3D Printed / Foamboard Auto-Gyro Stuff
Auto-gyros are awesome. I've wanted to build a full scale one before I ever got into RC. Since that's still kinda out of reach, I figured I might as well build a few out of foam first.
Recently got a 3D printer, so I decided to do something useful with it and start making auto-gyro components. My goal is to make easily printable parts like rotor heads, start assist gearboxes, and blade leading edges that can be swapped into just about any small to medium sized auto-gyro frame. Hopefully I'll have worked up to a Pitcairne in time for FliteFest East 2017.
I want the 3d printed parts to work on just about any FDM printer with a standard .4mm nozzle. I also plan to use readily available filaments than can be printed on most machines. I hope that everything can be printed in PLA, PETG, or ABS.
For parts that aren't 3D printed or made of foamboard, I want them to be cheap and easily available.
I'll be releasing all the STL's and such for use by anybody when the parts are ready for prime time.
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I've tackled what I figure is the most complicated part first, the start assist gearbox. For those of you unfamiliar with how an auto-gyro works, in place of a wing, there's a set of unpowered auto-rotating blades that provide lift. These blades auto rotate as the craft moves through the air. At RC scale, it can be difficult to get that auto-rotation momentum up and going, so a start assist makes takeoffs much simpler.
Basic pusher Auto-gyro for Reference:
First step was to draw up all the 3D parts I would need. I started with gears and went through several renditions and tooth counts before I found something that would come out ok in my slicer program. Best I could do without making the physical size of the gears bigger was a 12/36 tooth arrangement. I plan to power the start assist with an F or A pack motor, and so opted for a 9 to 1 reduction. That's (36/12)*(36/12).
F Pack motor with 12 tooth gear installed. An A pack will also bolt into the housing. Gears are all Taulman Tech-G (PETG filament), and the housing parts are all orange Hatchbox PLA.
Next I've installed the 36/12 tooth gear combo. I'm using a bit of 3/16" tig welding rod to hold it in place. I think I'll probably upgrade that to 3mm landing gear wire as it's very common in the RC world.
Then you can see the 36 tooth gear attached to a piece of 3mm landing gear wire with some CA. I modeled in some set screw mounts, but thought I would try and see if roughing up the rod with some sand paper and using glue would be enough to hold it.
Quick video of parts printing and a test runup.
As you can see, it works! It is a bit noisy though, even after adding some silicone grease. I think I'm going to add a couple 623ZZ bearings on the output shaft. That will help out a lot for longevity, and who knows, it might also be quieter. They're also super cheap and available pretty much anyway. I ordered a 10 pack off of amazon a while back for RC projects.
Several other things will be changing. I'm going to be using flexible driveshaft material between the gearbox and the rotor head so that aileron control will be an option, and I need to figure out how to make the blades freewheel. The powered start assist will only be on long enough to get you in the air. As things work right now, when you cut the motor, the blades slow down massively and have drag from the gears to overcome. No bueno if you want your craft to keep flying.
After I add bearing mounts to the casing, I'm going to get started on blade leading edges. I think that 3D printable leading edges added to foamboard blades will be easy, cheap, fast, and hopefully strong enough to carry the craft through the air.
Auto-gyros are awesome. I've wanted to build a full scale one before I ever got into RC. Since that's still kinda out of reach, I figured I might as well build a few out of foam first.
Recently got a 3D printer, so I decided to do something useful with it and start making auto-gyro components. My goal is to make easily printable parts like rotor heads, start assist gearboxes, and blade leading edges that can be swapped into just about any small to medium sized auto-gyro frame. Hopefully I'll have worked up to a Pitcairne in time for FliteFest East 2017.
I want the 3d printed parts to work on just about any FDM printer with a standard .4mm nozzle. I also plan to use readily available filaments than can be printed on most machines. I hope that everything can be printed in PLA, PETG, or ABS.
For parts that aren't 3D printed or made of foamboard, I want them to be cheap and easily available.
I'll be releasing all the STL's and such for use by anybody when the parts are ready for prime time.
****************************************************************************************************
I've tackled what I figure is the most complicated part first, the start assist gearbox. For those of you unfamiliar with how an auto-gyro works, in place of a wing, there's a set of unpowered auto-rotating blades that provide lift. These blades auto rotate as the craft moves through the air. At RC scale, it can be difficult to get that auto-rotation momentum up and going, so a start assist makes takeoffs much simpler.
Basic pusher Auto-gyro for Reference:
First step was to draw up all the 3D parts I would need. I started with gears and went through several renditions and tooth counts before I found something that would come out ok in my slicer program. Best I could do without making the physical size of the gears bigger was a 12/36 tooth arrangement. I plan to power the start assist with an F or A pack motor, and so opted for a 9 to 1 reduction. That's (36/12)*(36/12).
F Pack motor with 12 tooth gear installed. An A pack will also bolt into the housing. Gears are all Taulman Tech-G (PETG filament), and the housing parts are all orange Hatchbox PLA.
Next I've installed the 36/12 tooth gear combo. I'm using a bit of 3/16" tig welding rod to hold it in place. I think I'll probably upgrade that to 3mm landing gear wire as it's very common in the RC world.
Then you can see the 36 tooth gear attached to a piece of 3mm landing gear wire with some CA. I modeled in some set screw mounts, but thought I would try and see if roughing up the rod with some sand paper and using glue would be enough to hold it.
Quick video of parts printing and a test runup.
As you can see, it works! It is a bit noisy though, even after adding some silicone grease. I think I'm going to add a couple 623ZZ bearings on the output shaft. That will help out a lot for longevity, and who knows, it might also be quieter. They're also super cheap and available pretty much anyway. I ordered a 10 pack off of amazon a while back for RC projects.
Several other things will be changing. I'm going to be using flexible driveshaft material between the gearbox and the rotor head so that aileron control will be an option, and I need to figure out how to make the blades freewheel. The powered start assist will only be on long enough to get you in the air. As things work right now, when you cut the motor, the blades slow down massively and have drag from the gears to overcome. No bueno if you want your craft to keep flying.
After I add bearing mounts to the casing, I'm going to get started on blade leading edges. I think that 3D printable leading edges added to foamboard blades will be easy, cheap, fast, and hopefully strong enough to carry the craft through the air.
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