Fuselage Construction with Wings Attached

Getting ready to start buliding the fueslage jig, setting bulkheads and thinking about using the actual wings instead of a spacer at F303. I have plenty of room in my basement to do this. Would eleminate the need for a spacer at F303 and not have to worry about alignment or edge distances at the rear spar F305.

Wing alignment to a string center line down the center of the fuselage would make for very accurate alignment to reference points on the wings. Plan on using a laser level to keep level grade and wing chord alingment

I have read many posts on this site but never anything like this.

If feedback is not too negative plan to go for it.

I build alot of post frame buildings on a daily basis and know this is how my crew would tackle this construction.

Feedback and comments always appreciated.

I wouldn't do it for one simple reason: It about doubles the walking you have to do to get anything done.To go from the nose to the tail, you have to walk out to the wingtip and back. To go from on side to another, you might have to walk around both wings. It might not sound like a lot, but it all adds up to a less enjoyable and less motivating building experience.

Thanks, Bob K.

building fuselage around wings

I did it almost this way.
I noticed that quite a few RV's have a slight misalignment between the fuselage belly skin and the lower wing skin. Most of these are accommodated with a "Z" piece between the two surfaces.
To avoid this and have the fuselage belly line up perfectly with the lower wing skins I built my fuselage center section on the wings assembled. Mind you this was only the center section; from F-404 to F-407. I then turned this upside down on my frame table and constructed the "upside-down canoe" sort of per plans. The fuselage is now nearly complete and it has worked very well.

Having built a -3 fuselage in the past year, my thought is that there are side skins that are going to have to be riveted that will be hidden by the roots of the wings. You also have to figure out how to support the wings very securely so that you don't tweak the fuselage. Will it work? Probably ...but you'll be doing a LOT of pioneering, and many, many airplanes have been constructed the way the plans describe. If you look at it as a trade off between the minimal difficulty of building a spacer/temp spar for the center section versus pioneering a new method of construction, I might have second thoughts. You'll probably discover interesting challenges that no one else has faced. if you like solving those, go for it - if you want to be able to draw on the resource of those who have gone before, then there is a certain comfort in following the way most have done it.

If you really like the challenge of building, then your answer is going to be different than if you really want a flying airplane as soon as practical.

Just a few thoughts or you to consider.

Paul

I wouldn't want to build this way

Bob Kuykendall said:

I wouldn't do it for one simple reason: It about doubles the walking you have to do to get anything done.To go from the nose to the tail, you have to walk out to the wingtip and back. To go from on side to another, you might have to walk around both wings. It might not sound like a lot, but it all adds up to a less enjoyable and less motivating building experience.

Click to expand...

As someone finishing up the fuselage stage, I totally agree that the added work (i.e., walking around the wings) would slow down the build and add to my frustration beyond my tolerance. Working on the fuselage has been generally easy and fun. Having the wings on would have really bummed me.

Im not sure this method is really buying you any time or risk avoidance. If you have the wings in your shop then you should be able to easily measure the front to rear spar spacing. When constructing the fuse center section, you are basically trying to nail four dimensions.
1. front to rear spar distance - you have the wings so this is no problem
2. rear spar carry through level alignment - you have to nail this if youre using the stock carry though bar.
3. buttom fuse skin to bottom wing skin alignment - if this isnt perfect then you will get the Z bend sort of thing that larryj talked about (i have a bit of this on my plane)
4. relative incendence of left wing to right wing - as long as your spar slots arent twisted relative to eachother then this wont be an issue.

When I built my fuse I didnt have the wings on hand and the Phillipines wouldnt give me the front to rear spar distance. I rolled the dice and got lucky. Anyway, good luck with your build.

larryj said:

I did it almost this way.
I noticed that quite a few RV's have a slight misalignment between the fuselage belly skin and the lower wing skin. Most of these are accommodated with a "Z" piece between the two surfaces.
To avoid this and have the fuselage belly line up perfectly with the lower wing skins I built my fuselage center section on the wings assembled. Mind you this was only the center section; from F-404 to F-407. I then turned this upside down on my frame table and constructed the "upside-down canoe" sort of per plans. The fuselage is now nearly complete and it has worked very well.

Click to expand...

That's a pretty neat way of ensuring that everything fits together! I can see doing that just for the part of the build that involves the wings. Of course, that part of the fuselage has relatively little torsional stiffness on its own, so you have to be careful to preserve its torsional alignment until it is fully skinned and attached to the aft fuselage.

Another possible approach, the one I adopted for the glider I'm developing, is to build mockups of each wing root and use those to position the structural connections between the wings and the fuselage:





Of course, that's only practical if you can replicate the wing root structural geometry to some pretty close tolerances.

The story of those wing root mockups, and how we used them to align and drill the first set of wings, is told in this and this update.

Thanks, Bob K.

I used the wings to drill and cleco the center section, including the seat ribs and rear spar carry thru. Use the steel spar plates and bolt the wings together with standard AN bolts. Also used strips of aluminum as temporary diagonals then insalled the assembly into the fuse jig. Don't drill the rear spar until final assembly/rigging.
I'd do it again.
Mike

Fuselage Construction

Wanted to thank everyone for their thoughtful comments regarding my first post. Seems like this basic idea has been tried on a limited basis.

Like the idea of getting fuselage belly skins aligned with bottom wing skins and not needing the Z trim fix.

Also like the idea of aligning the wings to fuselage center line.

As for wing interference during fuselage construction the wings will come off once a rigid fuselage frame is established. May lengthen the legs of the fuselage jig to give better access to the wing root side skins.

Thanks again for the great comments

Mark McDonald