Thickness of 6061-T6 Wing Ribs

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BBerson

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If it won't form in 6061-T6, the first choice is to use 6061-T4, as its only a bake from T4 to T6 and doesn't tend to warp.
I assume you are talking about artificially aging solution heat treated 6061-T4 to T6?
What is the process? (time and temperature)
 

BJC

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I assume you are talking about artificially aging solution heat treated 6061-T4 to T6?
What is the process? (time and temperature)
I knew an old time professional AE and homebuilder who said, “put the [ribs, bulkhead formers, etc.] in the summertime attic for a month” to take T4 to T6.


BJC
 

BBerson

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2024 naturally age hardens in four days at room temperature. But I have not found this age hardening data for 6061.
For example, is the 6061-T4 at Aircraft Spruce naturally age hardening on the shelf?
John Thorp specified 6061-T4 for the ribs. But I don't recall anything about age hardening.
 

wktaylor

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BJC... one month in a desert-summer attic is inadequate for age hardening 6061-T4 to -T6.

Yeah... 6061-T4 is more ductile and forgiving for tight bend-radii forming than -T6. But for -T6, age-heat treatment is required, thus....

After forming-and-straightening the -T4 part can be reliably oven**-age-hardened to -T6 by heating the -T4 part @ 350F[+/- 15F] for 8-to-10-hours [for amateurs: 8.5 minimum]. This temp/time matches SAE AMS2770 and 'sorta'... MIL-H-6088.

** oven should be calibrated and have digital temperature stabilization.
 
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BJC

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BJC... one month in a summer attic is inadequate for age hardening -T4 to -T6,
Thanks; I never knew if he was serious or not. Good guy, though, built a MM and, the last I knew (decades ago) was well on his way to completing an Emeraude.


BJC
 

wktaylor

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BBerson… as I recall, T-18 wing-ribs could be made from 0.025 [0.032?] thick 2024-T3 clad sheet or 0.032 [0.040?] 6061-T4 sheet... no aging HT required.
 

WonderousMountain

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There's not enough difference to throw a ruler at, but, the replies are correct.
It's Copper in the Alloy that aids in forming. Slight strength increase and fitting fatigue resistance. No amount of oven baking is going to change that, but if you are on a budget, it's currently real savings. Marine grade can be used & it may with stand exposure, but there are different conditions for it as well.

To the original question. I would * use the same thickness in wing surface &
Rib webs, and build up the internal members irrespective of surface resistance.
Chord length is a matter of suitable process. If you can do ribs on a 2.5x10 foot work bench, then it is not for any of us to tell otherwise.

Sincerely,
CK LuPii
 

BJC

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For those that may be interested I have created a GoFundMe for my Phoenix project...
For those of you who may be interested, I have a bank account onto which I will deposit your contributions made via personal check or in cash.

I promise you that it will be used to fly, maintain, and or build E-AB aircraft. I well even post photos of said activities paid for by your generous contributions.

PM me for my snail mail address.

Thank you for your support.

BJC
 

WonderousMountain

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Towards technical success on your mission.

I formally suggest you obtain knowledge of Boundary layer suction & blown flow control. Removing a turbulent layer & accelerating air over the wing reduces drag & provides Lifting
force, which can be used in forward motion.

Best wishes,
CK LuPii
 
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wsimpso1

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BJC... one month in a desert-summer attic is inadequate for age hardening 6061-T4 to -T6.

Yeah... 6061-T4 is more ductile and forgiving for tight bend-radii forming than -T6. But for -T6, age-heat treatment is required, thus....

After forming-and-straightening the -T4 part can be reliably oven**-age-hardened to -T6 by heating the -T4 part @ 350F[+/- 15F] for 8-to-10-hours [for amateurs: 8.5 minimum]. This temp/time matches SAE AMS2770 and 'sorta'... MIL-H-6088.

** oven should be calibrated and have digital temperature stabilization.
This Thatone

A desert attic is a LOONG ways from 350F.

Billski
 

wsimpso1

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For the skin I’m looking at using 2024-T3 .040” thick so I can counter-sink the holes with 1/8” rivets.

What do you think about using .040” 1mm instead of .050”?
While I believe benchmarking comparable airframes is a good idea, the bigger question in my mind is always a matter of searching out a min weight structure that does the job. Skin thickness chosen to countersink? Backwards approach in my mind.

I recommend starting with minimum gage skin thickness for the application and level of skin damage risk you will allow, figure out needed rib spacing, needed rib strength, and that takes you to rib details. Then check weight of the whole thing.

Then bump the skin to the next available gage, and repeat rib spacing, rib loads and design, and weight check. Allowable rib spacing will increase with thicker skin, but you can check out the design tradeoffs of more lighter ribs versus fewer heavier ribs - each option will have its own needed strength, driving design of the ribs, check the weights on each of these. Repeat the skin thickness bump as needed to find the optimal structure.

I favor going with the lightest wing structure that does the job. IFF that allows countersinking instead of dimpling, would I then go to countersinking. Dimpling is widely used on thinner skins.

Billski
 

BBerson

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Greetings Builders,

I am building my own design, tailless, aircraft. Wingspan is 40’. I am going to use 6061-T6 for the wing ribs.However, I’m running into a little snag... What gauge should I use. What do most aircrafts call for? The only blueprints I have is for a Pietenpol and that’s all wood - no help there.
What most aircraft use is not relevant. What very similar aircraft use is relevant.
What are you designing? A light sport? A 300hp racer?
What is the wing loading? Top speed?
Ultralights use .016". Cessna 150 is .020". T-18 is .025. I don't know any thicker home built ribs. Not much choice in metal gauge.
 

rv7charlie

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Greetings Builders,

I am building my own design, tailless, aircraft. Wingspan is 40’. I am going to use 6061-T6 for the wing ribs.However, I’m running into a little snag... What gauge should I use. What do most aircrafts call for? The only blueprints I have is for a Pietenpol and that’s all wood - no help there.
OK...
First, What possible reason can you give for titling a GoFundMe appeal
World Wide Air Purifier (Phoenix) - New Concept

when you're really using the money to fund your personal aircraft? Could it be a fraudulent appeal?

Second, picking skin thickness based on
For the skin I’m looking at using 2024-T3 .040” thick so I can counter-sink the holes with 1/8” rivets.

Whaaattt???
 
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