Because thats how they where in real life....
Ask Earl1937 he actually flew the things, I could be wrong.
The ailerons had a 40 degree deflection when in the up position and a 30 degree down deflection when the yoke was turned to its maximum. In a turn, the 29 did indeed have a tencidy to over bank unless you held a little opposite aileron in the opposite direction and under 180 IAS, you must use rudder to correct back to a level position. Other than that, it was a aileron only aircraft when making standard rate turns. The reason for that was the large vertical stab and rudder which was very sensitive during turns. The aircraft in the game has a tencity to overbank and so there fore you must be concous of your bank angles at different airspeeds.
The flaps are over modeled as when you spawn out on the runway, it automatically gives you 50% flaps down for take off. According to Boeing, anything over 17 Degrees of flaps creates more drag than lift, so even at 128,00 lbs, we only used 15 degrees of flaps. Link for watching "Fifi" taking off and you will see that the flaps are barely visiable during takeoff. Now FiFi is no where loaded like we were, but the point is, in this game, you are better off at 0 degrees of flaps and even at a medium field, you will have about a 1,000 foot of runway left when you break ground.
http://www.bing.com/videos/search?q=b29+aircraft+taking+off&FORM=VIRE7#view=detail&mid=F1943A44F5ABD4645B03F1943A44F5ABD4645B03While there is no argument about the 29 lifting off the runway in this game, with full flaps, the problem comes when you start rasising flaps, it has a bad sink rate when rasising the flaps, because you can't "milk" up the flaps. In this game, I recommend no flap take offs wep ingaged as soon as you get to full power, and in options, "auto take off" be enabled to at least a 1,000 feet agl. The reason for that is when you disengage auto pilot to make a turn, the nose will immediaty drop down, because you have no trim wheel for correction when starting the turn. You of course can use back pressure on the stick to compensate for the lack of trim, but again, you must concous of how steep you intend to bank because the steeper the turn, the more back pressure you are going to have to use and as you do that, you will find your air speed decaying quickly. I recommend only "standard rate" turns at anytime in the 29 in this game as it is much easier to maintain air speed in any flight confg. A standard rate is 3 degrees per second of turn and the instrument they used in this game 29, you bank until the vertical needle on the turn and bank indicator is "laying" beside the center object on the instrument. A turn and bank in most aircraft during the 50's and later, had two little "dog house" either side of the centered position and when the vertical needle was on one of those "dog houses", that was the indication that you are turning at a rate of 3 degrees per second.
FYI about the Lancaster in this game. The turn and bank indicator has a different indication than American aircraft. it is a 2 in 1 instrument, but you have a option either a 2,3,4,5 and 6 degrees of rate of turn. I prefere the 3 degrees of turn indicator because it is easier to compute in my head how long to complete a 180 degree or 360 degree turn, one minute to complete a 180 degree turn and 2 minutes to complete a 360 degree turn.