Passive thrust vectoring with anti vibration mounts.

 

 Have constructed an enclosed ‘H’ frame carbon/Kevlar quad with soft mount front and rear arms for vibration reduction. Initially yaw was awful as the arms tilted in the wrong direction and opposed any motor torque so I had to stiffen the mounts to prevent yaw reversal. Now I have reversed the motors in the code and the tilt actually helps the yaw. The mounts on the video are very soft, just to help demonstrate the movement but I think they were bottoming out.

Am quite pleased with the lack of vibration showing on the camera.

Apart from the motor reverse all parameters are completely stock. Will tweak them when I get some time.

 

Vince

Views: 3716

Comment by Joshua Ott on February 3, 2013 at 3:25pm

Vince,

From OlivierD.'s suggestion in your other thread, I ordered some kevlar cutting scissors. In researching those I found information on modifying regular scissors so they will cut kevlar cleanly. What are you going to make MkII out of? 

Comment by Vince Hogg on February 3, 2013 at 3:37pm

Just from lovely, easy cut carbon but I may  just have a Kevlar pad on the belly because it has great abrasion resistance (try sanding it!).

Have you got a link to the scissor mod. It may work better than mine.

Vince

Comment by Joshua Ott on February 3, 2013 at 3:48pm

http://www.rcgroups.com/forums/showthread.php?t=644127

The basics of the scissor mod are grinding the edges to ~90degrees from the face and leaving a rough grippy arris. There is also the option of chucking up a rotary cutting wheel in a high-speed tool and freehand cutting many layers at once, yikes. Maybe your CNC could have a fabric cutting attachment, pizza cutter from hell?

Comment by Vince Hogg on February 7, 2013 at 4:09pm

Now had lots of flights with the MK1 and its flying really well. Z accns are below +- 1 and will probably improve with silicone O rings on the arm mounts. Had one big crash when the copter ‘died’ at 10mts and dropped like a brick. All the O rings snapped so that was the only damage. Problem was a small flake of solder between the input pins.

 

The body is spacious but the ends are virtually inaccessible due to the glued battery floor so all the cables are stuffed in and flapping. Not good.

Mk II will have removable ends, be all carbon/foam sandwich and have the arms below so any snapped O rings won’t lead to disaster.

 

Comment by Vince Hogg on February 9, 2013 at 10:34am

Messing about in stab mode


Developer
Comment by leonardthall on February 9, 2013 at 3:06pm

Where is your apm mounted? Looking great!! Could you take some photoes?

Comment by Joshua Ott on February 9, 2013 at 3:55pm

Vince, that looks like a smooth flying machine. Nice work.

Comment by Vince Hogg on February 9, 2013 at 5:18pm

Thanks guys.

Leonard, pics on page one. APM smack in middle below battery on ali block on 5mm foam.

Do you need more photos?

I am more convinced the key to a nice flying machine is lack of vibration, having experienced one with loads.

Ive seen the videos of people balancing motors with bits of tape. Im too lazy, just mount the vibrating bits on rubber. I have not seen any issues that could be attributed to the extra lag in the system.

ps MK2 design is pig ugly. Am having a re-think.


Developer
Comment by leonardthall on February 9, 2013 at 11:21pm

Ah nice. Sorry, my bad.

I wouldn't say pig ugly....

I will post mine when I finish it off. Personally I think practical is more important the beauty but it is nice to get both :)

Comment by Vince Hogg on February 14, 2013 at 6:41am

Interesting

Have just discovered it flies with a broken O ring with one arm up at 20deg, not great though.

I have just been adjusting some PIDs to see if I can smooth out its response to high winds and gusty conditions. Very nice with rate D up to .01

Must get on with MKII that will be more secure with a snapped ring.

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