Help! My jet floats.

I just ordered my copy of FSDS last week and I did this fictional jet as a way of learning the program. I looked for an answer, to no avail. Can someone please tell me what settings to manipulate to get the jets on the ground? I tried using 3 different jets as models and I get the same results. Is there somewhere in the FSDS prog I need to set something?
Thanks in advance.
Keni

Thanks in advance.
Keni
