t-rex 500 pro (FB) questions

[SamCassidy]

Has anybody on here done a FB 500 pro build?

I stated mine about two weeks ago and have some questions about some of it thats not answered in the FBL build thread

[animan]

I did a PRO build about a month ago. Have since converted to FBL with DFC head though.
I will try to answer any questions you may have.

[SamCassidy]

Awesome! that would be great.

First and foremost, did your main gear / main shaft assembly come with multiple thickness shims to put between the top of the main gear and the lower bearing block for the shaft?

Mine only came with one shim aside from the one in the main gear assembly, if I install everything w/o the shim I have maybe 3-6 thousandths vertical play in my main shaft / head, but if I try to install it with the shim there isn't enough clearance on the bottom of the shaft / gear to get the jesus bolt all the way through, I tried for a good hour.

Is there any way to make sure my torque tube is all the way in / installed correctly? I got to the last few hours of my build and found that the tube was slipping, there went 3+ hours of wiring + another 4 hours pulling the tail block and all out of the frame and getting it back in, pain in the ass.

third, how is the clearance between your servo wires and the gears for the TT assembly? (assuming your wiring is the same as mine) Its close on mine, have it shrink wrapped and zip tied but it is still close enough to scare me a little bit.

It's late, ill sleep on it and try to remember some other things I was having trouble with, I think there were one or two more.

Thank ya for the help.

[animan]

Ok, here goes

- Mine came with 2 shims, 0.3mm and 0.5mm thickness. I used the 0.3mm shim which allowed the bottom jesus bolt to go through with no vertical play on the shaft. With the 0.5mm shim the bottom jesus bolt would not go in. Most probably the shim you have is 0.5mm. You may also want to check whether the bearing blocks are mounted correctly, the align logos on the blocks should face each other, bottom one facing up and top one facing down. Also, I would double check the plastic bags or the work area to see if you have misplaced the other shim. I don't believe it is good to have any play on the main shaft. The shims are available separately also.

- I put the torque tube inside the boom and pushed it in all the way inside the tail mount, with the notch lined up until the torque tube gears engaged and i could spin the tube and see the gears turning. I installed the boom mount on the frame first, put the boom with torque tube in and finally the tail assembly. I didn't tighten any of the bolts until they were all spinning freely. I just pushed each piece in as far as it would go. Not sure if there is a way to ensure that the tube is in all the way. Perhaps someone else will chime in on that.

- On the tail servo wire, I zip tied it to the frame as it came out of the servo, went under the tail mount to the right side of the heli and zip tied it again to the frame and brought the wire up to the the gp900 which was mounted on the upper tray. May not be the most ideal wiring but seems to be holding fine for me.

Hope this helps.

[tomd27858]

Originally Posted by SamCassidy

Awesome! that would be great.

First and foremost, did your main gear / main shaft assembly come with multiple thickness shims to put between the top of the main gear and the lower bearing block for the shaft?

Mine only came with one shim aside from the one in the main gear assembly, if I install everything w/o the shim I have maybe 3-6 thousandths vertical play in my main shaft / head, but if I try to install it with the shim there isn't enough clearance on the bottom of the shaft / gear to get the jesus bolt all the way through, I tried for a good hour.

The .3 mm or .5 mm shims go in between the collar on the main shaft and the top of the bearing in the upper bearing block.

Is there any way to make sure my torque tube is all the way in / installed correctly? I got to the last few hours of my build and found that the tube was slipping, there went 3+ hours of wiring + another 4 hours pulling the tail block and all out of the frame and getting it back in, pain in the ass.

Insert the torque tube into the boom leaving approximately equal amounts exposed on each side. Put the tail case on first and push the torque tube fully into the tail case. You will feel it slip in. Next put it into the boom block while slowly turning the tail to spin the torque tube. When everything is line up, you will feel it slip in together. Put a mark on the boom where it is fully inserted. I pinned mine from the 450 pro days. If you do, be sure to cut the screw short enough so it doesn't rub the torque tube.

third, how is the clearance between your servo wires and the gears for the TT assembly? (assuming your wiring is the same as mine) Its close on mine, have it shrink wrapped and zip tied but it is still close enough to scare me a little bit.

Mine is going inside the frame from the right as well. The wire is run tight against the inside of the frame and zip tied. No problems.

[tomd27858]

Originally Posted by SamCassidy

there went 3+ hours of wiring + another 4 hours pulling the tail block and all out of the frame and getting it back in, pain in the ass.

Be sure to run your wiring so you can pull the boom out without going through a complete rewire.

[SamCassidy]

Alright, SWEET. Thank you all so much.

Tom, I had been trying the shim on the top of the main gear UNDER the bearing block hows that for an easy mistake! I still only have the one shim, which I believe is the .5mm, I will pull out the shaft and gears tonight and report back, hopefully with no slop. The play is literally only a few thou right now, maybe 3-5 thou, so it will be tight but hopefully it goes right in. If not I'm willing to bet I can find another .3mm shim SOMEWHERE around here.

As far as the torque tube goes, I think it is all the way in now. Everything feels super tight and smooth, and when I pushed it in I could feel it go all the way, I could tell because I had already mounted my boom supports and the horizontal stabilizer and after putting the TT and boom back on I had to move the support bracket and stabilizer further back on the boom, so everything should be good to go there now. I hope.

Tom, I shouldn't have to re-do any wiring to get the boom out, I just had to in that situation because I pulled out the whole tail block TT assy to make sure everything was alright there. I didn't know it just wasn't in far enough so I had to make sure everything was okay.

wheeeeww

[tomd27858]

Three thousandths if you are measuring it is not a concern if you cant find the thin shim. .3 mm is more than that.

Now get off of the internet and finish the build. We are flying Sunday and I'll give her a once over and let's do a maiden.

[tomd27858]

Told you the 500efl guys are top notch!

[SamCassidy]

It really isn't much, but enough that I don't won't it there, at a high head speed I think it could easily resonate some vibrations, I'm gonna try to find that shim if I can. Im about to go get started on it! I just got off work, wanted to sit down for a few minutes and relax some. Im not going to be able to make it down this weekend, my parents went to the mountains so I'm stuck here baby sitting a 8 mo. old puppy and 3 cats.

My 6200, sat, and ec3's will be here by mid next week, ill have somebody around here give her a look and hopefully get it maidened before the fly in next weekend! I can't wait! I was considering going ahead and soldering on the ec3's I have and just using what charge came on the lipo to center the servos but I think I'm going to wait until I get the other ec3 and new Rx / sat, plus I don't want to deplete my lipo so much it is dunzo before I get to fly with it, without having the ec3 for my charger I have no way to check it.

[SamCassidy]

Originally Posted by tomd27858

Told you the 500efl guys are top notch!

You were dead on about that one! Ya'll know whats up!

[GT86]

Originally Posted by SamCassidy

I shouldn't have to re-do any wiring to get the boom out, I just had to in that situation because I pulled out the whole tail block TT assy to make sure everything was alright there. I didn't know it just wasn't in far enough so I had to make sure everything was okay.

You may want to take a look at rewiring the next time you have the block out. If you have even a minor crash or you tap the tail on the ground when landing, you'll likely be replacing the front TT gears which means pulling the boom block. That's not going to be fun if it means you need to disconnect and then redo all of the wiring.

Definitely not something I'd spend the time on right now since you've got it buttoned up and ready to go, but something to think about the next time you have it apart.



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