I have been thinking about sending my X-UAV Talon on a 100km flight and despite pondering it for a long time today I hit the milestone in an unplanned way.

During a checkout flight for our spare support aircraft for West Coast UAV's entry in the 2016 Medical Express challenge I noticed that we had an amazingly efficient combination of airframe/motor/prop and the numbers were looking good for a 100km run.

So up the Talon went carrying 20AH of 3S Multistar batteries driving a NTM1100KV motor and APC 12x10 prop. The average speed was kept low and despite encountering some airspeed measurement issues it crossed the 100km mark at just over 1 hour and 40 minutes airborne.

Logfile Link

The landing was unfortunately a bit hairy and fast as the voltage had dropped fairly low and the airframe copped a few dents but really happy to have knocked over the 100km milestone.

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Comment by Pascal P. on September 10, 2016 at 12:29am

Nice ! Talon is still a good an robust platform.

Any details on RC / telemetry stuffs ?


Developer
Comment by John Arne Birkeland on September 10, 2016 at 1:42am

Impressive. But why 3S? On paper a least, you should get even better efficiency using 6S and a 550KV motor.


100KM
Comment by Ben Dellar on September 10, 2016 at 4:48am

Pascal - Given it was a test air-frame focused on distance traveled (rather then long range out and back) the RC was pretty vanilla 2.4Ghz and telemetry the usual 100mw 900MHz units on a Pixhawk. For the competition we are running a dual redundant RFD900 IP link plus 3G/4G VPN.

John - The setup is mainly for the competition where we only need to be able to travel a maximum of 60km with about 10 minutes loiter time. We stuck with 3S as a lot of the ancillary equipment for the competition (BEC running companion computers, cameras, radios etc.) was must easier to power from a 3S main supply. If configuring for ultra-long range would consider a higher cell count.


Moderator
Comment by Gary Mortimer on September 10, 2016 at 5:40am

Well done Ben and team, just given you a 100km badge ;-) I love the Talon have 3 of them.


100KM
Comment by Ben Dellar on September 10, 2016 at 5:48am

Thanks Gary - the Talon really is an amazing aircraft. Perfect combination of size (fits in car fully assembled), weight, endurance, speed, handling in air is great and very versatile for different payloads and missions.

Comment by Ravi on September 10, 2016 at 5:57am

congrats! how much range did you get on RFD900.

Comment by JB on September 10, 2016 at 8:22am

Nice one Ben!

Out of interest what can size NTM motor did you use? I can't find any red ones on HK. 


MR60
Comment by Hugues on September 10, 2016 at 9:05am

congrats! I also fly Talons and love them. In my opinion the best fixed wing platform (flies well, very customizable, able to fly with an AUW of 4,5Kg and still take off from a catapult, able to embark multiple cameras, stable, can be fixed after every crash even hard ones, etc)

Comment by Damian on September 10, 2016 at 2:28pm

The 12x10 prop seems a bit of thrust/power efficiency overkill for the Talon straight cruise flight.

Let's assume 2kg flying weight; nothing special lift to drag ratio  10/1; so required prop thrust would be 200g+ for a straight cruise.

In your case 100km in 1h40min equal to about 60km/h speed with zero wind.

The 12x10 prop and 60km/h cruise flight requires about 70W with generated 500g of static thrust.

If you go for e.g. 6x4 prop you would get about 72km/h cruise flight with about 34W consumed with 200g of static thrust; 10000rpm. Obviously you would like to have some extra thrust margin when needed so with 3S (10V) you should go for a 2000kV/3000kV motor, to run it about 30%/50% max power; what is also the peak motor efficiency. And you can go for full throttle to double/triple the thrust when needed.

So with the smaller prop you could almost double the flight time. Theoretically .. :)

Personally I have no idea how much 6s would be more efficient over 3s .Also some people claim that running motor and ESC on e.g. 40% is less efficient than 90%; but other disagree.

Comment by Damian on September 10, 2016 at 3:40pm

Also a tractor prop can give you extra 10%/15% more efficiency over your pusher prop ...

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