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Tube construction: Alternatives to conventional welding

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Vigilant1

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Sure, if we had a production line and we're going to build 300 airframes we'd make custom formed gussets for each one. Why not? We've got that big press just sitting there and it will make alignment easier during the build. Likewise with the precisely fitted tubes: jig it once, then cut 300 of them that will be perfect. Buiding one airplane in a garage, we'd like to do something more efficiently for the conditions we are in. Luckily, with today's technology, we can have flat or ready-to-bend brackets waterjet cut quickly and at low expense.
Apples to apples: Wel.... er..."heat bonded" space frames go together quickly in a factory where there are jigs and fixtures that make things easy.
 
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Mad MAC

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It crosses my mind that those gussets once installed (particularly the F4B ones) could easily be cut to minimum size with a router. So the process could be make one or two gussets shapes vaguely close to the final shape, trim on installation.
 

Winginitt

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Sure, if we had a production line and we're going to build 300 airframes we'd make custom formed gussets for each one. Why not? We've got that big press just sitting there and it will make alignment easier during the build. Likewise with the precisely fitted tubes: jig it once, then cut 300 of them that will be perfect. Buiding one airplane in a garage, we'd like to do something more efficiently for the conditions we are in. Luckily, with today's technology, we can have flat or ready-to-bend brackets waterjet cut quickly and at low expense.
Apples to apples: Wel.... er..."heat bonded" space frames go together quickly in a factory where there are jigs and fixtures that make things easy.
If we take the 100 brackets that I estimated from the one picture and knock 20% off just so I'm not overestimating what needs to be done.....that still means a minimum of 80 brackets to be made. There will most likely be at least 10 variations ( probably more) of shape and size. You will have to calculate bend radius for some brackets and hope none crack during bending and that all your bends are perfect. You will need to make extra brackets so you don't come up wanting if something doesn't go perfectly. Don't want to repeat the manufacturing process a second time for a few brackets. You will have to make dimensional drawings of each type bracket for the water jet operator to set up his machine. You will have to purchase at least one full 4x8 sheet of aluminum and probably two sheets. You will have to purchase aircraft quality rivets and a rivit tool. You will have to pay for the water jet machining . You will have to pay for bending in a brake....unless you already have one. You need to consider that Murphy's law most likely intercede somewhere. Remember that once you design all your brackets that your individual cutting and fitting of all tubing will have to match your airplane drawing virtually exactly in order for all your premade brackets to fit. Small errors in your accuracy can cause a "stack up" of tolerances and then your brackets may gradually stop fitting correctly.


What do you estimate the cost of materials,machining, and tool will cost for your proposed airplane?

Added note: I spent years in manufacturing....... I know how stuff doesn't always go as planned.
 
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Winginitt

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It crosses my mind that those gussets once installed (particularly the F4B ones) could easily be cut to minimum size with a router. So the process could be make one or two gussets shapes vaguely close to the final shape, trim on installation.
I don't think it's possible to control the depth of the cut with a hand held router on an already installed bracket. If you Nick the fuselage tubing it would be ruined.
 

litespeed

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I can not see the big problem with the brackets. Sure some can be complex but most are not and it all depends on the design.

The brackets/gussets will be either bolted but mainly riveted with pull rivets and they are simple, reliable, light and cheap
I have lots of experience in sheet metal and brackets/gussets and they are not hard or slow to make.

Just use a small 3-1 bender/brake on a bench, it shears, bends and rolls. Simply to use and fast.If you can cut some light cardboard, use a ruler, protractor etc you can easily make a gusset template.

Get it wrong? adjust or remake for a few cents. It is not hard nor difficult and far less so than a welded bracket.

I could easily make all 80 brackets/gussets in less than a day.

No need for cnc or anything like that when doing a single aircraft. Adjust them as needed or quickly make another. If you are making a homebuilt then a small investment in tools and a compressor driven rivet gun is cheap and easy to use for other things.

Wingitt,

All your criticism of above also relates exactly to a steel frames fuselage. Bends still have to be correct, tubes have to be very accurate etc. Yes welded can be great but you seem to be making up anything to **** tube and gusset and excuse steel of similar problems.

Each to his own, I can weld and do T & G and composite and wood. My choice is not just about what I am comfortable with, but what works.
 

litespeed

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I can absolutely be sure that if you give me two garages- one for building tube and gusset and the other for building a steel tube aircraft fuselage- The tube and gusset will win hands down for speed and construction cost. Assuming same fuselage and different materials.

If I have extra hands, then the alloy process is even faster- hard for two to weld at the same time.

If you add in any machine time for kitting, then its even better in favour of alloy. Machine speeds are much faster. A hand punch can do holes in alloy gussets very fast- can't do that in the thick bracket/gusset Steel. Want to drill a hole? fast in alloy and slow in steel. Cutting and notching tubes is a great deal slower in steel and will need to be accurate. Tube and gusset is fast to cut and notch and the tight fit is not a necessity.

