"The Joy of Home Winemaking" by Terry Garey is my winemaking Bible, and her recipe "Matched Pear" is exactly what you describe--cut them up and put them in a fermentation bag. I have a batch of "pear wine" aging right now, but I actually made it from some pear nectar that we canned last year while putting up pear preserves. I blended the nectar with white grape concentrate and water, fermented it, then blended the result with apfelwein. It's nice, but very sweet--probably not at all like what you're going for.
Here's her recipe--makes 1 gallon:
3-1/2 quarts water
2 lbs sugar or light honey
4 lbs ripe pears
1 crushed Campden tab
2 tsp acid blend
1 tsp yeast nutrient
1/4 tsp tannin
1/2 tsp pectic enzyme
1 packet dry champagne yeast
Boil water & sugar or honey together. Wash, stem, core, & chunk pears. Place pears in a fermentation bag and place in fermenter with crushed Campden tab. Mash pears in bag with a potato masher. Pour hot sugar water over pears, add tannin and yeast nutrient. When cool, add pectic enzyme. 12 hours later, add yeast. Ferment on the fruit for a week, remove & drain fruit bag, ferment another week, rack to secondary, rack in two weeks, rack again in two to six months. When clear, stabilize, sweeten if desired, & bottle.
I'm summarizing her recipe, so you might want to check the book to be sure, or adjust to suit your own experience. I'm still fairly new to the hobby, so YMMV.