Chris Barlow Posted January 29, 2017 Author Share Posted January 29, 2017 I'm liking the wide, chunky fuselage more every time I add another piece! Spent a bit of time on the Bronco so not loads of progress on the Skywriter yesterday. I have started fitting the cheeks to the chin, if that makes sense? Cheeks were cut and glued to the triangular chin piece and soaked on the outside with ammonia. You can see even after just a few minutes they're bending in the correct direction on their own! After the glue had dried enough to hold the cheeks were given another brush of ammonia and using the model stand were bent to match the curve of the former and left to dry. When it's dry I'll cut it to size and glue down. Quote Link to comment Share on other sites More sharing options...
Chris Barlow Posted January 29, 2017 Author Share Posted January 29, 2017 After a quick bite to eat it was back out to the shed to glue my cheeks up! They're nice and bendy when wet with ammonia but go back to stiff medium balsa when dry, but bent close to the shape I want. Easy job then to cut and glue in place. I also fitted the top front section using the same method although as the wood didn't require a twist in the curve it was a lot easier, maybe didn't need the ammonia. I have installed a 1/4 ply plate for the landing gear which is underneath a 1/8 strip of balsa for shaping. Wing bolt plate has been installed plus 1/2" triangle fillets. ...and the beginnings of the battery access hatch... Finally I've got around to adding the 1/8" fillets to the rear of the wing seat that I missed when adding the stringers to the sides! Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 29, 2017 Share Posted January 29, 2017 Very nice Chris, and well explained John Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted January 30, 2017 Share Posted January 30, 2017 Chris, you are 2 steps ahead of me. I will try the ammonia trick (only have used water before). Lucas Quote Link to comment Share on other sites More sharing options...
Chris Barlow Posted January 30, 2017 Author Share Posted January 30, 2017 A word of warning! Don't fit the undercarriage plate until you have bolted the cabane struts in! I picked up some 10mm ali strip from B&Q tonight, well actually 2 pieces of 10mm and 1 piece of 25mm. Not very expensive at all and useful to have in the workshop. Started by marking out the strip and cropping to legnth with a pair of side cutters. Note, on the plan and on Lindsays model the cabane struts bend up inside the fuselage sides which will leave a gap below where the struts exit the top sheeting. If you don't want this the extend the base of the struts to the outside width of your fuselage. Hope that makes sense? So, the ali strip was marked and cut I taped the 2 strips together with gaffer tape so that they would bend the same place and angle. If 1 was wrong the other will be wrong in exactly the same way! The struts were easily bent in a small metalwork vice. The flats connecting to the wing were checked for parallel by placing upside down on the bench. Finally happy with the shape I separated the two struts and drilled them ready for fixing. This is where I discovered that the u/c plate was going to get in the way. Easily remedied by placing washers with a magnetised screw driver, positioning an starting nyloc nuts with tweezers and tightening 1/16th of a turn at a time with a min spanner! Frustratingly slow with frequent breaks to relieve the cramp in my hands and fingers! But finally done ready for the rest of the top sheeting! Quote Link to comment Share on other sites More sharing options...
onetenor Posted January 31, 2017 Share Posted January 31, 2017 Posted by Chris Barlow on 25/01/2017 21:43:40: With my A-10 in the sign writing shop (read dining room table) and my TN electric Bronco stalled waiting for more 1/16th balsa I finally made a start on this years mass build. Having met Lindsay several times and seeing the models he comes up with I was quite pleased when Skywriter was chosen for this years build and although I don't particularly need another vintage style bipe I do have space for an small aerobatic electric one. So the plan is a little tweak to the wing section, strong foam core wings and a bit of lightening at the tail end to avoid any additional nose weight and we're away. I started on Sunday with the fuselage, cutting out the sides and doublers and laminating them together. Whilst the glue was drying I cut the forward formers and stuck the fin/rudder together over the plan, leaving to dry over night. Monday night these were peeled off the bench and the tail plane was glued up over the plan. I used slightly smaller widths for the tail plane peices, 19mm wide IIRC. Final task for the evening was to cut and glue some 1/4 sq longerons to the inside of the fuselage sides. Tuesday evening I was lazy and watched some you tube and fell asleep! Tonight having just received some electrical goodies from HK I was able to position and fit captive nuts for the motor and test the position of F2 before chucking the lot into the fuselage jig with some aliphatic. Amazingly it all landed like this! (the tail surfaces are there because I'm impatient) Captive nuts for the motor. I really don't like fixing the crucifixes with plain wood screws! This is where the tail is up too. Still need to cobble some elevators together. And finally the power plant. That's where I'm up to right now. Later I be back on it to pull the tail of the fuse together glue up an elevator. Nice work but that tail looks awfully heavy Quote Link to comment Share on other sites More sharing options...
