General 250 DFC - 3gx lift off problems

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scottwells

Member
This is my first CP heli, I got it in a trade for a nitro truck..... I have practiced on the sim (RF 6.5 couple hours a day for almost a month before attempting first flight)

I am using a 3GX with the 250 PRO DFC and a Dx7s radio.

When spooling up everything seemed fine, no wobbles or shaking, no pulling to one side or another. Then when I got it an inch or so off the ground the heli rolled hard left and the blades ripped into the ground. (I gave lot of collective to get it out of rotor wash, but this happened immediately)

I am waiting on some parts (main gear, main shaft) but I am trying to wrap my head around why this happened.

I checked the 3GX settings and they are all set as per instructions could this be something I have programmed wrong into my transmitter?

I have been told this is not an ideal heli for a first CP but I have flown the sim for almost a month before trying to fly this heli. I am able to hover in all 8 orientations on the sim and I am doing some mild 3D stuff, I was expecting a little learning curve going from sim to real heli but this happened as soon as it got light on the skids, not time to react, this was a hard roll left. I am stumped.

If it helps I can post my settings in the Dx7s?????

I am running one DSMX sat on the 3GX

When I put the heli together again I plan on re-programming the 3GX but other than that I dont know what caused it or what else to do???

Any suggestions would be appreciated.

Thanks

Scott
 
Slobberdog

Slobberdog

Well-Known Member
Sounds to me like you have the aileron correction reversed, when you tip the heli to the side the swash should rise away from the tip direction, check that out.
 
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scottwells

Member
Thank for the responses guys, I appreciate them. I have parts on the way then i will put it together and re-program the 3GX. I have another question about how my transmitter is set up??

The understand just about everything except for the gyro settings.

In SW - Select I have the Gyro = INH

In Gyro

Ch = Aux2
SW = On
Rate = 33.5%

Should I have it that way or should I have SW = F-Mode and set the three Gyro settings ? And if so where is a good place to start ?

I am kind of confused what this function does. Does it control the tail gyro or the three gyros ?

I cant seem to figure this out from reading the manual or get a straight answer on google searchs

Thanks

Scott
 
Tony

Tony

Staff member
Leave the SW-Select to INH. In the Gyro menu, you should have Aux2 as your channel, and your switch on Gyro. Having it set to ON will not allow you to adjust the gyro modes. You can put it on F-Mode if you wish, but I never have. If you are looking for max tail gain though, F-Mode is the way to do it. But again, you don't have to.
 
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pvolcko

Well-Known Member
Tail gyro, and those settings look reasonable. This setting will run the tail gyro gain at 33.5 all the time. You can assign it to another switch it you like (I usually use ail or ele D/R switch on upper right front face of Tx). I would definitely not assign it to f-mode since you'll be using that for selecting normal vs idle up mode at some point. Best to put it on an unused switch. When you do you'll be able to assign rate for each switch position.
 
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scottwells

Member
Where is a good place to start for my rates on 0, 1, 2 ?

I saw on youtube that Ron Lund had

0 = -70
1 = 60
2 = -70

or something like that???

Is that a good ballpark for my heli ?

I am looking for something to get me close then I can fine tune as I fly the heli more

Scott
 
Tony

Tony

Staff member
I would start with 0 (switch up) at 35 and 1 at -35. This will put 0 in HH mode, and 1 in Rate mode. I like to have a rate mode in there somewhere so that when I'm ready to take off, I just flip into rate, then back into HH mode and it will center the tail blades. But, I would stick to just one setting for right now (switch position) and find out where your max gain is in Normal, IU1. From there, you can start adding more gain profiles and even switch it over to F-Mode if you do a lot of IU flying.
 
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