Aqui tienes una diferencia, las dos son para 3D, y pesan lo mismo (120gr), pero una lleva en el nucleo una varilla y la otra dos, y esto ya es la explicacion definitiva:
D Blade is Hard and Higher Response , F Blade a bit more Flexibility, Motion is more consistence. Both blades have good floating feel. Super easy to do Autorotation.
F blade is normal Carbon Cloth Coating. D Blade is with 3K Carbon Cloth Coating where both are internally light wood material.
425F Carbon Fiber Blades H50111 425F carbon fiber blade developed by Align RC world, utilizes unique compounding technology, features great performance for 3D and auto rotation flights.
425D Carbon Fiber Blades H50104 425D carbon fiber blade developed by Align RC world, utilizes unique compounding technology, features great performance for 3D and auto rotation flights.