Building the Synergy N9
Simon Lockington

The parts laid out on the lounge floor

Fuel tank and skids are the first things to be assembled.

The little skid locks secure the skid braces to the skids. A bit tricky to fit!

Fuel tank end result. The aluminium breather can be tricky to install.

The engine, clutch and cooling fan assembly

The large fan is mounted upside down to draw air up and over the engine.

Dial gauging the fan hub on the engine output shaft.

The stock 15 tooth pinion is supported at the top by two bearings.

Completed engine and cooling shroud assembly.

Main gear and auto hub assembly.

The sprag bearing comes just like this and you fit it into the bearing enclosure for the autohub.

Main gear with auto hub fitted.

By now, you’d have to have been living under a rock for the last couple of years to have not known about the existence of the Jason Krause designed Synergy N9.

The long awaited N9 is a result of the experience and ideas built up over the years by both Jason and business partner and esteemed 3D pilot Todd Bennett.

First demonstrated to the public at the 2005 3D Masters in the UK, prospective buyers of the N9 feel like they’ve been waiting, and waiting and waiting as rumoured release dates come and go.

Well now, the wait is over, on July 28 th the kits start shipping from the various world-wide distributors (to find your local distributor, visit www.synergyrc.com). However I’ve managed to get one to build and review for you now.

LATEST INCARNATION
Last October I flew a prototype Synergy that had been shipped out to Australia for the 3D Downunder event. It had a Webra engine in it and was very much in the prototype stage. The helicopter itself flew quite well, given that I wasn’t able to change any settings.

Early this year I got to fly Jason Krause’s model at the Australian 3D Smackdown event that he and Alan Szabo came out for. There was a noticeable difference between the first machine and this one, as you’d expect Jason’s was much more precise and refined.

The machine that I have, is a final release pre-production packed model meaning that it’s the same machine that will go on sale, it’s just not in the nice box and the instruction manual wasn’t fully finished yet.

OPENING THE BOX
The box is dominated by the large gel-coated fiberglass canopy. The fiberglass work is by far better quality than what I have seen in my JR Vigor kits which are by far the worst I’ve seen in any kit. I feel the canopy is better quality than that of the MA Tempest I had, but as you’d expect, not as high quality as the Sylphide canopies as they come out of the box.

In my kit, all the smaller bags were combined in one large plastic bag while the larger items such as the frames, undercarriage braces, cooling shroud and fuel tank were free packed.

I was pleasantly surprised to find the kit comes with its own blade holder! Nice touch!

Other items that stand out are the included SAB carbon paddles and tail blades.

Naturally, I got straight into the parts bags to have a bit of a touch and feel session of some of the parts. Overall, everything about this machine seems ‘chunkier’, that is, the parts seem larger than a normal 90 size machine. Take for instance the swashplate, the thing looks like it’s been taken off a Sikorsky Skycrane it looks so heavy duty!

The pre-assembled metal tail gear box has a very large output shaft. The very large main gear makes the JR sized ones that I’m used look miniscule in comparison.

Also present is the innovative plastic engine mounts. While a lot of people have been turned off by the thought of plastic attaching their engines to the airframe, I really like the idea of the mounts smoothing engine vibrations by a small amount. More on this later.

This is a build article, and it’s an indepth one at that. I’m going to go page by page and tell you what I liked, and ofcourse, what I loathed about the new Synergy N9.

FUEL TANK AND LANDING GEAR
The first components to be built are the fuel tank and landing gear. I was gutted to see how the fuel tank ‘breather’ is implemented in the tank. I’m used to getting fuel tanks with the breather tube moulded into the plastic, I was disappointed to see that the Synergy tank uses a similar implementation to the Tempest I used to have in that it has an aluminum vent tube that has to be fed up from inside the tank and is threaded on via a nut on top.

With the Tempest I struggled to get this done and the Synergy was no different. Firstly I enlargened the hole a little with a drill as the vent wouldn’t fit which wasn’t a big deal.

The biggest problem with an implementation like this is getting your needle nose pliers to move the vent to the hole in the tank via the large tank hole. It ain’t easy. It wasn’t for the Tempest, and it’s only slightly easier on the Synergy.

What I did this time to make it easier was slide a small hex driver through the vent hole towards the main tank hole. Then, using the needle nose pliers, slide the aluminium vent onto the hex driver shaft. This at least keeps the vent pointing in the direction of the hole. It will then slide down the hex driver shaft and if you’re lucky, enough of it will come through the hole to pull it through, tighten the nut up and you’re done. The rest of the tank is very straight forward.

The landing gear was a bit new to me. The Synergy uses bolts that thread through the landing skid struts into the skid tubes and within those, some little ‘skid locks’ which are basically little round blocks that have a thread cut into them. They slide up the skid tubes and give the skid bolts something to lock into. I hadn’t seen this method before, but am told that the Robbe Millennium uses the same thing.

Getting the little skid locks down the tubes and into position was a little interesting. It took a combination of a Sylphide flybar to shove the locks up the tubes to clear away any machining burrs. Then, I used a T-Rex antenna tube to shove the tubes back down the other way.

The difficulty in getting this operation done is getting the locks to arrive in the correct position of the skid tube with the thread facing up so the bolt can thread into it. You see as you push the lock along the tube it tends to rotate. To get around this you can try wiggling it around with a small hex driver, or, you can try this:

Bob Johnston’s Tip
Try CA’ing the skid lock to the front end of a wooden dowel so that the skid lock is attached to the front of the dowel. Slide the lock with the dowel up the skid tubes and use the dowel to rotate the lock as necessary.

Once the bolt is threaded into the lock, rotate the dowel to snap it free of the lock.

ENGINE/CLUTCH ASSEMBLY
I decided to use a YS 91 engine in my machine, simply because my Sylphide’s have this engine and I’d rather keep a common stock of parts.

The Synergy uses a big cooling fan just like the Vigor and Milly. Infact, I’d be hard pressed to find the difference between either of these fans, which is great because I’ve never seen a cooling system that’s as good as either the Vigor or Milly.

The difference with the Synergy is that it is mounted upside down and draws air up over the engine then back down through the shroud to the head.

I mounted the fan on it’s hub and put it on the balancer and was pleasantly surprised to find it needed no work to make it balance.

The big clutch immediately reminded me of a Raptor one, the long start shaft is mounted into the clutch. The clutch is bolted down onto the fan, the clutch bell (which includes two recesses for fitting GV-1 magnets) rests on top with the 15 tooth standard pinion threaded in. The pinion is supported by two 10x19x5 bearings in addition to a smaller bearing for the hex adapter. These bearings are encased in a plastic bearing housing.

The standard pinion is a 15 tooth one which, with the standard main gear (124 tooth) yields an 8.27:1 gear ratio.

I dial indicated the fan hub onto the engine until it got to within 0.03mm of run out which I felt to be fine.

The large, fully ducted fan shroud is then fitted to the engine assembly. Once again, this is one of the best shrouds that I have seen on a helicopter bar only the Vigor and the Millennium. Many helicopters, even today, have very average cooling systems which doesn’t let you get the most out of your engine.

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