France Helices designs its’ drive systems starting with the propeller, and moving forward. Why?
One of the primary impediments to propeller efficiency is cavitation. Additionally, cavitation not inly impacts propeller efficiency, but in extreme cases, it can seriously damage a propeller. There is a fairly thorough discussion about cavitation and its’ effects on our Wiki, located HERE.
In order to accurately see the impact of propeller design changes on cavitation, one must use a cavitation tunnel. This is a step that many inexpensive propeller manufacturers do not perform, due to the expense associated with tunnels. However, it is our belief that in order for any propeller to truly achieve performance, one must use such facilities. In particular, this is important for surface piercing propellers that operate with a substantial amount of exposure to air. All France Helices propeller and drive designs have been extensively tunnel tested.
So, what is a cavitation tunnel?
It is a long trough, sealed for equal pressure, where water flow is forced from one end to the other. At one end is a dynamometer that meaures the speed of the flow. On the other end is a stroboscope, that flashes so that pictures of the propeller and the flows surrounding the propeller can be made. It is by using such facilities that France Helices can 100% guarantee propeller thrust on every drive sold.
Is this method expensive? Yes. Most tunnels, and there are only around two dozen globally, are located at research universities and other such organizations. France Helices maintains close relationships with the two major tunnels located in France.
So, for true performance, make certain that your propeller has been tunnel tested, whether manufactured by us or not, before relying on performance figures provided.
