In the last week, I have been working on the bending of the elevator skins.
To be honest, this part has been freaking me out for a while and I have been reading the forums over and over again to find more info on how to make sure to do the right thing.
Even more honestly, if I would have to do it again, I would skip the forum step. Many people have different ideas and they are all giving you the creeps in their own way.
Bending the elevators is a non-event !
Th important thing here is to have a radius in the bend of 3/32" and not to have any bulges in the trailing edge or in the ribs.
What is important is the following to do :
- make sure to have a aluminum, wood or steel dowel of 5mm.(I used 4mm but would use 5 if I had to do it again).
- tape the dowel in the edge of the bend.
- bend first close to the end of the bending brake to make sure you bend at the radius.
- then move the sheet forward and continue the bend.
GO SLOW !
DON'T OVERPUSH it !
You are ready when the skin falls on the rear spar without pushing.
Here you can see a picture of the dowel inserted in the right elevator. Notice I first taped some paper tape in to protect the skin from scratching.
This is my bending brake. It's a bit long for the elevators, but keep in mind you'll have to do this again for the ailerons which are much 2" longer.
Use lot's of hinges ! Using less hinges creates risk that the wood will bend and the result will be bulges in the bend. NOT GOOD ! Door hinges are cheap, get as much as you can
My girlfriend is holding the sheet in position while I'm contntrolling the pressure using the handles
The overall result is quite good. Not perfect but certainly acceptable. On the inboard side it is perfect.
Notice the ruler stays in contact with the skin until the start of the radius.
On the outboard side, the rules doesn't stay connected but there is no bulge.
The reason for this is because the radius at the end is too small. I used 4mm as dowel and it is clear that this is insufficient to have a perfect bend.
I contacted Vans support and they assuredme this is a good bend and this will not affect the flight characteristics.
Then the same for the left elevator. The left one is shorter and so a bit easier. I decided that I had to use the 4mm dowel again because of symmetry with the right elevator shape.
This time Jacques gave me a hand holding the skin. Awkward position :)
The left elevator bend and ribs temporarily clecoed in place
Bend result trim side.
Result rib side.Very good again, other side bit bend down again for same reason. Radius little too small.
