dirk tinck Posted March 6, 2021 Share Posted March 6, 2021 Still following Steve ! Those tailplane fairings must be the cleanest of the lot !Great work ! Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted March 6, 2021 Author Share Posted March 6, 2021 Hi all, Thanks for your kind comments. I have a few household chores to clear before I press on with the tailplane bearing issue. Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted March 7, 2021 Author Share Posted March 7, 2021 Pitchy Binders I encountered a problem with mounting the tailplane halves, due to me having them removable. While assembling the tailplanes onto the rods I found that the front rod slid sideways in its bearing tube, and the bend in the rod would then bind into the end of the bearing tube, causing the servo to stall. Without disconnecting the pushrod each time the tailplanes are slid into place, it was impossible to tell if they were free to move or jammed until the servo complained! Here's my solution to stop this happening and causing a crash due to a binding linkage: I carefully sawed a 3mm 'washer' off each side of the bearing tube, smoothed the cut edges with a small file and then glued the washers onto the rod with JB Weld epoxy leaving approx 1mm gap between the washers and bearing. Now it's impossible for the rod to slide sideways. Even if the glue does not hold, the bend in the rod will now bind into a movable washer instead of the fixed tube, and there should be no linkage binding. The washers were carefully spaced so as not to lie outside the edges of the tail fairings. This has made it much easier to slide everything together, and should prevent that feared binding: The inner bearing tube will be glued into the slots in F15, as per plan, but the washers must be free to rotate with the rod. 1 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted March 7, 2021 Share Posted March 7, 2021 Sorry if you have already covered this Steve, but what retains the two elevator halves on the rods? Lovely build btw, really enjoying it Cheers Danny Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted March 7, 2021 Author Share Posted March 7, 2021 Hi Danny, It's pure friction holding them on. I'm told a wipe of Pritt Stik on the rods is also an added insurance for those of a worrying nature, as recommended by Martin and Gordon. I can certainly confirm that mine are tight, due to a slight misalignment of the rods (woops!), so that the rods on one side need spreading slightly to line up with the tubes, thus putting the other side under tension against their tubes. Time will tell, but I'm assured it will be fine. Thanks for your comment. 1 1 Quote Link to comment Share on other sites More sharing options...
Martin Gay Posted March 8, 2021 Share Posted March 8, 2021 Steve/Danny, Pritt stick glue is a great way to hold the tail planes on. Highly recommended as very little is required. Martin. 1 Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted March 8, 2021 Author Share Posted March 8, 2021 Thanks Martin, I think it was your recommendation that I was recalling. Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted March 28, 2021 Author Share Posted March 28, 2021 (edited) Roll Your Own Following a similar principle to my Jet Provost tailpipe, and a few ideas borrowed from Chris McG, I made the tailpipe by rolling a ring of 1/32" ply around the best sized former I could find (other body cleaning products are available), and then added a few layers of 1/16" balsa to thicken it up. This was all wetted with water and left to dry: After overnight drying it was all laminated with aliphatic glue, the top flattened off, and a location tab added to the top to fit between the tailplane fairings. This allowed dry-fitting to the fuselage and rough shaping: Put Another Ring On It I wanted the ply ring to be as near to the fuselage skin as possible. However, my fuselage was not an accurate round shape and with the initial ring size it would have been too high up the fuselage to allow enough meat for carving the streamlined duct shape. Hence I added two more inner rings of 1/16" balsa and another 1/32" ply ring. This seemed to be adequate to carve a nice shape, albeit giving much thicker side walls than I wanted: With the duct still dry fitted I could remove it to carve the initial shape onto the tailplane fairings: Mistaken Identity Further study of the Avon Sabre's duct showed that it needed a different shape to that which I originally carved, which was based on other F86 marks. After gluing it all together, with a top ply plate as used by other builders and a further 1/32" ply liner inside the top of the duct, I ended up with this: The taper on the tailplane fairings extends further forwards and higher up: Here's One We Made Earlier It should have ended up with something like this, from a different Avon Sabre, but the shape is the same for mine: ... and this is how it turned out - final shaping and sanding still needed: The inner lining will be smoothed down in due course. The side walls of the duct can be thinned a little, but I can't get them down to the thickness of one layer of metal. It will definitely be 'stand well off' scale. However, I'm fairly pleased with the overall effect. Edited March 28, 2021 by Steve Houghton Problem with one image 4 Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted March 29, 2021 Share Posted March 29, 2021 Some really nice woodwork methods on show there Steve - you've captured the detailed shape perfectly! Quote Link to comment Share on other sites More sharing options...
