1,490 AUW

[the.ronin]

Am I really pushing this thing at 1,490 auw with dual (stock 2200mah) batteries? In this video, around 3:30 in, I engaged into a pretty fast descent (which the Phantom normally handles well) but this first flight running dual batteries the Phantom loses control and gets into this drastic roll wobble. I do regain control though.

http://www.youtube.com/watch?v=oHZRM8_fKIQ

I have not made any changes to the Naza gain settings - should I consider this at this weight?

[edit] I should add, without the dual battery setup, I'm just south of 1,300 grams. Flight times are 5-6 minutes, but at least I won't be putting as much stress on the motors and frame?

Merry Christmas everyone! :mrgreen:

 

[Gizmo3000]

That's one heavy Phantom!
I imagine you'd want to bump up the gains considerably (over stock settings)

always a bit better to move horizontally a bit when descending so as not to drop straight into the prop-wash.

How'd you do all the different videos? it looks like you had GoPro, GoPro feed w/iOAS, and FPV camera w/iOSD?
.did you have two iOSD's??

 

[the.ronin]

Gizmo, good call on descending at an angle. I decided to prune back just a bit. Going back to single battery at 1,280 UAW being sure to take it easy during my whopping 5 minute flights LOL. When I get more time, I will go back and clean things up. I know where I can get some weight savings without sacrificing too much of the cosmetics. I did a lot of hasty installs.

I have not touched the gains at all. Have you changed your settings to accommodate more weight?

I have a groundstation DVR recording video feed from a video switcher. The switcher toggles between the flight cam and the GoPro with the iOSD info overlaid on whatever video is being fed. Then there's the GoPro recording itself. And actually ... I've got two flight cameras onboard one for daytime and a 0 lux IR LED camera which I can also toggle between - I just didn't have reason to switch to it in this particular flight. I know I know ... weight!! :mrgreen:

 

[Gizmo3000]

I've not really played with my gains much, I think I have them still near 110,110,100,110,110.
I've flown with a heavier , 1290g phantom, (had the 3-axis gimbal attached, now back to a tarot, so it weighs 1190g), but never experienced serious flight instability similar to what you experienced. But I think anytime you descend too rapidly in your own prop wash things can get dicey.

Impressive rig you've set up! so the video switcher is on the Phantom itself? and switches different feeds to the OSD and then it's sent to the FPV TX?

What props are you using?
(I had some success flying with 9x4.5 MR APC props, plus I pushed my battery failsafe levels to 2nd level at 10.5, gave me a wee bit more flight time)

..and that flight area looks somewhat familiar, ..def looks like California (North Hollywood by chance?)

 

[DeweyAXD]

From my experiance anything beyond 1320g with a dual battery setup actually negates the extra power. I find 1300 is a comfort zone.

I tink you will find that you suffered from pendulum affect on that descent. The dual batts on either side can cause that in GPS mode because the centre of gravity has changed. The Phantom drops to the left (hard) and then the NAZA compensates (harder), this swings the weight transfer past the CG and the other battery creates the same problem in turn (only slightly lesser). If it happens in the future the reaction needs to be roll in the opposite direction to the wobble... this assists the NAZA compensation. Easy to say... much harder to react!

I had this when I was experimenting with my earliest Dual battery undertray prototypes and decided that one batt in the shell and one under the body is a much smoother affect. Don't get me wrong both ways work but because the NAZA is working harder because of the CG issue you are actually causing more power loss because of it.

Gains tweak would be good but be careful with it. I'd advise either remote adjustment with the X1 channel (on EACH setting... not all at once). Takes time to do though and you don't want the reaction of the NAZA to such affect to be too sharp or it will get worse (not good if over say a highway!?!).

9x5 Eprops or GWS tri-blades would be a minimal on that weight. I get 10 mins @ 1298g with my setup currently but that was on stock props and with a voltage level tweak. I find descents fast but controlled.

Frame and motors will handle that weight. Stock motors are the same as the red Flamewheel 2212's and they can cope with 2kg+ on a 450. ESCs will be taking the most strain. You seem like a man who is ready for a bigger frame IMO

 

[the.ronin]

Gizmo ...

That's hilarious - I'm at 1290 WITH the Tarot lol. I've left my gain settings as is for now but will make some adjustments if I continue to see odd flight behavior at 1290. Thanks - yes, the video switcher is onboard. I could have had the OSD between one of the cameras and the switcher such that the telemetry data shows only for that camera (or cameras) but decided it would be cool to know flight data even if I was switched to the GoPro since the GoPro has its own recording without OSD data. The tricky part was assigning what should be a three way switch to a Turnigy 9x where I already used the 3 way switch for the flight modes. So I'm using a throwback switch to switch between flight cams (the day and night cams) and the GoPro. The gear switch right in front of the throwback switch switches between day and night cam. I'm using the pot knob next to the throwback switch to control gimbal tilt since my finger will be near it anyway if I were viewing the GoPro.

