Knuckle H-Quad build - a few novice questions

[EEAA]

Hi all -

I'm undertaking my first multirotor project, in the form of the Knuckle H-Quad. I built the frame on Thanksgiving day and went to start mounting the motors on Friday. I bought the recommended Turnigy Park300 motors, and soon discovered that the screws included with the motor aren't long enough to mount using the (rather thick) 13-370 feet/motor mounts.

So - knowing that the FT crew recommended mounting everything with zip ties, that's what I set out to do, but was not able to sort out a decent zip tie arrangement that was relatively centered on the mount *and* secure.

Has anyone else run into this? I feel like I might be missing something simple with regards to the motor mounts.

The second question is regarding servo extension cables (is that the term used for the cables that go between the RX and the controller board inputs?). What gender do I actually need? Most of the cables I can find are listed as male-to-male, but looking at the connectors on the RX (Optima 7) and controller (KK2.1), they're both obviously male connectors, meaning that I need cables with two female ends, which I've not been able to locate.

So, to summarize:

1. Am I missing something stupid regarding mounting the Turnigy Park300 motors on the FT 13-370 mounts?
2. What cables do I need to connect my RX to the controller board (KK2.1)?

Thanks so much!
-Erik

 

[jhitesma]

1. Am I missing something stupid regarding mounting the Turnigy Park300 motors on the FT 13-370 mounts?

Personally I wouldn't worry too much about getting them exactly centered. The closer to perfect the more efficient the copter will be but a slight offset won't make a huge difference. It would be a good idea to try and make sure that you offset them all in the same way though.

And actually I wouldn't even use the plastic mounts if this is your first multi. I'd save them for once you're used to flying it. Instead I'd lengthen the wooden arms and mount directly to them then use big zip ties for landing gear. Once you're used to flying it then switch back to the shorter arms and plastic ends.

2. What cables do I need to connect my RX to the controller board (KK2.1)?

I found this quite confusing as well and finally just trusted the photos over the names. They're called male/male but they're for connecting male to male not male on both ends as you'd assume. So yes, those are the right ones.

 

[Craftydan]

I found this quite confusing as well and finally just trusted the photos over the names. They're called male/male but they're for connecting male to male not male on both ends as you'd assume. So yes, those are the right ones.

Those actually *are* the male servo connections.

I know, threw me for a loop the first time I saw that. I recall whining a the time, "don't they know anything about gender?" Apparently, no.

 

[Craftydan]

Erik,

The included screws are for the X-mount, so I wouldn't be surprised the fiberglass mounts are too thick. you can either stop by a local hardware store and get replacements, or mount the X-mount and use it's arms to ziptie around.

Normally I'd agree whole hartedly with jhitesma, but the shaft on turngiy's park300 motor is a problem -- it's got to mount through something to use the collett adaptor, so it's not well suited for the ziptie-to-the-frame-and-go method.

What I'd recommend:

- get the longer screws from a local source. you're going to have trouble getting that X-mount to fit under the fiberglass mount. if it can fit, ignore this and use zipties to hold the X-mount to the fiberglass mount.

- mount the fiberglass motor mount on the boom end with the mount on the top.

- mount the motor on the bottom, shaft passing though the mount.

- Connect the prop using the collet adaptor. You *could* use the prop saver, but I don't recommend them for multirotors -- you need hard connections between motor and prop. They're not just your thrust, they're your control surfaces as well.

- Do not mount the Delrin legs, but instead mount a loop of the heavy ziptie, like jhitesma suggests -- Delrin is a pretty resiliant material, but nowhere near buletproof. if you hit something soft it *might* pop free, but one hard strike on cement or asphalt and it'll snap like a dry twig. You'll want something with more bounce while you're learning, and the heavy ziptie loops work well. Alternitively, I've used 1/2" slices of 2" PVC pipe, ziptied on -- really cheap and rugged, but also not bullet proof. If you can cut your own slices, however, you don't have to wait for shipping for replacements.

 

[EEAA]

*Great* info, guys. Thanks so much.

I will definitely go with the X mounts for the motors as well as the zipties. I should be able to complete that assembly this week, and hopefully the kk2.1 (which shipped yesterday) will arrive next week and I can take a (gentle) maiden flight.