Danny Fenton Posted January 31, 2014 Author Share Posted January 31, 2014 Hi KC, yes the Bistormer has stringers, from the glimpses I have seen of the Barnstormer plan in the background of other builders blogs, it looks identical apart from the extra wing. I think the strength in the fuselage is due to the structure, and the stringers simply give it a nicer shape. Yes it would be even stronger, if the covering was against the triangle structure. I will build it as it is I reckon, certainly in the rear end anyway. I guess tissue the box structure, then build formers and stringers over that, would be the strongest way to go Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted January 31, 2014 Author Share Posted January 31, 2014 Little more done, very slow going with the ailerons. The wing centre section sheeting was completed, still some sanding and tidying of edges to do. The aileron upper trailing edge sheeting is fashioned, you can just about see the chamfer on the edge The area is glued, just before the wood goes down I spread that bead of glue with a scrap of balsa, (unless its a large area such as the leading edges then I use the palette knife) The sheeting goes on with plenty of pins The ailerons are cut from the wing so some of the leading edge of the ailerons needs to be removed to allow for the new 1/4 (6mm) leading edges. I am top hinging the ailerons rather than the central hinge shown on the plan, this is more in keeping with the sort of model I want. You will need to increase this angle if you want a more lively model and probably stick to the designers central hinging. I hope this will be enough travel? The covering will reduce this very slightly, the upward travel will be some thirty percent greater to create more drag on the upgoing aileron, and hence help fight any adverse yaw. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Dave Miller Posted January 31, 2014 Share Posted January 31, 2014 I have a similar aileron setup Danny, twice as much up as down. Having said that mine remains unflown so far so my settings are based on experience of similar types. I anticipate needing some rudder as well as ailerons to help it around corners. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 31, 2014 Share Posted January 31, 2014 very neat Danny you even put glue on tidy what you top hinging with? Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted January 31, 2014 Author Share Posted January 31, 2014 Thanks Dave, in theory it should work fine Hi John, I do try I am in two minds still. Tempted to cover the model in heavyweight tissue and dope, if this happens then I may use Mylar strips creased to probably 60 degrees, then inserted at a downward angle. Alternatively if I go with Solartex then I will use the solartex to hinge the surface.CheersDanny Quote Link to comment Share on other sites More sharing options...
Nigel Day Posted January 31, 2014 Share Posted January 31, 2014 Hi Danny. Do you have any pictures of the finished ailerons off the wing? I'm having trouble visualising the construction of the leading edge. There was a big jump between the pinned, sawn-off wing part and the working aileron. I can make a semi-educated guess (and read elsewhere doubtless) but I'd rather get it straight from the Jedi. Oh, and I can see how you might do it with a spatula, but how do you slap on the glue with a little bit of balsa? Edited By Nigel Day on 31/01/2014 19:52:48 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted January 31, 2014 Author Share Posted January 31, 2014 Hi Nigel, ooops sorry about that, it is a bit of a leap. I can show the other aileron in more detail when I do it if you want but I think I may be able to explain the process? If it isn't clear let me know? I think you are okay up to the point where I cut the leading edge of the aileron ribs to match a section of 6mm balsa: Once all the ribs were cut back ( I used the bit cut from the first rib as a template for all the other cuts btw) Then the leading edge was added, this was over size, and planed top and bottom to match the ribs. After this the capping strips were added to the ribs and to the leading edges. This brings all the wood to the same level. This picture may help to show how the sections are fitted together, hopefully the joints can be seen, I do try to keep them close fitting as it takes less glue to fill the void-lighter, and is stronger. Though I dare say BEB will now tell me to leave gaps in my joints Let me know if you still aren't clear and I will take more pics on the other aileron Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted January 31, 2014 Author Share Posted January 31, 2014 Oooo meant to say, its fairly obvious to the old hands, but when you are doing capping strips along the spars or in this case the leading edge 6mm stock. Don't bring it all the way to the edge of the spar, this way you leave a ledge for the rib capping strips to sit on. You can see what I mean in the above piccy. However, if that means nothing to you Nigel I will take a piccy of the process on the second aileron. Cheers Danny "Jedi" lol more like chewbacca Edited By Danny Fenton on 31/01/2014 20:18:21 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 1, 2014 Author Share Posted February 1, 2014 Rather than do the other aileron I thought I would push on with the linkage. I had hoped to bring the linkage out through the rear spar into the aileron leading edge, but I had forgotten that to preserve my Differential the horn point of connection has to be inline with the hingeline. This means the arm has to come forward a fair bit. So I have had to go down outside the wing and back. Not ideal, but with this flying fairly sedately it should be okay, if you were using a more powerful motor then you may want to angle your bellcrank plates down to keep the pushrod straighter, or more sensibly nowadays go for a servo in the wing. A small chunk of the aileron leading edge is removed, and a horn hashioned to sit in the gap. The horn is epoxied in and the missing wood replaced. This is sanded back flush with the aileron A short length of threaded rod is bent up to suit. Then fitted and throw checked in both directions, All is as planned The other horn was made at the same time with one clamped over the other, so it should end up in the same position, I hope.... Cheers Danny Quote Link to comment Share on other sites More sharing options...
