LSA140 Build

[Pinejuice]

Great description and nice solution to your engine mount issue. Glad to see you back at it with a vengeance, thanks again for sharing all of your experiences thus far.

[lsa140]

You are very welcome, it's good to be back working in the shop.

[Patrol28]

old pictures 291.jpg Nice work. Always nice to not have to build an engine mount if you can buy one reasonable. I left my spools a little long on the bottom and I'm glad I did.

[lsa140]

Looks great. Did you weld any portion of the cluster before installing the bushing?

[Patrol28]

I welded where the bushing lays in sort of an undercut fashion so the bushing would lay in without interference. Then I welded it up the usual way. That corner is a heat eater so I switched to 3/32nd tungsten.

[lsa140]

I paused for a moment and thought about doing the same. I can see that area sucking up a lot of heat and needing 3/32, though the LSA has less mass in that location than the Patrol.

[Patrol28]

I mostly use 1/16 unless I have a cluster or fitting that I know I'm going to be there a while, then I will go with 3/32nd. When I get into .065 wall and up I go with 3/32nd. Hope I'm not derailing your thread. I'm a Bhawk LSA fan. If mine wasn't so far along I would switch projects as my needs have changed. Keep up the good work.

[lsa140]

Not at all Patrol28, this great information to discus, and very relevant to scratch building any of the Bearhawks. I find the 1/16th tungsten very versatile, and have been impressed with how much electrode extension you can get with the right cup. I find myself using 1/16th ER70S2 filler rod most of the time, but sometimes .045 comes in very handy for slipping into a small puddle with the electrode in close.

[Patrol28]

I keep .045 around too and when I want something even less for a tiny edge weld I squirt out a length of .030 out of my mig welder, snip that off and use it for filler. It's also er70s2. When I need to really stick the tungsten out I ditch the gas lens and go to a skinny cup. There is several places on the Bearhawks that needs that.

[BTAZ]

I didn't want to derail the flying wire for the four place thread so am posting my response here.

I built my tail feathers as close to the plans as I could and then went looking on the Univair site for wire length information.

I used Citabria streamlined upper wires for the upper set and Cub round upper wires for the bottom set, nominally $220 total and delivered from Univair stock, They worked fine for dimensions/adjustment range but, given some of the items that drive wire length are “Scaled from Plans” this isn’t a guarantee they will fit factory fuselages or others. Of course with some foreknowledge of available wire length the mounting holes/ribs could be placed exactly as needed. Note the Citabria wires are right/left hand thread while the Cub wires are right hand thread on both ends.

For the bottom at the fuselage I used regular terminals while all the others were "hot forged" per Bob's instructions.

[lsa140]

Excellent info, thanks BTAZ.

[lsa140]

*Note: Deviation from plans. Changes to the LSA shown here have not been approved by the designer.

I will be lengthening/widening the landing gear slightly, and changing the shock strut attach point/truss structure on my LSA. The result will be a wider gear stance with a little longer travel gear. It will be a bit of a hybrid between the Bearhawk/Supercub landing gear. I've done quite a bit of work on the design, and will not be going into too much detail on the forum. There is nothing wrong with the stock LSA gear, and I would advise others to follow the plans. As I continue to show progress, photos will reflect small changes to my airframe, and I wanted to address this now to avoid confusion.

I nervously picked up the TIG torch for the first time since spring, and wonder "do my hands remember how to do this?" It is a totally different experience for me welding on an airframe, as opposed to something like a trailer, or truck rack. I can't help but keep in my awareness that this structure will be carrying me thousands of feet above the ground. It is good to be back welding again.

[lsa140]

Continued cutting and tacking additional fuselage tubing to accomodate the gear modifications. I finally gave in and ordered the Sharpie DX tungsten grinder from Arc-Zone.com https://www.arc-zone.com/sharpie-grinder-a-ptgk-dx I wish I had done it much sooner, it works very well.

[lsa140]

I have a belt grinding attachment on the right side of the bench grinder, and a wheel on the left. It is the perfect combination for notching tubing, but doesn't leave a wheel that can be dedicated to sharpening tungsten. I use a short back cap/tungsten on the torch, and do not like how close my finger have to be to the wheel on the bench grinder to get a good point. I've been meaning to try a magnifying insert for my helmet, some of those custers make it hard to get close enough for a good view. Half the battle of getting a good weld on an airframe is having a good view of what you are doing.

