Tuesday 2 October 2012

Mid-Range Multicopter

Moving on from the basic multicopter in my last post, now it's time to take a look at what you can get if you have a bit more money to spend. To put together a multicopter in this category expect to spend somewhere in the region of $500-$1000. Obviously if you're going to spend that much money then you're going to expect more features such as altitude hold, GPS and a camera gimbal. When I built my first multicopter about 3 years ago it cost me this much for the most basic copter with gyro only stabilisation and a basic frame. Oh how times have changed!!!

Frame

If you're potentially going to be carrying around an expensive camera then you will want a frame that is up to the job. In this category of frame, some additional features that are good to have is a high landing gear for mounting a camera gimble, better quality of materials such as carbon fibre and the option to fold the copter to make it easier to transport. There are a lot of camera gimbal designed to fit onto horizontal mounting tubes, so a frame with this feature will make it easier to fit a gimbal later on.

My recommendation is the AQ-600 from HobbyKing. It has all of the features that I just talked about above and has the added bonus of a cover to protect the electronics and make it look a bit more 'sexy' if looks are important to you. I also like the colour coded arms and the fact that it can take upto 12" props.


There are so many frames on the market nowadays and most of them are good quality and will do the job as long as they have all the right features for your needs. Here's a few alternatives, with a special mention to Jakub from Quadframe.com who I've purchased several frames from. He always includes so many spares in his kits that you can almost build another copter out of them. 

Control Board

This is what's going to differentiate the mid-range copter from a basic copter and it's also going to be the biggest individual cost in this setup. There are several boards that currently offer the more advanced features but only one really stands out amongst these as being top of the pile. That's the dji Naza. This is just about as close as you can get to being an RTF controller and it also has the option of the GPS upgrade which will allow for return to home function and position hold.  At $230 (without GPS) it is far and away the most expensive controller but I think it's worth it simply for the ease of use. I've heard good things about a site called UAV Products, so here is the link to purchase the Naza: Naza Flight Controller


It would be wrong of me not to mention some of the other great controllers in this category as there are many boards that can offer similar features for less than half the price, but which are not as aesthetically pleasing or user friendly.


At only $62.99 this has got to be one of the best bargains you can find. It is capable of running multiwii and MegapirateNG firmware and with the addition of a GPS receiver it can do everything that the Naza can.


Although this is by no means RTF, it is feature packed and offers features normally only available on much more expensive controllers such as performing programmed GPS missions with waypoints, but you'll need to know your way around a computer for this one!
I have to give an honourable mention to this because I really like what the guys have done with this project. It was so popular when it was first released that they sold out in hours and even now, sales are limited to 2 per customer.

Motors & ESC

As with the entry level copter, I'm going to once again suggest the ESCs from RCTimer that come pre-flashed with the SimonK firmware. Obviously you're probably going to want the higher current rated ESCs as you're going to be putting them under much more stress with a heavier copter and bigger motors. RCTimer 40A ESC

For the motors I would suggest a reasonably low Kv motor capable of swinging at least a 12" prop and make sure that you choose one that will work with a 4s Lipo as you'll probably end up switching to 4s eventually. I quite like the AX-2810Q-750KV motor from HobbyKing. It's reasonably priced, works on 3s or 4s and will happily swing a 12" prop, although maybe best to drop down to 10" or 11" if running at 4s. AX-2810Q Motor


Lipos

To get your copter airborne you're going to need some serious power and choosing the right Lipo battery is really critical. This is also an area where a major weight saving can be made by choosing the most lightweight battery that you can find. A Lipo with a high C rating is also a must, so don't consider anything with less than 25C. 

For those that don't understand the C rating, it's an indication of how much current the battery can supply. You multiply the C rating by the battery capacity to work out the maximum current draw, so for a 1000mAh 20C lipo it can supply 20A and a 1000mAh 25C lipo can supply 25A. Take these figures with a pinch of salt, but try to make sure that the maximum current draw of your copter is equal to about half of the maximum rated current draw of the Lipo as this will keep your batteries in good condition. 

For a good  lightweight Lipo it's really hard to beat the Zippy Compact batteries for value. This 5800mAh 25C 4s Zippy Compact will be ideal: 5800mAh 25C Zippy Compact. I used to recommend the Turnigy nano-tech batteries, but after testing, the Zippy Compact came out on top. Check out my article for the comparison: turnigy nano-tech v zippy compact



Camera Gimbals

I'm still doing a bit of research on this, but hope to get this part of the article finished by the end of the week. I'll also add some more links for alternatives for everything including RTF multicopters with some great features. Thanks for your patience.

1 comment:

  1. I'd be very interested in seeing the finished Camera Gimbals section of this post when you get a chance. Nice article! Thanks for the info.

    ReplyDelete