Masher Posted February 1, 2014 Share Posted February 1, 2014 This is a very informative thread with lots of tips and showing the standard some of us should be aspiring to. I particularly liked the tip about not bringing the covering to the edge of the spar thus leaving a ledge for the cap strips to rest on. I've never been happy with my results (after carefully trying to make covering come flush with spar) since I end up with twisted cap strips and always unhappy relying on end grain joint - such a simple solution! Thanks! Quote Link to comment Share on other sites More sharing options...
Nigel Day Posted February 1, 2014 Share Posted February 1, 2014 Many thanks Danny, that helps a lot. More piccies of the second aileron build too would be icing on the cake. I know that I can read up and find this info else where but this seems a good place to ask: Obviously it works and brings smoother airflow over the top, but the top hinging looks as though it severely restricts downward movement of the aileron. I can understand that you'd want the reverse for flaps (which only go down?) but how does this work in practice and why is it better (for what you want) than central hinging? Aside from old circuit board backs, what sort of material is suitable for the horns? Thanks in advance, Nigel Edit: Forget the last question. I see there's a thread on just this question just started up. Edited By Nigel Day on 01/02/2014 08:16:59 Quote Link to comment Share on other sites More sharing options...
cymaz Posted February 1, 2014 Share Posted February 1, 2014 As a rule of thumb I was taught "more up than down" on the aileron movement. This was to stop adverse yaw on a turn...I think. Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted February 1, 2014 Share Posted February 1, 2014 You're right Cymaz. Aileron differential (more up throw than down throw) is used on some aircraft to stop, or at least reduce, adverse yaw. Adverse yaw is an effect where ailerons banking the aircraft in one direction, actually also cause it to yaw in the opposite direction, which is obviously unwanted. This happens because when we increase lift, we increase drag. So, the down going aileron, which increases lift, causes more drag than the up going one. This is more commonly done with a setting in the transmitter these days, but of course that relies on each aileron having it's own servo. In the days of expensive servos and non computer radios, we would add the differential mechanically. This can be done at the servo arm end or at the aileron horn end, by arranging one of these so that the clevis hole is offset from the usual "in line and at 90 deg to the pivot point" Quote Link to comment Share on other sites More sharing options...
cymaz Posted February 1, 2014 Share Posted February 1, 2014 Danny as you only have a single servo then the servo arm like below and putting each push rod in a seperate horn arm would give you differential aileron Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 1, 2014 Author Share Posted February 1, 2014 If you go back a page Cymaz that is exactly what I have used CheersDanny Quote Link to comment Share on other sites More sharing options...
cymaz Posted February 1, 2014 Share Posted February 1, 2014 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 1, 2014 Author Share Posted February 1, 2014 LOL no worries Cymaz, we all do it Thanks for the clear explanation Chris, much appreciated. I am pleased that the servo full travel gives just the right amount of travel at the aileron too. And the differential amount looks about right. Chris has pointed out to me that the horn should be behind the hinge line, when beneath the aileron to produce differentail. Which is opposite to what I quoted. I have positioned it inline so will get maximum holding power as it will be acting perpendicular. But Chris's point is worth noting if you have perhaps two servos with a Y lead and want to create differental travel, angle the horns back away from the hingeline. There is a nice explanation here I will take more pics of the other aileron build Nigel And yes Glass board is my preferred material, and a jewellers saw to cut it Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 1, 2014 Author Share Posted February 1, 2014 Okay as Nigel asked for more details on the aileron construction here goes. I will add that I am no expert at this, and this is just my way. And If I did them again I might change some things First of all I packed the front of yhe aileron with some scrap 1/16 and then attached the 6mm leading edge. Not very easy to see are these little 1/16 sq strips either side of the ribs. They are because the fit of the ribs wasn't perfect The inboard end has a 6mm (1/4) gusset to help keep things true. Note the direction pf the grain. The leading edge is planed to the height of the ribs Then sanded until perfectly flush. This shows how a permagrit block can be used to sand neatly and more importantly perpendicular. the capping is added to the top of the leading edge. Notice I haven't continued it to the edge, I have left a lip for the rib capping to sit on. Just makes it easier and the rib cappings more stable as somebody already mentioned The first capping on, the scalpel is pointing to the ledge. I have included this shot to show my building board. The floor underlay is glued on top of a sheet of MDF with a gap to the edge. This edge gives you a nice edge for cutting and sanding Hope that helps Nigel? Cheers Danny Quote Link to comment Share on other sites More sharing options...
