Giving something different a try - gear train for mini helicopter
Posted: Mon Apr 12, 2021 5:59 pm
I have a fun project (to me anyway), that presents a bunch of challenges
I have some small Align Helicopters (450 size), and an older but new&unbuilt kit for a scale EC135 helicopter body, with a Fenestron tail kit
The challenge has multiple parts.
1) Drive gear box?
The original kit was meant for a belt drive, and I wanted to build one with a full gear train/torque tube (shaft drive tail) setup.
I may build one with a belt first, and then go on to a shaft drive model after
2) Tail Authority
These are full on stunt 3D helicopters, capable of flight parameters real helicopters will never match (it's insane what some great pilots are capable of, tbh)
these remote control birds are designed to spin the main rotor at high 2k/low 3k speeds, and the tail is geared to match that, and provide tail control with fast response. in order to run a scale model, with more than the 2 blade setups the stunt helo's use, the rotation needs to be slowed down significantly, as well as it not being needed if the blade pitch is setup for a slower speed.
This challenge is the big one - I need to speed up the rotation of the tail at these lower head rotor speeds, and thus make some changes to the drivetrain. A lot of folks gave up on the smaller helicopters running a real fenestron rotor for this reason.
I've modeled the gear train (the tooth counts are not yet verified, but it's got what is involved so far). It's been more than a couple years since I played with Gearotic, but I am reminded how great this tool is, by virtue of being able to spend a few hours, watch a video of Art's and make the model!
I have a bunch of questions and ideas, and wanted to build a thread, see if I can't interest some of the experts here, get some advice etc...
I have some small Align Helicopters (450 size), and an older but new&unbuilt kit for a scale EC135 helicopter body, with a Fenestron tail kit
The challenge has multiple parts.
1) Drive gear box?
The original kit was meant for a belt drive, and I wanted to build one with a full gear train/torque tube (shaft drive tail) setup.
I may build one with a belt first, and then go on to a shaft drive model after
2) Tail Authority
These are full on stunt 3D helicopters, capable of flight parameters real helicopters will never match (it's insane what some great pilots are capable of, tbh)
these remote control birds are designed to spin the main rotor at high 2k/low 3k speeds, and the tail is geared to match that, and provide tail control with fast response. in order to run a scale model, with more than the 2 blade setups the stunt helo's use, the rotation needs to be slowed down significantly, as well as it not being needed if the blade pitch is setup for a slower speed.
This challenge is the big one - I need to speed up the rotation of the tail at these lower head rotor speeds, and thus make some changes to the drivetrain. A lot of folks gave up on the smaller helicopters running a real fenestron rotor for this reason.
I've modeled the gear train (the tooth counts are not yet verified, but it's got what is involved so far). It's been more than a couple years since I played with Gearotic, but I am reminded how great this tool is, by virtue of being able to spend a few hours, watch a video of Art's and make the model!
I have a bunch of questions and ideas, and wanted to build a thread, see if I can't interest some of the experts here, get some advice etc...