I always had better luck flying the pt-19 over concrete or asphalt. My favorite place to fly is the cul-de-sacs at new sub-divisions where the streets are paved but there arent any houses yet. Also parking lots- good ones are at college or pro ball parks on days when there's no game- the noise goes un-noticed usually there.

The wheels on the pt-19 are too small to deal with any grass at all, even finely cut grass on a well-kept runway. The wire axle is only about 1/2 inch from the ground and any grass longer than 1/2 inch gets stuck in the crevice between the axle and the wheel.
You just have to take off from pavemet.

Also some 12v starters are too slow to really be good at starting cox engines, the typical yellow sullivan that is used on the larger .40 rc engines for example. On my pt19 the built in spring starter never took more than four or five tries to get things going.

Be sure your glow plug battery is fresh or freshly charged, and the glow plug clip is getting good contact.

After a while you will want to get a 6-4 prop (you may need a left hand prop for some pt-19- just bring the old prop with you to the shop- the stock prop is a 6-3) The pt-19 is transformed to a serious fun machine by the 6-4 prop.