What about a metal or other composite ring split into three pieces, with each piece being bolted to a blade? Then you bring the three pieces together around the motor and then bolt or clamp them together with some type of simple bracket or tab on the edges.Then some carbon over the top possibly.
Thanks for the input, yes if you want the $100 for a different mount, we first have to agree on your design ;-) What is crucial about this challenge here is: 1. the hoverboard motor is not modified, at least not opened. 2. The blade mount can be made in one step, at least only two steps (my glassfiber roving approach might need a backside stage and a frontside stage) 3. No welding or other expensive tools neccesary 4. Cheap materials. And yes, i also already had the idea to simply 3d print three blade-mount parts that simply get pulled onto the hoverboard motor with "Stainless Steel Metal Cable Ties" The ABS material would mostly need to absorb push forces while the cable ties would carry all the pull forces 🙂 concern 1: centrifugal force F = m v² / r v_storm = 30 m/s and tsr = 5 (tip speed ratio) v_tip = 5 * v_storm = 150 m/s blade length = 104 cm and blade mount radius = 12 cm v_12cm = 12/110 * v_tip = 16.36 m/s m_blade = 0.5 kg F_30 = 0.5 * (16.36 * 16.36) / 0.12 = 1115 N = 111.5 kg 40 m/s : F_40 = (4/3)² * F_30 = 198 kg 50 m/s : F_50 = (5/3)² * F_30 = 310 kg Stainless Steel Metal Cable Ties 7.9mm = 150 kg , 10 mm = 210 kg , 12 mm = 280 kg 2x 10mm (to avoid Rotating unbalance) = 560 kg one blade is hold from two sides at 60° = 2 * cos(30) * 560 = 970 kg :-) concern 2: Is the engery generating torque twisting the blade forward ? rpm = 14 rpm/V * 36 = 504 rpm and power generating: 500 Watt www.wolfgang-frank.eu/drehmoment.php => 9.55 N m divided by the three blades = 3.2 N m torque between the two mounting bolts = 3.2 * 100/4 = 80 N m = 8 kg :-) concern 3: resonant vibrations could easily doube, trible or tenfold any static forces like concern 1 or 2 😕 But the electric generator should absorb concern2 energy fluctiations. Biggest concern i guess are wind direction changes under full speed. The rotating mass of the blades will lead to tilting the blades forward or backward according to the wind direction (Coriolis force) 😞 But ABS is elastic and the strong centrifugal force should stabilize the blades.. So it might be worth a try. But big problem is that every blade is slightly different and it might be difficult to program a thingiverse OpenSCAD model where users can quickly make the neccessary stl file. Unfortunately, 900mm wind blades are not really cheap, so this challanges is not really helpful anyway. Yes, you could cut a metal ring into three segments, weld a blade-mount to each part and pull them onto the hoverboard motor with such cable ties www.aliexpress.com/item/1005005079856443.html But then it would be easier to open the hover motor and mount a metal disc with 6 M10 holes :-(
@robodurden Yeah..All of this is above my paid grade. I thought you were trying to figure out a simple way of mounting the blades. Made to be similar if not identical in weight for balance, not welded, secure, and easy to make. I wasn't saying to to weld a blade mount, but to bend one or two into the metal strap at 90°. You would start with 3 (T) or (+) shaped metal straps only bending them and drilling holes to accommodate for the hardware. Now that I'm thinking about how you would obtain metal shaped in that way I don't believe you could without cutting it yourself. That wouldn't be so easy without some expensive equipment to make it easier. Plus the Clamps or bolts that would be used to connect the the three segments together would now be adding weight to some or all of those forces now. In Reality your way is best with the carbon fiber. Need to construct a large enough spindle to hold all three blades and the motor in place while allowing full access from both sides. A spool of carbon and the patches on both sides. Spin it, wrap it all at once keeping everything perfectly even and in place. Basically a spinning jig. The clamps are adjustable for different blades and the motor mount should be the same or easily changed out. Once the jig is built it should be a easy enough to clamp everything in place and wrap it up tight. Not sure how you would attach the bolts to the carbon maybe weaving through the holes a few times laying some patches with holes cut, then putting the bolts through and wrapping and layering more. Maybe for the OpenSCAD you make the mounts but make the blade mounting points "blank" in a way where people would be able to easily drill holes or make necessary changes to accommodate for their blades. I know that's very difficult but I wouldn't say impossible. Once again this is all over my head I enjoy brainstorming ideas. I'd love to make one if i had a better understanding and the necessary materials.