I can also be sure it will cost a lot less in tools and consumables as well.

Hands up who can cut, notch, jig, and fully weld an aligned fuselage in a week? Now can you do it without having jigs first made up? How long then? Now do all the treatments for corrosion and such.

I could easily do a tube and gusset in a week- finished for fitting and have lots of time to drink beer and admire my work. IF it was a simple square tube version, i could also have it skinned as well. I would be well into the wings as well with the correct design.

This is proven time and again.

Why keep flogging the welding horse?
 
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cheapracer

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****, I was just down at the factory cleaning and straightening the place up for my re-start, note i have only dropped in a couple of times in the last year due to my heart operation (there's half inch of dust over everything), and found about 100 x 6 meter lengths of 1" x 0.040" 6061T6 square tube .... that's 25 x 1 mm for cultured people.

It may sound strange to some of you to have forgetten them, but I have been through quite a bit the last year.

I may have to re-consider the design updates I was going to do to utilise these tubes, and gussets!
 

litespeed

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I have not forgotten you Mate.

Us cultured people need to stick together, lest the imperial menace spread.

I have a spare spot here for that tube, just pop it in the post for me:).
 

cheapracer

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I know this is no welding, but one method I tried out early on, and I'm sure some have considered, is to weld joiners up from steel, then slip aluminium tube in and rivet.

My connectors here are a bit larger than might be considered in this thread, but the front 'i's, the crossbraced mid frames, and rear 'V's, or all the parts painted dark grey are of that system.

The only single reason i didn't use this was because I was very unhappy with the local welding standards and didn't feel I could get consistent, and hence safe, results, but fully I reccommend it if that welding service is available to you, and not much welding at that.

Since they are small and isolated, no need for jigging and concerns of warpage etc ..


first blood 2.jpg
 
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flywheel1935

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Hi WINGINITT, Ive had to make close to 250 gussets for the LMA 'Kit" I'm building, as per you observation above, As they went missing when I acquired the assets of the UK importer.
Be aware that they are bonded, with HYSOL, the rivets 'only' help in peel & sheer !!! I say kit, but due to poor design we are redesigning to make better use of UK supplied materials.
Its fabric covered, using stringers over the top of the gussets to hide them.
 

Aerowerx

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I have not forgotten you Mate.

Us cultured people need to stick together, lest the imperial menace spread.

I have a spare spot here for that tube, just pop it in the post for me:).
As a side note...

I was quite surprised. A couple of weeks ago I read that, in 1866, the US congress voted to make Metric the official system of the United States! I wonder what happened?
 

Vigilant1

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As a side note...

I was quite surprised. A couple of weeks ago I read that, in 1866, the US congress voted to make Metric the official system of the United States! I wonder what happened?
They've passed laws like that a few times, km even made it on to a few road signs. It wasn't popular with the public, IMO because the program seemed to put a lot of emphasis on learning to convert. That makes things much more cumbersome than it needs to be.
I'd much rather build a plane that had metric plans, but the stock available on the US is largely on inches. As a half measure, plans laid out in decimal inches would be, IMO, easier than using fractional inches.
 

Hot Wings

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and found about 100 x 6 meter lengths of 1" x 0.040" 6061T6 square tube .... that's 25 x 1 mm for cultured people.
For those of us that can occasionally act cultured which is it!? 25 x 1 mm or 25.4 x 1.016 mm? :p

As a side note...
I wonder what happened?
The uncultured masses simply went about their daily lives and remained ignorant of a better way? :oops:

I'm still learning to think in metric. Drives the wife nuts when she asks me how long or how much of something............"Give me some real 'mericuum numbers!!! :mad:"
 

cheapracer

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I still get 8, and one of them is a bit crooked thanks to being stupid with a drill press..........And 2 thumbs.

That is 12, base 8?
LOL.

Stupid thing is we still get 12 eggs, eg: a dozen, and milk is measured at 600ml, which is a pint, rather than 500ml, which is half a liter.
 

Aerowerx

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....IMO because the program seemed to put a lot of emphasis on learning to convert. ...
That's the problem. Much easier to just go cold turkey.

Having said that, I only have one length conversion factor memorized . That is, 1 inch=25.4mm, which is the definition of an inch. If I want to know how many feet is 12 meters, for example, I go down to mm, divide by 25.4, then divide by 12.

Humorous anecdote. My SO is still visiting family in the Philippines. The other week I texted her that it was 40 degrees here. She advised me to stay inside and drink plenty of water. Having been there for several months, she was thinking in Celsius! 40F=4C, but 40C=104F!!
 

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