Building the Fury Tempest FAI
A couple of months ago I made the decision to try one of the new Fury Tempest models that Miniature Aircraft in the USA have just released to the market. There were a few reasons for this. I wanted another 91 powered machine for 3D use and I had a feeling the new Vigor would be some time away. Therefore I decided to use my existing CS for 3D and get another machine for FAI work. I liked the flexibility of the Tempest FAI model in terms of being able to adjust dampening, paddle weight, flybar ratio, delta, gear ratios and various other settings quite easily.
I'm travelling to Australia in November to compete in the Victorian F3C Championships and this was the machine I was planning on using for this event so I was on a pretty tight schedule. Time to build the machine, set it up and get used to it before the event meant that I really couldn't afford to lose weekends of flying time.
I placed the order with the local distributor for a Tempest FAI with the 7.75:1 gear ratio and waited for the machine to arrive. I waited and waited then finally asked the distributor to find out what was going on. He found out that MA had shipped the kit on the 29th of July but as of August 21st it still hadn't arrived. Cyndi at MA tried to track it down from their end but to no avail and I was starting to get anxious as I needed to get the machine ready for upcoming competitions. However luckily at the eleventh hour, the kit turned up in one piece.
This is my first non-JR kit and I expected a few differences and anticipated quite a steep learning curve to get used to the design ideas of the Tempest. I'd also heard many stories of the complexity of Xcell machines in the past and was preparing myself for a bit of slog at building the thing up.
First impressions were that the box was a lot smaller than I expected, however
opening the box revealed a large gel-coated canopy and many bags of bits which
where fairly clearly marked. I was a little disappointed to find that the instructions
were separated into a book of text and a book of diagrams. What was nice though
was the supplied parts listing book.
Sunday night the building began on the rotorhead.
As per the initial recommended setup, I used the 0.9:1 (out of the available 0.65:1, 0.75:1, 0.8:1 and 0.9:1). The mixing arms are mounted on the very long flybar carrier which is very free. I suspect however that should a crash happen, the carrier will be stuffed given it's length.
The dampening system uses O-rings which seems to have become the defacto standard with new model helicopters now allowing pilots to customise their dampening with different O-rings pretty easily. The Tempest kit provides different combinations of O-rings (hard and soft ones) as well as different sized shims to futher adjust dampening. I chose a combination of 60 durometer O-rings inboard with 50's outside followed by a 0.25mm shim. This has yielded a similar dampening feel to my Vigors which have the Ron Lund O-ring system installed.
The assembly of the blade mounts and feathering spindle is quite different from what I'm used to. In this case you assemble the dampening, shims and bearings on the spindle while it's in the head. You then bolt it all up without putting the blade grips on. You then SLIDE the blade grips over the assembled shaft and press the pitch arms into the blade grips and bolt it down to the retainer sleeve. Not necessarily better or worse than the JR system I'm used to, just different, which in reality sums up the construction of this helicopter.
Following this, you setup the amount of delta you want on the pitch arms. You can have Positive 3.3 or 5.3 degrees, or Negative 3.3 or 5.5 degrees. I chose to use negative 3.3 degrees.
The paddles are supplied with a long strip of lead with which you can customise the weight of each paddle. At this point I have left all the weights out of the paddles to see how it goes, if it's too twitchy, I'll add some more weight.
I have to take the opportunity here and praise the extremely high quality of all the parts in this kit. All parts are just beautifully machined and designed. However is creating these has really got a handle on what's going on.
One of the first things you install is the tail drive shaft through the rear frame rail into the middle bearing block. This is one area where the Tempest has the CS over a barrel. The front of the Tempest's tail bevel gear is supported by the middle mainshaft bearing block whereas the CS's bevel gear is not supported at the front at all.
However having said that the CS takes the Tempest for simplicity of it's autorotation unit. This took me a couple of hours to get my head around and I have to say that at first I felt it was unnecessarily complicated considering other autorotation systems around. The Tempest system uses an assortment of O-rings and various combinations of shims in order to get it right. Not being the most mechanically minded, this took a little thinking for me, but once I understood what they were trying to achieve it all came together. Still, it's not the plug and play setup of the Vigor systems. Having said that, the unit does look very strong and durable.
Instead of using a bolt to secure the auto assembly to the main shaft Miniature Aircraft are using dowel pins secured by grub screws. At first I was a little concerned at how easy this would be to use, but if everything is lined up correctly the pin just slides in and can be easily pushed out again via a small hole on the other side of the hub.
What DID piss me off was the fact that the instructions call for the contents of bag '2B' which I spent about two hours looking (read 'stressing') for, even ringing up my mate's place where we had opened the kit to see if the bag had fallen out there. It turns out that the contents of bag '2B' are actually in bag '2A'...
Right Frame Assembly
Attaching the servo bell cranks is a non-event as you would expect.
Rudder control is passed back from the rudder servo to the tail via a bell crank mounted at the rear of the right frame and the gyro sensor sits atop a purpose built platform above and behind the radio tray.
Landing Gear/Bottom Frame
The assembled landing gear is then attached to the main frames.