> laying some patches with holes cut You do not need to cut holes for M10 Bolts. The fiber patches/layers are so loose and fall apart that you can easily make room for the bolts. That is why I say in the video that you have circle the bolts with a roving thread afterwards to achieve a tight grip of the M10 Bolts after the epoxy has cured. On AliExpress I see that all wind blades available now have a long shaft for the two (or three) mounting holes. Not like my blades where the two M10 holes are in the base of the wing. With these new blade design I guess it is easier to open the hoverboard motor and drill six holes into the side, as the blade shafts are long enough for the two M10 screws to reach that flat side of the hoverboard motor.
Better charge a 24V battery. 36V is only found with eBikes and hoverboards. These cheap mppt wind controlers (mostly) have a little step up booster to charge battery at low wind: de.aliexpress.com/item/1005006273365847.html Here is a wind/solar hybrid controler that says to also support 36V: de.aliexpress.com/item/1005003340726250.html . But i doubt that it really is a solar mppt charger. But i want to know what this hybrid charger does when 36V battery is charged and the wind power needs to be shut down or burned with a load. The cheap wind chargers can short cut the three phases of the wind turbine. You can also use the hoverboard controller as an active rectifier which can also step up to charger a battery. See my other video ua-cam.com/video/D_PfKFIc_kc/v-deo.html But i do not know how the efficiency compares to the of-the-shelf products. With the hoverboard controller however you could give the wind turbine a push to start spinning.. Might be necessary because the hoverboards bldc magnets need some force to be overcome in order to let the motor spinning.. That is why i think that i needs at least a 2 meter diameter to make the hoverboard motor spin at moderate wind.
Nice
What about a metal or other composite ring split into three pieces, with each piece being bolted to a blade? Then you bring the three pieces together around the motor and then bolt or clamp them together with some type of simple bracket or tab on the edges.Then some carbon over the top possibly.
Thanks for the input, yes if you want the $100 for a different mount, we first have to agree on your design ;-)
What is crucial about this challenge here is:
1. the hoverboard motor is not modified, at least not opened.
2. The blade mount can be made in one step, at least only two steps (my glassfiber roving approach might need a backside stage and a frontside stage)
3. No welding or other expensive tools neccesary
4. Cheap materials.
And yes, i also already had the idea to simply 3d print three blade-mount parts that simply get pulled onto the hoverboard motor with "Stainless Steel Metal Cable Ties"
The ABS material would mostly need to absorb push forces while the cable ties would carry all the pull forces 🙂
concern 1: centrifugal force F = m v² / r
v_storm = 30 m/s and tsr = 5 (tip speed ratio)
v_tip = 5 * v_storm = 150 m/s
blade length = 104 cm and blade mount radius = 12 cm
v_12cm = 12/110 * v_tip = 16.36 m/s
m_blade = 0.5 kg
F_30 = 0.5 * (16.36 * 16.36) / 0.12 = 1115 N = 111.5 kg
40 m/s : F_40 = (4/3)² * F_30 = 198 kg
50 m/s : F_50 = (5/3)² * F_30 = 310 kg
Stainless Steel Metal Cable Ties
7.9mm = 150 kg , 10 mm = 210 kg , 12 mm = 280 kg
2x 10mm (to avoid Rotating unbalance) = 560 kg
one blade is hold from two sides at 60° = 2 * cos(30) * 560 = 970 kg :-)
concern 2: Is the engery generating torque twisting the blade forward ?
rpm = 14 rpm/V * 36 = 504 rpm and power generating: 500 Watt
www.wolfgang-frank.eu/drehmoment.php => 9.55 N m
divided by the three blades = 3.2 N m
torque between the two mounting bolts = 3.2 * 100/4 = 80 N m = 8 kg :-)
concern 3:
resonant vibrations could easily doube, trible or tenfold any static forces like concern 1 or 2 😕
But the electric generator should absorb concern2 energy fluctiations.
