J

jcfields

Member
Please forgive me if this question has been asked by other newbs, and it's probably a goofy one, but I'll ask anyway...

I've been reading a lot of the other builders' blogs out there, and it seems they always go through this big, long, convoluted process of stringing plumb bobs/drawing lines on the floor/rigging up fancy laser levels/standing on their heads/praying to the RV gods/etc. when it comes to attaching the wings to the fuse. Now, I'm being lazy 'cause I haven't read ahead in the preview plans (so flame me :p), but I thought all these kits were pre-punched, including the location of the bolts connecting the center section to the spars. So what's the purpose of all this measuring and leveling if the bolt holes are already there? Or are they? If so, shouldn't it be just a matter of lining up the holes and sticking the bolts in? Somebody please educate a poor, nubly, newb.

Thanks.
 
Wings are pre-drilled. However, there are other attach points such as the bracket on that the rear wing spar goes into that has to be drilled and this allows you to make minor adjustments to ensure the wings are plumb and square.

Read on!!
 
The main spars flex and with just a little force at the tip you can move the location of the rear spar attach point very easily. The RV-10 attach point on the rear spar is already drilled so you don't have to do all this.
 
There are three possible "degrees" of freedom, as I see it: wing dihedral, twist along the wing's longitudinal axis, and fore/aft movement of the wing tip wrt to the attach point. Is this correct? Which of these do you have control over when attaching the wings? It seems overwhelming to think of how one could control all of these possible directions of movement while attaching the wings and get it to be perfectly symmetric b/n both sides. I've been dwelling on this (not sure why, considering it's a task that's easily a year or two away for me), but I'm already dreading it...

Thanks for the replies.
 
Jeremy, If you want a straight airplane you to will spend a LOT of time with plumb bobs, levels and lasers. One thing about digital levels is they are not exactly precise. I would set my wings up with a digital level and then come back with a machinist level and the rear spar attach would be off almost 3/16" between sides. I spent around 20 hours setting my wings and tail up perfectly before I drilled the holes. I was rewarded with an airplane that flys absolutely straight with no trim tabs. Don
 
jcfields said:
There are three possible "degrees" of freedom, as I see it: wing dihedral, twist along the wing's longitudinal axis, and fore/aft movement of the wing tip wrt to the attach point. Is this correct? Which of these do you have control over when attaching the wings?
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Dihedral is set with the predrilled center section. Twist, sweep and incidence are up to you.
 
Does anybody have a picture?

I'm a visual kinda guy. Maybe if I saw what exactly is being attached to what and what's being drilled to what, it would become more clear. Right now we're about as clear as proseal :)
 
Only two things really....

jcfields said:
I've been dwelling on this (not sure why, considering it's a task that's easily a year or two away for me), but I'm already dreading it...

Thanks for the replies.
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.....to be concerned with and they're really no-brainers. As Mel said, dihedral is done for you. Forward/aft sweep is easily taken care of with four plumb bobs made from string and 4 nuts tied on.....two per wing. Tape them on to wing, near the leading edge and drop 'em near the floor and you and a buddy pull a string across all 4 and see if there's sweep.

With the airplane levelled on jacks in both axes, we used a builder's transit to get the incidence set and rear spars drilled. Leave the transit in the same position for both wings....really simple to do correctly. BTW, you'd be surprised at how many RV's are out there flying hands-off level that had the incidence set using Van's simple method of a small block of wood and a bubble level.

Regards,
 
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how far is denton from 52F?

as a visual person it'd probably be beneficial to go LOOK at some of the RV's that live there.

i can't remember off the top of my head, but i think there's one currently in progress there...... if not there's a bunch of friendlies over there that i'm sure would be glad to show you around and explain it :cool:
 
I'm only 10 or 15 mi's from 52F; Hicks isn't too far away either. Guess I should take Jay Pratt up on his invite and go over there and poke around in his hangar. I might learn something and not have to ask silly questions on here :eek:...

Thanks again for all the replies.
 
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jcfields said:
I'm only 10 or 15 mi's from 52F; Hicks isn't too far away either. Guess I should take Jay Pratt up on his invite and go over there and poke around in his hangar. I might learn something and not have to ask silly questions on here :eek:...

Thanks again for all the replies.
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SHOOT!! ARE YOU KIDDING ME!! IF I WAS THAT CLOSE I'D BE THERE ALL THE TIME, SUCKING EVERY BIT OF INFO I COULD GET INTO MY HEAD!!

haha, one day i'm gonna head out there.... :cool:
 
jcfields said:
I'm a visual kinda guy. Maybe if I saw what exactly is being attached to what and what's being drilled to what, it would become more clear. Right now we're about as clear as proseal :)
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JC,

Go to the this page of my web site and scroll down to the 10/2/05 entries. There are some good pictures and comments about drilling the aft spar.

As mentioned above, Van's pre-drills the front spars to the center section but the aft spar still needs to be drilled. This hole is what sets the AOA and wing sweep. If miss-drilled the wing tips can be forward, aft, or skewed. It is fairly easy to setup and drill the holes, in hindsight.
 
Wing twist...

Jeremy,

Have you read many builder web sites yet? I was fortunate to have a builder about 100 mile away that I would visit in 2003/2004 when I was building my RV-9A in my garage. I documented just about everything when I bought a digital camera and started publishing my web site.

As for wing twist, you avoid that while in the wing jig construction phase. You can learn about that on this web page of my site:
http://www.n2prise.org/rv9a009.htm

The forward or aft swinging of the wings and wing incidence is definitely controlled when you drill the bolt to secure the aft wing spar to the fuselage. The precision design of the kit and how the wing spars are drilled at the factory minimizes the chances for error, but everybody checks with the plumb lines. To see how that it done, look at this web page:
http://www.n2prise.org/rv9a124.htm
 
N941WR said:
JC,

Go to the this page of my web site and scroll down to the 10/2/05 entries. There are some good pictures and comments about drilling the aft spar.

As mentioned above, Van's pre-drills the front spars to the center section but the aft spar still needs to be drilled. This hole is what sets the AOA and wing sweep. If miss-drilled the wing tips can be forward, aft, or skewed. It is fairly easy to setup and drill the holes, in hindsight.
Click to expand...

n2prise said:
Jeremy,

Have you read many builder web sites yet? I was fortunate to have a builder about 100 mile away that I would visit in 2003/2004 when I was building my RV-9A in my garage. I documented just about everything when I bought a digital camera and started publishing my web site.

As for wing twist, you avoid that while in the wing jig construction phase. You can learn about that on this web page of my site:
http://www.n2prise.org/rv9a009.htm

The forward or aft swinging of the wings and wing incidence is definitely controlled when you drill the bolt to secure the aft wing spar to the fuselage. The precision design of the kit and how the wing spars are drilled at the factory minimizes the chances for error, but everybody checks with the plumb lines. To see how that it done, look at this web page:
http://www.n2prise.org/rv9a124.htm
Click to expand...

Thanks for the links gents. The pictures help, but I think I need to see it up close and personal to really get it. I'm gonna try to get out to RV Central in the next few days to take a gander at some of Jay's projects. I have some questions about other stuff too that might all come together when I see an actual mature project (instead of my lowly rudder spar laying on my work bench :cool:).
 
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