MRC/Altech Hirobo: SST Eagle Freya

Model Airplane News, Jan 2002 by Bell, Rick

MODEL AIRPLANE NEWS

FIELD & BENCH

REVIEW

MRC/ALTECH HIROBO

Newest sibling in the Eagle family

One look at the SST Eagle Freya, and you can see that it originates from the Hirobo SST Eagle 2 Ex and Eagle WC that Manabu Hashimoto flew in 1997 and 1999 to win the F3C World Championship. With the Freya, Hirobe engineers have taken a proven design and refined it, for the 3D pilot. Don't be mistaken; this heli can be a serious contender in AMA and FAI competition.

To keep the price down, Hirobo uses high-- impact-engineering plastic main frames that absorb vibration. The Freya's innovative features include:

* the newly designed FFZ-II rotor head that allows different Belt-Hitter ratios.

* the flybar paddles have removable endcaps to allow quick and easy weight adjustment.

*the new split-gear constant tail-drive system drives the tail rotor during autorotations.

* the tail-rotor servo, is mounted on the tail boom for a direct linkage hookup to the tail rotor.

* the tail-rotor pitch mechanism is supported by dual pivot points for a very tight tailrotor control system.

* the tail fins are of a skeleton design for aggressive 3D flying.

* the sleek and narrow canopy allows fast forward and backward flight.

* all pivot points use ball bearings, not bushings.

ASSEMBLY NOTES

Before you begin assembly, it' always a good idea to pull out the manual and read it from cover to cover. The manuals starts off with safety warnings, items needed to complete the model and other information. It has little in the way of written notes, but it's very well detailed and easy to follow. I started by removing all of the numbered parts bags from the kit and laying them out in assembly sequence. All of the hardware (screws, nuts, etc.) is in separate bags and must be sorted. Be sure to degrease all the screws and use Loctite on all metal-to-metal fasteners. In this article, I'll cover the assembly steps that need special attention or are not so obvious in the construction manual. The molding of the parts throughout the kit was outstanding, and the fits were very precise!

* Elevator lever assembly. I first screwed the balllink ends to the A-arms because after the A-arms have been attached to the elevator lever, it's difficult to reach the screws that hold the ball links in place. I followed the diagram for the rest of the assembly with no problems.

* Upper frames. The frames have molded pockets for the bearings and cross-members. Before screwing the frame halves together, be sure the elevator lever assembly is oriented correctly between the frames; there is a left and a right side. Now is a good time to add the receiver switch (it's difficult to add later). I also used a tiny drop of epoxy to secure the outer race of the bearings in the pockets to prevent them from rotating. Again, the fits were very good and the frames were perfectly aligned.

* Fuel tank. Be sure the clunk does not hit the back of the tank, or you could have fuel starvation problems later. Also attach the fuel-feed and muffler-pressure lines from the tank now; they will be difficult to access when the tank is mounted in the chassis.

* Lower frames. The lower frames are now screwed to the upper frames, capturing the fuel tank between them. The tank is supported by six rubber cushions that fit into recesses in the tank. I used a tiny drop of thin CA to secure them to the frames to prevent them from falling out before the tank was in place.

* Main gear and swashplate assembly. When you screw the main gear to the autorotation unit (which is pre-assembled to the split gear), be careful not to overtighten the screws, or you could distort the unit.

The swashplate is made of a combination of molded plastic for the outer ring and metal for the inner ring. I used a 3mm bolt to start the threads for the balls on the outer ring. Also make sure that the two longer balls oppose each other on the inner ring.

* Rotor head. The feathering spindle is supported by two metal holders that must be glued into the yoke. I used slow-setting epoxy on the holders and used the spindle to align the holders while the epoxy set. The spindle should slide smoothly in the spindle holders. The seesaw assembly gives you options for the flying performance you desire: high stability (novice), standard (intermediate), or high aerobatics (aggressive 3D). I followed the instructions for the standard settings with no problems. Be certain to grease the thrust bearings and install them correctly. I followed the manual for the rest of the rotor-head assembly and then balanced it on a High Point balancer.

* Tail rotor/tail boom. The tail rotor is easy to assemble: be sure to capture the drive belt between the case halves before you screw them together. Just as with the main rotor, be sure to grease the thrust bearings and install them correctly. Before installing the tail rotor on the output shaft, I balanced the assembly on a High Point balancer-- must for smooth operation. I installed the tail-rotor pushrod guides and the tail-rotor servo mount on the tail boom before installing the boom on the chassis. Make certain the drive belt has the proper twist in it, or the tail rotor will spin backward.