Nigel Day Posted February 1, 2014 Share Posted February 1, 2014 Perfect Danny, thanks very much. Presumably the leading edge of the aileron (6mm strip) has to be the same height as the (now) trailing edge of the wing and then planed/shaped/sanded down to the height of the ribs? Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 1, 2014 Author Share Posted February 1, 2014 Hi Nigel, Yes you are right. I made the strip 6mm x 25mm wide, it has to be big enough to allow it to be planed and sanded to match the ribs. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 2, 2014 Author Share Posted February 2, 2014 Just a quick post to show something I tried to make fitting the control horn a little easier. I clamped a small metal engineers square to the aileron leading edge, having first marked where the slot would need to be. Then I slid the shank of a small router bit in my Dremel along the steel square. This kept the cut true-ish Worked better than free hand Filled the gap with epoxy and slid the horn into place Cheers Danny Edited By Danny Fenton on 02/02/2014 00:04:18 Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted February 2, 2014 Share Posted February 2, 2014 Neat idea Danny. That task is always a fiddly one and I'm sure I'm not the only one to have managed to split one the flanks away accidently! BEB Quote Link to comment Share on other sites More sharing options...
Nigel Day Posted February 2, 2014 Share Posted February 2, 2014 Invaluable tips and ideas Danny, thanks again. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 11, 2014 Author Share Posted February 11, 2014 Well have been working away so not much done I am afraid. However back now so onto the Fus. Now this is going to deviate from the plan a fair bit, I think the Barnstormer guys have covered the fus fairly well so I am going to "play" with it. First of all I am going to chat about the templates that came with the Bistormer. These are the major items that you will need to cut out. They are printed on sticky backed paper, however a word of caution for those of you that go down this route...... You can see from this picture the red lines are where the lines "SHOULD" be, you can see it is a little out. The template would not fit on a std sheet of wood, however the more accurate lines do. Those that have been following this blog will have seen how the dihedral braces caught me out on the wings. They were a degree or two out..... This is bulkhead F4 and sets the rear cabane angle and height. The red paper template is mine made striaght from the plan. The black lined one underneath is the template. As you can see it is out by a fair bit. I am not trying to knock Eddie and Judy, far from it, I love what they have done with DB Sport and Scale, and have a long list of their kits on my bucket list! But I think the template has perhaps been created from the templates used in the old kit version, and they were a little worn. So a word to the wise, use the templates as a guide, fettle them to fit the plan The main fuselage sides are from 3/16 and so I made two of these. They are unfortunately slightly bigger than half a 36" sheet, so the wastage is high. But if you strip the bits, some can be reclaimed. A long strip of 3/16 runs along the top of the fus side, all the way to the tail, this was stripped and attached. While waiting for this to dry, I looked at F4 First the outline was cut from 3mm lite ply (Birch ply on the DB version) The centre was found and a small hole made near the edge. The jewellers saw was whizzed around the middle after feeding the blade through the hole. It only took a minute to cut the centre away. Another couple of mins to clean the edges and we have F4 And this is where it will go All of this I am sure is old hat to most of you but just in case I have shown it. I will do the other bulkheads etc with less detail so that I can get a wriggle on Cheers Danny Quote Link to comment Share on other sites More sharing options...
jolliffee Posted February 11, 2014 Share Posted February 11, 2014 Thanks Danny - it isn't wasted I need this sort of help! Oh! I see you pilot looks keen to be in the air Quote Link to comment Share on other sites More sharing options...
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