I am new member in the X-UAV Talon club, I have just received my Talon with the extension wing.
I'm working to put the right combination of motors, prop and batteries:
I am looking to have the maximum flight duration over 90 minutes.
The weight of my FPV gear with all antennas, cables, cameras is around 750g.
The weight of the talon + motors + ESC + servo is around 1400g, So the total weight without the batteries is around 2150g
Regarding the battery, I can use multiple options based on motors and prop:
Multistar Battery Weights:
3S 5200 mAh is 325g.
4S 5200 mAh is 433g.
Option1: 3S configuration 2 parallel batteries => 3S 10,400 mAh: 650g. Total flight weight 2,800g
Option 2: 6S configuration, 2 series batteries => 6S 5,200 mAh: 650g, Total flight weight 2,800g
Option 3: 4S configuration, 2 parallel battery => 4S 10,400 mAh: 866g.Total Flight weight: 3,016 g
Option 4: 3S configuration 4 parallel batteries => 3S 20,800 mAh: 1300g. Total flight weight 3,450g
Option 5: 6S configuration 2 parallel + 2 series => 6S 10,400 mAh: 1300g.Total flight weight 3,450g.
What motors and prop should we use with every option, and what flight duration will we get?
I have those motors: but I can buy others if needed:
Motor 1: OSMG9530 http://www.osengines.com/motors/motors/motor-specifications.pdf
OMA-3825-750 (.30 Size)
Rotor Diameter (mm): 38
Magnet Length (mm): 25
Weight (oz/g): 6.7 (190)
Motor 2: Jamara E-Motor Magnum A2820/6
Specifications Revolutions / v : 1000
Internal resistance : 59mOhm
Idle current: 2.0A
Max A: 37A / 60S
Shaft Diameter : 4.00mm
NiMH Battery : 8 ~ 14
LiPo Battery : 3 ~ 5
Propeller NiMH: 11x8 Propeller LiPo : 3xLiPo 11x6 / 10x7 4xLiPo
Motor 3: Emax BL2826/06: http://www.toysonics.com/emax-bl2826-06-950rpm-v-outrunner-brushles...
New Emax BL2826/06 950Rpm/V Outrunner Brushless Motor
No. Of cells: 3-4 Li-Poly
Max. efficiency: 86%
Max. efficiency current: 20- 30 A (>78%)
No load current / 10V: 2.1 A
Current capacity 61 A/60s
Dimensions: 30x26 mm
Shaft diameter: 5 mm
Weight: 182 g/6.41 oz
Recommended model weight: 2-3.2 kg
Recommended prop without gearbox: 13*8; 12*8
I was following this on the main page but didn't speak up. I would think in the 6S configs you'd want ~600kv max but I am only guessing based on I know there are configs out there with 820-900kv motors for 4S. Very interested in watching this thread though as I run an Air Titan with 6S and have been considering switching my Skywalker X8 to 6S from 4S and 830kv with 13x6.5 eprop.
Well we don't know yet if the switching between the 6S and 3S or vice versa will give more flight time.
I saw some users saying it is better to have a bigger motor with less cells batteries, because you will use a little (25%) from the 750kv motor especially we are at the cruise speed so the consumption will be very low.
And also, I am thinking as we are at the cruise speed with 6 Cells and the 300 kV motor , then the little is around 50% of the motor, then it will consume more.
I don't know If i am correct. We need to see someone who did a real test on both options.
I bought 2 Talons and I can use both low and high kV motors with 3S, 4S and 6S and see the difference but it will take time to finish it.
Gustav test is below
I'm using a 3548 900Kv motor and 12X6 APC, 3S 12000 mA/h pack.
I suspected that the 3DR power block was in fact, giving me false information.
I signed out a LEM PR20 current probe, that we use to set up very expensive 2000 Watt TV amplifiers, to check my much cheaper HK-010 Power Analyzer.
I was suitably happy with my purchase...
Not the point of the story !
Talon specs, stationary, and it will improve in the air :-)
Throttle 0% A 0.1 W 1.2
Throttle 25% A 3 W 36
Throttle 50% A 8 W 94
Throttle 75% A15 W 180
Throttle 100% A20 W 230
From practical, my Talon is quite happy at between 50 to 75 % throttle.
For me, the speed to aim for is 60 Km/h, and that should happen at about 12 Amps,gives me at least 60 minutes flight time.
Yes, those were early tests.
