Phantom CoG - topple

[Danny-B-]

Howdy !

I have the Phantom v1.1.1 with a few upgrades, and i might answer my own question here but thought i'd post incase it was just me ...
Anyhoo .. Today i was out with a friend testing FPV as i've just got the black Pearl (7ch F band) screen. When i take off it tends to lean forward so i usually have to compensate by pulling back on the right stick to make sure it doesnt ground out. I thought that the compass might be out a bit so did a compass dance, but it made no difference, it still tends to do this on take off .. now, its not standard and my thoughts now are that its too front heavy so the flight controller will be compensating quite a bit to keep it level during normal flight.
Its fine when its up, it levels fine and can stick in one spot just fine.

Current setup is as follows ..

Phantom 1.1.1
Tarot 2D Gimbal
Extended Legs, wider and slightly higher
IMRC 600mW mounted internally, hole through the back shell, with a spiro out and pointing down
Sony FPV cam mounted on the battery door
Battery leads out the side of the battery door so i can use bigger batts
Zippy 2800 battery

Whats the best option if it is front heavy? i was thinking of buying an iOSDmini so i could mount this at the rear (Inside) for a bit of weight ...

Would pics help ?

 

[Phantom12014]

I ran into the same thing...I ended up installing the E300 upgrade kit with 9" props and motors with the extended motor mounts.. it takes off now like it did out of the box with all the other stuff, and with the motor mounts and bigger props it's so much more energy efficient and I get even loge flight time with faster speeds and it way more stable... it came out to a $300 investment but we'll worth it

 

[lake_flyer]

With only 1 heavy battery it will be difficult to maintain the COG in the centre.
The Phantom 2 shell is reversed for that matter so the weight of the bigger P2 battery is behind the centre instead of in front like with the P1 or FC40. That allows a P2 user to have quite some payload in the front without nose tipping.

To overcome this problem I decided to go for 2 2200 batteries and leave the battery compartment empty (perfect place for IOSD and stuff). I mounted 2 rails under the motor arms(made of pieces of simple plastic wall trunking from the DIY store), with tie wraps through the legs (needed to make a little hole in each leg), that allows me to slide the batteries over a length of 5 cm. I can get a perfectly centred COG every time now, no matter what payload. No matter how heavy (max was slightly over 1400 grams), it always takes off perfectly vertical this way. I just slide the batteries until it feels in balance. They are secured with some velcro.

Having 2 batteries also gives you a lot of extra safety. Many crashed have been caused by a single faulty battery. With 2 you always keep power.

Worth getting 9" props though. Be sure to get the latest 9450's, NOT the old 9443's, they suffer from VRS too much.

 

[Danny-B-]

Thanks for the replies folks .. I've often thought about dual batteries but was put off with the reports of them causing VRS with the carbon tray setup .. can you post a picture of your setup please, lake_flyer ?

I'm also tempted to just do the phantom 2 (1.5) conversion, but they want £50 for the plastic case !

 

[lake_flyer]

Here you see the self made battery mounting rails on the side of my phantom.