Biggest concern i guess are wind direction changes under full speed. The rotating mass of the blades will lead to tilting the blades forward or backward according to the wind direction (Coriolis force) 😞
But ABS is elastic and the strong centrifugal force should stabilize the blades..
So it might be worth a try.
But big problem is that every blade is slightly different and it might be difficult to program a thingiverse OpenSCAD model where users can quickly make the neccessary stl file.
Unfortunately, 900mm wind blades are not really cheap, so this challanges is not really helpful anyway.
Yes, you could cut a metal ring into three segments, weld a blade-mount to each part and pull them onto the hoverboard motor with such cable ties www.aliexpress.com/item/1005005079856443.html
But then it would be easier to open the hover motor and mount a metal disc with 6 M10 holes :-(
@robodurden Yeah..All of this is above my paid grade. I thought you were trying to figure out a simple way of mounting the blades. Made to be similar if not identical in weight for balance, not welded, secure, and easy to make. I wasn't saying to to weld a blade mount, but to bend one or two into the metal strap at 90°. You would start with 3 (T) or (+) shaped metal straps only bending them and drilling holes to accommodate for the hardware. Now that I'm thinking about how you would obtain metal shaped in that way I don't believe you could without cutting it yourself. That wouldn't be so easy without some expensive equipment to make it easier. Plus the Clamps or bolts that would be used to connect the the three segments together would now be adding weight to some or all of those forces now. In Reality your way is best with the carbon fiber. Need to construct a large enough spindle to hold all three blades and the motor in place while allowing full access from both sides. A spool of carbon and the patches on both sides. Spin it, wrap it all at once keeping everything perfectly even and in place. Basically a spinning jig. The clamps are adjustable for different blades and the motor mount should be the same or easily changed out. Once the jig is built it should be a easy enough to clamp everything in place and wrap it up tight. Not sure how you would attach the bolts to the carbon maybe weaving through the holes a few times laying some patches with holes cut, then putting the bolts through and wrapping and layering more. Maybe for the OpenSCAD you make the mounts but make the blade mounting points "blank" in a way where people would be able to easily drill holes or make necessary changes to accommodate for their blades. I know that's very difficult but I wouldn't say impossible. Once again this is all over my head I enjoy brainstorming ideas. I'd love to make one if i had a better understanding and the necessary materials.
> laying some patches with holes cut
You do not need to cut holes for M10 Bolts. The fiber patches/layers are so loose and fall apart that you can easily make room for the bolts. That is why I say in the video that you have circle the bolts with a roving thread afterwards to achieve a tight grip of the M10 Bolts after the epoxy has cured.
On AliExpress I see that all wind blades available now have a long shaft for the two (or three) mounting holes. Not like my blades where the two M10 holes are in the base of the wing.
With these new blade design I guess it is easier to open the hoverboard motor and drill six holes into the side, as the blade shafts are long enough for the two M10 screws to reach that flat side of the hoverboard motor.
Please explain is it hoverboard how electric circuit and voltage its 36 v generating
Better charge a 24V battery. 36V is only found with eBikes and hoverboards.
These cheap mppt wind controlers (mostly) have a little step up booster to charge battery at low wind: de.aliexpress.com/item/1005006273365847.html
Here is a wind/solar hybrid controler that says to also support 36V: de.aliexpress.com/item/1005003340726250.html . But i doubt that it really is a solar mppt charger. But i want to know what this hybrid charger does when 36V battery is charged and the wind power needs to be shut down or burned with a load.
The cheap wind chargers can short cut the three phases of the wind turbine.
You can also use the hoverboard controller as an active rectifier which can also step up to charger a battery. See my other video ua-cam.com/video/D_PfKFIc_kc/v-deo.html
But i do not know how the efficiency compares to the of-the-shelf products. With the hoverboard controller however you could give the wind turbine a push to start spinning.. Might be necessary because the hoverboards bldc magnets need some force to be overcome in order to let the motor spinning.. That is why i think that i needs at least a 2 meter diameter to make the hoverboard motor spin at moderate wind.
Are you going to build one Robo?
First rule of project chaos: you do not ask questions.