Tailrotor gearbox

Some Extreme Aluminium gearboxes have excess clearance around the bearing
seating on the tail output shaft bearings. This causes play found on the tail
output shaft. Either loctite the bearing in position (outer cage) or return
the case to Motors & Rotors to have set screws added.

Meshing the gearbox correctly takes care as the sealed gearbox case makes it
difficult to see whets going on. If the mesh feels rough, but there is little or no backlash then the gear teeth do not line up. Normally this is caused by the output shaft gear needing a slightly shorter spacer. The spacer can be shortened on a sheet of glass paper. The gears also stay square on each shaft if the grub screws are tightened evenly. If you have a problem M & R will do the job for the return postage cost.

When you build the tailrotor hub assembly it is typical for there to be a
little slack on each tail blade holder. This is what the thin shims are for.
DO NOT try and remove this by over tightening the M3 Nyloc.

Always balance the tailrotor assembly with your chosen tail blades. For sport
flying 100mm SAB 480's work well. For 3-D use 110mm SAB442's. On JR gyros the ideal length is 105mm so I shorten the 110mm blades with a sanding block.

When fitting the star washer on the tailpitch plate a 10mm tube is the perfect tool. A small socket will work (or a Steel Parker Pen body!!)

A smoother tail system is available if you counter sink the 0445 Tail Bell Crank hole with a sharp scalpel blade where the 0101 ball fits.

An error in the instructions meant that the section about balancing and checking fan alignment with a DTi was missed out. It is crucial on all motor/fan systems that the fan runs with in 1.5thou max run out at the tip of the fan hub. (see picture) This is especially so on 80-90 motors.

Although the frames have very close tolerance holes it is important to check
that the frames stay flat during assembly. Use a steel Ruler held against each side frame.

It's easier to tighten the fuel tank nipples if a 2.5mm drill bit is inserted in the nipple to stop it collapsing while it is held.

Radio Set-up

With the bigger motors expect a low mid point on the throttle curve (as low as 35-40%) It will take time to get used to the different sound a 90 makes. If you have access to an optical tacho like the MA 0524 use that to check the head speed. The OS 91 in the Extreme works well at around 1500rpm head speed in the hover.

Another thing that makes the Fury series of helicopters stand out against the rest is the fact that there are positions designed into the the radio installation for Gyro, Gyro box and Governor. The Velcro straps are even included in the kit. There is a nice soft mounted switch plate to avoid high frequency vibration killing the switch.