30th September 03:36
Fellow gassers: second round of questions...
I don't know about the rattleing sound when moving the helicopter, engine off.
That rattling sound at idle is more than likely, the clutch where it engages
the engines cooling fan. X-Cell uses a set of rubber dampers pressed into the
top of the cooling fan. These dampers have small holes in them that a set of
metel pins, pressed into the clutch itself, push into. When those rubber
dampers wear out, you get metal to metal contact between the pins and the
cooling fan and it sounds like a bearing is self destructing. Once the drive
train in under load, things quit bounceing around and the noise goes away but
the problem is still there. Replace those rubber dampers and your noisy idle
will be corrected. It might cure the other noise too. If you're moving the
model in such a way as to move the clutch too, you'd hear those pins tapping
the cooling fan.
1500 - 1800 will work on the gasser. Personally, I prefer not to go much over
1700 on the high end. As I recall, the gear ratios are in the neighborhood of
7.5:1, give or take a bit but don't hold me to that.
The bottom of the vertical tail fin is one of the first places to show any
vibration problems. What you're seeing can be caused by a number of sources.
1. A slight main rotor imbalance.
2. Engine to main drive gear mesh too tight.
3. If you're model is using a geared tail drive (no belt drive), the gear mesh
between the top of the main gear and the tail drive pinion gear being too tight
can contribute to this, not to mention the 45 degree bevel gears in the tail
rotor gear box itself.
4. If the engine mixture (carb) isn't set right, the engine itself can cause
this type of vibration.
I know it's a pain but this is just something you'll have to track down.
In my last response to you, I mentioned Larry Bergen in Cassopolis, MI. He
might be able to help you with the Zenoah engine manual. Miniature Aircraft in
Orlando, FL. sells the X-Cell line and they could help you with the plans and
assembly manual for the helicopter itself. The number is 352-383-3201. You
might also try Rick's RC at http://www.ronlund.com in Corpus Christi, TX. I don't
know if he'd have these items but I'm sure he could help you get them. I'd
fire of an email to Ron Lund and ask.