Going to try the TracX FBL head

[Bob O]

Due to a recent crash, which damaged some parts in the X50 factory FBL conversion head, I decided to try something new. I've just rebuilt the heli with a TracX FBL head.

I'll post up some pics, measurements, etc. in the next couple of days.

[x50B]

I was just looking at doing the same with a compass head, I look forward to seeing how you go and hopefully some pics.

[Bob O]

First thing first.........out of the box without any mods, this head sits higher than the factory head. This is due to the length of the pitch control arms. If you mod the delrin rods to make the arms shorter, the head can be positioned at it's lowest height, which is about the same height as the factory head.

As far as the head build, it came nearly fully assembled. The only thing not attached were the pitch control rods. I disassembled the head and found the following:

1. Thread lock was used on the blade grip arms.
2. Thread lock was not used on the spindle bolts.
3. Thrust bearings had only a slight amount of grease in them.
4. One spacer was used on each side of the head, but there was a little slop when pulling on the blade grips..

What I did was grease the thrust bearings completely, install an extra spacer/washer on each side of the head (two each side), and reassemble with thread locker. The extra spacers got rid of the slop. I stayed with the stock dampers for now. I have the KBDD lime green ones, but I couldn't get a proper fit after a few tries and got tired of messing with it. I'll install them when the stock ones wear out or if I don't like the feel of the stockers.

The pitch control arm/ yoke was installed last. It's pretty much a no-brainer, just place a brass washer on the bolt, put the bolt through the yoke, place a silver washer on the bolt and then screw it into the blade grip arm. One arm turned out silky smooth, while the other had a slight amount of drag I couldn't get rid of. I dry-fitted these parts prior to final assembly. I ended up swapping screws, washers, swapped sides, all different combinations etc., but couldn't get both sides to be super smooth. The only thing I could figure was that the threaded hole in one blade grip arm was drilled slightly off-square. Either way, there was no "binding" or notchy feeling, one was just not silky smooth like the other.

Here are two pics to show which hole in the head to use with with which hole in the main shaft. The spacing between the holes in both parts is slightly different, so there are four different heights to choose from. I ended up with the jesus bolt in the lower hole of the head and the lower hole of the shaft. This afforded the lowest head height with the least amount of adjustment of the ball link from it's fully turned-in position. I had to go out 2 turns to get zero degrees at the blades.





This third pic, although hard to tell exactly due to it being so close-up, shows how the TracX head sits higher than the stock head. If you modded the delrin rods so the head could be mounted with the jesus bolt in the upper hole of the head and the lower hole of the main shaft, the head height would be just about the same between the two heads.



While the head height can be adjusted lower if you took the time to do the mod, this next thing is probably not adjustable. The blade grip ball link spacing is different. The stock spacing is 30mm, and the TracX head spacing is 35mm. This will create a significant impact during MICROBEAST Setup Menu point "J". This could be a good thing depending upon your current setup, whether your chasing the blue LED at 6* or not. In my case where I already had early blue, I didn't need this wider blade grip ball spacing.

My previous setup, with 10mm ball spacing at the servo, using the 120* bell cranks and the factory head, I was getting the blue LED at 5.2*. With the TracX head's wider blade grip ball spacing, re-doing step J put me back at 4.5* and blue. That was what I had when using the factory head and 9mm ball spacing. The other issue with this is during Setup Menu point "L". Being that more swash movement is necessary with the TracX head to get the same amount of cyclic pitch as the factory head, this caused very slight binding with the blue LED while checking/setting cyclic limits. In order to eliminate binding, I had to reduce the limits a little bit, which took me out of blue and just into red.

At this point, what I have to do in order to get the blue LED closer to 6* during point J, is use wider ball spacing at the servo. I'm going to go from my current 10mm to 12mm spacing. This should get me pretty darned close. I realize my wording might be confusing regarding degrees and blue LED, so I'll clarify that I do validate the step at 6* regardless of color. I just like to reference at what point the LED goes from red to blue so you all can understand why I'm going to make certain changes to my mechanical setup.

So, once I get the servo wheels drilled with the new holes, I'll re-do step J and post what the results are. I'm going to stay with whatever it gives me, as I'm fairly certain it will be closer to blue at 6* than I've had with the three previous setups on this bird.

Heading to work in a few minutes. Catch up with you guys later.

[Bob O]

Got everything set up this morning. Drilled custom holes at 12.5mm (25mm total spacing) and redid steps J, K, and L.

During step J, the LED went from red to blue at 5.7 degrees, which is the closest of all four configurations I've tried.

During step K, I reset collective to +/- 12 degrees.

During step L, the LED was reset to blue and there was no binding at all so I left it as is.

