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proppastie

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For the most part done with the vertical tail. Needs fabric, holes drilled for mount fittings and for cables. The original wood/carbon reinforced is published at 5 lb in the builder's manual. This came in at 5.4 lb.
IMG_20161103_192510.jpgIMG_20161103_192452.jpg

I now have to finish the design for the mounting fittings, and mount them and the assembly to a 4x4 post for the limit load test. Limit load for this assembly is approximately 200 lb. (12 lb/sq ft) This will be a much more severe test than the horizontal tail as the load is all cantilevered.
 

proppastie

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Checking the fit of the fittings, I decided to do a look see of the whole tail on the boom.

IMG_20161107_130359.jpgIMG_20161107_153035.jpg

Stay tuned for the load test of the vertical tail. That's where I see and if I did my free-body diagrams correctly, and if the fixture and structure is strong enough.
 

proppastie

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tailloads2.jpg

Loading for the "Limit Load Test". Interesting coincidence ....notice the gal. and the sq inch columns.... off by 2 orders of magnitude but very close.
 

proppastie

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The Load test failed....I really screwed up in the design and stress analysis. I am not sure how much of the vertical tail I will be able to salvage, worst case the fittings only, but I think after I get back to it I may be able to use lots more. There were many good learning experiences with the this test. It will be a while before I will post again....sorry.
 

proppastie

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Just to let you know, I have not quit, salvaged/repaired/patched rudder. Re-designed (with generous help and encouragement thanks guys) stab. It is 8 times stronger and 1.2 lb heavier. Just finished the Spar fabrication. The weather stinks so I am getting a fair amount done because I do not want to go outside.
 

proppastie

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interesting way to line up the center of the LE, it is difficult to determine the exact center after bending as the skin could have shifted in the vacuum bag and any slight twist or offset will throw off the center location of the LE. Pictures: Vacuum bag, LE hanging from pipe, Plumb bobs around pipe to center up skin, measure in from each side, assembly going foward.

IMG_20161229_140419.jpgIMG_20161229_172655.jpgIMG_20161229_172616.jpgIMG_20161230_165942.jpg
 

proppastie

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Except for about 8 extra long rivets on order the vertical tail is assembled, and it weighs in at 7.04 # Original wood/cf vertical tail was 5 # but I am a little gun shy because of my load test failure. Also we do not know what the design loads were for the original.

IMG_20170107_114311.jpg
 

proppastie

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Load test passed. Several problems encountered, the 3 hinges did not line up after riveting, so I eliminated the middle one. I checked the stress but the hole where it was needs to be patched. One problem with using a tractor for a fixture base is the rubber tires move when the weight is added. I ended up having to jack up the near axle to get the tip of the tail clear of the table.

The rudder was tested first with the stabilizer spar blocked. The all the rest of the weight was added, and the tractor jacked up until there was light under the tip.

The weight was 201 lb total with 83 lb on the rudder. 12 lb/ft sq. minimum limit load.

The distribution was approximately as page 28 Fig 1-XII Faa Basic Glider Criteria.

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proppastie

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The revised vertical tail with 4 attach fittings is 7.23 Lb.. The original wood one is reported to be 5 lb. and I do not know if that includes fittings. It is not as bad as all that because the original had a large wrench bonded to the boom at the tail for weight and balance.
 

proppastie

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Sorry but nothing to show, worked on a Lathe, to cut my fuselage tubes to join them, worked on the stress analysis of the fuselage structure, worked on the design of the fuselage, controls, etc. still not done with the design of the fuselage. Did shopping for material at reasonable prices, lots of stuff but no airplane building. I need to make a steady rest for the lathe, and that will be my next project while finish of the design of the fuselage.
 

proppastie

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Working on "expanding mandrel". The plan is to make it round and turn it for uniform wall. Both size of tube are out of round about the same amount so if it springs back to out of round it should work. I have at least two other solutions if this does not work, both of which are more weight. Still having lots of fun with the lathe....but at .005 a pass it is getting old.

IMG_20170326_101651.jpg
 

proppastie

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The current design is to turn down the .120 wall to allow the .06 wall to slide over for 8" overlap, and bolt together.
 

proppastie

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Expanding mandrel worked, the test piece slid on. Now getting ready for the "money cut". I was worried the long overhang would be a problem but it looks like I will be able to do it. Turned a bevel on the end today no problem.

IMG_20170401_154621.jpg
 
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