450 Derek's Trex 450 Pro DFC

[Slobberdog]

As said in an earlier post, your rod length should get your slider in the centre of shaft, with the slider in the centre of the shaft, the blades should look like this



Hope this shows what I mean...

 

[Derek]

Thanks for that, Kev! Perhaps I was over-thinking the issue and I missed what was being said. Its also quite possible that I was doing some "speed reading" and I didn't actually absorb what was being said.

I fully understand what is being said now. The picture did help. Thank you!

I have to work again tonight but I should be off work on Monday and Tuesday so, if the weather cooperates, hopefully I can do another test run.

 

[Slobberdog]

Sometimes there's just to much info from a few people, I end up reading posts multiple times before I understand what's been said,

Good luck for getting it in the air, and more importantly enjoy it, you set things up well so trust in what you have done

 

[Tony]

As stated, you should only look at the tail slider and not the blades. Just center the slider, adjust yoru endpoints (yes, you will have to readjust those in the rudder menu every time you change the tail settings) then do a test hover.

 

[Derek]

Ok...got it..............center the slider with the tail push rod, adjust the endpoints in the 3GX, then go test hover.

 

[Derek]

Well, the test hover didn't go so well today. The helicopter spooled up nice and smooth. It sounded great and before I could react, it tipped over and chewed up a bit of grass. I was quick to get to the Throttle Hold. After deep inspection, the only damage seems to be a stripped main gear, slightly bent main shaft, and a bruised pride. I did replace the feathering shaft, just to be sure. Servos, linkages, blades...all ok.

Everything is back together. I'm going to recheck the tail slider and end points. I'll try again tomorrow, weather permiting. I do have video of todays test. I'll have to wait to upload it until tomorrow because my computer is still in my daughters room and she is sleeping right now.

 

[murankar]

If you want to check the feathering shaft, just chuck it in a drill and let her rip. If you go to fast you won't see the wobble.

Sent from my LG-E980 using Forum Runner

 

[Derek]

That's a good idea, Matthias! Thanks for that. I just went ahead and changed the feathering shaft as a precaution but if I could turn the feathering shaft in a drill and NOT see a wobble, then it might still be good.

I appreciate the tip.

 

[Derek]

Another confusion has arisen its ugly head.

I'm not sure how this happened, but I noticed that my swashplate isn't level on the elevator servo when I go to low stick. From high stick through mid stick, the swash is level...but below mid stick, the swash falls a bit. According to the manual, the linkage rods should be 32.5mm in length. My linkage rods are all the same at 32.7mm.

Also, with a linear pitch curve, as suggested, my aileron and pitch servos actually bottom out. I'll take the swash plate to the bottom of the linear curve andfrom there, there two servos have no more negative travel.

Any suggestions?

 

[pvolcko]

When you setup the level swash and 90 deg servo horns do you recall having to use a lot of subtrim to get it leveled out? It sounds like the servos are too far off from natural servo center at 0 pitch. Solution would be to redo the setup and reposition horns closer to servo center position or perhaps use mechanical adjustments on servo links to get the swash leveled instead of subtrim in DIR mode (assuming 3GX on this). Maybe?

Also, what pitch are you running for positive and negative? Maybe there is a wider range programmed into things on the negative than you think? I wouldn't expect full negative pitch to get all that close to the limits of the servos unless it was running 18-20degrees or something crazy like that. Even full neg with full cyclic deflection shouldn't max out the servo limits.

 

[Slobberdog]

Do the servos bottom out or have you just got to the end of the servo limits you have set up in your tx in swash mix menu, double check to see if you have any end point adjustment set in the servo travel adjust menu, as this is what caused my tip over,

 

[Derek]

When you setup the level swash and 90 deg servo horns do you recall having to use a lot of subtrim to get it leveled out? It sounds like the servos are too far off from natural servo center at 0 pitch. Solution would be to redo the setup and reposition horns closer to servo center position or perhaps use mechanical adjustments on servo links to get the swash leveled instead of subtrim in DIR mode (assuming 3GX on this). Maybe?

