sorry fat finger, pressed the wrong reply!
Twst alone is not very effective at preventing tip stall unless you use a very large amount (greater than that required for trim on a moderately swept flying wing) it may tilt the lift vector froward giving induced thrust and reducing adverse yaw, this is the Horten aproach, they used very large twist so although they had a strong taper the plane would not tip stall, the downside of course is a large static margin and higher induced drag, not to say that their designs are "wrong" just a different approach. The hortens did try a laminar flow wing but unfortunately chose an unsuitable airfoil (mustang wing I believe?) and it gave very poor stall performance.the designers of the superstol actually highlighted that they pop out as needed, some times just one of the 4 pops out and they seem to like that. i thought the opposite would be true. i guess lets say the right wing experiences a gust and starts to stall the slat(s) opens and restores lift preventing a wing drop. as soon as the flow is restored it retracts so it can probably act as a wing leveler more so than if both wings slats popped out.
their system is so simple it would be hard for them to jam, as far as i can see.
re laminar flow maybe wing twist would work better. does not the twist work with the increased vertical flow of a swept wing to tilt the lift vector forward?
gr8, just looks a bit short, but on second look the square extended center wing will lift a lot of the engine weight.The first consideration re balance was to establish aero centre of layout and then applied simple moments to balance an 86kg pilot with the engine weight to establish AC- engine distance. Finer balance by lead weights in nose to compensate for pilot weight variations. Hughie,,,,,,,,,,,
-do you know tailless KASPERwing philosophy=technology?I believe that the tip stall must be solved without any moving parts (except drag rudders could be used for stall recovery).
and this is where my question about high efficiency flying wing got started originally.
Just got back off my holls, so here goes...I believe that the tip stall must be solved without any moving parts (except drag rudders could be used for stall recovery).
Actually the X8 stalls quite straight and quite ok if stalled carefully and not too high aoa. At high angle of attack it becomes a like falling leaf, the winglet gets blanketed so that it virtually has no winglet at all, and it autorotates to the ground spinning furiously. I don't know if drag rudders could be used to straighten it. Or maybe there should be additional verticals nearer to the center of the wing to mitigate the winglet blanketing. It is very easy to get to such aoa with very good power to weight ratio, these problems generally occur when the nose points straight up and airspeed becomes zero, so the nose straight up situation needs to be made recoverable (and not preventing nose going straight up eg by limiting controls or the like, because it will go straight up). Software stabilization seems to even further aggravate the situation because it deflects elevons to counter wing drop at stall if wing drops. Stall recovery may need to be programmed on it too, not only stabilization.
So I am predicting that geometric twist of at least 5 degrees will be needeed as a baseline. I think Horten used even more than that. Excessive twist reduces efficiency obviously on a craft that cruises at low angle of attack because the tips may therefore be on negative angle of attack on cruise flight and will produce downforce, in other words, negative lift. And induced drag increases as there will be drag due to lift for keeping the craft in air, drag due to lift for countering the negative lift on tips, and then drag due to negative lift on tips, it could translate into poor efficiency in the worst case, and this is where my question about high efficiency flying wing got started originally. Of course in conventional layout, there is the tail, that does the same than the tips on flying wing, so that layout also has similar losses.