All that's left to do is slap the tail on and take her for a few shake-down flights. Sunday will be the soonest.

[DominicD]

With the KBDD dampers you will need a metal spacer between the damper and the headblock, as the damper aren't long enough. The KBDD dampers are a TIGHT fit, I generally have to use some tools and my body weight to install them. I have to make sure the spindle is well centered before i really push the dampers in as the spindle will not recenter itself even after 100+ flights (it is that tight).

P.S. Your geometry is really off because of the different swashplate, the one on the 6HV is crazy big compared to yours it looks like.

[Bob O]

I'll post some pics of the final setup tomorrow.

Sent from my phone

[Bob O]

Sorry, no pics today. I discovered a defective part in the new head and will have to wait until next week to get the heli back into the air.

[johnbs8]

Whats going on with it bob. Dont hold out on us

[Bob O]

Originally Posted by johnbs8

Whats going on with it bob. Dont hold out on us

The hole in one of the
blade grip arms wasn't drilled squarely, so one or both bearings in the yoke bind when I snug up the screw that holds the yoke on. Check the link for pics. Hopefully Nankin will ship a replacement quickly. If they do, I can have my bird back in the air by my next days off.

Sent from my phone

[Ah Clem]

Bob,

First of all, sorry you had the problem with the blade grip arm. Nankin has excellent service and it looks like that is being taken care of. If there is a problem, my offer is still good, sir.

Also, Capi mentioned the spacer washers required when using the KBDD Dampers. These are available in Delrin, made specifically for this purpose, from KBDD (part # 4105). The delrin washer is inserted into the damper pocket on the head, then the damper. You will still need the metal washer between the damper and the blade grip bearing.

These are almost always a tight fit (again, as Capi pointed this out, as well). In several cases, upon reassembling the head with the KBDD Dampers, occasionally one grip will be notchy (sometimes both). This goes away after a few flights, as the dampers settle in and the spindle finds its exact center. This has happened on one or two of my Compass/TracX heads, and on my stockTrex 700 FBL head.

Make sure the dampers are thoroughly coated with silicon grease, inside and out. This will help from ease of installation, longevity, and performance, standpoints.

I am getting ready to install a Compass head on my Raptor 50. It will, likely, be several weeks before I get this done, so you are well ahead of me on your, much more modern, Thunder Tiger model. I am looking forward to your results.

I have already upgraded my Trex 600E, Chaos 600E, and Caliber 700 to this head, so I am confident you will like it.

As far as the height of the head goes, in the case of the Caliber, with its unusually long main shaft, I cut one inch from the shaft and re-drilled the head retaining bolt. I am in the process of converting an Odin and am using a 7HV main shaft. I had to cut it to length as well.

Please continue to keep us posted on your progress, sir.

[Bob O]

Thanks Ah Clem, I'll keep you posted.

Sent from my phone

[johnbs8]

I had the small screw that bolts the grip arm to the grip stripped out. Sucks but it happens. Other then that i just dropped it on my x50 and had it flying in a matter of no time. The kbdd delrin shims and dampners are rock solid. Just as said above, my one grip was notchy but worked itself out after the first flight. I loved the head so much i had to have another.
So did or are you gonna mod the main shaft or the linkage arms?

[Bob O]

Nope, not going to mod the head or shaft. I just want to get flying again.

Sent from my phone

[Bob O]

John,

How do you like the longer main blades on your birds?

[johnbs8]

Yah man get that baby in the air asap... and really theres no need to do any modding. just the stock dampners when ya wear on them a bit. mine lasted a couple months or so.the head started getting really sloppy.
the compass 615's fly great. they are fast on cyclic, good pop and they track real nice. when i bought the 615's they were $65 a set in march which was an awsome price for quality blades. i bought 2. now they are $80 a set. the word must have got out !!! DANGIT!! lol. i just got a set of 625mm Radix V2 but havnt flown them yet. maybe next week when my engine comes in.

[DominicD]

I wasn't a fan of the stock dampers, the KBDD make the head super stiff, seems to work very well with the BX that Bob likes.

[Bob O]

Going to fly this afternoon. Mostly to break in the new ring. At least I'll have gotten that out of the way by the end of the day.

Talk to you guys later!

[Bob O]

Originally Posted by DominicD

SNIP
P.S. Your geometry is really off because of the different swashplate, the one on the 6HV is crazy big compared to yours it looks like.

Here's a pic of the TracX head on my X50.

[DominicD]

does the BX even have a 140 swash setting ?

[Bob O]

Originally Posted by DominicD

does the BX even have a 140 swash setting ?

Yes. But I'm back with 120* for now. The pic is with 120*.