Vario Bell 212 Construction Project

 

Fuselage Manufacturer: Vario Kit No. 2120
Scale: 1:7.2
Length: 1660 mm (65.4 inches)
Width: 340 mm (13.4 inches)
Rotor Diameter: 1810 mm (71.3 inches)
Approx. Weight: 9.1 kg (20 pounds)
Mechanics: Vario Benzin Petrol No. 8300
Engine: Zenoah RC230
Radio: JR 10X /w digital servos
Gyro: Futaba GY401 /w S9253 servo
Governor: Futaba GV-1

Estimated Completion Cost: More than a glow plug but less than the real thing.

Features:
– Opening Cockpit Doors
– Cockpit
– Sliding Rear Cabin Doors
– Mirrors
– Navigation Lights
– Antennas
– Rotary Light
– Rivets
– Strobe Light
– Landing Lights
– Wire Strike Protection System
– Pilot Figures

I started flying RC Helicopters in the summer of 2001 after being involved with RC Fixed Wing for about 15 years. Helicopters had always fascinated me so I decided to take the plunge. As I had been flying mostly gas-powered standoff scale planes, I decided to stick with a power plant I was familiar with and purchased a JR Ergo Z230 for my first “trainer”. After a few flights, I was hooked. I spent the rest of that summer and the summer of 2002 trying to learn the basics of this challenging hobby.

I decided to build a scale heli over the winter of 02/03 so the Grumman F7F Tigercat (twin Zenoah G-62’s) got pushed to the back of the closet. I selected the Vario Bell 212 model for this project for several reasons:

experience in flying the full-size helicopter,
size,
reputation and experience of the local distributor,
availability of scale accessories,
price, and
access through the Internet Scale Forums to top scale builders who have built similar projects.

I did some research and decided to build the heli utilizing a flybar (instead of the # 702/70 Semi-Scale Rotor Head) to make the model easier to fly. Also, the tail rotor gearbox would be flipped over to place the tail rotor in the scale location.

Next, I had to chose a full scale helicopter to try and copy. I had narrowed things down to either a Canadian Armed Forces Rescue 212 or a Canadian Coast Guard 212. The Coast Guard scheme won out – it was bright and distinctive, a full-size model flies out of the Halifax Coast Guard Base and, thanks to the kindness of the two other Steve’s in our club who work for the Coast Guard, it was possibe to get actual pictures of the real thing.

The kit was ordered though the Vario Field Rep and and I found both him and the distributor to be very helpful. They were able to tell me exactly what “extras” I would need to make this a realistic project. Having built several fine scale models himself, Daniel Grandmaison was able to give excellant advise on exactly which scale accessories would be appropriate for the model. We added such items as:

Different main and pinion gears (# 90/18) to lower the head speed to about 1300 RPM,
A longer mainshaft – 214 mm (# 35/30)
A longer flybar (# 79/30)
Longer ball-end bolts ( #060/4) for the swashplate

When the kit arrived, I was shocked to see the size of the box. Oh Well, I said – the box must be large to allow for lots of protection around the fuselage. Once I got the box open, I realized I was wrong – although every piece was securely and individuallt wrappwd in bubble wrap, the fuselage was  HUGE – what had I gotten myself into?

An inventory of the contents was completed and all parts were accounted for. The kit includes the fuselage, the glazing panels (windows), green top cockpit windows, 40 degree gearbox, landing gear, woodwork, bolts, screws, instructions etc.

The instruction books are about what I expected after building the Benzin last winter – sparse but adequate. They consist of two booklets of isometric drawings – one showing construction of the Bell UH-1D with the second showing extra or different steps that are required to build a 212 or a 412. I was thankful when building the Benzin that Daniel Grandmaison included his own construction write-up with pictures. Having said that, I’ll admit that the drawings do show all required dimensions, give a numerical sequence for the installation of parts and do indicate which type of glue and Locktite to use where. I’ve build giant-scale fixed projects with less instructions supplied (the Grumman F7F is basically just a couple of line drawings). I don’t think most scale builders like, or need, to be told to “put Tab “A” into slot “B” – part of the thrill in doing a scale project is the challenge. First time scalers should be able to figure it out with a little effort – Run Ryder Heli Forum and Flighline Forums are only a few clicks away for help. Just remmber to be sure you understand the intent before you start cutting or gIuing. I also found some good advice was available from other modellers in our club, whether they fly scale or not.

One confusing area, for me, was the installation of the piece of plywood that holds the blind nuts for the bolts for the attachment of the skids. While the drawings would indicate that this would be epoxied to the exterior of the fuse, common sense and experience would cause you to install it to the interior floor. I installed it inside and found that the plywood fits perfectly between the longitudinal formers – maybe that was where it was supposed to go all the time!