McG 6969 Posted March 29, 2021 Share Posted March 29, 2021 I had similar head scratching when shaping my laminated 'roll' to a Dog tail pipe, Steve. Well done, young man. ? Cheers Chris Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted March 30, 2021 Author Share Posted March 30, 2021 Thanks Gents, Chris, I did draw inspiration from your roll. It all helps us to develop new ideas and techniques. I am seriously contemplating my first glassfibre covering for this build, so may be coming back for advice on the Sauce. I've read your's and Phil's blogs on the matter, so I think I understand the principles and ingredients. I'm still hoping to meet the September deadline, but progress needs to be significantly faster than last year! 1 Quote Link to comment Share on other sites More sharing options...
McG 6969 Posted March 30, 2021 Share Posted March 30, 2021 Hi Steve & thanks for the kind words. Regarding the glassing, please remember to use as less resin as possible. Ideally the weight of the resin should equal the glass cloth weight but that is close to impossible to achieve. Even if you're left with some pin holes in the unfilled wave, don't worry the Sauce will take care of them. Possibly two thin coats of Sauce if needed. As for the Sauce recipe - from my Ballerina build in 2016 - I posted a 'reminder' recently as the old blog wasn't easy to find. I you visit the Dog's blog, my post of March 18 shows a link to the original thread. Possibly helpful to refresh your memory... ? Cheers Chris Quote Link to comment Share on other sites More sharing options...
Skip Posted March 31, 2021 Share Posted March 31, 2021 Thanks for taking the time to post the detailed explanation and the photos Steve - very helpful for me. Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted March 31, 2021 Author Share Posted March 31, 2021 Chris, Many thanks for the reminder of your link. I have already downloaded your orignal Ballerina posts about the sauce, to save as a reference document. If anyone wants references to the glassing technique (after reading the excellent blogs on this forum, of course): RCM&E Special Issue 2019, article by Danny Fenton. RCM&E June 2018 Workshop Supplement, article by Tony Nijhuis. I ordered some materials from Phil Clark at Fighteraces, and he also sent a helpful article of his own. Skip, glad my struggles are helping. It will be great to see some photos on your Avon Sabre blog in due course - I hope the shoulder is clearing up to allow you to proceed. You have some useful photos, especially of the tail end, which I have only just spotted. 1 Quote Link to comment Share on other sites More sharing options...
Skip Posted April 1, 2021 Share Posted April 1, 2021 Thanks Steve, the shoulder has turned the corner and is slooooooowly getting better. Lack of sleep has made it hard to get enthused about things, the blogs and particularly that of another Avon builder are great motivation though. About to get back into it. I've posted a good Avon Sabre walk-around on my blog with a note at which point the tail is shown which you may find helpful. 1 1 Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted October 11, 2021 Author Share Posted October 11, 2021 (edited) They think its all over!! It isn't now! A 6 month deficit of spare time has set me back a little and I missed the main event, but I'm pressing on.... It was great to see that stunning array of 16 Sabres at the Great Orme in September - I'm sure there must still be a few in hiding, along with mine. Closing the Loop Here's a general shot of the radio bay progress. The elevator pushrod is disconnected to show the closed loop operating crank - I like to take any strain off the servo bearings if possible. The take-off points for the cables (not yet attached) are +/-16mm from the pivot, to match the spacing of the holes in the rudder horns. The cable guide tubes are still free to slide back into place when I'm ready but I aimed to set them to the same spacing as the attachments to the crank, which I managed fairly well. I couldn't get the required rudder throw from the standard Hitec servo arms, so I've used one of these Hitec adjustable arms for the first time - it works a treat, and allows very fine adjustments to the throw (I prefer mechanical to electronic adjustments - it doesn't matter if I lose the radio settings then!). Blending In I'm fairing the fin with 1/2" triangular stock along the base of the fin, and will use thinner stock along the strake. I chose to keep the fin fat while I add the fairings, and then trim the trailing edge later to blend in with the rudder. The reason