Add thrust. Hmmm.
Firstly, I would like to state that I too think it would be beneficial but the question is by how much? Well, better to give it a 'handful' than do nothing...
If you get so slow that increasing the AoA on the wing doesn't give you any more lift, there is a word to describe the situation. Stalled! So at that point, you are doing a 'stall recovery' - full power, etc. When I fly something like a Piper Cub, I try and stall it a few inches off the ground. I definitely do NOT do this in a jet transport. Not only would you run out of runway but the tail would probably hit the ground.
I'm thinking of force resolution. You need somehow to reduce the vertical component of the aircraft's motion so it doesn't hit the ground so hard.
If we examine the act of adding more thrust more closely it gets interesting. Take the B777 (just because I have some of the data next to me). Go into the 'flight with unreliable airspeed' section and look up the landing config. body angle at a normal landing weight: -0.3 degrees, i.e. slightly nose down. This is almost identical to the angle when sat on the ground, so the extra thrust has a direct effect on the vertical motion of the airframe of approximately...nothing! I would assume that other jets are not that far away from this in terms of body angle.
So, we are now looking at secondary effects. Underslung engines will give an 'uncommanded' pitch-up moment with increasing power. (Not on the 777 as the FBW deliberately counteracts this.)
We are left with trying to increase the airspeed to get more lift out of the wings. Not only does this take time (you are in a high-drag configuration) but the percentage increase in lift for a 5-10kt change in IAS is quite small because of the higher approach speeds of jet aircraft.
{Explanation: I am coming in to land at 40kts in my 'cub. I apply some more power to pick the speed up to 45kts. The lift from the wing (all else being equal) has increased by (45/40)^2 = 26%. I now do an approach in the 777 at 140Kts. An increase of 5kts IAS will give me (145/140)^2 = 3.5% more lift. Not a lot, really and certainly nowhere near enough to affect the outcome.}
Where does that lead us? I still remain skeptical about anything other than pulling back on the controls but remain to be convinced...
Last edited by FullWings; 25th Sep 2004 at 11:30.