I did an experiment to explore this. My results found that their is an optimum mass of a ski jumper. I am unsure about the maths behind this. Can anyone help.
Most interestingly it is the opposite of what I find when riding a bike down a hill and what was hinted at above.
Long distance ski jumpers benefit from maximizing their surface area while simultaneously decreasing their weight. The less they weigh and the more drag they can produce, the farther they go. Their bodies are the primary source of weight and, as a result, there is incredible pressure for competing ski jumpers to be as thin as possible.
Which comes from many articles about this!
Again anorexia rears its ugly head.
The downward acceleration in addition to g is also due to air resistance....
For speeds such as those of the ski jumper the air resistance in Newton's is taken to be proportional to velocity. ie -KVy hence the total downward acceleration is...
-(KVy/m + g)
So we see higher the mass m the lesser the downward acceleration and fitting this in the trajectory equation we get a higher range.
Interestingly air resistance offers a force opposite to direction of motion in horizontal direction as well...even here for the same force the negative acceleration decreases with mass.(-KVx/m)
In other words: Increasing the mass makes air resistance have less effect ( as @DirkBruere points out ) ...other factors remaining constant.
See Trajectory of a projectile' Wikipedia.
Note that const K will increase with the cross sectional area of the jumper...so what we are looking at is higher mass for same cross sectional area ( As @CarlWitthoft observes)
But is it really projectile motion?
Wikipedia page on ski jumping suggests that gliding is also at play here...so much so that a variation of ski jumping is called ski flying. In view of this @Farcher s remark may be correct ie having a greater x section area and less mass may be advantageous ...at least that's what appears to be the case.