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Canard

The canard wing design has been successful over the years but there have been a couple of changes that I have incorporated to reduce cost, reduce draughts and to make a little safer, these are:

  1. Improve the pins for the alignment tabs; and,

  2.  Improve the penetration of the fuselage side.

Alignment Tabs Pins

I had originally installed the canard alignment pins strictly in accordance with the plans and had made a very tight installation. The problem resulted the next day when I tried to remove the canard, only to find that if the pins are a good fit into the alignment tab bushings, it was almost impossible to remove the canard. Removal requires that there is some 'slop' in the bushings for the alignment pins. It took over an hour of wriggling and pulling to get the canard off the fuselage. I decided that this was not a great design and felt that there was a better way of doing this.

The drawing below indicated the standard way in which the canard is attached and it can be seen that to elevate the forward edge of the canard there is a need for significant play in the bushing imbedded in the alignment tab.

The solution is relatively simple and can be seen in the following drawing. In this instance a nut plate is installed on the forward face of the alignment tab and a long AN3 bolt is installed through the length of the doubler. A piece of bushing stock is inserted and floxed in place to provide a hard surface onto which the bolt may react. The real benefit of this design is in that it adds considerable support to the rear end of the Canard and would provide additions support in the unlikely event that a single main lift tab let go through fatigue. There is no forward aft movement on the canard once this modification is made so fatigue is probably reduced.

A photograph for the installation can be seen below along with the hinge bearing for my forward hinging canopy.

Alternative Elevator Offset

I have never liked the double offset that the Ronce Elevator uses. The offset is in place so that there is no large cut out of the fuselage side resulting from the arc of the elevator torque tube but why is the offset reinstated? I believe that it is only there to maintain the same bearing support as those used outboard. I found that the parts were expensive and since I had a lathe it was easier to fabricate my own design. To this end it is necessary to fabricate the following parts:

  1. Excentric Shaft,

  2. Bearing Holder; and,

  3. Bellcrank Attachment.

The bronze bearing is a modified bought in unit found at the local bearing shop. The excentric shaft is fabricated from 4130 steel stock and requires the use of the four jawed chuck to make the excentricity.

The bearing holder was made as a 4130 steel weldment  but could easily be manufactured from 6061 Aluminium bar.

The bellcrank attachment was turned from 6061 Aluminium bar stock.

 

The assembly drawing for the excentric shaft is shown below. The bronze bearing is a press fit into the bearing holder and the bearing holder is attached to a foam block that has been attached to the underside of the canard and had some nut plates installed into the block. Side views are also given in the subsequent drawings.

The photographs below show the installation but still require some finishing glass work.

I authorize Chrissi & Randi of CG Products to take this design and modify the design as they feel fit to benefit the Canard community.

Last Updated:   

Monday June 24, 2013