Designing a multi-rotor for very high endurance

B

barnytj

Member
I have been asked to propose a multi-rotor for use by anti-poaching patrols in East Africa.

They want rangers to be able to launch a multi-rotor so they can scout the ground ahead to avoid walking into an ambush, and in the event of a contact, to locate the poachers before engaging.

All the previous rigs I have made, have been designed with film work as the priority, with endurance being very much a secondary consideration.

I plan to keep the machine as simple as possible, probably running off a Naza FC with GPS, and it will be equiped with switchable IR camera and daylight camera (although both will be very lightweight. It will also need video Tx of course. May just keep the gimbal to tilt only to keep the weight of that down.

Has anyone out there done testing to maximize endurance above and beyond anything else and if so, what Lipo, motor, ESC, and prop combinations would you recommend?

Thanks in advance

Barny
 

FerdinandK

FerdinandK

Member
Possibly it would be helpful to tell us about your aim in terms of endurance.
The IR-Cam (e.g. Flir Tau + Standard cam + BL Gimbal) is about 1kg payload, if you reduce to tilt only, you can possibly reduce to 500gr payload.
Since the Equipment is very expensive (IR-Cam) I would think of a copter that can handle a motor-failure (e.g. X8), with a quad you will get more flighttime, but it will fall out of sky if on motor fails.

Here my X16 with flir-Tau and Sony CX250, the flying time here is about 40min (4x4S12500):
20130823_162203.jpg


This copter is much oversized, but can take quite a number of motors failing (I also like my flir tau).

A foldable alternative would be this, currently only with a GoPro and Gimbal (500gr payload) flying time is also about 40 min (2x4S12500):
20130823_162236.jpg
20130823_171013.jpg




A typical setup would be a quad with about 1kg, 1kg battery carrying your 1kg payload, that will also give arround 40min flying time (when correctly setup)

Other interesting points will we the ambient temperature, the max wind-speed it should be able to handle, ...

best regards
Ferdinand
 
Last edited by a moderator:

R

R_Lefebvre

Arducopter Developer
This is something I'm very interested in. I like to compare performance numbers between multicopters, helicopters and airplanes. I've seen a number of "endurance specials" where they have a quad hovering for over an hour, but the machines seem restricted to hovering in windless environments with no payload. I'm only interested in machines that perform a function.

Ferdinand, I respect your work quite a lot. You you seem to be suggesting that the flight time limit for a "working" multirotor is about 40 minutes? How well does a machine like that handle windspeeds of 20, 30, 40 km/h? How fast and how far can it fly?

So far I've gotten a 700 heli to fly for 25 minutes at >40 km/h on 8S 10,000. AUW is 16.5 lbs. I believe that I could double the battery capacity and get pretty close to double the flight time as helicopters do not suffer from the same loss of efficiency that multirotors do. And then there's gas powered... ;)
 

FerdinandK

FerdinandK

Member
@R_Lefebvre
What I am saying is, that at the moment I have two copter that can do such things and fly for about 40min. If you want redundancy (in case of a motor failure) you have to pay for this. I think with a quad you can get 70min, with an X8 50min, possibly one hour, with some reasonable batteries (GensAce 4S12500 with 1000gr). But There are new batteries upcoming (e.g. GensAce 4S16000 with 1250gr, or some fancy cells with 4S24000 having 1400gr) which will allow even more flightime (all these cells have low C ratings 1C, 5C, ...), so nothing for a standard multicopter.

The "cruising-speed" of both copters is around 50km/h (full forward in WKM/NAZA GPS mode) you can go faster in manual mode, but then it becomes very inefficient. At "crusing-speed" you still get 30 min (with one of the setups above), which gives a range of 12,5km (tour-retour). (The Klappfixx video I posted above is one flight).

If you can fly 50km/h (full forward GPS-mode), you can handle wind up to 30/km/h, here a video (the end has nothing to do with the wind ...)

One last point is, that you can build such a copter very silent (using the correct props, or doing the correct mods).

best regards
Ferdinand
 
Last edited by a moderator:

R

R_Lefebvre

Arducopter Developer
What do the two copters you have look like? X8 and the X16? So you think you could do 70 minutes with a quad while carrying a payload? And where do you find the special high-density GensAce batteries?
 

FerdinandK

FerdinandK

Member
Can you see the pictures in post #2?

I think 70min with 500gr payload on a quad with 1kg and 1,5kg battery is possible.

Also I already would have (a pretty ugly) copter, that is able to do so, this one can (4kg copter) can take 4kg payload with 4kg battery (so 12kg AUW) for 44min in the air. If now I remove 3kg payload and add 3kg payload (so 4kg copter, 1kg payload, 7kg battery) I have 77min flying time:
(but I am not happy with it in windy conditions for the moment).

There is a lot possible within the next year.

best regards
Ferdinand
 
Last edited by a moderator:


B

barnytj

Member
Thanks guys, some really interesting stuff there. That X16 is quite a beast I have to say.

Although it's always good to have redundancy I think we may be stuck with a simple on quad on the basis that ideally it will be backpack portable by rangers who are on patrol. This obviously also means that overall size is quite restricted. I also want to make it as weather resistant (light rain and moderate wind), and lastly as robust as possible. Those Gensace batteries look very interesting indeed.

From my current understanding the best motor efficiency comes with low rpm and high torque for larger props. Unless it has a folding frame, and gets carried about in a "tube", then the props would have to be fitted before each flight as otherwise the frame would end up taking too much space to be man-portable.

Ambient temperature will also become an issue in some parts of the country, and so I guess motor temperatures will also need telemetry to prevent overheating.

40 minutes is a respectable flight time, but is it realistic to make a machine that has that endurance, and also has the portability and weather resistance mentioned above?
 



E

Electro 2

Member
barnytj said:
I have been asked to propose a multi-rotor for use by anti-poaching patrols in East Africa.

They want rangers to be able to launch a multi-rotor so they can scout the ground ahead to avoid walking into an ambush, and in the event of a contact, to locate the poachers before engaging.
Click to expand...

To me this mission begs for a fixed-wing aircraft. All these targets and more, could be easily hit.
 

R

R_Lefebvre

Arducopter Developer
Yes, that's true but... Don't underestimate the difficulty launching and landing a high performance airplane in unprepared areas. A foam flying wing that can fly for 30 minutes, and crash land is easy. But a fragile, high performance airplane does not like crash landings on rough ground. So then you need a parachute or something crazy like that... Plus the large, complicated parachute launch.

Just something to keep in mind. It's not all sunshine and roses.
 

T

triise

Member
FerdinandK said:
Here my X16 with flir-Tau and Sony CX250, the flying time here is about 40min (4x4S12500):
Click to expand...

What gimbal setup are you using for the Sony? I'm looking for a solution to mount my Canon HF100 on my quad, but haven't found anything yet. Your gimbal seems to work quite well! Also I'm looking for a gimbal for my FLIR Pathfinder unit, which I'm going to mount on the quad.
 

You must log in or register to reply here.
Top