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Hey guys, new member here.
First I want to say this has been a fun journey so far. As a Aircraft guy, I am a boat newbie, and I wasn't quite expecting so much development with designing a micro rigger! That being said, it has been very fun and entertaining!
I first set off wanting a small pond racer, but not wanting to drop $100+ on something so small. (although, now I do have one of those micro Bolt's coming as it looks like too much fun.) The goal was to get these things over 20mph, 180g or less, and 99% 3d Printed. The project is open source, and anyone who wants to help design or tweak the design is more than welcome! Simply PM me for the Sketchup files.
Here is the development so far:
I was inspired very much by AmpAbuser who built this little rocket:
As It currently sits, I have a motor capable of 120 watts. The motor is very excessive for this size boat, but the original goal is to use what I had laying around. The motors weighs a whopping 24 grams with only 2300kv, but it has a lot of grunt! It is currently runnning on a 3s 340mah pack. I think the sweet spot would be a 4000 kv motor on 2s. I have also designed 3 different props. One 25mm 2 blade prop, one 18mm 3 blade prop, and now a 22mm 3 blade prop.
During the design and learning process I very quickly learned you can have too little of a planing surface on your sponsons, I learned the seriousness of rudder placement, and learned the horrors of prop steer (from prop step, and torque). When I finally got this boat moving 18-20mph it was hopping like made, and had a hard right hand turn. After quite a bit of research, I decided to change props before CG etc. Sure enough, the 25mm 2 blade was the cause. The 3 blade 18mm had NO prop step (most likely since there is always 1 blade 100% in the water to counter the effect of the incoming penetrating blade), however I can't utilize the potential power in this motor due to the prop completely unloading at right around 75% throttle.
I am currently printing a new rudder and rudder mount, as well as the larger 3 blade prop to give it another try today.
Please chime in with your thoughts and opinions! I would love for this to be a group project.
I do want to apologize for those that do not have 3d printers, but hopefully as a community, those that do can maybe build a few and charge for their time and materials, or something of the sort. I did try to upload it to shapeways, but they do not allow you to adjust the infill or wall thickness, therefore the empty hull would weigh 160G as opposed to 64g!
Enjoy!
-Justin
PS, please be nice, this was my first RC boating experience, and I have learned a lot so far!
20150102_212245.jpg20150102_212310.jpg
First I want to say this has been a fun journey so far. As a Aircraft guy, I am a boat newbie, and I wasn't quite expecting so much development with designing a micro rigger! That being said, it has been very fun and entertaining!
I first set off wanting a small pond racer, but not wanting to drop $100+ on something so small. (although, now I do have one of those micro Bolt's coming as it looks like too much fun.) The goal was to get these things over 20mph, 180g or less, and 99% 3d Printed. The project is open source, and anyone who wants to help design or tweak the design is more than welcome! Simply PM me for the Sketchup files.
Here is the development so far:
I was inspired very much by AmpAbuser who built this little rocket:
As It currently sits, I have a motor capable of 120 watts. The motor is very excessive for this size boat, but the original goal is to use what I had laying around. The motors weighs a whopping 24 grams with only 2300kv, but it has a lot of grunt! It is currently runnning on a 3s 340mah pack. I think the sweet spot would be a 4000 kv motor on 2s. I have also designed 3 different props. One 25mm 2 blade prop, one 18mm 3 blade prop, and now a 22mm 3 blade prop.
During the design and learning process I very quickly learned you can have too little of a planing surface on your sponsons, I learned the seriousness of rudder placement, and learned the horrors of prop steer (from prop step, and torque). When I finally got this boat moving 18-20mph it was hopping like made, and had a hard right hand turn. After quite a bit of research, I decided to change props before CG etc. Sure enough, the 25mm 2 blade was the cause. The 3 blade 18mm had NO prop step (most likely since there is always 1 blade 100% in the water to counter the effect of the incoming penetrating blade), however I can't utilize the potential power in this motor due to the prop completely unloading at right around 75% throttle.
I am currently printing a new rudder and rudder mount, as well as the larger 3 blade prop to give it another try today.
Please chime in with your thoughts and opinions! I would love for this to be a group project.
I do want to apologize for those that do not have 3d printers, but hopefully as a community, those that do can maybe build a few and charge for their time and materials, or something of the sort. I did try to upload it to shapeways, but they do not allow you to adjust the infill or wall thickness, therefore the empty hull would weigh 160G as opposed to 64g!
Enjoy!
-Justin
PS, please be nice, this was my first RC boating experience, and I have learned a lot so far!
20150102_212245.jpg20150102_212310.jpg
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