Setting wing incidence ...

[Spike]

So I am about 1/2 page away from setting the wing incidences on the RV. The issue that I am going to face is that I only have the space to be able to do one wing at a time. That is set the fuse up, do one wing, remove that wing, rearrange the workshop (its an L shaped workshop) and then do the opposite wing.

My alternative to that methodology is to keep on with the build and set the incidence, control rods lengths, etc., at the hangar when doing final assembly.

Having been around enough people / projects I am a really big believer in doing as much as possible before the big move to protect productivity of the project. Once its at the airport the time available and effectiveness of it drops. What I don't have an insight into is how much the build would be hampered by putting this step off or alternatively the pitfalls of doing it one wing at a time. It seems to me the biggest risk with the latter option is getting identical incidence between the wings because making adjustments to the first also makes assumptions about the second and at that point we dont really know where the second is going to end up.

I know some builders have done one wing at a time, but don't know any first hand.

Thoughts are appreciated.

Spike

[bullojm1]

Spike,

I know Mike Reagan down at KGAI set his incidence at the airport on his -7A. It wont set you back at all really. Once you set the incidence, drill the root fairing, take if all off, clean up the holes and put it together for good. I really don't think there is any "wasted" time in this approach - it's just more work to be done at the airport rather than home. I personally got a lot more work done at the airport than at home. No distractions!

I think it much harder and more error prone to try to do it one wing at a time. Is there any way you could pull the fuselage outside for a night or two to set the incidence at home?

[Bob Barrett]

Mike,

I can't remember if you are building the 7 or 7A and the answer is probably the same either way. I was able to set my wing incidince in our garage without the engine hung, which is 23 feet wide. However the wing tips were not on. I know the 7 wing span is 2 ' wider so that may rule you out. I know the tips add almost a foot to the length of each wing. I believe that it is almost impossible to accurately set the wing incidence with only one wing Therefore if you cannot have both wings on at the same time then you will be forced to wait until you get to a hanger unless you can pick a nice day and your driveway is level. With help you should be able to do it in one day

[cjensen]

My friend Larry (f14rio here) set his one at a time in his garage. Worked out just fine. I went over to his house two different times to install each wing, and it took him just a few days apiece to get them done. Get in touch with him Spike...

[Spike]

I wish I could do it outside. My property is on the side of some nice rolling farm country. I literally don't have enough level area to do this. My parking pad doesn't even qualify.

Thanx for the data point Chad. I will send him an email.

Spike

[hydroguy2]

You painting before it goes to the airport? if not....I would just wait.

The time it takes to slip the wings in place, measure everything, think about it then re measure everything, drill is < 1/2 day of work. To slip it all apart and deburr/dimple is another hour or two. Put it all back together is another 1/2hr.

You spend more time worrying about getting it right while you are juggling stuff in your shop.

[BSwayze]

Spike,

I just did mine recently, and I had to take it all outside in the driveway because I don't have room for the wingspan in my shop. I'm glad I did. I documented all of it with lots of pictures on my web site.

One of the measurements you should make is to triangulate; that is, measure from the aft end of the fuselage to the wing tip. (Note: this has nothing to do with the angle of incidence) It should be the same for each wing. Doing it that way, I suppose you could do one wing at a time and get them both the same. However, I still wouldn't recommend doing that. The reason is, you will want to hang 4 plumb bobs over the leading edge of the wings (2 on each side) and stretch a line under them all. This will reveal if you have any unwanted sweep. They should all line up on the string. I don't know how else you could check this if both wings aren't on at the same time. Triangulation can get both wings the same, but they may both have the same amount of unwanted sweep.

Regarding the angle of incidence, you want the fuselage as perfectly level as you can get it before checking the incidence. With only one wing on, the plane will tilt to that side and it will have to be supported so you don't tip the whole thing over. So picture yourself trying to support the wing, keep the fuselage perfectly level, and move the wing slight amounts at the same time to set the incidence, while not messing up the sweep or the level. You'll drive yourself nuts trying to get it all just right. And then repeat for the other side. It sounds to me like a recipe for enormous amounts of time, and lots of frustration. And then you'll still be haunted, wondering if you got it right.

It's better with both wings on at the same time because it balances perfectly, so you don't need any support and you only have to level the fuselage once and it will stay put while you tweak with the incidence. Double check that everything is just right, check the sweep once more, then drill those holes.

Once I had those critical holes drilled, there's no more need to be outside. I was able to take it all apart and put it back in the shop. Over the next few weeks, I was able to take my time in the shelter of the shop with only one wing on at a time to finish all the rest of the wing root tasks at my leisure. That includes installing the fuel tank support brackets, cutting and flaring the fuel lines, making vent lines, drilling the wing root fairings, and so on.

I agree with previous comments. If you can't take it outside, wait until you're at the hanger for final assembly.

One caveat about working outside that never occured to me until I was out there was the wind. I considered the weather and chose a day when it was clear and sunny, but little gusts of wind came up and the whole aircraft would wiggle and rock around a bit. I was amazed how sensitive it was to this. It made it a bit of a challenge to keep things level, with all the movement going on. Fortunately, those windy moments were short-lived, and it was calm most of the time on that day, so I was able to finish it.

[Wicked Stick]

After reading the thread, I'd suggest waiting until you get to the airport.
It sounds like you don't have anywhere to do it outside thats level, so just wait, it won't eat up that much extra time doing it in the hangar and it will be much easier there.

[airguy]

I am building mine in my 2-car garage, my dad and I moved it into the driveway for the fitting, worked just fine. You will have to ensure you are level and plumb all over again - most garage floors and almost all driveways slope some for water drainage.

[Spike]

Mine doesn't slope some. Its on the side of a hill. I can't even drive up it in the winter.

Sent via DROID on Verizon Wireless


-----Original message-----

From: RB Lists - General Construction <support@rivetbangers.com>
To: generalconstruction@rivetbangers.com
Sent: Thu, Nov 18, 2010 15:22:02 GMT+00:00
Subject: Setting wing incidence ...



I am building mine in my 2-car garage, my dad and I moved it into the driveway for the fitting, worked just fine. You will have to ensure you and level and plumb all over again - most garage floors and almost all driveways slope some for water drainage. Greg Niehues Midland, TX RV9A - tail and wings done, fuse in progress http://websites.expercraft.com/airguy/ Building a 9A with too much fuel and too much engine - should drop dead any minute now. rivetbangers.com - Discussion topic http://www.rivetbangers.com/forums/viewtopic.php?p=35563#35563

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[bullojm1]

There's a simple solution Spike.....buy a new house. You'll need a bigger one anyways eventually for the little one!

[Bob Barrett]

Spike, Mike B has the best solution yet just buy another house to bad none of the rest of us weren't smart enough to suggest that! Maybe you should buy with a hanger adjacent or attached to it

[BSwayze]

Yeah, good one, Mike!!