Looking at Gear Boxes
I was thinking today that Brian has a lathe so he could probably bore out the pinions used in the gearboxes on Huntington rather precisely. When I did it back in the day I was using a hand drill so they're not exactly straight or precise and hence wobble a bit.
Huntington's gearboxes 1.7:1
Then I got thinking about how other people are often looking for gearboxes to put in their boats and thought I might share links to similar products. They are all made by Great Planes and are supposed to be used at MUCH higher rpms on airplanes but I think they'll do just fine in our boats.
Box 2 is similar to the one in Huntington but 3:1
This 3.8:1 gearbox is nice because it should be easier to change motors but the ratio is pretty high and the pinion appears to require being pressed onto the motor shaft but I'm sure if someone could find the specs that I could find a similar pinion that used a set screw.
The last 3 boxes are designed for 24mm, 28mm, and 36mm outside diameter motors and can be used with many different pinions for different gear ratios and have rather large output shafts but commensurate with the size of motors they are intended to be used with.
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Re: Looking at Gear Boxes
I was doing some research today on possible upgrade options for huntington and ended up thinking about the gearboxes already in her. I originally thought that "box 1" and "box 2" were essentially the same but with different pinions but when I crunched the numbers I realized that was impossible. Box 1 has a 24T bull gear and a 14T pinion while Box 2 has a 34T bull gear and an 11T pinion. The size of the pinions intrigued me so I pulled a spare pinion I have for my Furion out and checked to see how it meshed with the gear boxes in Huntington. It turns out it is a perfect match. This means that more than likely all these boxes are Mod 0.5 gears which means that through Readyheli.com and Revco "Hard-One" you have your choice of pinion anywhere from a 9T to a 17T for 3.17mm (1/8") shafts or 9T or 13T in 2.13mm. There are many other companies that make "after market" pinions for helis but I prefer the Revco pinions. This opens up a great number of ratios for gearboxes using off the shelf parts.
I also spent some time fiddling with the motor performance analyzer on Mabuchi's website and I think the following motor should be a good choice for anyone running 12V. The key will be to tune your gear boxes to get the motor spinning at peak efficiency (which works out to be about as fast as possible or ~4000rpm). I am hoping to get prop/rpm/speed data from everyone in the club so that maybe we can take some of the guesswork and mystery out of motor and prop selection.
http://www.allelectronics.com/make-a-store/item/DCM-330/3-20VDC-MOTOR-MABUCHI/1.html
The jist of all this is that if I decide to upgrade Huntington's power plant that I will be able to easily fine tune her performance by swaping pinions until I have the top end prop speed that I want and that these great big motors should have plenty of torque to spin her huge props.
Re: Looking at Gear Boxes
While fiddling with Huntington tonight I discovered that the gears used in her gearboxes are not mod 0.5 but 0.6 meaning that while there are a lot of pinions available, they are made for 5mm shafts. This makes me want to just build my own gear boxes but I need to find some gears first.
Re: Looking at Gear Boxes
That looks like the motor I use in BB Lion...