Hey all,

Has anyone used Variable pitch propellors on their quadcopter?? I'm thinking about using them on my new project and was wondering if anyone had any experience with them or could let me know if its a dead end or if its even done??

Any help would be greatly appreciated :)

Thankyou,

Harry 

Views: 7474

Reply to This

Replies to This Discussion

Vibration is the unfortunate bane of every lifting airscrew.  I know some engineers invest virtually their entire careers in this field on full-scale single-rotor choppers.

Which brings me to my next point about variable vs. fixed pitch - making the rotors rigid (like an airplane propeller) drives the fundamental resonances and harmonics up the frequency spectrum where they are easier to dampen.  That said, on my 46" diameter rotors, with some blades made out of carbon fiber and some fashioned from polystyrene over aluminum (7075 alloy and yes, it sounds strange but it works), the center hub is a solid 6061 aluminum bar.  Yes, it does flex a little, but the point is that some of the yield pieces had to be thrown out because they exhibited excessive vibration for reasons that are beyond my ability to discern.

The lesson was to balance and test every component individually before attempting to fly.  The variables are too many to account for them all.

Very nice video!

I don't know why or what i can do with it (except crashing), but i want that!

Cheers

Kraut Rob

Mike,

The project looks very interesting. What was the frame based off of? I wanted to try and replicate this project for myself and it would be nice to use all the same parts. My intent is to do something slightly different though and use only one motor to run all props. Anyway, any help could be useful. Thanks in advance.

The frame was a custom cut carbon fiber foam core. 

The variable pitch system I believe is posted somewhere in this forum but I can find it if you need it. 

The motor in the middle is difficult. They tried that paired with trex 450 tail blade assemblies before my time and were unsuccessful. I think they ran into vibration issues and i dont think it actually flew because it didnt have enough power. It was one of the early prototypes. 

I can get into more details if you would like, email me at mklinker@mit.edu

Hello Harry,

currently we work also on an variable pitch quadrocopters

it fly's since ~ two weekends :) designed as a fast video plattform, not as a 3d model.

Under the video on youtube, you find some data.

Best Regards

Askan

Mike,

It is funny that I just read your comment here since I started a project back in December to build a variable pitch hex copter using 450 tail assemblies. (single motor) I just finished putting the assembly together and have begun configuration.

One of the first problems that I have encountered is the servo behavior when connected to the APM2.5. The basic response is as expected, but they are very twitchy/jumpy as if there is significant electronic noise on top of the signal. I have tried connecting the servos directly to the receiver and the behavior is normal.

I have started with ArduCopter (latest build) and have tried changing the default ESC UPDATE SPEED (RC_SPEED) to 125 Hz with no improvement.

Are you aware of any reason the output from the APM2.5 would be different than that of the receiver with respect to the ESC/Servo signal?

(Yes, I am hoping that the stability logic in ArduPilot is sufficient with careful tweaking of the PID control parameters, but if that fails, I will have to dive into the code. But first things first.. need to get the servos a clean signal.)

Todd

Reply to Discussion

RSS

© 2017   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service