The next mod to my Easystar, a larger rudder made out of balsa and installed with dubro hinges.
There seemed to be 2 main ways to increase the performance of the rudder on the Easystar the first would be to just extend the length of the current rudder and the second would be to increase both the height and the length by completely replacing the rudder surface, for my mod I opted for the second option.
I started by cutting the old foam rudder off the airframe and then continued the cut up to the top of the vertical fin this will allow me to make a rudder that would have a full height control surface.
I decided that I would make the new rudder out of balsa and would attach it with dubro nylon hinges. I made a paper pattern from the foam rudder and fin part that I cut from the Easystar I then extended the length so that the new rudder reached out as far as the elevator trailing edge.
I cut 3 identical patterns from a sheet of 2mm balsa, on one of the patterns I marked out and notched cutaways for the hinges, this will be the centre layer. I decided to make this a laminate part so that I could neatly install the hinges and then sandwich all the parts together. Next I glued the centre and the first of the outer parts of the balsa together, this can been seen in the picture above. I left the join to cure over night with 20 hardback books stacked on top.
The hinges were then glued into the notched area's with CA before finally gluing the balsa part on top, again this was compressed and left to fix over night. It is worth while to tape around the exposed hinges while doing any gluing.
The picture above shows the parts laminated together with some initial shape sanding done. I also drilled the rudder at each of the hinges and pinned through each hinge with a cocktail stick to secure the hinges.
I completed the shape sanding by checking the shape and clearances against the airframe and adjusted where necessary. I applied 4 coats of sanding sealer rubbing down with fine sandpaper between each coat and then 2 coats of red paint. The final task on the rudder was to install a new control horn and I decided to fit a bolt on version instead of the glue on version that came with the Easystar kit.
For installation onto the airframe I marked the 4 hinge positions on the vertical fin and using a sharp blade made incisions into the foam for each of the hinges. After a test fit and a few dry runs I glued the hinges in with CA, you must be very careful not to get glue on the actual hinge area!!
Now i need to get some practice flying in while I wait for flyable APM code to be released.
Comments
Very nice work. I don't have a lot of experience with balsa wood but would love to try this at some point. I have just enlarged my rudder on my second EZ*. I didn't extend the rudder but simply extended the air resistance area by taking about 1 1/2 inches and seperating the rudder, sanding and shaping, then reattached with nylon hinges. Then taping the stock rudder to create a more aerodynamic surface.
I will have some flight video maybe in a week or so, I probably will add ailerons at some point, I want to see how it fly's in this configuration first.
If you add ailerons, like I did, to your EZ* you really do not need to enlarge the rudder anymore than you have already. I found that only using the rudder to turn causes the EZ* to nose down which meant that I had to give up elevator during a turn to avoid going into a death spiral. The aierons, on the other hand, roll the EZ* into the turn and there is much less nose down attitude during the turn.
Instead of building an even bigger rudder, which I have already done, I think that your time would be better spent investigating the addition of ailerons to the EZ*'s wings. I think that you will like the way that it performs in relation to rudder only operation.
Just a thought.
Regards,
TCIII
This should be the ardupilot default and included in the hardware wiki. If you have a .h file and note of motor/esc etc that would make a very nice standard airframe