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  1. L

    Sheet Metal Bending - Equivalent Material Gauges

    Mechanical bending brakes are usually sold as 22, 20, 18 or 16 gauge - meaning thickness of mild steel sheet that they can bend. Sometimes you have a table which lists the equivalent thickness of aluminum that can be bent. However, there's never any mention of aluminum series or temper. Does...
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    Heinkel 222 Reference in Ladislao Pazmany Landing Gear Book

    Never mind... my calculation on weight was off by a factor of 8 --- I had 8+ not 8* in my spreadsheet. Total rod weight = 219 lb :depressed
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    Heinkel 222 Reference in Ladislao Pazmany Landing Gear Book

    Thanks for everybody's input here. I'm always impressed with the depth of knowledge that shows up in this forum. In the absence of any sources of information, I tried to assess the applicability of this landing gear design for my project (3600 lb taildragger). From the web I found the...
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    Heinkel 222 Reference in Ladislao Pazmany Landing Gear Book

    Anybody ever heard of the Heinkel He 222 - referenced in Pazmany's "Landing Gear Design for Light Aircraft", page 186. I quote - "The landing gear illustrated in Figure 10-121 employs a unique torsion spring arrangement. Four torsion bars are restrained from rotation at the top by means of...
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    Strut Wire Interference Drag Conumdrum

    That's probably true - but what I'm getting at is - if you were to build a strut and wire (streamline tie-rod) braced biplane today, does it make sense to have one interference point (strut/wire/wing), or two (strut/wing) and (wire/wing) where the strut and wire are separated by some multiple of...
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    Strut Wire Interference Drag Conumdrum

    I went to the Beechcraft Heritage Museum at Tullahoma TN recently (much recommended). They have a "cut-away" Staggerwing without any skin there... and I took the following picture of the intersection of the lift wires with the strut at the top spar (unfortunately the uploaded image is on its...
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    Fuselage C Frame - How good does it have to be?

    Hmmm... Let's see if this works. The first of the photo's shows 3 frames in the vertical jig prior to the attachment of the corner skins. Second and third photo's show the current waviness in the inner flange.
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    Fuselage C Frame - How good does it have to be?

    I would like to raise a somewhat philosophical question. I have been working on a aluminum stressed skin tailcone, constructing C-Frames of a roughly rectangular shape with curved corners. The top corners approx 5 inches radius, the bottom corners roughly 8 inch radius. The frames...
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    SN Diagrams for 6061-T6 - Where to find?

    Thanks for the input dcarr... The diagram seems to be more useful than most (it shows the test scatter), and it does seem to be closer to the Bruhn diagram for 2024 - but the devil still seems to be in the details. From what I have pieced together - there are many SN diagrams, depending on...
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    SN Diagrams for 6061-T6 - Where to find?

    Seems MMPDS-01 is the same as MIL-HDBK-5J. No new SN data on 6061-T6 - but it has a nicer index at the front :-) Thanks.
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    SN Diagrams for 6061-T6 - Where to find?

    Can anyone with access to MMPDS check to see if SN Diagrams have been added for 6061-T6 (notched). I only have MIL-HDBK-5J, and it only includes one SN diagram for 6061-T6 in an un-notched state.
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    SN Diagrams for 6061-T6 - Where to find?

    So I've been re-working a design to work with 6061-T6 instead of 2024-T3. In my original design, I selected the limit stress for airframe life using the SN diagram for riveted lap joints from Bruhn (Fig C13.14). This same diagram is reproduced in Hiscock's "Design of Light Aircraft" (Fig...
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    Aging 6061-T4 to 6061-T6 - What's the catch?

    The design has a lot of curves - both in the inner and outer flanges on the fuselage bulkheads. I've been bashing out the inner flanges on the form block; and then form and flute the outer flanges to get close to the final shape. I then tweak the outer flanges in the fuselage jig to get the...
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    Aging 6061-T4 to 6061-T6 - What's the catch?

    I have been weighing various aluminum sheet selections against the formability requirements for my design. The hard tempers impose limitations on formability; the formable tempers have reduced yields limits. I have tried forming a particular bulkhead (the usual problems with shrinking and...
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    How long can you work 2024 sheet starting from condition W

    A quick question for those that have more experience in the sheet metal field than I... Assume I solution heat treat a flat blank made of 2024-O and then hand work it over the form block after quenching (the blank starts in condition W). How much time (roughly) do I have to work it before it...
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