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  • Hey Guys, I worked on the airbox again. I got the hot air flapper working. I got the carb connector on with brass screen between the connector and the airbox. I got the flange around the front of the airbox. Also got the escutcheon for the filter with brass screen in it and fitted the filter into the front of the airbox. Im waiting on the 2 inch flange to come in so it can be attached to the hot air hole in the top of the airbox. I also found a way to make a joggle by first bending an angle then backing one side of the angle to a 1/4 inch thick steel bar and clamping everything down to the table and beat one edge of the angle down on the steel bar.
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    This gallery has 8 photos.
    Last edited by davzLSA; 06-06-2021, 05:31 PM.

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    • Frank
      Frank commented
      Editing a comment
      Nice work Dave! Engine gonna love it!

  • Hey Guys, I finally finished my airbox. I had no idea it was going to be such a big project. I didn't keep exact time on it but I know I had over 40 hours in it. It is not as pretty as Robs box but I'm not the craftsman he is. It is functional though. It has a removable filter and a heat control valve. It is now connected to the control lever in the cockpit and it is functioning.
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    This gallery has 15 photos.
    Last edited by davzLSA; 06-23-2021, 06:43 PM.

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    • Hey Guys, I have a question that is directed to built and flying LSA;s. Does anyone have an idea what the weight is of a completed seat front and rear weigh on the LSA? Im thinking of buying a ready built race car seats. I have found them with a low weight as low as 24lbs. I dont really like the looks or the expense of a "real" aircraft seat.

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      • Hey Guys, I dont have any pic for today but I have been working on my LSA. I now have my fire wall all sorted and all my engine connections figured out. My next step will be to completely disassemble the fuse as it is and sand blast all the parts I have welded on and get it primed again and painted. At this point I will be at the fast build stage and can start to permanently began to assemble the fuse and then I can get started on my wings. I want to bring up a safety point as well. My good friend William Wynne was almost burned to death in an accident many years ago. The reason was rigid fuel lines that fractured in the accident. As a consequence he now recommends flexible fuel lines. I have thought about this a lot and it is more expensive than rigid lines but I think the safety factor out weights the cost consideration. And the cost is not that much more than rigid lines. Recently I was looking at some of the newest general aviation aircraft reviews and the Diamond DA62 and as far as I know all their other models are using flexible fuel lines. So if you have not yet installed your fuel system I offer this for your consideration. I believe it has the potential to save lives. Here are 2 products that will satisfy this safety requirement.

        Earl's Performance 610006ERL - Earl's Performance Speed-Flex Hose
        Earls 809106ERL 90 Degree -6 AN Female to -6 AN Hose Adapter

        Last edited by davzLSA; 07-16-2021, 09:22 PM.

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        • Bcone1381
          Bcone1381 commented
          Editing a comment
          I like that hose reference you gave. I think Flexible Fuel hose is an industry standard. Have you build any of these Earls Speed Flex hoses yet?

        • davzLSA
          davzLSA commented
          Editing a comment
          Hi Brooks, yes I have and they are very easy to build.

        • Bcone1381
          Bcone1381 commented
          Editing a comment
          The context of my comment #304.1, regards Flex Fuel hose only in the Firewall Forward area to accommodate vibration and engine movement without fatiguing a rigid fuel line.. Posts after this indicates that I made an error, and the context rather was regarding the entire airframe.

      • Before we consider changes to the designed fuel system, let's keep in mind that there are any number of ways to cause fuel leaks in a crash. There also many ways to cause a crash, including inadequately designed fuel systems. Bob's design is not arbitrary or without considerable experience and thought.

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        • Hi Jared, I don't advocate changing Bobs' design, only replacing the rigid lines with flexible lines.

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          • Originally posted by davzLSA View Post
            Hi Jared, I don't advocate changing Bobs' design, only replacing the rigid lines with flexible lines.
            You are changing the design, perhaps without changing the general routing. The materials are an important part of the original design and are also not selected arbitrarily. I think you are likely to find that the flexible lines have a much larger minimum bend radius, which will impact routing, a much shorter shelf life, and perhaps other complications that are yet to be uncovered.

            Can you pose an example where a flexible line will mitigate a risk that 5052 aluminum lines (which are also, to a degree, flexible) will not?

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            • Hi Jared, I have found many examples where a flexible fuel line can mitigate the risk of a post crash fire. There have been studies of this and all of the examples I have found support this. Here is a large PDF document of a study put out by the FAA and the DOD. Here is an excerpt for that document. "4.2.6 Fuel Lines.Damaged fuel lines frequently cause spillage in aircraft accidents. Lines often are cut by surrounding structure or worn through by chaffing rough surfaces. The use of flexible rubber hose armored with a steel-braided harness is strongly suggested in areas of anticipated dragging or structural impingement. In systems where breakaway valves are not provided, these stretchable hoses should be 20 to 30 percent longer, before stretching, than the minimum required hose lengths. This will allow the hose to shift and displace with collapsing structure rather than be forced to carry high tensile loads. For this reason, it is equally important that couplings and fittings be used sparingly because of their propensity to snag and restrict the natural ability of the hose to shift." The document in its entirety can be found here : http://www.tc.faa.gov/its/worldpac/techrpt/ar01-76.pdf, I believe the most vulnerable area of the fuel lines in a crash is where the lines connect to the tanks at the wing roots. But anywhere in the system exposed to other crash forces would benefit of a more flexible line. But as has been said this is an experimental airplane and we are free to build anyway we see fit. Here in another document put out by the FAA and DOD that also seems to support this conclusion. https://ntrs.nasa.gov/api/citations/...0030033927.pdf, Everyone must make up their own minds how they want to proceed. I am just offering information for ones consideration.

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              • The idea is that in a crash, the parts will be able to move without separating the lines? This seems like a very narrow window, where there is more movement than the 5052 lines can provide, but less movement than will still rip out the flex lines.

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                • Im my friends case it was a Pietenpol aircraft ; when the nose hit the ground the wings shifted forward and the rigid fuel line connections to the fuel tanks at the wing roots broke and covered him with fuel. I was just thinking that our Bearhawks are high wing like the Peitenpol and could possibly experience a similar failure in a crash. So yes the main idea is that the lines can move as opposed to breaking. The line slipping out of the fitting is not usually seen in these systems if properly built. As with most systems we use it is recommended that one would stay with the same manufacturer for all the fitting and lines through out the system. As you know in a very rigid system movement of any kind, even vibration can cause fatigue fractures and then very little movement can cause a complete failure. This is where the flexible lines can be used to mitigate much of this possibility. I don't think any system will keep a turn to base and stall and spin in would do much to save anyone. I believe the flex lines and self sealing frangible couplings are just one tool we can use to make flying a little safer. And it is something worth considering.
                  Last edited by davzLSA; 07-17-2021, 01:50 PM.

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                  • Mark Goldberg
                    Mark Goldberg commented
                    Editing a comment
                    Dave, most builders use a small length of rubber line between the wings and the fuselage. For the example of what happened to Will - that might have sufficed if in fact the rubber line would not break loose like a rigid line. If there was enough movement, it would seem like the lines would come loose no matter what they were made of. Mark

                • I agree with you Mark that in some cases no matter what you do serious injury cannot be avoided. But any extra safety precaution you take can mitigate the severity of any possible injury.

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