Canard range of motion

[kwmoore]

Question for Todd:

In the PPP video on the history of the 260se/230se, a short segment shows operation of the Wren's canard. In that segment, the range of upward and downward motion is substantially greater than on our planes. For the 260se, it's about 1 degree up and 7 or 8 degrees down I think.

Why the difference? How was the desired deflection range determined for the 260se canard vs that of the Wren?

Thanks in advance...:confused:

[Todd Peterson]

The range of canard elevator movement on the 230SE/260SE is the same as the Wren. The range of movement cannot be altered as it is built into the various bellcranks and the torque tube. The only thing that can be adjusted is the elevator neutral point and the rest is automatic.

Normally the canard elevator will be in a neutral position when the tail elevators are also in a neutral position. This is determined by taking a straight edge and running it from the center of the leading edge on the stabilizer then extending the line back through the center of the elevator hinge bolt. Continuing back with the straight edge the trailing edge of the canard elevator will then be aligned with the straight edge thus giving us a neutral position. In some cases we can give the elevators a little droop in the neutral position which helps us on the bottom end with out any problems. Note that the tail elevators are not in the neutral position with the control lock installed. The canard elevators do not look quite the same when viewed from directly in front of the airplane and that is the way they were designed. I would imagine that it is to compensate for the airflow behind the propeller.

[kwmoore]

Ah, perhaps the canard operation close-up shown in the video was from the Skyshark, not the Wren? It's the downloadable video on the PPP site, right at the beginning during the description of the control surface modifications.

[C-GOEM]

I notice that the video of the Wren shows a two component "elevator" on the canard. Also, the canard tip is attached to the "horizontal stabilizer" section rather than the movable part as on later Wrens and the 230/260 SE series. Is it possible that this more complex system was part of the early production Wrens? I think Chris has a very early model. Is his a one piece or two piece system?

Rod

[Todd Peterson]

The very earliest Wren canards did have a hinged elevator which was quickly replaced with the version we have today. I don't think they had produced but a couple of the early Wrens with this type of canard elevator.

Chris' Wren did have the early style canard but the assembly did not come back with the airplane. Needless to say he will be updating to the current style.

Chris is coming along well with his Wren. He now has the engine/prop installed, all new glass, wings on, tail assy on and rigged with a very nice custom instrument panel that he fabricated. The interior is off being redone and the only parts left he has to install are the fuel tanks. Unless he runs into a problem I would think he would have it flying sometime this summer.