Searched the forum but couldn't find anything will answer my question.
I have mated the wings to fuselage. All went well. The hardware store bolts slid right in, no issue. Wings are square with the same distance from wing tip to tail on both sides. No fwd or aft sweep, the four plumb bobs are all 1/8" or less from the straight line tip to tip. Until it is time to set the incident angle and drill the rear spar. I used the van's 3 inch block method and a bubble level to do the job. All is well for the left wing, the bubble is centered from root to tip. The surprise came on the right wing. If I centered the bubble at right wing root, I had to raise the 3" block about 0.06" to keep the bubble centered at the wing tip, indicating the wing is slightly twisted. I don't have a digital level that can measure the angle, but the distance between front and rear spars is about 26.5", with 0.06" difference, the angle is about 0.15-degree. So, the right wing tip will have about 0.15 degree more incident angle. My questions are:
1) Is this really due to a twist. If it is due to a twisted wing, the angle is more than what I expected. When I clamped down the wing skeleton, the difference on distance between the rear spar and the plumb bob line at root and tip is only about 1/64, instead of 1/16 showing right now. see my build log: http://rv7.yolasite.com/09-14-2011.php
2) Anything else could cause this?
3) if there is a twist of about 0.15-degree, how that will affect its flying? I would expect a heavy left wing, but how much? Should I set the incident angle of the right wing based on the angle measurement in mid span?
I will hold on drilling rear spar before this is cleared. Appreciate anyone's input on this.
I have mated the wings to fuselage. All went well. The hardware store bolts slid right in, no issue. Wings are square with the same distance from wing tip to tail on both sides. No fwd or aft sweep, the four plumb bobs are all 1/8" or less from the straight line tip to tip. Until it is time to set the incident angle and drill the rear spar. I used the van's 3 inch block method and a bubble level to do the job. All is well for the left wing, the bubble is centered from root to tip. The surprise came on the right wing. If I centered the bubble at right wing root, I had to raise the 3" block about 0.06" to keep the bubble centered at the wing tip, indicating the wing is slightly twisted. I don't have a digital level that can measure the angle, but the distance between front and rear spars is about 26.5", with 0.06" difference, the angle is about 0.15-degree. So, the right wing tip will have about 0.15 degree more incident angle. My questions are:
1) Is this really due to a twist. If it is due to a twisted wing, the angle is more than what I expected. When I clamped down the wing skeleton, the difference on distance between the rear spar and the plumb bob line at root and tip is only about 1/64, instead of 1/16 showing right now. see my build log: http://rv7.yolasite.com/09-14-2011.php
2) Anything else could cause this?
3) if there is a twist of about 0.15-degree, how that will affect its flying? I would expect a heavy left wing, but how much? Should I set the incident angle of the right wing based on the angle measurement in mid span?
I will hold on drilling rear spar before this is cleared. Appreciate anyone's input on this.