First Crash but why???

[coolice]

I use a flat throttle curve on mine, 0-80-80-80-80.

Always have always will. That way it spools up to full power at mid stick then it's just a case of using collective to get 'er up!

Hey all.

This is good advice, on any electric model runnign just straight throttle curves you ideally need to keep the throttle above 80% at all times to avoid excess heat building up within the ESC and causing premature failures. The exception to this is ESC's with decent govenors onboard, which rely on a throttle percentage to govenor at a set rotor RPM.
I to ramp up my throttle in normal mode from 0 to 80% within a 1/4 stick movement and then height control is achieved by the collective pitch.

Hey helimadness.

Your thoughts on the training undercarriage are spot on, with it fitted the FBL gyros will have needed to be turned down to avoid them compensating for any vibes introduced into the airframe by the trainign legs wobbling. By then removing the training legs, you will need to up them again to have the gyros working as well as before.

It is advised as posted to avoid using the cyclic controls during take off, the reason being if the pilot demands a right aileron input for instance and the FBL unit does not see movement due to the skids still being in contact with the ground, then the FBL controller can throw in more cyclic to effect a response. The model then rolls quicker than expected and runs the risk of tipping over.
However I have found having flown the 3G on a 700N, 550E, 450 PRO and 3GX on 550E & 450 PRO that small cyclic inputs on the larger machines (500 and up) do nto seem to be so worrying as on the 450. The latter size machine I found more daunting to take off at times, as it wanted to wander off on the cyclic on the odd occasion.
I think the best advice is that if you do need to make cyclic adjustments during take off, only use small amounts of control.

When it comes to spooling up I do so in normal mode on all my models, allowing the rotor rpm to rise as my transmitter stick approaches the mid-stick zero degree position, then lift off still on normal mode. I flick into and out of idleup as necassary mid flight and land again in normal mode, unless auto'ing down.
A lot of how you fly in general is personal preference and what you get used to, from my old F3C days I am used to flying in normal mode for any hovering manouvers before flicking in and out of idle up's to suit what manouvers I plan on doing.

With your blades be careful of the main damaged one, I had similar damage to my own Align blades recently and while they looked ok on flexing the blade and root area I could hear the carbon fibres within the blade giving slightly. It sounds almost like fabric rubbing together and this was still apparent even after I had dribbled a thin cyano glue into the damaged area. Because of this I scrapped the blades to be safe.
.

[tourerjim]

Ian (Coolice) post says it all so the only thing I can add to this' I have 1, 3G & 2, 3GX's & my setup on them is such that with smallest amount of stick input heli floats on lift off with no drift at all & this is the initial setup you need achieve which will also give you a smoother hover manoeuvres, as your flying progresses so your 3GX setup will need parameter changes.

[helimadness]

Hi Guys, Thanks for the feedback. My brother sent me this very good article below. Related to full size helis but has to be the same principals. Mine was really quite fast when it started to go. After doing 10 or so take off previously it would just slowly drift one way after leaving the ground and I could correct it was airborne. I will put the training skids back on and try some different things to see what happens to the 3gx and swash. It must have been fairly tilted as the heli started rolling a long way before take off power. I thought it should have leveled once placed on the ground.
Anyone got any thoughts on Aileron gain effecting the roll rate on take off with the 3gx? Throttle curve and Aileron gain were the 2 things that were changing. Sounds like the Throttle curve is ok. Negative pitch on spool ups a no no. Aileron gain is the only other variable I don't have my head around.
Cheers.
Helicopter Aviation

[helimadness]

Another thought. during the initialization stage of the 3GX does it remember a level point? Eg if the ground is not flat when I turn it on then carry the heli to flat ground for take off will the 3GX think the heli is rolling and try and correct? The ground is not that flat where we fly. I do always try and find a flat bit to take off but have never thought about it when powering up.

[coolice]

Hey.

