Long distance mission flight

Has anyone flew long missions with their Y6? I'm planning a 3.8 mile flight mostly above straight roads, and will follow in the car.

A few questions:

1) What is the maximum advisable speed to fly for the most efficiency? I've been using 12-15 m/s.

2) The current in MP is calibrated as is the voltage. What is the best way to calculate the required

power to fly 3.8 miles? I haven't done a lot of testing, but looking at the current draw I think

it was ~25A at 13 m/s. Does that sound right?

3) My Y6 seems to handle two 6000 mah batteries quite well. The 8000mah battery may be cutting it

close, or maybe not.

Also, suppose battery failsafe engages (FS works in all modes). FS will be in land mode, but what is the proper way to get into stabilize mode without dropping out of the sky? I tried it the other day and it dropped like a rock until I went full throttle. It stabilized but didn't recover altitude and landed hard. I thought the throttle was above 50% when I switched out of FS, but don't know. Is there a time delay when doing that?

Thanks.

Yes, I've flown about 25-30 missions, the longest being ~3/4 mile round trip. With the 8000mah battery it made the trip no sweat with several waypoints, but 3.8 miles is my goal for this Y6. I also made the mistake of switching out of Auto (while fumbling with the camera doh) and swear my throttle was over 50%.....but could be wrong. That's why I asked if someone has successfully switched out of FS mode without dropping.

I'll have to watch the current draw at various speeds and fly a few missions to get an idea of what's the best speed to make the trip. For 3.8 miles I'll need between 9-10 min of flight time at 12 m/s, not including the waypoint stops to turn. I tried using spline but the turns are way too wide as I want to keep it in the middle of the roads; not even sure spline works in 3.1.7.

15 m/s it's moving pretty fast, but I don't know the current draw at that speed compared to 12. As a warning, going too fast horizontally in Auto will allow the copter to drop altitude. I think there's a fix in AC 3.2, just something to watch out for. At 14 m/s I saw no drop in alt, and 15 is the max speed it's flown. There's a point to where drag and the mechanical limitations of the copter/motors begin to rapidly decrease the efficiency, but I don't know what speed that's at.

Hopefully someone will chime in and give some pointers. I switched to CF props thinking to gain a bit there.

Replies

T.C. July 19, 2014 at 10:36pm

I ve been testing speed, i happily fly up to 15m/s. I managed to get 18m/s max one day (no wind) without loosing altitude. IMPORTANT: This only worked at 600m above sea level. I went testing in 2000MASL (on a mountain) and do not get these values any more, i have not measured precise figures concerning speed reduction in altitude. But what i tested in altidude was flight time. I loose 1% flight time per 100m altitude e.g. if i fly 15min in 600MASL i only fly roughly 12min50 in 2000MASL. I conducted these flight-time-in-altidue-tests hovering.
Spencer Willis July 19, 2014 at 10:04pm

I have been up to 10m/s but noticed it buffeting around more in the wind. Glad to hear it's okay up to 15m/s.

In answer to your last paragraph, I start auto missions with the TAKE_OFF command. With the transmitter pre launch I set to stabilise, arm the Y6, set to auto mode and then nudge the throttle up. Auto mode takes over. At this point the throttle level doesn't matter. You could set it back to zero. However I always set throttle to around 50% during an auto mission. This way I can switch to loiter or stabilise if there is a problem mid mission and it will not fall out of the sky. This works - doesn't appear to be a time delay or anything. I learnt that the hard way once when I accidentally set to stabilise and it just dropped.

I am interested to hear other responses to this for efficient speeds.
- DG > Spencer Willis July 19, 2014 at 10:49pm
  
  Yes, I've flown about 25-30 missions, the longest being ~3/4 mile round trip. With the 8000mah battery it made the trip no sweat with several waypoints, but 3.8 miles is my goal for this Y6. I also made the mistake of switching out of Auto (while fumbling with the camera doh) and swear my throttle was over 50%.....but could be wrong. That's why I asked if someone has successfully switched out of FS mode without dropping.
  
  I'll have to watch the current draw at various speeds and fly a few missions to get an idea of what's the best speed to make the trip. For 3.8 miles I'll need between 9-10 min of flight time at 12 m/s, not including the waypoint stops to turn. I tried using spline but the turns are way too wide as I want to keep it in the middle of the roads; not even sure spline works in 3.1.7.
  
  15 m/s it's moving pretty fast, but I don't know the current draw at that speed compared to 12. As a warning, going too fast horizontally in Auto will allow the copter to drop altitude. I think there's a fix in AC 3.2, just something to watch out for. At 14 m/s I saw no drop in alt, and 15 is the max speed it's flown. There's a point to where drag and the mechanical limitations of the copter/motors begin to rapidly decrease the efficiency, but I don't know what speed that's at.
  
  Hopefully someone will chime in and give some pointers. I switched to CF props thinking to gain a bit there.
DG July 19, 2014 at 9:49pm

I tried using ECalc but it doesn't list the motor used by 3DR (blue) 850. What's the closest match to it? Has anyone found the specs for these motors? ECalc asks for # of rotors, plugged in 6 and apparently it only uses a hex configuration for its calculations. Then it asks for number of blades, so is it 2 or 6?

Knowing the specs can make a big difference in the calculations.

I believe these are the specs, not enough info:

http://www.robotshop.com/en/apmcopter-motor-850kv-uav.html

• Volts: 7.4-15V
• KV(rpm/v): 850
• Max pull: 880g
• Shaft size: 3.175 x 45mm
• Max power: 200watt
• ESC: 30A
• Propeller size: 10x47
• Battery: 2-4 S LiPo
• Cables: 35cm/18 AWG with bullets

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Arducopter Y6 Owners

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