Hi Friends,
               Am about to build an Agriculture spraying uav with a 5 liter tank capacity. Reason for 5L capacity is because a 5L tank with spray system is readily available at aliexpress. I ve been searching for information on the setup since a while but got confused in many a things. They say the more you search the more you get confused. So my problem here is decide everything from frame to FC. The setup what I thought that ll work is as follows. Tarot X4 960mm, sunnysky 340Kv motors, 60a esc, 18-22 inch props, 22V 10000mah battery, Pix Hawk Controller. But I am not enough confident of this configuration that it ll work. I am restricted to build a Quad coz we have a very tight budget (as usual). So please help me in deciding for the best suitable configuration for this setup. Thanks in Advance.

Hi Rocky,

While I can't help you with your build, except to say that it sounds like a LOT of weight.... I can say welcome to IntoFPV!

If you're looking for a great in-depth discussion about "heavy lifters" then there is an epic thread here on the site with some very smart people discussing it that may be of help:

http://intofpv.com/t-heavy-lifters

Hi Rocky and welcome to IntoFPV!

Which particular Sunnysky motors were you thinking about? What's the overall weight of your spray system (before adding 5L of liquid)?

Rocky, I was thinking a bit more about your proposed frame and I really don't think it's up to the job.

The Tarot X4 is designed for a maximum take off weight of around 10Kg. With around 6.5Kg of payload from the 5L of liquid and the (guessed) 1.5Kg of the spray system, along with the weight of the craft and batteries, you'll be looking at a take off weight around 16Kg. The Tarot X4 is designed to lift a DSLR camera and gimbal - at around 2Kg.

I also can't come up with any configuration that would only use four motors, but still give you enough power to lift that kind of weight, especially not on a 6S battery. The closest I could get was an X8 configuration with 10S power and two motors mounted coaxially on each arm.

FoxtechFPV make a frame that is much more appropriate for your application: https://www.foxtechfpv.com/a4-multipurpo...-only.html

It's far from cheap though!

I'm not sure a quad design is appropriate for this type of application. We are talking about a very large and heavy craft. A crash with such a craft is likely to completely destroy the craft and given the amount it will cost, I'd say that redundancy, in the form of a six or eight motor configuration is needed. With a redundant setup, you'll still be able to land safely if one motor was to fail. With a four motor configuration, the only option available when a motor fails is to crash.