so I have my bristish longbow whish is #45@28 and I like it a lot, accurate and powrful, but my question is about FPS, I'm told that a flatbow or a recurve with the same draw weight and draw length would have a high FPS than th roundbellied longbow. is that true? and whats the physics involved?
thanks in advance.
Generally that would be true. There are 2 sides to the physics-on the one hand there is the quetion of energy storage-generally round bellied longbows follow the string a little-recurves aan at least some flatbows have the tips reflexed when unstrung-thus more energy is stored in the limb by stringing(this energy you can't get back out via the arrow) which means the tension on the string at brace height is higher....which means that the first few inches of the draw are "stiffer"-More energy is stored in the limbs during the draw because it starts higher though both bows may stop at the same weight(45pounds @28") More energy stored means more to impart to the arrow.
The second issue is effiency in getting egergy stored from the limbs to the arrow. Round bellied longbows tend to have higher mass weight in the limb than many recurves-This means that more energy is used in getting the limb itself moving leaving less for the arrow. The "recovery rate" for certain limb styles and materials also differs -wooden longbows once again tend to be a little slower than some other designs and materials.
So , yes your longbow may give fewer FPS than a similar weight recurve bow.....but your bow is certainly "fast enough". Slow hits always beat fast misses.
thanks treeman.