Short flight time (what to trouble shoot?)

[jfro]

I just start flying a new build (my first RC craft). I am very happy with my custom built x8 or xy8 as it's called. It's flying as expected but my flying times are terrible.

My build is as follows.
34” or 863mm motor spindle to spindle.
1” carbon fiber arms
8” center plate w/ plastic dome.
8 – Avroto 2814, 4x2 coaxial style.
30 Amp Turnigy Plush
11x 4.7 genfan props
Currently using 5000mAh 4s batters (have 4 but just mounting 1 for right now).
Hoverfly Pro (black board).
Futaba 8fg.
Weight (no camera or gimble) 2.4 lbs and battery is 1.25 for total of 3.65 lbs or

2 batteries are Turnigy 4s 30-40C discharge rate
The other 2 are Gens Ace 4s @ 40C.discharge rate.

I am getting 3 min 51 seconds flying time on the Turnigies. Haven't done an exact timing on the Gens Ace, but it's close to the Turnigies.
Voltage after balance charging on an iCharger 306 shows 16.68v to 16.73v.
After easy flying and hovering till I can't keep it up, I'm 12.75v. and if I use the voltage alarm, I come down at 3.3.
Once beeping starts, I have about 30 seconds to get down.

I've been googling my issue, but haven't really found a checklist on what to go over other than the obvious battery capacity, wiring etc....
I can't find it, but I thought I saw something related to the HoverflyPro that said something about certain setting(s) would reduce battery life, but I can't find it now.

I was expecting 7-9 minutes without the camera or gimble based on what others are reporting. Under 4 minutes seems unreal to me.

Anybody have a suggestion. I'm no where near to figuring this out yet.

Call me Perplexed!

 

[Dewster]

It's hard to to figure out diagnose problems just from reading the specs of your build alone. You craft is pretty light for the build that you mentioned. Is that the combined weight including the battery? My Y6 F550 is just shy of 7 pounds with batteries and a Sony Action Cam attached. Here are some starting points.

1. Check eCalc online. You can type in your specs and get a rough comparison for flight times with different configurations.

2. Props: Check eCalc for different prop and pitch to see if you can squeeze more flight time in. I gained a lot of flight time
when I switched from APC 10 inch to Graupner 11 inch props. Don't forget to look at the pitch angle.
3. Motors: Avroto motors are great. I use them on my Y6. They have lots of power, but they are heavy.

4. Batteries: A ship like yours probably needs to run two batteries in parallel. Having more motors = more power
consumption...and weight. I run two 3s 6000 mah lipos and get a max flight time of 9 minutes. Also look at the weight of
your batteries.

Question? What do you plan on carrying with your craft? You may not need your current configuration. I built my Y6 to carry point and shoot cameras like the Sony Nex 5. If I were only filming with a GoPro camera I would use a small quad or a flat Hexa.

5. Check your low voltage settings on your DJI flight controller. You may be short changing yourself on flight times. Get a lipo battery checker. They are around $5.00 it will sound an audible alarm when your battery is low. Compare its alarm with you low voltage setting alarms on your craft.

 

[helloman1976]

I just start flying a new build (my first RC craft). I am very happy with my custom built x8 or xy8 as it's called. It's flying as expected but my flying times are terrible.

My build is as follows.
34” or 863mm motor spindle to spindle.
1” carbon fiber arms
8” center plate w/ plastic dome.
8 – Avroto 2814, 4x2 coaxial style.
30 Amp Turnigy Plush
11x 4.7 genfan props
Currently using 5000mAh 4s batters (have 4 but just mounting 1 for right now).
Hoverfly Pro (black board).
Futaba 8fg.
Weight (no camera or gimble) 2.4 lbs and battery is 1.25 for total of 3.65 lbs or

2 batteries are Turnigy 4s 30-40C discharge rate
The other 2 are Gens Ace 4s @ 40C.discharge rate.

I am getting 3 min 51 seconds flying time on the Turnigies. Haven't done an exact timing on the Gens Ace, but it's close to the Turnigies.
Voltage after balance charging on an iCharger 306 shows 16.68v to 16.73v.
After easy flying and hovering till I can't keep it up, I'm 12.75v. and if I use the voltage alarm, I come down at 3.3.
Once beeping starts, I have about 30 seconds to get down.

I've been googling my issue, but haven't really found a checklist on what to go over other than the obvious battery capacity, wiring etc....
I can't find it, but I thought I saw something related to the HoverflyPro that said something about certain setting(s) would reduce battery life, but I can't find it now.

I was expecting 7-9 minutes without the camera or gimble based on what others are reporting. Under 4 minutes seems unreal to me.

Anybody have a suggestion. I'm no where near to figuring this out yet.

Call me Perplexed!

I have a DJI F550 clone that weights about 4-5lbs and with 2 4S 4,000mah I get about 12 minutes maximum flight time if I take it easy and there's little to no wind. I'd expect about 7 minutes with a single battery of the same type. Answer the following questions and I'll be happy to help you out.

What's the total flying weight?
What's the total amperage you are pulling at hover?
What's the total battery capacity you are flying with then you get X flight time at X total flight weight?
When you land what's your resting voltage of your battery pack/s versus your in flight voltage under load when you land?
Do your motors/ESC get burning hot?
If you have GPS mode, does your model stay in one position or is it "trying to find the center"?

I'll be happy to help just need this information. Thanks!

 

[jfro]

Dewster & helloman1976 I MIGHT GET THE DUMB AWARD TODAY.

In starting to answer your questions, I decided to check everything. Did batteries first, then grabbed the copter and weighed it on a different scale then before. Number wasn't even close to what I posted. Went and grabbed another scale.
Looks like I read or weighed it wrong when I finished the build (sans battery).

It is in fact 7.75 lbs with 1 battery. When I mount the 2nd battery, it will be 9lbs. Camera I'm going to use is 1.5lbs and gimble is unknown.

If I would have had half a brain or experience, I would have realized my motors alone probably weigh what I thought he copter did.

I do plan on flying with 2 batteries, but I haven't figured out where to mount them yet. Once I get the camera gimble set up during the next week, I'll figure out a mount.
For right now, I am just using velcro to strap down 1 battery and flying. Where the battery is now is where the camera mount will be.

One battery is carrying 7.75lbs right now, so 2 would carry 9 lbs, or 16% more weight. I'll have to see how long that I can fly with 2 batteries.

I may have just FREAKED out over nothing or just too early.

I'm going to shelve this discussion till I can can get flying times with 2 batteries.

Thanks for taking the time to help out.