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proppastie

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As I plan the load test and layout the fixture for drilling I decided to try to check the deflection so the wing would not deflect into the ground. A fit use of FEA as the the spar is a somewhat complex with all the stiffeners and changes in cap thickness.
One little mistake and the results are garbage. Shown deflection with the E at 1050000 instead of 10500000. Also shown with Leading Edge attached
Wrong E spar deflection is 162" Correct E deflection is 13" Adding Leading edge and the deflection is 7" (In Theory) I used SimScale.
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proppastie

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First cut on load test was not a winner....got it attached and immediately saw without any loading that it was very weak at Wing Station 0 at the carry through. When the stress expert says "take a cut through here" it really means something. I am now doing more math which had I known what I was doing I would done before....oh well nothing bent and I am learning lots. Time to order some angle.

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proppastie

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Decided to save some weight given that the 150# tip load is not realistic considering the rotational inertia of the glider when dragging a tip is going to lessen that number somewhat. In other words 150# is only real if the glider does not rotate when dragging a tip at at a force of 150#....hope that makes sense.

Removed one angle (center aft) ....shown calculations 27K psi .....pictures of the added angles...2.6# added weight. center fix.pngA2A44C59-C26A-4119-B7F7-7B9095A5C396.jpeg60DD5166-0D33-4753-9FF0-D6DD464A9A2E.jpeg
 
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proppastie

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Back on the load test fixture, added angle to tractor to make up for missing other half of wing and other drag spar that would stiffen up center section.

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proppastie

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about 700 lb of sand (made rough measurement and built a 3d model of the pile to come up with that number) only need 500 lb as I already have sand for the aileron test.
aileron attached

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proppastie

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Aileron load test passed 9 psf per FAA Glider Criteria, P 27. 243 pounds limit. The wing was twisting on the fixture and I had to weigh the tail down. Actuation at aileron control hook up. The test was done in 5 increments (the reasonfor so many bags of sand) so to learn the failure point load if it fails. The reason for that is to then check calculations to see where you made a mistake and then to reinforce the failed member properly.

Whereas the aileron had been tested before this test was of the attachment to the wing to the aileron. The Wing did not fail at the attachment points/rear spar/ribs.
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proppastie

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Back at it,....lots of calculations, test panels, annual on Mooney, .....probably all winter on adding the stiffeners as it is very tedious work, but now it is plug and chug.....adding first rib (one to each panel),( will be riveted together inside wing, not all shown in this picture), adding Z stiffeners,.....not even 1/2 done the first panel as shown.

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proppastie

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First panel (11 left) split into 2 panels, with extra rib, and stiffeners.....was not happy with initial solid rivets on bottom, ordered 5000 ss break stem rivets as one does not ding up the .016 skin when driving alone.....I prefer to work alone. Took a hit in weight as regards the SS rivets, but the top came out almost perfect. Much Much stiffer.....should be as there is probably as much alum now as if I had used a thicker skin.......live and learn.

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proppastie

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ready to finish the second panel (outboard half already finished).....added rib and stiffeners all through an inspection hole. .....make sure you drill undersize because diameter is very critical for break stem rivets.....the dimpling opens up the hole...I used a #43 (.089) and just before riveting use a 3/32 drill to get the hole right on size.

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proppastie

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finished another panel (2 panels if you count the extra added rib) does not look much different, so no pictures but you can see about how long I take to do it by looking at the dates.....no hurry because I do not plan to do the load test outside until it is warm

The time includes CAD work and strength calculations as regards the span of the stiffeners.... I started out a 2.5" span and the panel finished today is a 3.5" span.

here is a screen shot of how I find the contour of the extra rib...1608488076978.png
 

proppastie

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another panel done....picture of rivet of extra rib inside the leading edge......somewhat difficult to hold the rivet gun, bucking bar and rib at the same time .....have to palm the bar and grab the rib with fingers then rivet......this end/joint is the easiest as I can bring it up partway through the inspection hole.

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proppastie

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I am wanting to destroy a BMX wheel to see how strong they are.....trash picked a 14" one and if I transition to one wheel I only need one of the wheels I have.....So 4 G at 400 lb gross is 1600 lb ....it will be interesting to see where the wheel strength is. ....I have my new homemade ram pressure gauge and I need to change it to a hanging scale for the test......Here is the wheel, and the test of the gauge..... that pressure translates to 900 lb and now you know how much the front of a John Deere Model A tractor weighs.....The rope is 3/16 Dyneema fancy boat stuff....used extensively on the Goat Glider......I am now planing to use it for my control cables (7/64) it does not need pulleys just some boat things and a knowledge of knots.
 

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proppastie

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I was thinking of going to 1 wheel instead of 2 but I did not know if one wheel was strong enough....so I went to the junk yard to fine another like what I had but they were gone.....however I did find a smaller and probably stronger one.....only 6 " dia. I got it for $2

I save about 3 lb doing this...the axle is smaller, and it is 1 wheel vs 2 but the mount is bigger.....I also will be going to an aluminum axle and spacers to make up for the bigger mount.

I decided to test it to see how strong it was....if it did not break at a reasonable number I would use it. The spec is 4 g which is 4x 400 lb gross = 1600 lb

I got to 1300 lb and was happy...another click on the tractor jack would have put me way over and I did not want to break it and have to find another.

shown old wheel vs new one 2.3 lb vs 2.1 lb for the new one......test set up and gauge reading of 580 psi which represents 1300 lb (580x2.25 sq in ram)
that rope is 1/4 Spectra with a breaking strength of 6600 lb
 

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proppastie

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new used single wheel setup,....alum axle, one jam nut, all for less weight....I still need to paint the spacers clean up the aluminum and add the missing bolts which were not necessary at this stage.


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