Simmer turkey wings in water to cover. (Use celery ribs and leaves, chopped onion, and bay leaf to season the cooking water.) Cook until meat is tender, about an hour. Let cool in broth, then remove the skin and bones from the meat. Cut meat in bite-size pieces. Strain broth and chill. Remove fat that comes to the surface of broth. Drain pineapple. Measure the juice; add defatted turkey broth to make 3 cups of liquid. (Water or chicken broth may replace turkey broth if leftover cooked turkey is used.) Combine brown sugar, cornstarch, and ginger in a 3- to 4-quart saucepan. Stir in the 3 cups liquid, vinegar, and soy sauce. Bring mixture to boil, stirring constantly until thickened. Add carrots and onion. Cover and simmer 10 to 15 minutes, until vegetables are tender-crisp. Cut green pepper into 1/4-inch strips; add green pepper and turkey to sweet-sour sauce and heat for another 5 minutes. Serve on hot cooked rice. This recipe may be doubled. It may also be made with already cooked, left-over turkey. All of it keeps well, though the green pepper loses its color if held too long in the mixture. Leftover turkey stock may be used for a turkey soup or for enriching gravy.