Brodak 'Tanager'

Written for 'Aeromodeller', August 1996.

Assembly - Flying - Conclusions

Quick to build and easy to fly, the 'Tanager' is a 52" span profile flapped stunter
for 0.35 to 0.40 cu. in. motors

I needed a back-up model for the Nationals and was offered a Brodak 'Tanager' to review. This fitted the bill perfectly, being a profile model with simple sheet tail surfaces. Added to that, I rather liked the idea of having all the controls hanging out in the breeze where they can be easily adjusted.

The first impression is very good. All fittings are included: a metal bushed bellcrank, a flexible leadout kit, adjustable line rake fittings, nylon thrust wedges for the motor in 1, 2 and 3 degrees offset (side mounted motor), nylon control horns, spring keepers for the pushrod ends and an undercarriage fitting kit - but strangely no tank. Otherwise it is a comprehensive kit with virtually everything cut out and mylar for the hinges. A fully illustrated step by step instruction manual is included which leaves nothing to be decided. 'Fully illustrated' is, if anything, an understatement as there is a good quality photograph on every stage.

It is so well prepared that a plan is almost unnecessary, yet there is a full-size rolled plan. The fuselage is based on a piece of half-inch sheet balsa which is already sawn (fairly accurately) to shape. Hardwood bearers fit into slots and then each side of the nose is covered with 1/16 ply. Everything fitted together beautifully here.

The dedicated contest flyer might feel that some of thc wood is a little hard and heavy but my model came out at a satisfactory 42 ounces. So, it is hardly worth all the bother and expense necessary to shave off a couple of ounces. The wing is of conventional construction. The overall impression is quality and forethought. Just look inside the box and you will probably buy one.

Assembly

Inboard wing tip

The adjustable lead-outs after relocating them to maintain the shape of the tip

The only real work is in the wing and even that goes together exactly as described in the instructions. The adjustable leadouts are accommodated in a box built onto one side (upper or lower) of the sheet tip. This is a little obtrusive and interrupts the smooth shape of the tip, so I elected to cut away the tip and build the box on each side, which is much neater. All fittings are superb and it seems odd that there is no wingweight box. This is easily put right and we added a piece of brass tubing at the outer tip.

Outboard wing tip

Here we can see the brass tube added to the outer wing tip to accommodate
variations in tip weight if required.

It's worth noting here that the wings are of equal length. One other small item we changed was that the elevators have small aerodynamic balancing tabs glued to their ends. I felt these would be vulnerable and served no real purpose, so attached them to the tailplane.

On the fuselage there is a half inch sheet doubler attached to the inboard side. This is shown as tapering gradually back to blend into the fuselage at the wing leading edge. Having built the model that way, it occurred to us that it would have been stronger to leave it at the full thickness back to the leading edge and then taper, so adding reinforcement to the wing/fuselage joint

Nose construction

At this stage in construction, you can see the wheel fixing and that the plastic
tank was let into the fudelage to try and keep it more in line with the motor.

The instructions show the use of blind nuts fitted under the doubler for mounting the engine. We did it this way at first but later opened up the doubler around the nuts to use nylock nuts and keep them tight. A neat point is that the flap/elevator pushrod is supplied in two parts with a tubular joiner (soldered joint) and is so easy to set up. Two separate U/C legs are used which are attached to the fuselage by nylon clamps. The top of the leg is bent over and goes into a brass tube. Simple and effective. As it is easily removed, you can try different lengths and angles, or even have different types for grass or tarmac.

The outer ends of the flaps are blended into the tips by a small fixed section. I elected to make this part adjustable as an aid to trimming. This proved the old adage, 'make it adjustable and you won't need it'. At this point we questioned those mylar hinges. The instructions tell you to cut a slot and cyano them into position - not even to peg them. Everyone knows (don't they?) that stunt models need a nice free movement of plus or minus 45 degrees.

Mylar would deflect this far but would they be free enough? Anyway, sewn hinges are easier. Read on for the humorous sequel! The entire model was covered with heavyweight tissue and I restricted the use of coloured dope (what's that?) to the foselage. 'Aerocote' was used as a fuel proofer

I tried a plastic tank with a double clunk system, based on a four ounce Sullivan 'slant tank'. An incidental advantage is that one can actually see how much fuel is in the tank. The motor used was a well run and trusted Super Tigre ST35 which actually started life as an R/C motor and, unlike most stunt motors, does not have a piston baffle.

The control horn layout shown on the plan needed some simple adjustinent to give the usual '45 degrees each way on everything' we all take as standard. The CG came out a little in front of the advised position, but that's a good thing for the first flights.

Motor installation

The neat front end when the original tank was in use. Later changed to a conventional metal tank.

Flying

The first flight took place on a very blustery evening. The takeoff was smooth and long, level flight seemed quite groovy with a steady up/down osefllation (new controls with no slop). The first loop produced a dramatic surprise - it was about three feet diameter! Consecutive loops were possible within an area about five feet square.

The bunts were the same size too, this was a very good sign. What's more, there was virtually no tendenry to roll or 'hinge' (some people always said that unequal length wings were a mistake). The landing was fine with a fast approach and 'wheely' (on grass) producing no attempt to nose over. However, something had to be done about that turning radius!

A little adjustment of the controls had the movement reduced to about 30 degrees each way, equal on flap and elevator. This was much better but the level flight was still uneven. Square manoeuvres were fine but wlth a distinct tendency to overshoot the turn and 'bobble'. Later we opened up the hole in the elevator horn a fraction to introduce a little play around neutral.

Since then, further flying has revealed that the plastic tank leaves something to be desired in the reliability department. Two runs out of three are fine, but the third can produce a misfire when the tank is half full, which persists to the end of the tank. Another problem was that the motor goes rich on outside turns, a legacy of the side mounting. The cure to all this was a metal tank mounted with its centre above the thrustline.

I also tried fitting a two-and-a-half ounce Dubro propnut (yes, two-and-a-half ounces) and reducing the movements still further. This is better, except that it needs full up elevator for about a lap before the landing. Quite why the model is so extremely manoeuvrable is hard to say. Possibly it is due to the sewn hinges and very tight control surface gaps. Certainly, by most standards, it is now very nose heavy and the control movements are no more than about 20 - 25 degrees each way. It is great fon to fly. Perhaps not ideal for out-and-out contest use - but then it wasn't designed for that.

After a while of flying it in this form to get used to it, I tried going back to more movement with about 35 - 40 degrees each way and found that it really didn't make that much difference. This made the point that most models have too much movement anyway. In desperation I tried using a smaller handle and this was much better. The moral here is that it was the 'feel' of the model that needed changing, not its turning power. One problem was that of the motor repeatedly came loose so we fitted the nylock nuts mentioned previously. The nylon thrust wedges contributed to this situation and a harder material would be better.

Conclusions

The 'Tanager' is a practical general purpose stunt model which is quick and easy to build. It has the great virtue of having everything adjustable making it readily set up to an individual flying style. As a back-up contest machine, a testbed for motor/tank combinations, or as a fun machine it is perfect

It's flying characteristics are excellent. Control-line kits, particularly for .35 sized stunt models, are hard to find these days and this one is well worth consideration.

The 'Tanager' is produced by Brodak Manufacturing and Distributing Company, Inc., 100 Park Avenue, Carmichaels, PA 15320.
Phone (724) 966-2726
FAX (724) 966-5670
Email:
flyin@brodak.com
Website: http://www.brodak.com

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