A LOT of added weight here but hopefully you can see why I've sacrificed lean for this functionality.

Dewey ...

I'm pretty much arriving to your conclusion in regards 1300 being the sweet spot for duals. The "pendulum effect" as you describe makes perfect sense and reminds me of the same phenomenon we encountered skateboarding down steep hills if our trucks were too loose - we would be too late to compensate resulting in what we called "speed wobble."

I've also heard the same warning on gains adjustments which is why I've opted to keep it the same for now.

Yes, a bigger frame would probably be best. But in all honesty, I never even touched a rc anything more than 2 months ago when I first got this Phantom. As likely every member in here can attest to, it started off with just a GoPro on a anti-jello mount, then the FPV setup, then the gimbal, then tweaks to the FPV setup, then tweaks to the gimbal ... my imagination exceeded my grasp, to say the least LOL.

Thank you for the advice guys!! Hope you are having a great and safe holiday!

 

[ElGuano]

With heavier Phantoms, descents are definitely the most dicey. I can't say whether it's exactly settling with power/vrs but it's easy to get into a seriously attitudes impairing wobble on descent. I think !one is tuned out but as a rule I never descend faster than 1\4 my max ascent rate, and I always do so with some lateral movement, never straight down unless I'm going very slowly.

Another reason is the phantom seems to need 10-15ft of air-braking space to come to a hover from a fast vertical descent, and I've brushed grass a few times on close calls in the past!

 

[the.ronin]

Hey guys, just got back from Vegas. Brought the Phantom and did manage to get some footage but the weight was really noticeable. I had even reverted back to a single battery setup with an auw of 1,286 g. I was topping out at 6 mins but that wasn't so much the issue rather the handling of the Phantom. In the open road middle of the desert, we had lots of winds. I had to constantly compensate for drift and the thing just felt heavy to maneuver. This got even more sketchier when I took an early morning flight from our hotel's parking lot roof. The tight confines called for constant adjustment and landing the thing felt a lot more stressful.

I'm going on a weight losing purge seeing whatever I can knock out. I installed a lot of these components hastily with only some consideration to weight. I have a lot of excess wire, an ubec where I could just use my video tx power, a lot of stuff like this. I would however like to keep the FPV cam ... both if possible. Might have them plug & play as needed. Also would like to keep some of the cosmetics but we'll see. Am really hoping to get this much closer to 1,000 much less below the 1,200 stated capacity.

 

[the.ronin]

Ok this is proving much trickier than I anticipated. Completely redesigned my video wiring such that the FPV cams are plug and play using only one onboard at a time. Got rid of some other nice-to-haves and really cleaned up the wiring. STILL only managed to shave off hardly 50 grams!! Still at 1,238 auw.

Came up with a few more ideas but I'm thinking even getting this thing below 1,200 might be a stretch never mind anywhere near 1,000.

 

[the.ronin]

Took some test flights this morning at 1,229 auw. Flight times were about 8 min which is ok with me but more importantly, no out of control descents. I will continue to shave off what weight I can but definitely seeing a lot of improvement even with what little weight I was able to remove. Here it is with the plug-n-play 0 lux fpv night cam next to it ...

 

[OI Photography]

Excellent job on the swappable FPV cams. Which 0 lux did you get?

 

[the.ronin]

Excellent job on the swappable FPV cams. Which 0 lux did you get?

Thanks OI. It is one of those cheap approx $40 ones on eBay - this one has 6 IR LEDs while there are others with 8. I was skeptical at first but am quite surprised by its effectiveness. I have only tried to compare it in a pitch black room with the normal camera and it's quite good. I have not had the chance to actually try some nighttime flying with it though.

 

[WReimer]

Wow...I'm glad to see you were able to knock that weight down a fair bit...that's an awfully heavy Phantom, especially with no adjustments!

I think you would be really well served looking at a bigger multi...f450, perhaps even an f550, since you have enough equipment that you want to carry to take a 450 to a point where you don't have a lot of head room left with that airframe either.

I think you'd also likely be unhappy if you went larger, and sold your Phantom. I have now got four different multi's; 2 Phantoms, a Gaui 500X and a DJI F550. While I really enjoy my 550, there are some things that it just won't do well, and the Phantom excels at. Conversely, there are things the Phantom won't do well...and I think you've already found the biggest drawback...it can't carry the weight of all of the really cool technology that there is to mount on these modern-day multi's.

Things have advanced so quickly...when I bought my Gaui, it was one of the first real options that most everyone could afford. With the electronics available at the time, it was actually stabilized (sort of) on 3 axis. That was pretty much it, and it was VERY cool. Now...a couple of years later and to make it a marginal competitor, you have to invest hundreds of dollars in new electronics