Rob Ashley Posted January 31, 2017 Share Posted January 31, 2017 Extra Slim, I take my hat of to you sir, that workshop is worse than mine - but I have made a bit of an effort to tidy as I go for this build. I do however have to admit to loosing tools when I have just used them. I am not sure what happens - I put them down in a place I know where to find them and within 10 seconds they have been moved by someone (not me) and I spend ages looking for it, only to find it turns up miles away from where I left it and ususally buried under stuff I don't remember using ?????? Rob Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted January 31, 2017 Share Posted January 31, 2017 I am glad I put blind nuts in the cabane struts.... Will you make a hatch so can get to the cabane fixing bolts? I intent to do so, than I can finish the fuselage without the cabanes sticking out and -if needed- get to the bolts afterwards for tightening (or for changing out the cabanes if I really messed up an arrival). Lucas Quote Link to comment Share on other sites More sharing options...
Chris Barlow Posted February 1, 2017 Author Share Posted February 1, 2017 I had given that some thought Lucas. My Flair Puppeteer has a very similar mounting system for the cabanes and I've never had a problem with them that required their removal. In the event of damage due to an unfortunate arrival it's quite likely there will be other structural damage to assess and repair so stripping off some the 1/8th balsa over the cabanes would probably be a part of the repairs! The fixing bolts are however captive in the struts in that they have been (self) tapped into the aluminium and the nyloc nuts are (just) accessible from the underside so checking for security won't be too much of a problem after the maiden and every so often after that. Having said that I don't remember ever having a new nyloc nut ever vibrate or work loose before, but it would be nice to be able to check for peace of mind! I like your idea of fitting the cabanes after the fuselage is finished though Lucas. A lot less fiddly especially if you're glassing it. I have found with the Puppeteer that where I have finished the balsa tightly around the struts it has cracked and opened up the joint, usually when the struts are moving when fitting the top wing. This time I intend to leave a 1/8th gap around the cabane struts and fill with clear silicone after finishing to allow for some movement. Quote Link to comment Share on other sites More sharing options...
Chris Barlow Posted February 5, 2017 Author Share Posted February 5, 2017 No great progress on the Skywriter apart from sheeting the cockpit area but plenty of experimenting and practice before cutting the wings. After deciding that my 12v 10A power supply wasn't up to the job I plumbed for a new 30v 10A variable power supply which is now capable of powering a 4' bow. Still need more practice in handling the bow and sheeting the cores but these are the final wing sections for my Bronco. Foam cores were cut from 50mm building insulation foam and covered with 0.8mm Obeche veneer glued down with PU adhesive. I did have a couple of areas where the veneer hadn't pulled down to the core on the leading edge which required forcing more PU into the gap and taping down with masking tape but it seems to have worked OK The Bronco wing section is 10mm shorter in chord but a similar length as it's split into 3 sections. Currently without the leading edge and trailing edge/ailerons it weighs in at 92g but is stiff enough to stand on! BTW as I was laying a chipboard floor at work I had a look at the different PU adhesives availabla at Travis Perkins. For similar quantities "Gorilla" glue worked out at £34 "Bonda" £28 and "CaberFix" £11. The only problem is that the CaberFix is quite rapid taking around 5 minutes to grab and foam up, and even faster if there is any moisture in the foam (or floor boards) So now the Bronco wing is taped together and looks OK it's time to cut the Skywriter templates and cut the foam cores! Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted February 6, 2017 Share Posted February 6, 2017 Man of many talents They look fit for purpose Chris, the sky's the limit now John Quote Link to comment Share on other sites More sharing options...
John A Cole Posted February 19, 2017 Share Posted February 19, 2017 Really looking forward to seeing this come together. As a separate question (hope you don't mind), where do you get those blue pins from? A lot better to push with effort than ones I'm using. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted February 19, 2017 Share Posted February 19, 2017 Balsa Cabin Quote Link to comment Share on other sites More sharing options...
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