Plugging in wings to do list

I am getting ready to plug the wings in for the first time.

I plan to drill set the incidence angle and drill the rear spar, locate fuel and electrical line entry points, rig ailerons and flaps, set HS incidence

Should I also rig the VS incidence at this time, or wait till later. I had an RV-4 builder tell me to do this later, after engine installation, but I can't see a reason for this. I think it would be better to set it when I am in measurement mode, then unplug the wings and complete as much as possible in my air conditioned garage, including the empennage fairing, then install the engine, then install the wings one final time at the airport.

In setting the VS, he also states that it should be offset to one side to avoid a trim tab. Should I offset it to one side or set it straight. The engine mount is offset, correct?

If I offset it, how much?

What other items should I look at during this first wing fit exercise?

Regards,
Dale

RV-6 finishing kit

drilling the rear spar

if i had this to do again i would drill and ream the rear spar to .311 you need this reamer for the landing gear stuff get it now and make that bolt fit like it should.mho i offset the vs 1/4" to left at the leading edge. mine is a 7a

A transit

Hi Dale,
We just flew our 6A last November but we used a builder's transit to set the incidence since it's so much more accurate than a level. As I recall, the rear spar top is around 3 3/32 lower than the main spar (It's in the manual). If you place the transit about fifteen feet away from the side of the airplane, you can shoot both wings without moving it (you shouldn't, either!). Be very careful to level the airplane fore and aft and sideways, with no rocking....make it solid and stable.

Secondly, install the nutplates for the lower skin attach (the skin that's attached to the fuselage), and also the upper nutplates for the fairing strips before you do the final slide-in of the wings.

The transit did such a good job that our airplane flew/flies hands-off level with the flaps and ailerons all in line with each other.

Regarding the VS, we used the offset attach bracket from the 7 series even tho' the motor mount is offset. Initially we needed a smidgen of rudder trim but that went away after we installed the gear leg fairings and wheel pants..go figure. I recall the VS being offset around 3/16 to 1/4".
Kind regards,
Pierre

Transit for wing incidence

Hi Pierre,

The transit sounds like a much more accurate way to do the alignment. I am having trouble visualizing where you are positioning the transit. You said 15 feet away and able to do both wings. Is it, then, in front, in back or to the side?

If I understand correctly, you level the fuselage in a very stable position, have the wings plugged in at the main spars and then drill the rear spar attachment after you have everything aligned. Are you using the transit in the process of leveling the fuselage?

That being the case, please help me understand where you physically put the transit and where, exactly, you are measuring the wings and/or empennage to get the alignment correct.

Thanks,

Michael Wynn
RV 8 Wings (ailerons)
San Ramon, CA

Okay....

We placed the transit about three feet away from the right wing's trailing edge (out from the wingtip) and yes, we also used it to level the airplane in both axes. The upper longeron is straight and level and we turned the transit towards the rear and stood a machinists rule (graduated in 1/64's) on the longeron aft of the rear bulkhead and marked it with red fine point pen at the transit's crosshair alignment. We then turned it toward the canopy rail area and stood the rule on the sill and jacked the airplane by the lower motor mounts until it was level. We then moved the rule to the other side of the airplane canopy rail and levelled it left and right. This is all done WITHOUT moving the transit's location at all, just rotating it as necessary. You can see thru the canopy area with the canopy off to the other side of the airplane.


It takes several tries with the rule at the rear then the canopy rail back-n-forth to get the airplane perfectly level in both axes. We used two bottle jacks under the motor mounts so we could let either up or down as necessary to level everything up.

When we were ready to position the wing incidence, we taped the small rule to a yardstick so that the transit could "see" it and stood the yard stick on the main spar. My buddy looked thru the transit and told me where to mark the rule, which I did. I then added the amount of difference between the rear spar height and the top of the main spar (3 3/32".I think) and made a second mark on the rule that distance up from the mark of the main spar.
The yardstick is then placed on the rear spar and with my buddy looking, told me to 'raise the trailing edge'...and so on until the mark aligned in the crosshairs. At that point, another buddy used a vice grip to "pinch" the rear spar tabs together, locking the incidence. We then stood back, rechecked the main spar reading and redid the rear to be sure........then the big question "Do you wanna drill the spar or do you want me to??" He said you drill yours and I'll drill mine!

A word of caution here....be sure and have the 5/8ths edge distance from the hole in the rear spar and the attach points that Van wants to see. All the levelling, jacking and transitting only took a couple of hours or so and we had the rear fuselage on a sawhorse with wedges under the rear bulkhead to firmly support the airplane, two bottle jacks up front. The better you do all this, the better/truer and faster your airplane will fly. Don't even think of rushing this phase and it will pay big dividends down the road.

Hope this helps,

The level approach

I used two levels to cross check each other and that also worked out fine. I did not offset the vertical stabilizer and I had to add the rudder wedge to center the ball in cruise with my feet off the pedals. Roll has always been fine. The plane could use inflight rudder trim but the offest to the left vertical stabilizer leading edge (effectively right rudder) is a move in the right direction in my opinion. It sounds like the previous post authors have the actual numbers you can use. I've seen enough wedges on the left side of the rudder trailing edge to believe all of the straight RV-6/6As have this characteristic. I would would offset the vertical stabilizer if I had it to do over again. I am going to add rudder trim and get rid of that wedge when the other things I want to do are dealt with.

Once you have the reference plane level established I can't see any reason not to do all the rigging at once. However, it's not a big deal to re-establish the reference plane level state at a later time - just check and recheck everything to get it as perfect as you can get it.

The wing on the RV-6A is physically the most difficult thing to install I have run across. I did mine in the garage for rigging and then had to take it apart so my wife could put her car back in her side of the garage (her car probably set out two months while I was working throught this phase). Some modified cheaper bolts (some ground to a point and and some ground to a "D" shape) are good to have - a reamer, drift pins and a good plastic mallet are also usefull. The RV-6 is easier because the landing gear are independent of this task.

Good luck, it is a great airplane well worth the trouble.

Bob Axsom