Also, what pitch are you running for positive and negative? Maybe there is a wider range programmed into things on the negative than you think? I wouldn't expect full negative pitch to get all that close to the limits of the servos unless it was running 18-20degrees or something crazy like that. Even full neg with full cyclic deflection shouldn't max out the servo limits.

Yes...the 3GX is on this helicopter. No, there wasn't very much sub trim used to level the swash. I just got back from my LHS. I was talking with the semi pro that works there. He pointed out that I have the linkage balls in the outer hole of the servo horn. According to the manual, the linkage balls should be in the inner hole. With the linkage balls in the outer holes, I'm getting too much throw and my geometry is off, too.

Do the servos bottom out or have you just got to the end of the servo limits you have set up in your tx in swash mix menu, double check to see if you have any end point adjustment set in the servo travel adjust menu, as this is what caused my tip over,

The servos actually bottom out.

So...that all being said...I'm going to simply start from the beginning. I'll start with a fresh profile in my DX8. Move the ball links to the inner holes. Level the swash. Reset the blade pitch...and all that. Since it's snowing here, AGAIN, this will give me something to do to occupy my time.

The semi pro at my LHS also mentioned that he thought my Swashplate numbers were a bit off. For the aileron and elevator, I had it set at 46 and 46. The pitch number was 30. I forget what he said those numbers should be, or something close to it, but he said they will most likely change after getting the ball links in the appropriate holes.

I'll report back this afternoon.

Here is the video of yesterdays test. It didn't go so well, lol

Trex 450 Pro DFC test 2 - YouTube

 

[Derek]

Well, now I have another problem. One of my DS430M servos is no longer working. Perhaps it was damaged in the mishap yesterday. I dunno. I guess I'll have to check with my favorite rc ebay seller to see if he has another set of servos. If one servo was damaged in the mishap, I'll just replace all three.

 

[pvolcko]

Keep the old ones for gear spares at least!

 

[Derek]

Oh wow! I've been working on my 450 for nearly 13 hours and it still isn't right.

When I first got started working on it today, one of my new DS430M servos got hot. I shut it all down and tried to test it on my servo tester and got nothing from it. I plugged it back into the 3GX on the helicopter and nothing. It doesn't work at all anymore. Not good. I do have quite a few other, non-Align, metal gear servos that I use on some of my planes. I have 8 extras so I took 3 of them and put them on my 450. No, the speed and torque doesn't thoroughly compete with the DS430M servos but they are close.

So..installed the servos, centered the servos, leveled the swash, etc etc, etc. Then my blade pitch is off. Then the I see that the swash isn't level. then this, then that, then this, then that. I'm frustrated enough, it's just time to put it away. I was hoping to have it all setup tonight because I'm working the next two nights and I was hoping to try another test hover on my weekend off. Well, I'll just have to wait until Friday to start over from square one....again.

 

[Ken Jackson]

That's crazy Derek. The only problems I have ever had setting up a 450 is the tail.

 

[murankar]

I hope things are improving now. Sounds like the issues I have had with my new kit and old electrics.

 

[Derek]

Well, the only reason why these issues are now happening are because something is bent because of that tip-over that I had. I ordered new DFC arms and linkages and a few other things. These new parts should be in by Tuesday.

 

[Graham Lawrie]

Bad luck Derek, I have had similar with my 450, due to my stupidity I have not read all of your thread yet but will go back to see if I can pick up on something that happened to mine.

Maybe training gear would have saved it?

No matter how confident I am everything is ok after every tweak or work I do on mine I put it on just in case Done what you have too many times not to.

 

[Derek]

Thanks Graham! You might be on to something there. Maybe some training gear would be helpful for the first few tries until I get more familiar with the 450. I do remember how many times the training gear helped me with my 500. I'll go see if I can find a set today.