If you want a kit Sig sells the 1/2A Skyray and a few others,Brodak has a whole line of 1/2A kits including a trainer, and Blackhawk Models sells a variety of Walt Musciano designs and other 1/2A kits.
Another option is to get plans from Flying Models for one of the Dick Sarpolus 1/2A profile designs, he did a bunch of semi-scale sheet balsa warbirds, etc.
The cheapest alternative is to get a sheet of 1/4" x 4" , and 1/8" X 3" balsa and scratch build one. For a reed valve engine like the one in the PT-19 the following dimensions will get you a flyable / stable model on 25' to 35' lines. these were taken off a CG Wizard I pulled down from the shelf.
wing is 1/4" sheet with a 22" span and a 4" chord- sand to an airfoil
Fuselage 1/4" sheet with a length 12" X 1 3/4 to 2 1/2" tall, firewall approx 2 1/2" forward of the wing leading edge. Taper thickness aft of the wing.
Stab / elevator / fin are made from 1/8" sheet, stab / elevator are 8 1/2" wide, 1" chord on elevator and a 1 1/2 to 1 3/4 width on stab, fin is 3 wide X 2 1/2 high.
Draw these dimension on the appropriate thickness sheets, put some taper / sweep back on the leading edge of the fin and stab, Draw a fuselage profile that looks good to you with a minimum 1 3/4" at the firewall to fit the engine mount.
You can mount the engine with a couple pieces of 3/4" aluminum angle, or build up a mounting surface using balsa triangle stock and a piece of plywood.
It's pretty easy and the grandkids can help. Any needed accessories like bellcranks and horns can be purchased from your local hobby shop or ordered from Sig or Brodak.