RE: Hydroplane weight?
Hi Guys
Thanks for your response which has proved enlightening – ahah no pun intended! and as a result have spent the morning weighing and balancing which has proved interesting indeed.
As said ‘hydros’ are a very new experience but I have spent many years building and flying control-line aerobatic models where the CG and weight are major factors to be considered at all times. With this in mind your advice is timely and understood.
Currently as it stands it weighs 6.7 pounds all up of which 3.7 is the engine, radio gear and hardware (strut, rudder, uncut shaft, coupling) I do not have a pipe for this engine at this time. If I aim for a max of 15 pounds and keep lightness in mind I would imagine the 8.3 left would be more than enough for the rest of the build and finishing.
The balance however is a bit more difficult.
HJ – I can move the fuel tanks about 2 inches forwards which will put them roughly evenly over the desired CG. The engine position though is more problematic. If I move this forward then the intended position for the radio gear is lost and it will have to go to the rear. Checking this out as it stands now there is minimal distance of balance point between either option. The mass of the engine is forward of the CG so I think this will have to remain. Laying out all the hardware gives me a very rough idea of the weights involved and I would (g)estimate that I will have to put about 6 ounces of ballast at the front. I think the best place for this will be under the front of the fixed part of the cowling but on top of the bridge piece between the sponsons. I would reinforce this area to take the stresses that this will undoubtedly create.
Thanks again guys, your input is much appreciated. This build is alongside but secondary to another project so it will be a while before I can take it further though I would hope to finish it by May or so.
Regards - Ramon