I used four hobbico cs71 in the wings & four in the tail, I think they are the same as the hitec 645, they are 110 oz/in b.b. metal gear servo's, work great. about $38 per servo @ tower. I think they have discontinued the cs71 & replaced it with a cs70. I am using a g-62 for power with a 22x12 mejzlik prop.