450 Derek's Trex 450 Pro DFC

Derek

Derek

Well-Known Member
Ok, I hovered the 450 for the first time. It felt pretty good but I need to lengthen the tail push rod, just a bit and I'm going to take off the 12T pinion and put on the 11T pinion. This 3600kv motor is a screamer. I took the helicopter to my LHS and had the guy there fly it ( I trust him ), he also recommended going with the 11T pinion and trying to fly it again.

I did setup my video camera when I was hovering the 450. I'll upload that video tonight. I have to take the wife out for dinner now, lol.
 
Derek

Derek

Well-Known Member
Something I did notice is when its in rate mode, the tail blades aren't lining up when they are folded. I thought they are suppose to line up. So, I'm gonna adjust the length of the tail push rod, in hopes that the blades will line up. Then I think the heading hold mode will hold better.

Gonna change out the pinion, too. I have my throttle curve as follows:

0,30,60,60,60 normal mode
70,70,70,70,70 stunt 1
80,80,80,80,80 stunt 2

Pitch curve as follows:
46,48,50,75,100 normal mode
Linear curve in stunt 1 and 2

My buddy, at my LHS, is afraid that the helicopter will destroy itself if I run the throttle with this motor and pinion. I may just decide on getting the Align 450 motor and doing this whole thing appropriately. I think the Align motor is 3400kv. The motor I bought is a 3600kv from Hobby King. It just sounds like the 3600kv is going to be too much.

What are your thoughts?
 
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Derek

Derek

Well-Known Member
hmmm, i just noticed that I am missing a shim. There is suppose to be a shim on the main shaft, just above the main bearing block. I don't have a shim there. I just took a look at the PDF manual and I see the measurements for this shim but I don't have any here. I can't seem to find one in my box of parts and pieces. Not good!!!
 
murankar

murankar

Staff member
First question is there play in the main shaft?

Second is does the 3GX want 0 degrees pitch in the tail blades?
 
Derek

Derek

Well-Known Member
murankar said:
First question is there play in the main shaft?

Second is does the 3GX want 0 degrees pitch in the tail blades?
Click to expand...

to answer your first question, yes, there is play. I can grab the metal stopper button and pull the main shaft up and down about 1/16 of an inch..maybe a bit more.

second question...I honestly don't know. I'll need to talk with Kev or Tony to be certain.
 
murankar

murankar

Staff member
With my X3 if I 90 the push rod and the pitch slider I will have pitch in the blades. My gyro (ZYX-S) wants there to be 8 degrees of pitch at setup time. That's why I asked, I am not sure about what the 3GX.
 
Derek

Derek

Well-Known Member
ok, thanks for that. I'll go back through the manual and see if I can find something on that.
 
Derek

Derek

Well-Known Member
Ok...we have definite progress.

Well, I couldn't find a shim to take the place of the missing shim. I did check out the manual and got the dimensions of the required shim. I found a washer, in my workshop, that had a slightly larger outer diameter and was slightly thicker. The inner diameter was perfect. So...I made a jig to hold the washer and I put the washer in my lathe and turned it down to make it very very close on the outside diameter and thickness. I am pretty happy with how that turned out. So...I added the new shim and that took up a great deal of the "play" that the rotor head had. Awesome!!!

It took me a couple of hours, due to my lack of experience with the 3GX (but i'm learning), but I did get the tail to work very well. The servo arm is probably 88-89 degrees to the servo case and the tail pitch slider is also very very close to being 90 degrees. I had to reset the tail limits so I referred back to Tony's videos and I was able to get the tail slider to move to the complete left and right without binding and then recenter with just a bit of pitch to the right.

I'll see about getting another test hover tomorrow before I go to work. It's gonna be a long weekend at work.

Oh...and another thing...I did get the 12T pinion removed and the 11T pinion installed and then the gear mesh reset and all screws cleaned up and re-locktited.
 
Slobberdog

Slobberdog

Well-Known Member
The tail should be set up with slider in centre this should give you approx 4-5mm of separation between the blade tips

- - - Updated - - -

The play in the main shaft should be minimal and I think they give you 0.8mm of shims in the kit, try spreading your main blocks a bit
 
Tony

Tony

Staff member
V4.0 likes to return the tail to center even in HH mode.

The blades will not line up, the slider does need to be in the middle of the travel though. If you line up your blades, it will wonder like this.
 
Derek

Derek

Well-Known Member
Tony said:
V4.0 likes to return the tail to center even in HH mode.

The blades will not line up, the slider does need to be in the middle of the travel though. If you line up your blades, it will wonder like this.
Click to expand...

I'm using v3.1 on the 3GX.

As far as the blades...I think you've told me this before, Tony...I don't know why I keep thinking the tail blades should line up. I'll work on it.
 
Derek

Derek

Well-Known Member
Question time!!!

I mentioned, in the above maiden video, that I was going to switch the 12 tooth pinion for the 11 tooth pinion. Well, I just had a subscriber, on Youtube, tell me that using the 11 tooth pinion would increase the head speed on my 450, not lower it. Is this right? I would think, "a lesser tooth pinion would result in a lesser head speed". Or, am I wrong?
 
Derek

Derek

Well-Known Member
That's what I thought, too. Thanks Tony! And thanks for posting that comment on my Youtube video.
 
Derek

Derek

Well-Known Member
So, the other day, I was thinking that the tail blades had to be lined up. I got them lined up. To get the appropriate right thrust, do I need to shorten the tail push rod?
 
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