Synergy N9 – Part One


Designed and developed by world-renowned 3D pilots Jason Krause and Todd Bennett, the Synergy N9 has been long awaited by heli’ hungry pilots. It created widespread interest amongst the cognoscenti even before its first public showing at the 2005 3D Masters here in the UK, although a production version was a long time coming.

With a wealth of experience under his belt Jason spent some years working with X-Cell and helped design the ever-popular and very precise head that’s used on many of its machines. However whilst competing at the 3D Masters a few years back, word got around that he was to cut his links with the company and concentrate on making his own helicopter. It was rumoured that he wouldn’t compete at the Masters again until he had his vision of ‘the perfect helicopter’ on the market. As time passed there was much speculation about whether the N9 would ever arrive, but arrive it did and I confess to being pretty excited at the prospect of reviewing it. Designed by one of the best helicopter fliers in the world as his version of the ultimate rotary-winged machine, the N9 is surely the most important helicopter to hit the market for a long while. But did Jason get his sums right?

Having taken eager delivery of a pre-production kit I wasted no time delving inside the box and was instantly greeted by a beautiful, white gel-coated fibreglass canopy. I dug around further in search of the instruction manual but couldn’t find one. The reason for this was that the manual for the production kit wasn’t quite ready, so I asked for an email copy of the pre-production booklet. Examination of the individual parts indicated that they’d been manufactured to a very high standard, and were tough with it. Included with the kit are SAB tail blades, paddles, and a very, very, green blade holder (nice touch). I also came across a pre-assembled tail box. That’s good! Incidentally, the tail has a 4.67:1 ratio and with the SABs fitted, giving a rotor diameter of 111/2″, there should be significant tail authority for anything you care to chuck at it.


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Having examined the parts for some time I finally got around to putting them together, starting with the fuel tank. This uses a breather fitting as opposed to a moulded nipple, which made me sit up and take notice as I’ve had issues with two Millennium tanks in the past when trying to seal them to take the high pressures delivered by pumped systems. Given that I had a pumped YS 91 lined up for the N9 I made sure to get the breather fitting right first time, the trickiest bit being to line the fitting up from the inside. This is made easier by pushing a length of thin, stiff wire through and out of the main fuel bung hole, before slipping the breather fitting over this, guiding it back out through the breather opening and then securing it with the outer nut. Anyway, I’ve not had any issue with it so far, and my tank is running at a very high pressure!

Next comes the undercarriage, which can be tricky to those not accustomed to this type of fitting. However, all you really need is a little patience. I found the best approach here was to secure the inner fitting to a kebab skewer using cyano’ and push it up the skid, then insert the locking screw and break the glue joint by twisting the skewer.

With the undercarriage sorted the engine, clutch, clutch bell (which has two recesses for governor magnets) and fan assembly can be added and dialled in for balance. A notable point here is that the fan is upside-down, the idea being that it draws air over the engine and then forces it down over the head through the shroud, fresh air therefore cooling the block first and head second. When building up the engine clutch and main gear assembly I noticed that all the bearing blocks and the engine mount are made from a composite material, which is reported to give greater durability and improved vibration dampening. The other thing that grabbed my attention was the fantastic main gear and sprag bearing. The latter could be described as oversized, but given the wear and tear on such an item I think Jason has been correct in over-specifying the thing. Once built the whole assembly is stunning; the bearings are free-running and everything has a tremendous feel of quality about it.


Right, that’ll do for now. Be sure to look out for Part Two, where I’ll talk composite frames, servos and swashplates.

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