No, I've never experienced any problems relating to how level the ground is on power up. The 3GX's neutral positions are stored during the DIR phase, hence why you must not move the sticks untill the 3GX has initialized.

What type of ground are you flying from, grass, concrete or other? Hard surfaces can give a problem, again due to vibration or ground resonance feedback through the skids.

Also what settings are you using in the 3GX and what main blades?
.

[helimadness]

Hi, Stock standard out of the combo box trex 500efl. ill attach my file I save from the 3gx after the crash. Ground is sort of grass. All brown and dead and very dry hard dirt. As this was my first time setting a heli up I read the manual and read heaps about the setup. DIR mode was done on my kitchen table so fairly flat. I did about 30 flights then reset it up after changing settings on my TX to allow for idle up. Did about another 10 flights then took the training skids off and have done about another 10. Started to increase the gains as explained before. I found this thread as well. Sounds exactly the same problem I had. I know Im not very experienced but totally felt like something had gone wrong. It tipped too early too fast. Maybe a combinations of small errors that built up.

Another 3GX Success But Weird Ground Behavior - HeliFreak need to get new blades and might get new tail blades as well to be totally sure. They have a few very small chips out of the paint.

Cant seem to work out how to upload a txt file. Will get some screen shots of the 3gx setup when I get home.

Thanks for the help appreciated.

[helimadness]

replied before on the go but didnt come through.
Stock standard 500efl pro combo kit straight out of the box. Standard blades and everything. Ground is grass but totally dry and dead, fairly hard dirt might be more accurate. here is about my 12th flight. you can see the ground. Trex500 efl flight 12.avi - YouTube

Here are my setting, Just realized opening it again it says its for a 700 custom. Have no idea how that happened. I did the DIR setup as per the manual. Are you meant to go back into the software after you do the dir and select the model and rewrite it back to the 3gx?

3gx elevator.JPG3gx other.JPG3gx rudder.JPG3gx aileron.JPG

Also found this like with someone having what sounds to be the exact thing that happened to me.

Another 3GX Success But Weird Ground Behavior - HeliFreak

Thanks for the help appreciated.

Cheers

[helimadness]

My Conclusion.
So last night I checked the main shaft bearings and found they were noisy and not so smooth when turned slowly. Not sure if this was caused in the crash or maybe normal after 50 flights? How often should they get replaced. So what I think happened.
1) spooling up too slow. (pilot error)
2) Maybe small vibrations from the tail rotors (they have a few small chips) or worn main bearings made the 3gx tilt the swash. I was slowly increasing the gain with no training gear which maybe highlighted the problem with the gain being more sensitive to vibrations.
3) lack of experience and didnt pick up the swash tilting early enough. Once again pilot error.

Let me know if you think this sounds like a realistic outcome. Certainly something you need to be vary aware of especially for a newbee.

Cheers.

[jamiew12]

them first lot of blades are really bad

[tourerjim]

My Conclusion.
So last night I checked the main shaft bearings and found they were noisy and not so smooth when turned slowly. Not sure if this was caused in the crash or maybe normal after 50 flights? How often should they get replaced. So what I think happened.
1) spooling up too slow. (pilot error)
2) Maybe small vibrations from the tail rotors (they have a few small chips) or worn main bearings made the 3gx tilt the swash. I was slowly increasing the gain with no training gear which maybe highlighted the problem with the gain being more sensitive to vibrations.
3) lack of experience and didnt pick up the swash tilting early enough. Once again pilot error.

Let me know if you think this sounds like a realistic outcome. Certainly something you need to be vary aware of especially for a newbee.

Cheers.

Worn bearings can cause high frequency vibration that would greatly effect gyro's & I already change the bearings in mine due to previous experiances with my old esp, the Align 500 main bearings are crap so always woth keeping spare set.
From what i seen from your screen shots i think your overhaul sensativaty is too high but would need to check mine but not near me laptop for a bit.
If you want if you pm' me with your tx settings, the link possition of your servo horns then i can give you the settings that will suit your level flight.