Have been building up a basic octocopter (already have other quads) based on cost looking to eventually go to a nice frame.
Whilst the Hobby King frame is nasty and cheap it is a start and for under $40 it seems OK (yes it has its problems)
My intention is to figure out best prop motor configuration for longer flights, etc.
Hobby King Octocopter frame - landing gear is woeful!!!
Turnigy 35-36 910kV propdrive motors with prop drive adaptors
12x4.5 props - at present
30 Amp Turnigy plush ESCs (wiring needs tidying)
2 x 3300 Turnigy 4S batteries in parallel
HK antivibration foam (orange) under a range video mount with APM 2.5 on top
Waiting for external compass and to mount GPS at present
Turnigy 9XR radio, FRSky module and receiver
3DR radio link
Intention is to put my brushless gimbal with Sony NEX5 on it for some video just for fun.
Have not done a compassmot or compass calibration to date but did actually fire her up and see what happens.
Jumps in the air alot more aggressively than the quad and the noise is a bit frightening, response to throttle was a bit more sensitive than expected. Was really stable in windy conditions during initial tests. Remarkably more stable than smaller quads I am used to.
Have not looked at tuning so far as only preliminary tests on stabilise.
Anyone looking to do the same thing happy to share experience or any advice or considerations are welcome.
Cheers
Brian
Comments
Hi Bruce
My memory is not great and I actually hadn't had it out for 2 years as I had moved house. I see it under the stairs and wonder when I will use it again. I have many others so don't have time.
I think my setup on the control is pretty much the same as the quad from memory as the flight controller takes care of everything else. My quad though had some extras such as retracts and I did adjust some expos on the controls.
I can see if I can find the file from the Turnigy for you but might take me some time.
Hi Brian, How's your memory! How do you set up a Turnigy 9X to operate for an Octocopter. I know very little about radio setup but have successfully followed instructions to set up for a quadcopter.
cheers, Bruce
Hi Magnus
Already done my ESC's. Might look into the SimonK firmware as you suggest even if it means replacing ESC's
My radio I reflashed with ER9X as per my old radio. Mode switches I have as you suggest already.
HAL bowl not sure I like to I might just mould/ vac form one.
My GPS is going to go on a DJI mount from goodluckbuy to get it and the compass up and away.
That landing gear still has to go!
Cheers
Brian
Hugues - weight is 1.9kg without batteries, cover I have to do but sorting out GPS mount. Also might weld up an aluminium landing gear as cannot use the HK one.
Magnus - Thanks for the reply. Good to hear someone else has the almost exact same thing. Will start to mess PID tuning this weekend. 12" props, your description of trigger happy is much more accurate than mine. I think I will swap the props to 10" for more testing and as you suggest when more weight will go to 12" and see how that goes. Does look mean with the 12" props though.
Have to put on a cover so will look also at the HAL parts.
I have a lipo alarm coming from J-Drones. Also I have a Y connector to the batteries I don't like as if it fails I have nothing. Think I will solder another lead straight to the power distribution board. The concern I also have on the APM PM is the size of the wires and how delicate it is....this powers the APM and receiver so I am thinking this may need to be looked at.
The thing is so big compared to the small quads must be frightening when it crashed!
nice. what is the total weight without battery ?
The landing gear for such beast is indeed a problem that I have experienced with my X8 (Octo quad coaxial). Because of the weight and span of these crafts, the landing gear needs to be really solid and stiff. However that goes against being light.
I have tried to build my own landing gear based on openbeam system (squared aluminium beams that can be attached quite easily between each other at various angles). It was a really nice result but not stiff enough for the craft : it vibrated too much, especially in torsion.
I would also think about a cover on top of your electronics (to protect APM against sun light and heat which is known to cause issues).
Thought so. Dubro markets the same type of material in a few different thicknesses. HERE is one seller. I picked mine up at the local hobby shop but probably could also find it at a fabric store or sewing department.
I am trying a section of it on my 2nd scratch build, documented on Instructables HERE. Double stick 3M tape holds the foam to the APM on one side and to to the upper most (for now) plate.
There has been robust and lively debates on vibration preventing/mitigation on other threads. I hope to maiden the 2nd build soon and will take a look at the logs and compare the results to my rigidly mounted APM2 on my 1st scratch build. That aircraft is documented in my blog section HERE.
Build on! Fly often!
-=Doug
anti vibration foam -
http://www.hobbyking.com/hobbyking/store/__26457__Anti_Vibration_fo...
range video mount (on top) -
http://www.rangevideo.com/index.php/accessories/vibration-mount.html
Big build.
Is that a slab of foam rubber under your APM mounting plate?
-=Doug