/2012 23:36:45 Quote Link to comment Share on other sites More sharing options...
Taco Posted March 6, 2012 Share Posted March 6, 2012 Good result Stuart! Very nice. What's the next project? Taco. Quote Link to comment Share on other sites More sharing options...
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