RCExplorer BiCopter prototype spotted at FliteFest!

[billyd]

Perhaps 2 motor pairs, one up one down on each side, would resolve the oscillation issue.

[RCExplorer – David]

Wow! I love this community!
I hadn’t even finished the design before you guys start working on making Bi-Copters to fly better.
Very good discussion here as well.
I tried to make the FC sit as close as possible to the pivot point of the motors and in the center of the frame:

The copter does fly well in forward flight and hover. But it does not like flying backwards. It get’s into a pretty violent oscillation but surprisingly it does not crash. It sits in the oscillation rather stably if that makes sense. If you push the stick slightly forward it comes out if it.

This is going to be a fun one to try to figure out 🙂

@litterbug I tried replying to your email last week but it seems the email address was wrong? Keep getting delivery failed messages. Really cool test platform! Very clever as it will allow to test all kinds of setups.

[Kevin_Erik]

@David

A duct would help shield the props from turbulence. You dont need anything fancy so long as the gap between the prop and the duct wall is within 1mm. Imo a Nylon / Kevlar mix is the best material for printing a duct. If using 5” props, you would need clearance of almost 6” to accomodate a properly designed duct.

If you’d like i could design a duct that combines your tail mechanism with a simple duct?

[Kevin_Erik]

I’ve almost completed work of the rough draft of the 5” Duct that’s compatible with the impossible tail mechanism. Should be able to post pics soon along with the build files. While this should be compatible with the impossible tail mech, its my version of it tweaked for use with a 5” Duct. At first I considered using David’d mechanism but saw no real advantage as its much heavier and sits much higher up.

Edit: Going to have to redo the placement of the arms as they are sitting in the path of the Servo. This will require me to redo most if not all of my previous work due to Fusion refusing to save the build history.

[LitterBug]

Bah. Been on another trip and had catastrophic wheel bearing failure on my truck during way home. Thought I’d have it in the air by now, but haven’t had time to get any air testing done yet. Have the dRonin servo mix responding correctly on the bench. Should have something soon. 😀

@david, Sent you a different email. My primary email is on some “spam” lists for some reason and also rejects pretty easy.

Cheers!
LitterBug

[Kevin_Erik]

Tail Duct completed and avalible for download: https://rcexplorer.se/forums/topic/impossible-tail-duct-wip/

[LitterBug]

Posted my EZ BiCopter plates and the OpenSCAD files to https://www.thingiverse.com/thing:3028557

LB

[Dave Mak]

Very keen to try setting up a bicopter, but alas, too many projects on the backlog. Wish I had seen the bicopter in flight at FFOhio, but the videos posted are a great alternative! So close, yet so far away 🙂

[LitterBug]

EZBi is still in the highly experimental stage and is evolving and progressing slowly as I build. Needed to extend the motor wires, so I’m going to swap out the ESCs with some I got in a grab box that have motor wires and also use bullet connectors on the motor wires. Everything will be pluggable at that point, which will allow me to easily swap the orientation, rotation, and other design params. Fear not! Flight will be soon!

Cheers!
LitterBug

[LitterBug]

eh, Had to reverse the Roll mix for the motors but have all the mix bench tested and am ready for maiden. Had a mis-configuration on flight modes, so couldn’t arm when trying today. By the time I got it fixed, there was a “30nm VIP NOTAM/TFR” in the area and couldn’t try again. Should be a go for tomorrow. 😀

Cheers!
LitterBug

[Kevin_Erik]

@Litterbug

How it fly?

[RCExplorer – David]

Really interested in how dRonin handles the copter! Would love to try that out. Will be back in Sweden next week. Would be cool to fly it back to back with betaflight.

[RCExplorer – David]

Also the kit will be available for pre-order on Monday the 13th. If all the parts are ok from the manufacturer they should start shipping out that week or the following week.

[LitterBug]

YES PLEASE! 😀

Managed to get a few test flights and some tuning in yesterday with the EZBiCopter in my back yard. In it’s current form and tune, I could not get a stable hover. It would oscillate like yours was when flying backwards. Flying forwards was better, but would eventually get into a state of oscillation. Trying to switch from forward to backward flight did pretty much nothing. Think the weight was transferring in pendulum rather than the pitch of the props changing. I have some ideas to try with the PIDs and the mix. Will also tape things down a bit more to make sure no excess movement is contributing to the oscillations. Hope to get out to the field where I have more room to play without running in to trees n stuff.

Cheers!
LitterBug

[Kevin_Erik]

+1

@David Does this mean you’ve solved the Oscillation problem and are their options for FPV?

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