trinidefender, for aircraft that spend most of there time cruising or loitering e.g airliners, cargo planes, refuellers, then perhaps you are correct. For fighter aircraft that are required to operate over a wide range of flight conditions, the described alleviation techniques aren't band aid fixes, but fundamental design principles I believe.trinidefender wrote:Having both ailerons set above 0 degrees to reduce outer wing loads and reduce induced drag is inefficient and something that a designer would add in only if they needed to as a result of problems found in testing when it is to late or costly to change the design. It is inefficient as it increases form drag, parasitic drag and you get some weird drag inducing flows from permanently offset ailerons while in cruise instead of being flush with the wing. If the problem is caught early enough then they will generally design some more washout into the outer sections of the wing. This will achieve many positive results over the method proposed by TC. It has the same benefit of reducing load on the outer sections of the wing and helps reduce induced drag (to a certain level), at low alpha levels it helps keep the outer part of the wing stable and reduces turbulence felt by the aircraft. Washout helps the outer part of the wing to stall at higher alpha levels than the inner portion, this maintains airflow over the ailerons and helps maintain control when flying the aircraft close to stall speeds (very important for safety and something every pilot will thank you for). Lastly with washout on a swept wing when the inner, more forward parts of the wing stall first the centre of pressure moves aft and drops the nose of the aircraft helping it to recover from a stall.Tommy Cookers wrote:yes, some planes have used thisbhall II wrote: ......I tend to think a front wing equipped with what would almost be ailerons is sensible, because there's no reason for a car to carry peak downforce along straights. It's counterproductive for a formula that strives for greater efficiency.
(both wings) ailerons could be selected to 'upset' slightly above the neutral position, in cruise
so the outermost wing section has 'cancelled' camber/incidence effect equivalent to zero AoA/zero Cl (or close to that), and less drag
(though the benefit for the aircraft is reduced or zero lift far outboard, so reduced bending moment throughout the wing)
eg this was used on elderley UK RAF aircraft eg the VC10 and Victor to conserve their wing life
similarly, by extension, Tristar 'active ailerons' and modern equivalents alleviate outer wing gust loads (if not steady load)
Before somebody states the obvious and says that it is rare that the ailerons would be flush with the wing that often because they will constantly have to adjust slightly let me say that at cruise speeds commercial airliners rarely use the ailerons for roll control. Above a certain speed the aircraft uses the airbrakes on the wing of the side of the plane that they want to roll to. The flight computers (whether they be analog on older aircraft or full FBW {fly by wire} on the modern Airbuses and such) decided how much roll input and deflection to put on the airbrakes of the wing to control roll. Using the airbrakes on the inner wing of an aircraft in a turn means that the rudder has to be used less as drag is already on the inside wing, this helps keep the turn coordinated.
TC for the Tri-star are you referring to the DLC (dynamic lift control)? It is a brilliant piece of kit and I've yet to meet a pilot yet who has flown that aircraft and didn't love it. It allowed very stable approaches and just made the pilots life a breeze even with autopilot off.
Note: alpha used here means angle of attack
P.s. Sorry for the OT, I'm just trying to give some context to some information presented in another post.
What you say about the Tri-Stars DLC is correct. I remember reading posts from a few pilots on an aviation forum and they absolutely loved it.