OBSERVATIONS & RECOMMENDATIONS SO FAR:

Measure twice before starting any cutting or gluing.

PLAN AHEAD! If you are going to add scale accessories, make sure that you plan for their installation early. wiring for lights is extremely difficult to run after the flor has been glued in place ( don’t ask me how I know this!).

Have all parts available at the start of the project, if possible. I know it owuld be nice to spread the cost out over a period of time but you’ll run into snags throughout the whole process waiting for parts you didn’t order yet.

The mechanics must be on-hand at the start of the project – they are bosted in early in the construction process.

Most parts were readily available from the dealer within a 2 week period.

Buy a good set of small files, small drill bits and a Dremel Tool – you’ll use them every day.

Following are pictures of the construction process so far:

The 212 fuselage deglazing was done with 600-grit wet / dry paper. I added a few drops of liquid detergent in the water to act as a lubricant (a trick picked up from other builders). The doors, windows and vents were cut out after the deglazing was completed. This kept the fuselage more rigid during the sanding process. The deglazing will take hours – be patient and be sure that all of the shiny surfaces have been dulled.

 

The Vario Benzin mechanics were bought in the spring of 2002 and flown throughout the summer in Pod & Boom form. The auxillary cooling fan (included with the kit0 can just be seen under the base plate. It is held in place by the same bolt that holds the clutch to the engine.

 

The Benzin mechanics fit nicely inside the spacious fuselage. The top is removable for access to the servos or for removal of the mechanics. You can easily reach through the side doors behind mechanics to access the tail rotor servo etc.

 

The oil cooler under the exhausts is one item the kit manufacturer leaves up to the builder to duplicate. As in other areas such as the coskpit, you can get as fancy as you want. The full-size heli’s cooler has three units – the top with the cooling vanes running horizontally with the two lower units sitting side by side with the vanes running vertically. My oil cooler was fabricated from a plastic sheet material (Great Hobbies: EVG4051 Clapboard .050 Spacing). Three pieces were cut out from the sheet, orientated and glued to a backing plate (1/16″ balsa sheet) with thick CA. This will be painted a matte light grey.

The woodwork was lined up and tacked together with thick CA. The mehanics were bolted in place and the whole structure was removed and the gluing was completed.The woodwork structure with mechanics still attached was then reinstalled, lined up and tacked to the fuselage with thick CA. The mechanics were then removed and the whole structure was permanently attached to the fuselage with PFM Adhesive. This adhesive is flexible, bonds to fibreglass extremely well and should be resistant to vibration.

 

The GV-1 governor sensor was mounted on the side frame directly above the main gear. Three magnets will be glued into the existing holes in the main gear and the ratio will be set to 3:1. Three magnets are necessary as 3:1 is the lowest the governor can be set to. You can mount the sensor in many places and can use optical sensors if you want. Check the internet forums for info on this.

The governor can be turned on / off using the Aux 2 switch on the transmitter. The Aux 5 knob will be used for adjusting the RPM.

The throttle servo location located on the drawings is for the stock Zenoah G-23 engine where the throttle arm connects to the bottom of the carb. As mine is equipped with the RC230, I needed to access the carburetor from the top. Building a box from scrap ply left over from the woodwork raised the servo. This will allwo the throttle arm to be attached in a straight line.

The servos are mounted in a new tray made of aircraft ply. This keeps the servos up close to the cockpit roof (out of site). Another way to accomplish this is to use different side frames where the servos mount directly below the rotor head but that is more expensive.

The tail rotor has been moved to the right side, as in the full-size heli. This involved only the insertion of a brass tube in the gear box and a different control arm. The shaft was reshimmed utilizing the shims that were included with the Benzin kit.

Changing the tail rotor to the right side meant that the tail rotor servo tray had to be relocated also. The stock tray was used but modified slightly to allow it to sit on the right side. The two formers in the tail boom must be reversed also. The unit builds up easily. Just be sure to be fussy and don’t forget the Locktite.

The vents were cut out carefully with a Dremel Tool and finished with a small file. The grills are made from the supplied screen and are glued in place with thick CA. Be careful when gluing the screen in place that the orientation of the weave is the same for all vents.  Note: you can see where I have filled the seam in the fuselage. This was done using a two-part primer which was then wet sanded. All of the seams were done with less than 3 ml of primer.

Construction is continuing with the installation of the lighting units, buildup of a basic cockpit, attachment of the horizontal fins etc. I’ve practicing placing rivets using the syringe / white glue method and they wil be placed after the last coat of primer is installed and sanded on the whole model.