Originally Posted by
Sniper
I would say that this is likely something that most pilots with non-heavy experience don't immediately think about, the HUGE difference, not only pure weight wise, but % wise too, between a 'light' and a 'heavy' t/o in a very large aircraft.
Think a 747 out of JFK. Could be just going empty to Boston, or could be going to Seoul full of 14+ hours of fuel and passengers/cargo. We're talking a difference of over 300,000 lbs here b/t these two t/o scenarios (more than 125% of the entire Emirates t/o weight miscalculation), a difference of almost 40%, weight wise, b/t min and max scenarios. The engines obviously have to have the thrust to do an 800K lb t/o, so, if you give them full power but 40% less weight to pull into the air to BOS (think of an 18K lb ERJ @ max thrust, 'Cornholio'), you've got a serious amount of power, considering the 74 will usually reduce T/O thrust out of JFK @ MTOW.
The centerline thrust difference is one thing with heavies v/s RJ's and military fighters, but the huge weight range that a 'heavy' operates in is a easy concept to grasp once pointed out, but perhaps not immediately obvious without personal experience.
This makes sense. I know that I notice a huge difference in how the ERJ acts when heavy compared to when light...and we are talking of a diff of only about 15,000 to 20,000 ish lbs....or just shy of 50% weight. Although we go to max thrust on the good engine regardless of our weight. While I've thought a few times about how heavys have many times my MAGTOW in fuel alone I've never thought about weight in the V1 cut. In everything I've ever flown if you lose an engine you have to give the good engine all its got in order to miss the trees at the end...and some times all its got isn't good enough and you will hit the trees anyways (light piston twin). I'd say if there is one thing about RJ's that makes me mad (other than pay etc) its the fact that we are typically under powered. There is no reason we shouldn't be able to climb and cruise as fast as mainline jets. I guess on the plus side for me it seems V1 cuts will get easier or simplier as I go on. Turboprops to RJ's was a nice change and now it seems like I can take the little extra rudder out when we "goose the good engine" when I get to the big iron.