A little progress XL H-58

[Chuck in Indiana]

First set of strut attach/landing gear fittings ready to be welded. A piece of junk aluminum milled to .875" holds them in location.

[Steve]

CiI - now that looks warm & fuzzy Steve

[fwilly]

Sorry if this is a de-rail of this thread, but I've been practicing my tig welding in hopes of getting to the point that you're at, and looking at the aluminum block scares me.  The thicker plate against the thin tube is something that I think is a hurdle for a novice like me.  To me, it looks like the aluminum will be a heat sink and make it harder.  Is that something that OA gas welding is better at than tig?

Thanks

[Chuck in Indiana]

^^^^ Actually TIG is a lot easier than Ox/Acetylene if there is a big heat sink like that aluminum block. Fortunately, I have both systems. Trying to operate the foot pedal with my knee or between my legs when crawling around on the floor would be a challenge for me. 

[Dan_]

Tig or gas, best to angle the torch more to the bigger heat sink. 

To confirm the correct angle, fire up on it at an arbitrary angle and make the metal glow. 

Shut down and if the angle was right the glow will be the same on both pieces (same readiness to puddle).

[Chuck in Indiana]

If I *had* to gas weld these fittings, I would use 7/8" bushings between the bolts instead of the aluminum block. The block just makes it easy to locate them.

[fwilly]

Good info!  Thanks

[Chuck in Indiana]

I thought it might be a good idea to get the gear pivot points in the same plane.
Even a blind hog finds an acorn every now and then..

[Chuck in Indiana]

Welded in the fittings except for the "Hammer to fit in field"    to make the 7/8" wide areas touch the 5/8" tubing. Did all that.. the aluminum fixture held everything in location.
comma but..
What about this area on the rear fittings?

Hmmm, that's not going to work. I guess a guy could make a triangular piece to fit in there.. and then the light bulb came on. Ahh, I could make that a seat belt mount.

Yeah, that's the ticket. Tomorrow, or whenever I get to it.. I get to weld all this stuff up.
But now.. it's beer o'clock.

[Chuck in Indiana]

Gave Bullet her first aerobatic lesson today. 

Actually, I needed to weld where I'd been holding it in the rotisserie. I hadn't welded the bottom of the lower longerons, and was welding along thinking (like Wiley Coyote) I was doing pretty good  when there was a shower of sparks and a hole. Why? I had welded the rest of it with gas..maybe some contamination? What I don't know about TIG would fill several volumes. I'm pretty sure it's affected by phases of the moon.. I'll go with that. 
The deep dark recesses of my memory dredged up "Don't I have a bronze bushing in my good junk drawer?"

Not only did I have one, but it's the exact size I needed for the tailwheel gizmo. Just goes to show you that if you live long enough, something will turn out right. 
Ran a reamer down the tailpost to clean out the weld slag, and it slid right in.

Another bite off the elephant..

[Theodore]

coil spring tail wheel w/boot, maybe put the levers at the bottom of rudder tube.

Wanted to ask  heating and bending longerons did uyou do this with help or buy yourself? I'll read back this thread to early stages of welding...

 Reply #201 on: February 09, 2021, 10:04:52 AM

This Award winning championship thread!
Thank you Chuck!

[Chuck in Indiana]

Thanks, Theodore.. I'm really happy it has been of some use on your project.
On the tailwheel steering.. tailwheels take a *lot* of abuse, and I'm afraid that steering it from the rather dainty rudder spar is asking for trouble. What I'm planning is what Les Homan is using, a simple spring on a shaft on the tailpost. That's what the bushing I found is for. I'll drive it with cables nicopressed on to the rudder cables to take the load off the rudder entirely.
Just MHO.

[Chuck in Indiana]

Continuing on the landing gear, I drew the 67" prop disc and 20" wheels per the drawings, and found I would have 4 1/4" clearance.

Obviously, that won't get it. The Friendly Aviation Agency sez a minimum of 9 inches for a tail dragger with the tail up.
So (throwing a dart) I don't see any reason I can't raise the thrust line 3 inches (anyone?) and lower the wheels 1 3/4"

[Dan_]

I flew a design that had 4 inches prop clearance with the tail up...  I hit hard more than once  perfecting the wheel landing.  Never hit the prop, but the landing gear stiffness is the controlling variable there.  I hit hard...

[Chuck in Indiana]

A little bling showed up today. 

It's heavy, but the military type latch is hard to beat for sustained inverted flight..
Maybe I can forget to bolt it in when doing weight and balance? (whistling)
I had paralysis by analysis all day yesterday. Searched and searched wondering what people were doing with the landing gear. Leonard says to put the center of the axle under the leading edge of the wing.. or 6 inches in front. Ok, that gives quite a bit of leeway.
Comma but.
He shows the V to be on a 12 degree angle. Hmmm. 12 degrees is shown on this cad sketch in green.

The leading edge of the wing is 6 3/4" in front of the Center Line of station 2. I've forgotten the dimension already  but it seems that 12 degrees was something like 2 9/16" aft of the leading edge..if you use the leading edge of the wing, it's 19.3 degrees.
After much searching, contemplating my navel, etc.  I decided to just go with 6 3/4". Too far forward makes an airplane difficult to wheel land. Too far aft tends to make nose overs too easy.
Time to quit thinking and do something.
Found the center line of the airplane and station 2, and quit for the day.

Edit: Station 2. Duh.