I’ve been lucky enough to have owned an Aurora for over a year now and I must say it’s an amazing machine. For sometime now I’ve been running a custom head configuration based on the “Active” setup in the manual. Let just say active is truly active, which is fine on those still dead calm days but when the wind is up I find the heli a little flighty or jumpy which can be a little unnerving.
At first I attacked the problem by adding more expo but really once you get up to about 30%+ it’s just getting a little silly. I then moved to the outer hole on the flybar carrier, then finally tried the inner hole (on the flybar cage side) on the upper mixing arm. You’ll also notice that I flipped the upper mixing arm in order to give the link from the swash to upper mixing arm more clearance to minimize the possibly of binding.
Basically this an “Active” setup with the “Ultra Stable” flybar configuration which I’m finding really smooths out the flight characteristic while maintaining the edgy-ness of “Active”. Needless to say I can now drop the expo down to a more reasonable value, at the moment it around 20% but I’m sure it can go further.
The last couple of flights on my Aurora have been plagued with governor surging issues. Turns out the sensor cable had one of the plastic tabs broken off that holds the wire crimp in place. That plus some standard heli vibrations was enough to cause a bad sensor connection (gov on, gov off, gov on, gov off) …cut solder job done 😛
The clutch bell bearings have started to get quite knotchy on the Aurora (100+ flights) so I decided to replace them. It turns out only the middle bearing part: AV00-200-216 needed replacing (that’s the larger of the bearings which sits just above the pinion) which presumably takes most of the force. A tip for any one needing to replace clutch stack bearings is:
- Drop the engine,
- Leave the ratio plate in place but remove the clutch block bearings (x8 bearings)
- Undo the starter coupler set screw and remove the starter shaft by sliding it down
- Slide the top bearing block up out of the frame
- Slide the lower bearing block and clutch-bell down out out of the frame
The stock Aurora sprag bearing needs to be lubricated in order for it to function and with stand the abuse of 3D flight. I’m not entirely sure what type of grease the bearing is packed with by default but it lasted about 10-15 flight before I noticed the sprag slipping (the governor was hunting wildly in 3D flight). The simple fix is to flush and degrease the bearing, just use nitro fuel, WD40 or similar. You will need to take the plastic bearing side case off (careful of the tiny springs inside) in order to degrease the bearing. Once the bearing is degreased soak it overnight in Automotive Transmission Fluid (ATF) then replace the plastic side case and your done.
ATF is very thin and will eventually work it’s way out so regular lubrication is required but that’s really just a maintenance thing. Future re-lubrication can be done whilst leaving the sprag in the maingear housing and just removing the plastic side case and dabbing ATF on with an ear cotton bud. The bottle pictured below is the ATF I used and is available at most auto-stores and service stations in the UK for about £5
After 50 or so flights I noticed engine running lean and fuel dripping from the tank. As it turned out I had a crack in the fuel tank around the fuel stopper hole. The problem was when the tank is under pressure (it’s a lot as I’m running a OMI Cline carb mod) and expaning it caused the plastic fuel stopper cap to press against the top engine mount bolt. In turn the fuel stopper hole is levered and all the engine mount vibrations where going into the fuel stopper hole. Obviously the tank eventually gave out and broke. You can see from the picture of the tank below which I epoxyed where the crack developed.
A simple solution to the problem is to swap out the offending engine mount bolt with a 4mm rounded head bolt. The fuel stopper cap then easily clears the bolt when the tank is pressurised.