Looking for best way to level airplane.

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Eugene

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Spent all morning today trying to set my wings into 1.5° dihedral. And of course was trying to make everything perfect, and of course nothing was working for me. I was using pretty good $400 construction laser from work. Every time I think I got it just right, strut showing me different links within 3 mm difference. Wondering if I should throw away 21st-century technology and go back to water tube? Waterline will not lie to me and it is very liable for last thousand years or so.

I was right. Lift strut needs to get a little bit shorter. Drag strut will need to get longer and there is just enough room for conversion into adjustable fittings. But first I need to find a way to set everything 100% perfect.

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TerryM76

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Are you setting dihedral or incidence/twist?

A good digital level can be used on the bottom of the wing, running along the front spar line to set dihedral. If the wing airfoil has a flat bottom then place the digital level on the chord line between the front and rear strut attach fittings To set incidence/twist. Of course you will need to level your fuselage both longitudinally and laterally but you could just zero out your level to the reference used on the fuselage for the leveling reference.

ive seen laser levels used on Boeing and Airbus aircraft but you can get by with simpler methods……we’re not building Space Shuttles here.
 

dog

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You can get,for free,phone apps,that are super easy to use and very acurate.
Can test against whatever you have now,again
its free.
 

Eugene

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You can get,for free,phone apps,that are super easy to use and very acurate.
Can test against whatever you have now,again
its free.
Yes, I do have a digital levels. Several of them. Also have laser as well. Where I get confused is when I level airplane from the front with laser and then I raise both wings to 1.5° dihedral - Wings looking in-line with laser level line, but struts don't measure the same with 3 mm difference.

I was already back home when I start thinking that wings possibly built differently and have different dimensions. I will check that next time.

IMG_5850.jpegScreen Shot 2021-06-12 at 17.55.13.png
 

Dana

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3mm is just under 1/8", which is the accuracy of the laser you posted the info on. Or did you mean 3cm, which is what it looks like in the pictures you posted?
 

Geraldc

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Laser level is only as good as last calibration (if any).
Water tube is always right even out of line of sight.
 

Eugene

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3mm is just under 1/8", which is the accuracy of the laser you posted the info on. Or did you mean 3cm, which is what it looks like in the pictures you posted?
No,no. It was about 1/8". Now that I'm thinking, I can always check accuracy of my laser with a water tube. Why didn't I think about it before? It almost feels like I'm getting smarter every day!
 

proppastie

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only thing sure about a laser is a straight beam of light.....how close that laser is aligned with the bubble or level mechanism in the plastic or aluminum housing is subject to manufacturing tolerances....
 

Eugene

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3mm is just under 1/8", which is the accuracy of the laser you posted the info on. Or did you mean 3cm, which is what it looks like in the pictures you posted?
Struts don't lined up with wing brackets because I moved cockpit forward by 2 inches. Naturally lift struts need to get shorter and drag struts will need to get longer. That was expected and no surprises there
 

Eugene

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only thing sure about a laser is a straight beam of light.....how close that laser is aligned with the bubble or level mechanism in the plastic or aluminum housing is subject to manufacturing tolerances....
So, I am making conclusion that $400 laser is good enough for building houses but not really good enough to build in airplanes.
 

proppastie

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if 1/32 or1/8 total is what you want ......that is a lot better than a house
 

proppastie

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usually there is a part of the airplane fore and aft and right to left that needs to be the level references......using a bubble level......then you would set a protractor level from a combination set on the top of the spar to adjust the both wings are the same dihedral......... set the wings where you want them and adjust the struts to fit in the holes.

 

TFF

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The water level is great because it’s a comparator. Numbers at some point round off if digital. Laser measuring something not laser straight is off some too. Now your brain has to judge the quality of the instrument. You are not NASA who can spend a year repeating something. I watched a guy adjusting a flying wire on his biplane. Back and forth back and forth. Calling out the numbers 6 the 4 then 6 and 4. We go over and say what’s the deal 2 degrees. No tenths of degrees. Reality is you have to know when to stop.
 

Eugene

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set the wings where you want them and adjust the struts to fit in the holes.
That was my plan this morning. I didn't really care to be exactly100% of 1.5° dihedral. In my eyes wouldn't make any difference if I end up with a 1.4° or 1.6°. But really was trying to make everything symmetrical and for some reason I couldn't.
 
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