being so that I didn't lose any width from the fairings - on my photos they seem to be the full width of the tailplane fairing and then taper off towards the front. I hope I can achieve the correct rudder blending shape with this method. For the strake at the front of the fin I used 1/4" balsa. This leaves quite a step in front of the leading edge of the 1/2" fin, even after shaping the LE. The triangular fairing has to bend downwards and sideways at this point, so I applied many saw cuts underneath, and a dampening of the top wood, to coax it into shape while the glue dried. Again, I tried to keep the closed loop tubes +/-16mm apart, and they'll eventually be trimmed flush with the wood. I glued the fin strake onto the top stringers rather than onto the planking because I wanted to leave the last pieces of top planking until the last minute in case I needed to see inside to re-thread the cable guide tubes through the fuz. Having satisfied myself of an adequate cable routing, I then butted the top planks against the fin sides: Edited October 11, 2021 by Steve Houghton 2 Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted October 12, 2021 Share Posted October 12, 2021 Very accurate building as always Steve, lovely stuff. Sorry not to see you and your finished model at our event last month, I understand the pressures of time, we look forward to seeing you on the slope with the Sabre at an event early next year!! 1 Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted October 12, 2021 Author Share Posted October 12, 2021 Thanks Phil, and well done to all the builders who completed on time. I'm hoping my continuing efforts may inspire others who haven't reached the finishing line yet. At least it will keep the build threads active until the next Mass Build! 3 Quote Link to comment Share on other sites More sharing options...
David Sack Posted December 13, 2021 Share Posted December 13, 2021 Loving your build Steve. Any updates on your progress ? I'm still tinkering with mine :) Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted December 14, 2021 Author Share Posted December 14, 2021 Hi David, Thanks for your query. The fin fairings are now finished and shaped, but I didn't think they were significant enough to post pictures. I'll try to post some shortly. Tailplane Incidence I wondered if anyone can tell me what incidence the all moving tail should be set at relative to the wing? With my wing propped up at 0 degrees (parallel to my bench), I have -1mm at the leading edge of the tailplane. Alternatively, with the tailplane propped at 0 degrees I have +2.5mm at the wing leading edge. Does this sound about right? Regards, Steve 1 Quote Link to comment Share on other sites More sharing options...
Martin Gay Posted December 14, 2021 Share Posted December 14, 2021 Steve, My recommendation would be to have it set to 0:0. Make sure you are able to get enough up elevator as well. It may require opening the top of the fuselage slot a bit. I will take a photo of the prototype when I get home this evening. Martin. Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted December 14, 2021 Author Share Posted December 14, 2021 Hi Martin, Thanks for that. The main restriction on up elevator on my model is the leading edge catching on the fuselage. However, I don't think it needs to move that far for the movements quoted on the plan. If I now remove the -1mm tailplane incidence in line with your recommendation, that will give me even more clearance at the LE and TE.. Quote Link to comment Share on other sites More sharing options...
Martin Gay Posted December 14, 2021 Share Posted December 14, 2021 Steve, It sounds like you already have the maximum possible movement. Well done on that. Be prepared to adjust elevator trim after the first launch to set the model to your preferred flying style. However, this model likes to be flown fast, but will slow down well for landing, especially if you are using flaps and CROW. Martin. Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted December 14, 2021 Author Share Posted December 14, 2021 Thanks Martin, Yes I will have flaps and have started experimenting with programming crow brakes - never used either before, so it will be an interesting exercise. Quote Link to comment Share on other sites More sharing options...
Martin Gay Posted December 14, 2021 Share Posted December 14, 2021 Steve As is usual with any new program, try them out when the model is three mistakes high, just in case! Martin. Quote Link to comment Share on other sites More sharing options...
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