Couple of options:
- Ultimate Heli. Behind 4x4 motors in Garhoud. Probably the best overall variety. Not just rotors.
- Hobbycentre. One store in Dubai Mall, next to the food court. The other one on airport rd. Behind the old Honda showroom. Pretty pricey.
- There is a shop in Al Aweer. Forgot the name. Al Ain Rd. between the Emirates Rd and the Nad Al Hamar interchange.
- Dragon Mart. Various stores close to E entrance. Specialised in Chinese stuff, such as the Walkera heli range.
Overall: Ordering through ebay is a lot cheaper. Local prices are higher than Europe despite the absence of VAT and shipping.