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EXI 450 & Blueray Main Shaft Replacement:
This
page will describe the steps to replace a Main shaft. Very often
the Main shaft is bent in a crash. When visually looking if the
mainshaft is bent. Look at the base of the top hub and not the head
button. Even so, you can not always visually tell if the mainshaft is
bent, you must remove it and roll it on a sheet of glass (like from a
picture frame) to really tell for sure. 99% of the time in a
crash (especially if the blades are damaged), the mainshaft is bent.
(Click image to enlarge)
In general, you can use the Trex 450 SE V2 manual as a reference. For the blueray 450, the servo placement is different though (2 servos in rear, vs. 2 in front)
1) Use a pair of ball link pliers and remove the linkages to the 3 outer swash balls
2)
Using a 1.5mm hex tool and pliers, remove the top 2mm bolt and nut at
the bottom of the rotor hub. Note, if this shaft is bent or damaged,
replace it, or it may snap in flight.
3) Pull the top head assembly off.
4) Using a 1.5mm hex tool, remove the bottom 2mm bolt
5) Pull the mainshaft up and out from the top.
6) Using a 1.5mm hex tool, loosen the grub screws on the shaft collar about 3 turns and remove collar.
7)
Slide the maingear out to the side. note not to loose the spacer on the
top that is around the top of the onewaybearing sleeve.
8) Roll the mainshaft on a sheet of glass to view the amount of bend in the shaft.
Note:
99% of the time that a mainshaft is bent, the feathering
shaft(horizontal shaft/spindle) is also bent. You should service
this part of the head as well at this time. Click to view this procedure.
9) Inspect the teeth on the maingear to make sure they are not damaged. Replace maingear of necessary.
10)
Pull the maingear apart from the bottom smaller tail drive gear.
Inspect the oneway bearing that is attached to the maingear. Clean out
and re-apply silicone grease (DO NOT USE VASALINE or any petroleum
based grease near plastic). Make sure you don't lose the spacer (shaft
ring) on the top.
11) Inspect the oneway bearing sleeve that is
attached to the tail drive gear. This is what the oneway bearing rides
on. If worn, the oneway bearing sleeve will sieze up the oneway bearing
and particles of metal can fowl the oneway bearing.
Re-assembly
1) Verify your replacement mainshaft is straight by rolling on a sheet of glass.
2) Re-assmeble your maingear and don't forget the brass shaft ring goes on top.
3) Insert maingear into the heli.
4)
Insert the mainshaft and make sure you insert the correct end. Verify
that with the hole aligned with the bottom of the maingear assembly
hole that the recess for the shaft collar is just above the top
mainshaft bearing where the collar will go. If not, flip the mainshaft.
5) Using a drop of blue loctite on the bottom nut, insert and tighten the bottom bolt.
6)
Using a drop of blue loctite on each grub screw, put the mainshaft
collar on. The bottom of the collar should have the recess on it so it
rides on the inner race of the top mainshaft bearing. Before tightening
the grub screws, pull up on the mainshaft then tighten the mainshaft
collar. It should have no verticle play once the collar is tightened.
7) Insert the head onto the mainshaft and put the swash linkages onto the swash.
8) Using blue loctite on the nut, replace the top 2mm bolt and tighten.
9) Verify pitch curves are as you once had it.