Q: Cradle needed for wing installation?

[KenB]

Folks,

I'm a week or two from temporarily mounting the wings on my RV-9. I've searched the forums but haven't landed on an answer to this question.

Here's the question: do I need to make a cradle to support the weight of the first wing to be mounted in order to avoid it tipping over until the second wing is mounted?

Thanks in advance.

Cheers, Ken

p.s. Yes, I've already made drift pins from hardware store bolts by grinding off the threads into a nice smooth bullet shape.

 

[Ironflight]

It’s been many years since I mounted the wings on my -8, or we mounted the wings on our -3….and as I recall, they both stood level with one wing….but a saw horse under that single mounted wing sure made me feel a lot better!

 

[PilotjohnS]

No.
I did make a cradle with wheels to support the wings and allow me to slide them in by myself. It served me well. I ended up putting the wings on and off about three times. Once because wires were pinching, once for the pitot lines hitting the ail push rod, and once just for fun ( actually cant remember why the last time)

 

[Desert Rat]

Short answer=No.

Long answer= I had the same thought and threw together a stand out of scrap I had laying around (basically a low saw horse) but it really wasn't necessary. The wings are surprisingly light. It did come in handy though since there were only two of us.

How it played out, I ended up with a cooler with a moving blanket on it out by the wingtip and the stand inboard so that we could rest both ends. I put my brother in law out on the wingtip and me at the root. We maneuvered it close, then I sat my end on the stand, scampered into the plane, reached over the side where I could lift it up then guide it into position while he pushed and wiggled back and forth as needed. Once it was on with a couple of rig pins we stuck a heavy cardboard box under the tip just in case, but it didn't show any signs of wanting to roll to the heavy side. I doubt if it makes a difference as far as tippy-ness, but mine was still on the fuselage cart, not on the gear and I didn't have the engine installed.

Have your drift pins, a soft face hammer and a couple of wooded blocks in the plane where you can grab them. An inspection mirror and flashlight make it easier to see when the holes line up. Spray the spars with something like LP3 ahead of time. You might also want something like a putty knife or deburred piece of .032 aluminum that you can use to help line up the aft spar with the ears.

Don't be surprised if they end up swept forward and you have to pull them back off and trim a bit off the end of the aft spar or spar flanges to get the sweep close to neutral without it bottoming out. If I recall correctly, the plans for my RV7 said to strive for zero sweep but up to 1/2" in either direction is acceptable as long as it's the same on both sides.

 

[rockyfatcat]

Good information! My -7 still has the wings off from shipping. I was wondering many of the same things.

Thank you all.

 

[Weefle]

5 or 6 stacked pallets with castors on the bottom one and a moving blanket on the top one works great.

 

[PhatRV]

Folks,

I'm a week or two from temporarily mounting the wings on my RV-9. I've searched the forums but haven't landed on an answer to this question.

Here's the question: do I need to make a cradle to support the weight of the first wing to be mounted in order to avoid it tipping over until the second wing is mounted?

Thanks in advance.

Cheers, Ken

p.s. Yes, I've already made drift pins from hardware store bolts by grinding off the threads into a nice smooth bullet shape.

When I mounted the wings to drill the rear spar of my RV8, I didn't need any cradle to support the 1-wing. I even stood on the wing after I inserted the four drift pins. It is still a good idea to have a rolling support to hold the wing at the level to the spar box in order to make it easier to slide in the wing, and to support it when you slide it out.
This is a picture of the two wings mounted. Notice the location of the landing gears position midway at the fuel tank. With the heavy weight of the engine, it will take a whole lot of weight to rock the plane with one wing.

 

[KenB]

Thanks, all, for the input. I'm pleased to hear that the fuselage won't tip over with just one wing installed. I also like the idea of adding some support during the installation/removal process. Cheers, Ken

 

[wirejock]

I used my lift. I fabricated a lift for the fuse. Worked great for mating wings all by myself. A sawhorse on the outboard end keeps it from squatting toward the one wing. Sawhorse was removed temporarily but you can see the lift.
Basically, I set it higher than needed. Placed the wing on the lift and sawhorse. Slip the shim on the fuse skin. If you don't, the wing skin hits and won't slide in. Lower the lift till the spar is at the correct height. Push. Slide the shim out. Adjust the position of the sawhorse in or our till the holes line up and slip the drift pins in place. Easy peasy.

 

[Ralph Inkster]

Of course I do it a little bit differently. One man operation. I have a 3x4 foot plywood panel with 2x4s tacked on the widest dimension, it acts as a cradle under the wing as I lift the wing up with an engine hoist. One hand stabilizing the wing & one hand on the lift jack. Get it to the right height & shimmy it into position. Get the first temp pin in than adjust the jack height to line up the other holes.
I’ve used this process on multiple 6/7/8/9 projects.