ORIGINAL: dick Hanson
To clarify - you can have wash in/ wash out - set the wing at what ever angle of attack you like - BUT to fly along in level unaccelerated flight - the ENTIRE wing will assume a position (AOA) equal to that task.
The reason most warbirds have washout - -in models is simply to follow a scale look -
also most "warbirds" have high wing loadings and in the model - all of the wash in is just hogwash - to resolve the problem of "tip stall) what ever that is - you either must increase speed or reduce weight - no other options
You can't reshape a given area and increase lift- --you CAN make the wing more controllable at a given speed - but thats it.
Flaps do that too The lift does not increase (tho drag does) but the descent angle is more controllable.
The comment by Tall Paul is of course correct - Add inboard flap - the entire wing (and airframe) assumes a new angle - You can't do one with out the other
What you say it not correct. Wash-out does have a big effect on tip stall! Adding washout to the wingtips will give them a smaller 'angle of incidence'. If you then slow the aircraft down and keep the same altitude you would have to pitch up. The angle of attack will gradually increase untill it reaches the stalling AOA at which you should have a pitch down effect (if not the aircraft should never be stalled since you would not be able to get out of it, real aircraft with this behaviour are fitted with a 'stick pusher' but that's another thing...)
Having wash-out will make the inner portion of the wing reach its stall AOA first (before the wingtip) so you avoid tip stall.
Other options to prevent tip stall: use aerofoils which create strong vortices, use rectangular wings, using bigger thickness and chamber at the root, leading edge slots towards the tip to give the boundary layer more energy, using stall strips at the root, place vortex generators at the tip, do not use swept wings, use wing fences to prevent the outboard movement of the airflow, vortillons, saw tooth... So you see there are many ways to prevent tip stall besides keeping the speed up.
Flaps do not increase lift???? Explain please.
Bart