The sUAS market for surveying applications are dominated by fixed-wing aircraft instead of multicopters. The reason is obvious, the multicopters have very short flight time and can not run long flight plans.
I'm not sure that this will go on for long. There are already many multicopters exceeding the hour and half flight time(only experimental flights without payload). Right now there is technology to stay one hour with a reasonable payload. Part of the "secret" is that the payload represents a small portion of the vehicle weight, which in practice is equivalent to using a larger multicopter.
The advantages of multicopters with respect to planes to do this kind of work where you have to move to an area where, almost certainly, you will not find a meadow of green grass is obviously the launch and recovery. Multirotors no need catapults, nor any parachute and not need landing strip, the roof of a vehicle can serve.
We are working on a very special model, it is a quadrotor with 1280mm diagonal for 27-29 inch propeller and a takeoff weight of about 12Kg. Though not proven, estimate flight time will be about 1 hour with 2 kg of payload.
Printing huge multicopters. All parts of this multicopter but arms and frame plates has been printed in PLA. it have about 112 hours of printing:
Pixhawk. Watch this! Pixhawk size compared to the frame:
(ADDED PICTURES 2-SEP-2014)
Best regards,
Jose Luis Cortes
Quaternium.es
Comments
Wow, 112 hours of 3D printing! When you could get the parts machined from solid inside an hour on a good CNC mill. Not intending to be critical of your choice Jose, but it does confirm my suspicion about the how 3D printing isn't actually going to change the world so much!
@eduardo: It depends on the application / total area, it just needs to fly enough distance.
Multirotors are great because they're easier to control and follow than planes and produce higher precision survey material as they fly slower (so better GSD's).
The biggest downside is that they will be heavier than foam counterparts. For example, this multirotor weighs 12kg for 1hr of flight, whereas a 680g wing can cover the same distance in about half that time. Multirotors also have more potential sources of failure, as they multiply ESC's, motors and props. Given the weight difference and that there are lots of spikey parts on the frame, I consider multirotors less safe than foam wings if there's a failure.
Still, for complex precision surveys near buildings and trees I'd get a multirotor out. In larger areas with lots of ground to cover and no specific requirements on precision, planes are a better choice.
I think the rotorcraft never beat the wing in distance.
I work with geoprocessing and i am pioneer in UAV using here in my country.
I started with rotorcraft 7+ ago and go to planes 1 year after because the rotorcraft cant fly long distances.
Success to your equipment.
We have tested many different types of ESC's.
I would recommend the Afro HV's, however HobbyKing stuffed up the first batch...
12S is fine, however HobbyKing also misprinted the label saying they were only good for 8S :-(
Remember with such high voltage the amp draw is very low, hence these great flight times.
Simon
Cool, I have never used more than 4s for my quads, so I hope this works. What motors and speed controllers do you have that can do 50 volts!?
Actually ALK this is not the case.
Sure slow turning large props and low KV motors don't like wind.
However this can easily be overcome with lots of Volts, the voltage gives us response time :-)
Running some 28inch props at 50volts. No problems!
Simon
Super design btw, what props do you plan on using? Custom?
Regarding the wind this has been my experience to a T. A smaller diameter propeller that has a little higher loading handles wind MUCH better, but is not as efficient. This is not to say a large quadcopter will not withstand wind, just the super efficient ones typically do not do as well.
It has many advantages but one big disvantage, it hates wind. The combination of big props and slow kv motors takes the setup to a dangerous level when flying in wind, even light wind... these big quads has a lot of trouble in this conditions. A big X8 is much better regarding wind...
This looks very nice! I agree with you that these type of systems are a nice alternative to fixed wing aircraft. I noticed you are planning to fly a Tetracam Mini-MCA 6...it might be worth checking out this product to help you get high accuracy position/attitude data and visualize coverage after flight by creating a rapid preview through direct georeferencing techniques: http://fieldofviewllc.com/geosnap-vn-tc/
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