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ElectroHub Octocopter advise...

#1
Hi guys... So I want to build an octocopter based off of the electrohub system, but I just have no clue what batteries, motors, or how to distribute the power.

I'd like this heli to be on the small side, maybe 6 or 7 inch props, but I'm not one to scavenge the internet looking for each individual part to use, so I would prefer to stay with one of the "power pack" websites like RTF Quads. Therefore i could just order most of the parts from them and only use other sites for things like batteries, and alternate props.

My budget is quite small, and I know what you're thinking; an octocopter doesn't happen on a small budget. This heli would only be used for line of sight flying right now, but it would need payload capacity for my GoPro3, and eventually I may install a small FPV system on board. I definitely want to use a KK2 board as the flight controller, and maybe install a gimbal if my budget allows. Anyway I was wondering if anyone could help with the correct electronics, because I am an experienced multi rotor pilot, but this is my first build. My complete maximum budget is $400 but id really like to stay in the $325 range to maybe purchase a gimbal.

I hope this may help others in the future who want to build an octocopter from this platform.

All help is appreciated! Thanks!
 
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jedisalad

Mad Scratch Builder
#2
There must be something in the air, because your timing is perfect. I've been considering doing the same thing. I just finished building David's tricopter. After finally tweaking and dialing it in I LOVE IT! Flies amazing. I'm currently building a 250 blackout clone, but I also have 1/2 the parts for a larger multi and am considering starting up the build.

After building the Tri, and my experience building the 250 so far, here's my advice (and my current plan)...

Don't build the Octa yet. Build a hex. Nice thing about the FT parts is you can easily add 2 more arms later, and it'll save you a decent amount of cash up front. Also, a hex will give you a very similar flight characteristic, be very stable and smooth for video, and easily lift a camera + gimbal (and FPV gear if you decide to upgrade at some point).

Instead of wood for the arms, I'm going to use the arms that David sells for his Tri. He has them custom made for his shop (you can't really find anything similar online) and I was really impressed by their quality and their weight. They're pretty cheap too at just over $6. Plus, they look GREAT! An added bonus is you can run all your wires in the booms, whereas with wooden arms, you have to attach everything to the outside, and it just isn't as clean. Even though they're coming from Sweden, they arrived very quickly. David's awesome.

http://rcexplorer.se/product/10x10mm-woven-carbon-fiber-arm/

As for motors, ESC's, controller, etc... I've honestly been very satisfied with the setup David recommended for his Tri. Everything works great, easy to use, and I love the LCD screen and the programming buttons on the KK2. Just make sure to buy the latest version and then make sure you upgrade to the latest firmware. I think this same setup would work great for a hex as well.

Here's what I'm using right now:

KK2.1.5 Flight Controller - $21.99
NTM 28-30 900kv Motors - $15.20
Afro 20A ESC (SimonK Firmware) - $12.97

I'm slinging 9x6E and 9x6EP APC props (I buy them at my local hobby store for about $2.50 each) and they work great.

Buy the rest of the necessary parts (motor mounts, landing gear, etc.) from the FliteTest store.

Anyway, I think going with a HEX and the above electronics to start will give you everything you're looking for, and not break the bank. Let us know how it goes, I'll be following your build. Also, keep your eyes open for my build, as I'll be soon doing the same thing! :)

Good luck!

EDIT: Also, I should add that for this build you can follow about 80% of the Tricopter build video David did on his website, and a good majority of the KK2 setup video he did as well, and it'll get you really really close to being ready to fly. You'll obviously have to do a few things differently, but not much, and he's very easy to follow.
 
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#3
There must be something in the air, because your timing is perfect. I've been considering doing the same thing. I just finished building David's tricopter. After finally tweaking and dialing it in I LOVE IT! Flies amazing. I'm currently building a 250 blackout clone, but I also have 1/2 the parts for a larger multi and am considering starting up the build.

After building the Tri, and my experience building the 250 so far, here's my advice (and my current plan)...

Don't build the Octa yet. Build a hex. Nice thing about the FT parts is you can easily add 2 more arms later, and it'll save you a decent amount of cash up front. Also, a hex will give you a very similar flight characteristic, be very stable and smooth for video, and easily lift a camera + gimbal (and FPV gear if you decide to upgrade at some point).

Instead of wood for the arms, I'm going to use the arms that David sells for his Tri. He has them custom made for his shop (you can't really find anything similar online) and I was really impressed by their quality and their weight. They're pretty cheap too at just over $6. Plus, they look GREAT! An added bonus is you can run all your wires in the booms, whereas with wooden arms, you have to attach everything to the outside, and it just isn't as clean. Even though they're coming from Sweden, they arrived very quickly. David's awesome.

http://rcexplorer.se/product/10x10mm-woven-carbon-fiber-arm/

As for motors, ESC's, controller, etc... I've honestly been very satisfied with the setup David recommended for his Tri. Everything works great, easy to use, and I love the LCD screen and the programming buttons on the KK2. Just make sure to buy the latest version and then make sure you upgrade to the latest firmware. I think this same setup would work great for a hex as well.

Here's what I'm using right now:

KK2.1.5 Flight Controller - $21.99
NTM 28-30 900kv Motors - $15.20
Afro 20A ESC (SimonK Firmware) - $12.97

I'm slinging 9x6E and 9x6EP APC props (I buy them at my local hobby store for about $2.50 each) and they work great.

Buy the rest of the necessary parts (motor mounts, landing gear, etc.) from the FliteTest store.

