Initial Flight Test Challenges

[johna58]

Hi Everyone - Newbie JohnA58 here. Once again I want to thank everyone for your great suggestions and guidance. I took my F550 out for its first flight. My wife named it Frakencopter or "FC" for short because I assembled it from it kit pieces. This is what I ran into.

- Weather conditions: The temperature is 58 degrees, the wind is at 4 to 5 MPH from the northeast and a it is a clear blue sunny day:excitement: .
- Time of Day: 1230 hours (eastern time - US)
- FC is facing North.
- I am standing behind about 10 feet away.

When I apply power and start to increase power, FC flipped over from right to left several times (I think I better put in an order for extra props:greedy_dollars. before hand, I made sure all positions of the stick is was calibrated and true to the center in Assistant. The other thing I notice is that when bringing the throttle down to its stops, the motor did not turn off. I guess I need to read the NAZA instructions and my Tx manual again and keep adjusting both until I get the right setting but my fear is that if I throttle down to it stop, the motor will turn off in flight:grey: then that will bring another set of problems.

At one point (I don't how or why, I was able to get it off the ground and was able to maintain an attitude hold about 10 feet. At that time, I was able to rotate it left and right with the left stick and forward, backwards and bank left and right with the right stick. it seem to level off when a released both joysticks. I think I might need to play with the gains a bit to compensate for slight drifts (I think?).

The second thing I have not done is to to set the GPS and the declination for my area. I am sure I should find how to do that in the manual. I am still waiting for my batteries to come but I found out that the place I purchase them from [online] said it will take up to 60 plus days because my order is being filled from out of China. I've been using a smaller battery from my AR Drone (which I now have to replace due to a damage cell) for testing while on the bench. I just wish I can drive to a reputable hobby shop. The closest one is in Atlanta (a 4-1/2 hours).

After my 2 minute hovering flight, I notice that when I reached for FC and my fingers [accidentally] touched one of the motors it was very hot. I don't know - at that time - if the other motors were also as hot but I like to know if this was common?

Thanks again - Johna58

 

[OneStopRC]

What props are you using and what battery?

 

[johna58]

I am using the smaller of the two size props that came in the kit. As for the battery, I am not using what I should be using but was trying to see it get in the air so I used a battery came with my AR Drone which is a LiPo 3 Cell 11.1 volt, 1300 mAh. Needless to say, I have damaged that battery where it charges to only 25%. As I am new to all the different types of batteries, what battery types would you (and others) recommend for either size prop?

 

[OneStopRC]

I am using the smaller of the two size props that came in the kit. As for the battery, I am not using what I should be using but was trying to see it get in the air so I used a battery came with my AR Drone which is a LiPo 3 Cell 11.1 volt, 1300 mAh. Needless to say, I have damaged that battery where it charges to only 25%. As I am new to all the different types of batteries, what battery types would you (and others) recommend for either size prop?

8" props are used for 4S batteries, 10" props for the 3S, I know it does not make much sense, but that is whats recommended. with the 10" props, your motors will not work as hard, and will give you more flight time.

I run 3S Nano-Tech 2650mAh Batteries, with my GoPro on board I get around 11-12 minutes flight time, without it is almost 14-15 minutes.

 

[johna58]

I did read something about this and, you are right, it does not sound logical but go figure! I did order a 3S and a 4S battery. I have to wait for it to be delivered.

 

[OneStopRC]

I try to stick with one size, all mine are 3S, I do this so I can stay with one size prop. Saves on unnecessary prop changes, I am sure you will find what is best for you and your setup.

The props, I think it is down to the surface and pitch, the 10" I think (don't quote me) are 2" longer but have less of a pitch, which would make them work less in theory.

 

[mbsteed]

Often if everything is setup right with the props turning the right way etc., the one element missing is a vigorous take off. If you are tentative with your take off and it isn't tuned perfectly it may very well flip, so give it some throttle and get it into the air so you can make fine adjustments. This is exactly the problem that you described above and would be the cause of sometimes flipping but other times getting into a hover.

 

[johna58]

I thought that I was being too cautious being my first flight. That and that fact the I was using my AR Drone battery (since I am waiting for my order to arrive) that does not have the power range needed for six starving motors. I did put enough power in and was able to have it hover. I did not dare to do more at this time until my batteries arrive and my connectors so I can solder them on.

 

[mrbonk]

8" props are used for 4S batteries, 10" props for the 3S, I know it does not make much sense, but that is whats recommended

This is because the 4S battery will spin the motors faster than the 3S battery will. The number of revs per volt (or KV as it's commonly referred to) that the motor can produce determines prop size for a given number of volts.
For eg. let's say your motors can do 1000KV. A 4S battery is nominally rated at 14.8volts. This means your motors are doing 14800 rpm. A fully charged 4S pack has 16.8volts (4.2volts per cell), so would yield 16800rpm.
A 3S pack nominal voltage is 11.1, so that's 11100rpm, or 12.6volts fully charged, so 12600rpm.

So, the prop has to be larger when using the 3S pack because it's spinning slower than it would be on the 4S pack.

 

[johna58]

OK, I finally was able to start my motors. I don't know how or why it decided to work but I attempted my first flight at midnight (I could not wait until daylight). Everything seem to start out fine but I think I still need to make some adjustments. Even though I calibrated the joysticks and made sure they move in the correct direction, I notice that as power was added and it broke ground affect it flew (what I mean to say is it shot off) to the right. I also notice a right yaw and a drift rearward. would that be due to gains I have set. I am using the following: Pitch=190, roll=225, yaw=125, attitude=110 and both attitude gain set to 80. These were suggested but my craft is not carrying anything but a 20 oz Venom 3 cell 7500 30C LiPo and I am using the larger props that came with the kit.

I want to be able to have a stable test flight with full hovering and a GPS failsafe RTH before I install my FPV system (that should be delivered Friday (today). For those who have experienced this what suggestions do you have to offer for me and other newbies?

 

[Tahoe Ed]

That is a HUGE lipo. Get something smaller. The most I use on my F550 was a 4S 4000mAh.

 

[johna58]

I have a smaller 3300mah 3S and a 4000mhs 4S but it is coming on that slow boat from China. I was told it would take another 40 days before I get my order so I got this one from Amazon.

 

[BorisS]

Johna to really help you.

Post some pics of your setup, we need to see where the components are placed. Give us screenshots of your assistant ! Otherwise it just guessing.
For a F550 your gains are also to high. Start with 130..140 on roll pitch yaw, vertical just keep on 100, attitude both 100. More important to get it into the air and give a constant performance and than touch close with the gain later !

Boris

 

[OneStopRC]

I would say, more than likely your CG is off. Make sure your battery is taking up the CG, or move it around to balance the bird more.