LibrePilot Forum

General Category => General Discussion => Topic started by: zukenj on June 13, 2016, 08:26:11 pm

Title: How heavy
Post by: zukenj on June 13, 2016, 08:26:11 pm
Hello,

I have a question.

My quad is an Q450 (F450 Clone). I was flighing with the following:

Frame Q450
Motors EMax 2213 935 Kv
EMax Props 10x4.5
HK 30A Blue Series ESC
NEO-7N GPS with Compass for Revolution
ATG Universal DIY FPV ANTI-Vibration Multifunction Landing Skid Kit for DJI F450
FlySky FS-R9B 8Ch 2.4Ghz RC Receiver
ZOP Power 11.1V 5000mAh 3S1P 30C Lipo Battery

It is really steady and nice to flight.

I added a Gimbal, and now is a lot more dificult to flight. I think, because is heavier and it take more time to respond. I don't fill constable and I am more afraid to crash it because the response time.

With the Gimbal and camera, it sits at 4 pounds 2Kg.

is there a way to improve it?

Thanks
Title: Re: How heavy
Post by: NicholasDavid on June 14, 2016, 02:05:38 am
Do you think it's a power issue? Not enough thrust? 

Make it lighter
Bigger prop
Bigger battery? Higher cell.

Or does it have plenty of thrust but now it has no control?
Title: Re: How heavy
Post by: nitromethane on June 14, 2016, 08:39:36 am
While at very quick first glance, the setup to me feels a tiny bit under powered for a 2kg machine, but your problem might be elsewhere.

Have you retried retuning the PIDs?

How is your weight distribution?
You should be aiming at having as much of the weight concentrated around the geometrical center between the motors in order to get the smallest moment of inertia, so the motors need to work less to produce desired angular accelerations.
Also if the center of gravity is, for example a considerable distance in front of the geometrical center between motors, the front two motors are loaded far more than the rear two and might be maxing out, beating the air into submission, just trying to keep the frame level while the rear two are just lightly mixing the air.
Title: Re: How heavy
Post by: 12many on June 14, 2016, 08:45:00 am
What throttle setting does your vehicle hover at with that load?  Just guessing by looking at your configuration I'd guess it's pretty high.  Asking that motor & 10" prop to lift a pound each is probably pushing it too far.

Probably your best option is to consider running a smaller battery to lighten things up.  Get two 2650mAH batteries and swap them between flights.   And/or as NicholasDavid suggested try a larger prop (watch your temps though).

There is a lift efficiency sweet-spot for every motor / prop combination - the vehicles I've used it's usually around 60% throttle.  If you're hovering at >80% throttle you're probably inefficient which kills flight time as well as being unstable.  My guess is if this is the case a 2560mAH battery could give you 75% the flight time of the heavy 5000mAH battery or more.
Title: Re: How heavy
Post by: zukenj on June 14, 2016, 07:07:46 pm
Thanks for replying. Now I have some direction to go.

My next steps will be:

Title: Re: How heavy
Post by: MSilva on June 18, 2016, 03:43:48 am
I have the same problem and i found that the battery has low voltage (3S) and low C's (10C) so the response of the power is lower.
I am go to change for 4S 35C 5000mah batterys.
Title: Re: How heavy
Post by: Joe_D on June 18, 2016, 03:16:41 pm
Hi, if you are using nylon props I would recommend to try a carbon / nylon 1045 Gemfan replacement, they don't bend under heavy load and are more efficient.

Joe
Title: Re: How heavy
Post by: DivenParker on October 15, 2016, 05:32:33 am
If you add a Gimbal, it means your Q450 get heavier, so your 5000mah 3s lipo battery can't support it, so you need replace a Motorse a drone.
Title: Re: How heavy
Post by: zukenj on October 28, 2016, 03:06:41 pm
I been off for a while. My lapt is Dual boot, and a recent windows 10 update damage the MBR (Master Boot record), and enlarge the partition, causing windows to step in to the Linux partition, long story short. I lost my linux partition, and can't be recovered. I tryed  :'( ,different utilities, but it was a no go.

So I am in the process to get everything back together.

Last time I flew with the 5000mAh, it was like it has been. Normal flight fo a dicent time. the I replace the battery for the small one, and looks like the connector got off some how, and the quad got no power in mid air. I end up with a big crash.

1. The gimball got bent (Streched out, Ok now)
2. Gimball controller USB port crush and all pins bent (Streched out, Ok and working fine)
3. The fiberglass pipes on the frame got all crush (Can flight, but looking for a replacement)
4. The pins in the FC bent (All strech out, Ok now)
5. GPS mast broke (Cut the broken part, Mast Ok now)
6. Camera lost the battery cover (I found it 10m a way from chrash)

I was able to recover all.

As soon as I finish with my Laptop and been busy with work I will be givin a try.

Thanks to all for your reply.
Title: Re: How heavy
Post by: jtrout19 on October 30, 2016, 03:36:10 pm
I have 2216 920kv motors with 12 in props on a quad that weighs in at 9lbs 4oz. I run a 5200mah 3s battery and can hover at a little above 40% throttle. I had issue with it a while back because i forgot to take into account center of gravity and it was very front heavy. Flew like crap. One day it just hit me and i felt like a dummy move my battery back a whole bunch and it flew like a dream.
Title: Re: How heavy
Post by: zukenj on October 31, 2016, 08:06:09 pm
I think I try to move the battery back, but looks like I did not moved far enough. I will have to test again.

Thanks for the sujestion.