Propjockey
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- Sep 16, 2002
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Do all sport hydros have flat bottomed hulls at the rear? If so, why?
Sport Hydro Hull Design
- Thread starter Propjockey
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I dont know if it is the same in the US but here they have to simulate the look of full size boats hull wise ..... in other word no rigger types no 3 wings either so it important to keep the rear up .. i would say it would be similar to the answer i got about flat bottom tubs on riggers a couple weeks back
missbudpilot55
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- Mar 10, 2003
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Sport scale is exactly what the name implies, ie building a scale looking hydro simular to the big hydros except that the documentation that is required for the 1/8th scale unlimited hydro's is not required. The rules state that the boat must look like a full size boat with paint scheme to simualate a racing team. Looking at all of the full size hydro's they all have flat bottoms and most have air traps coming off of the rear side of the sponsons to keep air under the boat center section for lift. I believe the rules for sport hydros state that you cannot have sponsons or lifting shoes under the rear of the hull nor can you have a chute cut in the bottom of the hull either. If the bottom of the hull were rounded or convex shaped the air traped buy the sponsons would not support the hull, as it would spill out the sides and would cause the prop to be the lifting mechanism for the design. A convex shaped hull bottom would definately trap more air but is also illegal not to mention harder to build. Flat bottoms that are smooth and unobstructive also let the air traped under the hull flow and support ther hull better than other shapes.
Look at Phil Thomas's sport designs, they are very slim with as small a frontal entry as is loggically posibble for the size of motor and equipment that can be run in that class, "steath looking" hulls, with a good balance of tunnel width to length ratio. Aerodynamicly as low drag and and lift that is good as possible with the wing shape of the center section that also generates lift from the top of the hull.
Don't know if this is the answer you where looking for but I tried.
Look at Phil Thomas's sport designs, they are very slim with as small a frontal entry as is loggically posibble for the size of motor and equipment that can be run in that class, "steath looking" hulls, with a good balance of tunnel width to length ratio. Aerodynamicly as low drag and and lift that is good as possible with the wing shape of the center section that also generates lift from the top of the hull.
Don't know if this is the answer you where looking for but I tried.
