Phil Cooke Posted January 17, 2012 Share Posted January 17, 2012 Considering the model type I think the Eppler 205 section would be more suited to slower (more scale) flight than the Selig section, but to be honest they are both very good, well proven aerofoils for PSS models. Dont forget to add a degree or two of washout at the tip section - with the swept tapered wing this will buy you some margin on the tip stall. Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 18, 2012 Author Share Posted January 18, 2012 Sounds like a plan Guru of the Slope!!! Question then..... How do you include washout when cutting foam cores? or do you do it when sheeting it? Questions, Questions!!! I think I will check everyones favourite search engine for answers also!!!Edited By David Gilder on 18/01/2012 10:38:56 Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 18, 2012 Share Posted January 18, 2012 You will need to do it the cutting stage. Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 18, 2012 Author Share Posted January 18, 2012 Just got the answer from google!!!! When you put the rib template on the tip end of the foam, you raise the T.E. to the disired amount of washout, then cut!! Now on another point, the AN72 has had 2 different wings used on it, 1 has a straight T.E. all the way along, the 2nd has straight from fuselage then a further swept tip section. I plan on building the 1st of the above wings as in picture below: The next picture shows the 2 section wings with swept tip section!! I am thinking about having approx 1/4 inch washout on each tip. Think that should be sufficient!! Will let you know what happens when I get it all sorted. Got to do more work on the fuselage when my new NiChrome wire arrives!! Dave Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted January 18, 2012 Share Posted January 18, 2012 actual dimension depends on the size of the wing - you dont need more than 2 degrees max, 1/4" sounds too much to me unless its a big, big model. Whats the chord of the tip section? Edited By Phil Cooke on 18/01/2012 14:26:20 Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 18, 2012 Author Share Posted January 18, 2012 Thanks for that Phil, Maybe 1/8" will be more likely. I will have to check later what the Tip Chord Length is when I get home as I'm currently at work so dont have that info with me!! Cheers Dave Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 18, 2012 Author Share Posted January 18, 2012 I now have a further dilemma...... Should I fit a tow release into the nose so it can be aerotowed. Just thinking about Greenacres.... Its the only way it will fly there (as long as it is finished and "maidened)!!! Thoughts please!! Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 18, 2012 Share Posted January 18, 2012 Its a no-brainer - fit one!! Cheap, easy to fit, but a pig to retro-fit. Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 18, 2012 Author Share Posted January 18, 2012 Understood Tim!! Is THIS a suitable release to use? If so, I will get it ordered!! Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 18, 2012 Share Posted January 18, 2012 Yup, 'tis on my BUFF ...ooo err missus. Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 18, 2012 Author Share Posted January 18, 2012 Okay Phil, The tip will be 7cm long so I will just add in approx 2 degrees of wash out!! Tim, I will get one ordered then, If its strong enough for you BUFF, it will be more than strong enough for the AN72!!!! Cheers peeps Dave Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted January 19, 2012 Share Posted January 19, 2012 7cm x Tan 2 deg = 0.244cm or 2.4mm - so 1/8th of an inch will be plenty. raise the tip profiles T/E by this much relative to the L/E position, cut you wings and that will build you in the 2 deg wash out you are after. Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 19, 2012 Author Share Posted January 19, 2012 Perfect Phil. Thanks I'm glad that someone is good at mathematics!! I hated all that Tan Sin CoSin stuff!! All double swahili dutch to me!!! Going to order a tow release for the nose so it has the aerotow option!! So a slight delay till that arrives!! Does anyone know of a good FREE wing template programme I can download that I can print the wing root and tip templates from. It appears the ones I have dont allow you to print them!! Cheers Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 19, 2012 Author Share Posted January 19, 2012 Well when I got home tonight, I found a little delivery had arrived.... The NiChrome wire I had ordered! So I fitted some to my bow and statrted to cut out the fuselage foam. the imperfections will be sanded and filled to smooth finish when all the fuselage foam is cut.. So this is what it looks like I then removed them and cut out a hollow area on the internal side which will be used for battery housing area and allow for servo leads to be run through to the Rx. So they look like this on the inside!! Will keep you updated as the build progresses!! Dave Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 19, 2012 Share Posted January 19, 2012 Coming along nicely David....gonna get her ready for the first PSS meet then? Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 20, 2012 Author Share Posted January 20, 2012 Unfortunately Tim, It is unlikely that I will be at the 1st PSSA Meet due to new shifts at work, but she will be ready as soon as I can and then a trip to the orme will be in order to maiden her!! Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 20, 2012 Author Share Posted January 20, 2012 For those of you who are not sure exactly what an Antonov 72 looks like, here is a video link of one! http://www.youtube.com/watch?v=j3TxeVffslQ&feature=relatedEdited By David Gilder on 20/01/2012 12:00:43 Quote Link to comment Share on other sites More sharing options...
Matt Jones Posted January 20, 2012 Share Posted January 20, 2012 I got some nice aerotow releases from HK last week, machined from ali and very nice and, in usual HK style, very cheap Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 20, 2012 Author Share Posted January 20, 2012 Just had a look at those ones now Matt... Shame I did not spot them earlier as I have just put in an order from HK!! Never mind!! I have started to cut out the foam at the pointy end today before work but did not have time to take a pic and upload. I will try and take a pic tomorrow and show how its looking. Its just the 1st rough cuts so not shaped fully yet!! Back to work !!! Roll on 0200 hrs!!! Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 21, 2012 Author Share Posted January 21, 2012 Heres the video I linked to above!! Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 23, 2012 Author Share Posted January 23, 2012 Just an update, I decided that for the nose I would use block foam which can be cut and sanded a lot easier in order to shape it. So 2 blocks cut and tack glued to the spine to enable me to start shaping it. Here it is part way through... Will finish it in a few days when I get done with a course I am going on!! See you all soon!! Dave Quote Link to comment Share on other sites More sharing options...
Matt Jones Posted January 23, 2012 Share Posted January 23, 2012 Have you cut out the 'spine' for the wing to sit on? Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 23, 2012 Author Share Posted January 23, 2012 Matt, The wing on the AN72 is actually above the fuselage so I will be making a central wing seat that is shaped to go on top of the fuselage. It will be strengthened with ply cross formers that will be let into the main spine. All the foam it just tacked on currently to allow it to be removed to make any further cut outs that are required on the main fuselage spine!! Heres a drawing view from the nose so you can see the wing seat above the fuselage... Hope that answers your question. Dave Quote Link to comment Share on other sites More sharing options...
David Gilder Posted January 26, 2012 Author Share Posted January 26, 2012 Update time...... Done a little more today... rear fuselage foam cut and tacked in place and then the Horizontal stabaliser started.... (No elevator on it yet though!!) Starting to look a bit more like an aeroplane now! Even SWMBO thinks so!!!! So heres the latest picture with the Stabaliser layed on the back... As always, Comments very welcome!! (even bad ones!) Dave Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 26, 2012 Share Posted January 26, 2012 Thats coming along really well David, it is gonna be a T tail though yes? Quote Link to comment Share on other sites More sharing options...
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