[Chris In Milwaukee]

As a software nerd, I spend an enormous amount of time in front of the computer screen. My eyesight has degraded over the past few years, and I'm trying to find the right combination of cheaters. Like U2, I still haven't found what I'm looking for.

[Luke68]

I recently bought a pair of miller auto darkening glasses that work well in tight places where regular helmet would be clumsy.if I recall they were a little over $200
When you tig weld on your airframe do you do any post weld heat treating?

[Bdflies]

"Meaning to try a magnifying insert". Ha! Now we know you're a youngster. .
To sharpen tungsten, I chuck it in my cordless drill and spin it slowly, while holding the tip on the belt sander (parallel to the sanding belt). Works pretty good. But I like your sharpener!

Bill

[lsa140]

That is how I learned to sharpen tungsten as well, though I don't really like using a drill for 1/16". I prefer to keep tungsten dust completely away from my regular grinding. This little tool tucks nicely under my welding stool. It has a slot for trimming the contaminated tip, and it puts a perfect point on the 1/16" tungsten very quickly.

[Bdflies]

Regarding welding cheater lenses; A number of years back, I noticed that my welding skills were degrading. Strangely enough, I decided to replace the clear cover lenses and voila! I could see the weld process better and my welds improved. Imagine that. The cover plates were so messed up, I could barely see through them. Who'd have thought that would be a problem... At that point, I figured I'd try my reading glasses, under the helmet. The welds improved further! Now, don't get me wrong; I'm not a great welder, but I can hold my own, when I can see the puddle. No matter how great your equipment is, if you're not in a comfortable position and you can't see the weld, your welds aren't going to be optimal. My helmet doesn't use standard size lenses, so I can't put a cheater in it. But reading glasses, a notch or two above what I read with, work just great.
Moral of the story; Don't sweat getting the perfect cheater lenses. Reading glasses work fine.

Bill

[lsa140]

Great info Bill. I wear glasses for a slight astigmatism. This spring I ordered a pair of glasses from Zenni Optical for under $40 shipped. I use these for work and in the shop. I have been meaning to order another pair with some magnification. Some of those clusters keep your helmet a little far away to really see what is going on with the weld. I'd highly recommend getting set up right with your helmet/vision before welding an airframe. It is well worth the time and effort.

[bergy]

Anybody tried these inside a welding helmet?

https://www.walmart.com/ip/Hydrotac-Stick-on-Bifocal-Lenses-1.50/38092965?sourceid=csesh02b332809c87fd4d5fb2f26224d52439ec&wmlspartner=shoppingcom2&affcmpid=1921384467&tmode=0000&veh=cse&sdc_id=1105544726399

[marcusofcotton]

O[QUOTE=bergy;n25980]Anybody tried these inside a welding


I use them in my helicopter flying helmet to see the gauges. For me personally, I don't think they would be terribly helpful in the welding helmet. Too small of an area.

[lsa140]

*Note: Deviation from plans. Changes to the LSA shown here have not been approved by the designer.

Should be finished with the additional fuselage tubing to accommodate the gear modifications tomorrow. I'm welding some of the joints as I go for ease of access.

[dcstrng]

Don't sweat getting the perfect cheater lenses. Reading glasses work fine.

Bill

Yep; I think this is a good idea, what I do as well... inside the helmet I use the full-sized reading glasses in the correct diopter, I've tried the smaller "look-over" glasses that are popular, but seemed like they were always in the wrong spot, so I use cheap, full-sized... although once the helmet is off, I'm immediately "blind" until I take the glasses off...

[Bcone1381]

x2. When I am having a "welding day" I am going back and forth between my regular bi-focals and welding goggles with my strong reading "Welding" glasses. Its common to light the torch, put the goggles on, and get ready to resume welding only to think "Why can't I now see?"...shut everything down, take off the goggles to clean the lenses only to find that they are not the reading "welding" glasses rather my bifocals...another frustrating Alzheimer's moment.

[Bdflies]

Hey LSA140!

Haven't seen you in a while. Whatcha been up to?

Bill