Accelerated Slipstream Effect: FAA Airplane Flying Handbook

[oldman04271940]

I need to understand just what is meant by this Effect. How much added lift does this produce? On yahoo answers they say that this has a minimal effect. However the FAA say's differently.
From the FAA Airplane Flying Handbook.

In the twin, an application of power blows large masses of air from the propellers directly over the wings, producing a significant amount of lift in addition to the expected thrust. The multiengine airplane, particularly at light operating weights, typically has a higher thrust-to- weight ratio, making it quicker to accelerate out of a stalled condition.
Source: http://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/airplane_handbook/

 

[oldman04271940]

My question is, how much added lift does a twin engine aircrafts propellers accelerated slipstream generate over the wings create? I have found many sites that says that the added wind from the wing mounted engines over the wings creates some lift. I would like to know about what percentage or approximately how many pounds for a particular twin aircraft. Like the King Air b200 turboprop that crashes here in Wichita, Kansas USA a few weeks ago, because he lost his left engine (The aircrafts critical engine) upon takeoff (Rotation). How does the V-22 Osprey, with such short wings fly straight and level when the engines are tilted forward? Is it because of the accelerated slipstream from the massive propellers? I have ask on aircraft forums and most pilots don't know. Not knowing is a safety issue, 4 people died here, because the pilot may have not known that making a sharp left turn into a dead engine would result in the wing stalling out. I'm trying to educate pilots, because it is apparent that flight instructors either don't know themselves or don't teach the significance of it.