My name is Sam Barker, I 'm a 31 year old captain currently flying the Boeing 737. I have a passion for designing and engineering projects. Some will work others not so well. But its all fun and games! I hope you enjoy.
Did you guys know the historically accurate way to coast a PF is by flopping your legs over the front of the handlebars? That's a real thing I learned from old pictures.
Everyone knows that best way to drive a penny farthing is to use pressure drive with a 4250 560kv drone motor. It'll be lightweight, no wobbly ride, and advantage of 1" to 56" gear ratio reduction
You guys remember that type of bicycle that was so dangerous that people kept on dying on them? Ok how bout they make it electric to make it go faster.
I THINK you can reduce the cavitation by putting the propeller inside of a cylinder.... or at least I thought that's what I understood they were for whebn I watched a video on boats that had steerable props... but i could have understood it wrong... BUT I would think the best way would be to slow them down... so just make them bigger... you've got plenty of power that bigger props would slow them down enough and push WAY more water.... or you could always try those new style of props that use loops instead of blades... I think Tom even tried them out..... - ALSO I way thinking about why some prints wouyld have been been mismatched... it's probably the room temperature, humidity, and barometric pressure that day.... alone each one of these variables do affect much, but when all three are different AND you're doing such large prints I would think all three variables would make such huge swings over such a large distance - PLUS you're printing them quite fast, so they aren't going to be very accurate over so many layers..... - I think the perfect person to ask would be James Bruton .... he does A LOT of very large prints and dowen't seem to ever have issues with this... you shoudl probably ask him
Your propellers need to be under water. Look at how outboard boat motors look - they have a neck long enough for the whole propeller to be below the hull. If the water detaches from the rear of your boat (typically around 7 knots), your propellers start sucking air from above the water line and you get that nasty cavitating noise.
Maybe build it shaped like 2 hulls side by side. With a space between where you can sit to control the boat. Then you can use 1 motor in the middle and make 2 rudders. Locate the rudder brhind the hull. Just like when you buy an boat. Then you can use a bigger motor with more power. Instead of 2 motors.
You will significantly reduce cavitation by reworking those motor mounts. Not only do they have a flat front face plowing in the water, theyre blocking the water from flowing through the prop. Instead they have to suck in water from the sides.
You need a bigger wheel. you have to keep your weight centered with the wheel or you introduce a lean to the wheel and it wants to shoot off to one side, IE Lean with your lean.
All consumer 3D printers are off square. You must correct the frame and then run skew calibration XYZ. Next, run a test print to correct the expansion/contraction and scale the model with the corrections to get accurate results. In XL parts use .8 nozzle to speed up the process and get strong parts. Even the .6 will work better. BTW what a waste of filament, time, money. Insane!! Just use playwood and fiberglass. Or made the shell in 3D print, then use it as a mold to cover it with fiberglass
Cavitation is generally caused by props being too high for the application, or disturbed water flow. In this case, I think it is both. Larger propeller likely will help it (enough) though it would have been better if were below the center on pod(s). In the end, if it gets to planing speed, then you'll likely want the props level with planed out water level, or above. The hydroplanes you built is designed on the "3 point" design and are meant for much higher speed than 30. Normally, the boat will plane on the back portion of the sponsons and at lower speed the back of the boat. At extreme speed, they'll nearly just ride the propeller which will be roughly halfway out of the water at top speed. They are a bit different on prop placement than conventional v-bottom boats (where I have a lot of experience with small boats going fast). If larger props didn't help, or help enough, you might also experiment with 'set-back' i.e. putting the motors BEHIND the boat instead of inside. This helps with stability, bow attitude (which may not help much on hydroplane), and overall speed. My 20' Hydrostream needed 8" of setback versus mounting the outboard directly on the stern with prop 2" above center line to hit its max speed of 104 mph. Regarding the fit, fit all the parts together and glue before filling with foam. I discovered a long time ago when I used spray foam behind a door frame that it can expand and greatly flex the space. In my case, the small amount I used was enough to where I couldn't get the door open until I took a saw and cut out some of the foam. It looks like the molds did fairly well, but more internal bracing near connection points will help. I used to have to do that with huge fiberglass subwoofer boxes so they didn't flex under use.
