Short flight times, in the hope of increasing made it even worse. Please explain what to do!

Very interested in building a drone similar to your flight times. I am looking at a zd 550 or 680 frame with pixhawk fc and 360kv motors on 6s would this be a good setup to get around 20 min flight time minimum

Yes, probably so but it depends on take-off weight of course. Those long flight times on mine were on a bare craft carrying no accessory hardware. Buy a subscription to eCalc and run the numbers.

I have the ZD550 frame. Itā€™s a little heavy for what it is. Iā€™ve managed nearly 20 mins with a 6500mAh LiHV 6S battery, 660kV motors, 14ā€ Master Airscrew props, and no significant payload weight.

If I were looking to really stretch the flight time, Iā€™d find a lighter frame without folding arms.

I do like the frame, though. Itā€™s been a fun platform to modify and fly, testing all sorts of AP features along the way. The 6S power train will carry a fair amount of payload weight, at the expense of flight time, of course!

Thank you for the responses i went with a 680 frame 380kv motors and 15 inch props we will see how it does

What does eCalc say it will do? I have used that application for 3" to 16" craft and it predicts very well. Buy everything but the battery, build it and weight it. Then buy a battery such that the total take-off weight produces ~45-50% linear hover thrust.

I may have put something in wrong but with 8kmah 6s ecalc said 53 min hover

What motors, props and weight?

Jmt 3508 380kv 1500g approximately 1555 props

It will weigh more than that. A 6S 8000mah battery would be >1kg
Follow the advice and you get a craft with good thrust/weight balanced with flight time.

What does yours weigh @Yuri_Rage?

That thingā€™s gonna weigh closer to 2.5 to 3 kg (AUW). And thereā€™s a breaking point for batteries where more capacity just equals more weight and doesnā€™t contribute to flight time. With these component choices, Iā€™m guessing that point is between 6000-8000mAh. I have some big 10,000mAh batteries that actually decrease flight time due to their size/weight. Good inputs to eCalc will bear all of that out.

Mine weighs 2.5kg with a Here3+, TeraRanger LIDAR, and naked GoPro.

I am open to any advice you may have as this is my first large build

At 2500g 6000mah Iā€™m showing 23 min

Iā€™m also planning minimal load weight with only a small fpv camera setup

That seems optimistic but maybe achievable with the slightly lower kV and larger props.

The largest props that will fit the frame and the motors will support. Donā€™t be too concerned if eCalc says motor overload at full throttle if you only have fpv gear on it.

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Here is some information on a lightweight 15 inch drone without payload. It flies 50 mins:

There is also information on battery weight and individual component weight and even CAD files, maybe it helps.

So I got my drone together with no camera gear yet just the basics to fly and it tends to want to flip over on takeoff. I have gotten it to fly a few times and it does decent. When armed and waiting to takeoff it seems thereā€™s always 2 props spinning slower amd it will flip in the direction of those 2 props. Any input on what may cause this?

Yes, that is caused by incorrect configuration.

There is a good step-by-step configuration Blog post instructions. If you got that configured wrong, you probably have done configuration errors on other areas as well.

Failed to mention its not always the same 2 props spinning slower it seems to change based on drone being level

Post a link to .bin flight log.