Same setup, "In the air" tests are better.
At 60 Km/h airspeed, Talon draws on average 7 Amps.
This is well above stall speed, and gives me the most accurate flight lines.
Full throttle level flight gets Talon to 90 Km/h, and draws 17 - 19 Amp.
I hand launch level @ full throttle, with full Up Trim on elevator.
In no-wind conditions Talon descends to about 1 m above ground, before climbing out.
10 Km/h headwind, it flies straight out after launch.
Stronger than that, I think I should reduce the up trim !
In your ground speed test, you were saying at the 60 Km/h, the consumption was 12 Amps which gives at least 60 minutes flight time.
But in the Air test which is more accurate, at 60km/h, the consumption was only 7 amps, which means it is supposed to give more than 90 minutes flight. isn't it?
and you were using the same 3548 900Kv motor and 12X6 APC with the 3S 12000 mA/h pack.
So, if you go for 6S on the same motor 3548 900Kv, will the consumption be the half and you will get more flight duration?
If not the same motor, will it be like 360KV motor with the 6S? what do you think will be the flight duration then?
and will you change the prop also or no need.
I saw someone posting online this configuration in real test:
Tiger motor MN 3510-360kv
16x10 APC prop
4s 8000 mah
approx 2570 AUW
60min runtime with 3.78 left per cell.
What do you think about it? will we have a good power to go for the 90km/h for safety with this configuration?
In a previous post, you wrote for me this: "" Work from 100 Watts per pound of total weight."" How can i calculate the Watts in my case?
And also you told me I can use 6S for the OS motor 750KV that I have instead of 3S, but then I will give very high power, isn't it?
I have this comment from Dave:
Comment by Dave Smith 7 hours ago
So, to go for 6S pack, do you think we need to get a motor with less KV like the Tiger motor MN 3510-360kv ? or we keep the same motor?
Our target is to get the longest flight duration.
On Rcgroups you find experiments from a known XUAV Talon flyer with the following config:
(rcgroups thread here : http://www.rcgroups.com/forums/showthread.php?t=2017893&page=2)
-MN3508-29 380kv motor
-6S Li-Ion batteries 6S2P config
Estimated flight time : 2.7 hours !
Thanks for your help. I have few questions:
1- Are the motors Tiger motor MN 3510-360kv and MN3508-29 380kv similar or there is a huge difference ?
2- will those motors handle a plane with a weight of 3.2 Kg?
3- By using this low Kv motors, will we have a good thrust and power in strong wind or to go by 90km/h fr safety?
4- Are the Li-ion battery have power enough to go for 90km/h when needed? Do they have a good thrust for a 3.2KG plane?
5- If we were not able to get the Li-ion battery and we go those multistar 3S pack to get this 6S configuration 2 parallel + 2 series => 6S 10,400 mAh: 1300g.Total flight weight 3,450g. What will be the flight duration?
The motor manufacturer should give the max Watts the motor can deliver.
Normally they also specify prop sizes.
And max cell count.
100Watts/pound is used for "Sport Flying", and is overkill for Talon.
My Talon works out to about 40 Watts/Pound.
The only way to increase that, in my setup, is a longer prop, but 12 inch is the max ground clearance for me.
As I said, not an optimum setup, but good enough, for me.
The only way to get close to manufacturers Watt rating, is to use maximum voltage/ maximum prop.
LiPo's have a certain "Watts per weight", Whether you use 1S at 10A, or 10S at 1A, the watts stay the same, the weight of the battery stays the same.
With our currency against the $, I don't have the luxury of experimenting too much :-(
For longest duration, google "Speed to Fly, drag, etc"
Every aircraft has an optimum speed that gives you the best efficiency, for me, that is 60 Km/h.
At 90 Km/h, you will suck too much power, to overcome drag.
Elios, I have to ask...
Why do you need to travel 90km/h for a long duration? What are you actually trying to achieve?
I have been told that the 90km/h is needed for safety only, when needed.
Most of the time we will be flying at the cruise speed.
I saw your post telling me: "" Elios, Work from 100 Watts per pound of total weight.
Also, you would want a top speed of say 90 Km/h, for safety.""
In my case listed at the top, which combination is the best for me and which one is the optimum if the ground clearance is not an issue, our target is to get the maximum flight duration at the cruise speed.
How does having a higher top speed make the plane safer? By that do you mean you wish to have reserve power?