With fixed gear, a paved runway and the TT 46, you should have no problem getting a stock built Learjet flying. The TT 46's I have had in the past put out power similar to an OS 46 FX which would flies the Learjet just fine, even from grass and with mechanical retracts installed. Even a good running 46 SF will do, just won't give you a high top speed.

In terms of flaps, not sure if they are really needed. The Learjet I flew did not have them installed, but could still be landed at a reasonable speed once you are comfortable with the plane. Even the GP Patriot and DC F-20 could be landed at a fairly slow speed once you got a handle on when it would stall.

Steve