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Thursday, March 22, 2012

Tarot 450 Flybarless Rotor Head

I purchased a Tarot 450 Flybarless Rotor Head from CNC Helicopter, along with a Tarot ZYX 3-Axis Flybarless gyro, with which I am having a few issues. This rotor head is the best I have found at one helluva great price. I will buy this one exclusively from this point forward! In this blog post I take it apart, inspect, grease and Locktite it, then install it on my Frankenheli 450.


The head comes as seen here, without the control rods.



I took it apart. It uses the standard Align feather shaft arrangement on a 4mm shaft. I realize now that I failed to measure the length, so I can't say its a standard length, but given the design is otherwise that of an Align head, I don't think its anything but standard. I am soaking the closed ball bearings in silicone oil.



I love it when designers keep things simple. Here are the four closed ball bearing, all the same size!



Here in profile.


ip

One inside the grip.



One bearing on the head side. You can see the grip control horn here.



 I removed it and Locktited it; it has a short segment that is threaded, that inserts into the control horn, and it all screws into the grip. I Locktited both ends. Screw everything snug, but not gorilla tight. 



I used to use white lithium grease, but it dries and cakes up. I like TriFlow red grease on the thrust bearings and a little on the feathering shaft. I use silicone oil on all bearings and moving surfaces.



The thrust bearings have two sides, one side with a flat surface, the other concave to hold the grease. Grease the whole thing, but when you reinstall it make sure that the concave side faces the main shaft so that the centripetal force will not pull the grease from the bearing. Remember that there are tremendous loads on the thrust bearings in flight.



Make sure you get the order of the parts correct: screw (a little Locktite, remember just a whiff and keep it out of the bearing. Grease inactivates Locktite, so don't mix them), small washer, back thrust bearing plate (remember that with both sides of the thrust bearing keep the raceway, the bearing groove, against the bearings), bearing ring (concave side to the shaft), inner thrust bearing plate, thin larger washer.



The dampers are quite hard. A little grease.



A thrust bearing set about to be installed onto the feathering shaft.



The head is well constructed. In addition to the Jesus bolt (just across from my thumb), it has two screws, one on each side, just across from and under the swash stabilizer arm. The bottom hole of the rotor head is split allowing these screws to bring the sides tightly together on the shaft. The cheap ones often need to be stabilized as the Jesus bolt can't keep the head from teetering on the top of the main shaft. I like the long body and these tightening screws, great design.



The head all put back together. I always hold my breath when I tighten things up expecting things to bind, but everything remained smooth and snug!



One of the shaft tightening screws. I removed these and the Jesus bolt to install the head on the main shaft.



Removing the Jesus bolt.



Installing the rotor head onto the main shaft. In a moment I will realize I have the swash stabilizer arms going the wrong way and will remove them, spin them around, and re-Locktite them in place...



All installed with control rods in place. The gyro stand is empty awaiting the replacement Tarot ZYX 3-axis system to be installed.

This Tarot 450 FBL Rotor head is well constructed, well designed, tight and easly installed! Can't wait to put the FBL computer on and wind this thing up!

2 comments :

  1. Hello,
    I got myself a tarot fbl head+zys gyro combo, and my feathering shaft seems to be bent. How do you remove it? I tried pushing it with my hand but with no luck...Any ideas?
    Cheers
    Florin

    ReplyDelete
  2. Sorry to hear that... I would return it. Bummer... lets assume its not bent until you can roll it, unless of course its really, well, bent. Hopefully you have removed the grips and are looking at the shaft itself. If its bent and needs to be replaced you can put a pair of vice grips on it (locking pliers) on the BENT end, pulling the non-bent end though the head, and twist it out. It should come out fairly easily. If it doesn't return it... Doing this will damage the shaft, so only do it if you are sure its toast.

    If you are not really sure, try tapping it out with a hammer, pushing the suspected bad end out, the good end through. Then roll the shaft on a flat surface to see if it wobbles.

    Honestly, I would just return it... you shouldn't have to do anything to it.

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