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Fabricate the longerons

PostPosted: Fri Oct 30, 2020 7:57 pm
by Carlos Trigo
Guys

I am at the stage of fabricating the Tail longerons, and I see that one must cut those long angles legs in a big extension.

How is the best way to make those cuts, and leave perfect and parallel edges?

Thanks
Carlos

Re: Fabricate the longerons

PostPosted: Fri Oct 30, 2020 10:59 pm
by Rynoth
I made those cuts with a miter saw.

Re: Fabricate the longerons

PostPosted: Mon Nov 02, 2020 11:19 am
by pappas
Most of the aluminum can be cut with a miter saw. Be sure to finish all of the aluminum cuts with a fine file or on your bench grinder with a 3-M ScotchBright polishing wheel. No burrs mean no stress fractures later.

Fabricate the longerons

PostPosted: Mon Nov 02, 2020 2:12 pm
by Carlos Trigo
pappas wrote:Most of the aluminum can be cut with a miter saw. Be sure to finish all of the aluminum cuts with a fine file or on your bench grinder with a 3-M ScotchBright polishing wheel. No burrs mean no stress fractures later.

To be frank, I’m not seeing how can you make a longitudinal cut in a 136” long angle with a miter saw...
I tried a band saw, but mine has a very unstable blade and the cut began deviating after less than 1 inch long :-(

Perhaps a table saw...?

Carlos

Re: Fabricate the longerons

PostPosted: Mon Nov 02, 2020 3:13 pm
by gammaxy
Carlos,

The other posters and I all built Sonex/Waiexes. Until trying to understand your question, I was totally unaware that the Xenos longerons are different.

Here's a relevant thread. Sounds like a couple others used table and band saws. The band saw technique sounds interesting. I'd probably use a tablesaw with a jig to hold the material down and against the fence. Doesn't seem like a lot of fun :-)
http://www.sonexbuilders.com/viewtopic.php?f=4&t=1557

Re: Fabricate the longerons

PostPosted: Mon Nov 02, 2020 3:17 pm
by XenosN42
Hi Carlos,

Michael here ... built a Xenos in the past.

The Xenos is the only Sonex model that requires a cut of the type you require. Might be best to specifically say you're building a Xenos with your questions. The other responses answered a question, just not your question.

To make that cut you need the right tools and practice, practice, practice .....

The cut is made with a band saw. The proper blade is very important. You need to use the widest blade you can get. Not the thickest, the widest. Usually when you shop for a blade you'll first see many narrow blade options (~ 3/8") wide. Look for blades that are at over over 1/2" wide. The reason: once you've established a straight cutting line it’s easier to keep it straight with a wide blade. With a narrow blade the cut line can and will wander more.

Before you attempt to cut that long angle (Is it 7 feet long? Is it expensive?) practice cutting short pieces of scrap metal. Cut next to your line, leaving at least 1mm of space. Later on you’ll use your Vixen file to clean up the cut and meet your drawn line. GOOD LUCK!!

For the Sonex/Waiex/OneX/SubSonex builders this is what Xenos builders must do. I don’t have the plans in front of me so the dimensions are estimates based on memory.

Imagine a 7 foot long 1" by 1" aluminum angle. Place it so that it runs lengthwise from left to right. Make a mark six inches from the left end. Make another mark six inches from the right end. There will be 6 feet between the marks. Now turn that six foot span from a 1" by 1" angle into a 1/2" by 1/2" inch angle. Leaving the 1" by 1" sections on each end of course. Sounds like fun doesn’t it. ( This is needed to reduce the weight. Remember the Xenos has a very long fuselage. )

I suggest you run my ideas past Kerry to see what he thinks. He may have some more tips.

Re: Fabricate the longerons

PostPosted: Mon Nov 02, 2020 3:27 pm
by Rynoth
Ah, so it is a rip cut. Yea, a miter saw won't help you there.

While I didn't have to make any rip cuts that long on my Waiex, I did have some that were at least a foot long or so. For those cuts I used a band saw (followed by a lot of filing since I made the cuts generously to the outside of my marked line.) What Michael said about band saw blade width is 100% correct. The ease of making straight lines between a 3/8' blade and a 1/2" (or more) blade is drastically different.

A belt sander may be your friend when it comes time to clean up those long cuts. Just be sure not to overheat the material.

Fabricate the longerons

PostPosted: Mon Nov 02, 2020 5:04 pm
by Carlos Trigo
Thanks guys

I did forget to mention that I was referring to a Xenos, my bad.
But I did mention longitudinal cuts...

Having failed to make those cuts in my own band saw, I decided to bite the bullet and bought a table saw, changed the cutting disc from wood (less and spaced teeth) to a multi material disc (more teeth), and just tried to cut that loooong angle.
It seems it will do the job.

Thanks again for your help
Carlos
XENOS B #020

Fabricate the longerons

PostPosted: Mon Nov 02, 2020 5:07 pm
by Carlos Trigo
And these XENOS longerons are nothing less than 11 ft long...
It is quite a job

Re: Fabricate the longerons

PostPosted: Mon Nov 02, 2020 7:30 pm
by racaldwell
Carlos,

I cut my longerons with a table saw with a carbide nonferrous metal cutting blade. I used a candle for the wax to lube the blade and longeron. I made a fence to keep it straight. I drilled holes in the corners where the cut would stop. This worked out fine. I just went slow and kept both hands on the longeron to keep it against the fence. Also, I set the fence so the gap was slightly greater than the exact dimension. I figured a file and scotchbrite wheel would take in down. It did.

Rick Caldwell
Xenos 0057