Anyway, I think going with a HEX and the above electronics to start will give you everything you're looking for, and not break the bank. Let us know how it goes, I'll be following your build. Also, keep your eyes open for my build, as I'll be soon doing the same thing! :)

Good luck!

EDIT: Also, I should add that for this build you can follow about 80% of the Tricopter build video David did on his website, and a good majority of the KK2 setup video he did as well, and it'll get you really really close to being ready to fly. You'll obviously have to do a few things differently, but not much, and he's very easy to follow.
Thank you so much for your help! although there is one question in my mind... I know what battery the tri runs off of, but could I run a hex off of a 3s 3200 that i have from my apprentice? I have no Idea how to choose what size battery is right for me...
 

jedisalad

Mad Scratch Builder
#4
Thank you so much for your help! although there is one question in my mind... I know what battery the tri runs off of, but could I run a hex off of a 3s 3200 that i have from my apprentice? I have no Idea how to choose what size battery is right for me...
As far as battery goes, that 3S will probably be fine. As an example consider my Tricopter. A 3S 4500 is recommended, but I'm flying a 3S 2200 instead (it's all I had). Even running 9x6E props on 900kv motors I'm still getting 10 minutes flight time. Obviously, you'll be spinning 3 (or 5 if it's an Octa) more props, so you'll be drawing more from the batteries, but you'll also be generating more lift than a Tri, so you'll actually be able to fly more efficiently, so it actually might work out to be kind of a wash. How hard you fly will make a difference as well. Only experimenting a bit will really tell.

As far as voltage goes, 3S will be great for general flying and getting used to the multirotor. If you want more performance for acrobatics, or the power to lift a heavier payload, you might consider a move up to 4S. The mAh will determine how long you can fly. If you're only getting 5 or 6 minutes from your 3200, move up to a 4000, or even a 5000. You can get the Turnigy ones on HK for around $25.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=15006

Dang, I just realized my posts in this thread make me sound like a Hobbyking rep. I promise I'm not. What I am is CHEAP! ;) HAHA

Anyway, just remember:

"Voltage" (# of cells) = Horsepower (lifting power/speed and performance)
"Milliamp Hours" (mAh) = Size of gas tank (How long you can fly)

I recommend starting with your 3S 3200 and see if you like the performance/flight time it gives you. If you need more, move up accordingly.

Keep us informed on how the build is going! :)
 
#5
Thanks!

As far as battery goes, that 3S will probably be fine. As an example consider my Tricopter. A 3S 4500 is recommended, but I'm flying a 3S 2200 instead (it's all I had). Even running 9x6E props on 900kv motors I'm still getting 10 minutes flight time. Obviously, you'll be spinning 3 (or 5 if it's an Octa) more props, so you'll be drawing more from the batteries, but you'll also be generating more lift than a Tri, so you'll actually be able to fly more efficiently, so it actually might work out to be kind of a wash. How hard you fly will make a difference as well. Only experimenting a bit will really tell.

As far as voltage goes, 3S will be great for general flying and getting used to the multirotor. If you want more performance for acrobatics, or the power to lift a heavier payload, you might consider a move up to 4S. The mAh will determine how long you can fly. If you're only getting 5 or 6 minutes from your 3200, move up to a 4000, or even a 5000. You can get the Turnigy ones on HK for around $25.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=15006

Dang, I just realized my posts in this thread make me sound like a Hobbyking rep. I promise I'm not. What I am is CHEAP! ;) HAHA

Anyway, just remember:

"Voltage" (# of cells) = Horsepower (lifting power/speed and performance)
"Milliamp Hours" (mAh) = Size of gas tank (How long you can fly)

I recommend starting with your 3S 3200 and see if you like the performance/flight time it gives you. If you need more, move up accordingly.

Keep us informed on how the build is going! :)
Im Going to use the hexacopter kit from altitude hobbies made for the electrohub, however I may end up building a spider quad if I want to do some aerobatics...

Im just not sure if this can lift a gimbal or not...

I'm probly going to use a gimbal+controller from RTF Quads, but if you think this CANT lift a gimbal, can you advise me on what motors/esc's to use for more power?

I know i ask a lot of questions that seem like "no-brainers" to those with experience, but I'm quite a noob when it comes to DIY...

Thank you so much for your advise!
 

Grounded Gremlin

The guy that doesn't fly
#6
Im Going to use the hexacopter kit from altitude hobbies made for the electrohub, however I may end up building a spider quad if I want to do some aerobatics...

Im just not sure if this can lift a gimbal or not...

I'm probly going to use a gimbal+controller from RTF Quads, but if you think this CANT lift a gimbal, can you advise me on what motors/esc's to use for more power?

I know i ask a lot of questions that seem like "no-brainers" to those with experience, but I'm quite a noob when it comes to DIY...

Thank you so much for your advise!
I don't know whether you are still doing this, have done it or whatever, but I'll voice my opinion anyway.

I've seen tricopters on similar setups lifting gimbals. Mini-quads can lift GoPros, plus FPV gear, so a hex with at least three times the lifting power, with a far larger battery will easily lift a gimbal. If even seen gimbals on the Electrohub spider quad with the recommended ReadyToFlyQuads setup. As long as the frame is light and strong (which the Electrohub is), the setup is efficient (which yours is), and you've built it well, your multi rotor will carry a considerable payload. Don't worry, when you're ready for the gimbal, FPV etc., your quad/hex will perform.