LSA140 Build

[lsa140]

Continuing to fabricate the gear/wing strut attach pieces for the fuselage.

[lsa140]

Fabricating bend fixture for forming wing strut attach points. Other than tacking the doubler plates in place, I didn't want to do any welding before forming. It will be a little tight welding the top teardrop doubler, but should be very workable with TIG. Trying to keep the heating cycles to a minimum. It would have been better to bend the fittings, and then tack the teardrops in place. The bending fixture would have been simpler.

[lsa140]

Back to welding the fuselage. It was nice break to step away from the welding for a little while, and fabricate some fittings.

Received a wheel and brake setup from Matco today, hopefully the rest of the order will be here tomorrow. Looks great. The combination is right around 9.5lbs including the second brake caliper, I will put it on a better scale tomorrow. It is interesting to note that there are 6 through bolts around the perimiter of the wheel. I don't know if this is something that Matco is doing now on all 8" rims, or just for those intending to run tubeless. Most of the photos I have seen of the 8" rims do not have these bolts.

I was reading through the most recent Kitplanes and noticed Larry Vetterman's Cub on the cover running the double caliper 8" Matcos with 27" Dessers. Beautiful airplane, very light.

[lsa140]

I've been blown away with this little Makita LC1230 carbide toothed metal chop saw. It is worth every penny. The production and quality increase you get is substantial. Very smooth and square cuts. No smoke or dust. Little to no burs on cut edges. Cut pieces are not hot, and can be handled right away. You can shave a small amount off the end of a piece without the blade flexing out of track. Highly recommended.

[lsa140]

Now that I have the Matco wheels, I can better see why it may be advantageous for a surface to contact the bearing seal face. The bearings have a very large inside radius, and only catch the very edge of the 1.5" axle spacer over the 1.25" axle. I've decided to go ahead and fabricate a wheel spacer that slides over the axle, rests against the brake mount flange, and captures one of the brake mount bolts to keep it from rotating.

I may just fabricate an ear, with a larger hole that slides over the outside of one of the bolt heads.

[lsa140]

Fabricated the first wheel spacer. The double caliper Matco brake mounting plate (gold) slides over the axle and bolts to the wheel side of the welded axle flange with 4 bolts (evenly spaced on a 2-1/4" diameter). The brake mounting plate has an 1-1/2 hole, leaving room for the wheel spacer to slide past it and rest against the welded axle flange. The spacer has a 2" round surface that engages the face of the bearing seal and an ear with a 1/2" hole to slide over one of the AN4 brake mounting plate bolts to prevent it from rotating on the axle. I'm using a slightly longer wheel spacer to allow the Matco brake rotor spacers. This facilitates running Bushwheels on 6" rims in the future. (Matco MH series 6" wheels require brake rotor spacers on large diameter tires to keep adequate clearance between the brake calipers and tire side wall)

I left the spacer ear slightly away from the Matco brake mounting plate, to make sure the spacer bottomed evenly against the axle flange, not the ear.

Since the bearing is now resting against the 2" surface, I didn't really need to use the thicker wall 1-1/2 spacer. It is just what I had on hand. I think 1-3/8 x 058 would work well, and be lighter.

[stinger]

Now, that looks much better ! Stinger

[Chris In Milwaukee]

Do the wheels ride entirely on the beatings? Nothing touches the axle at all other than the center of the bearing, right? Trying to paint a mental picture of the setup,

[lsa140]

The bearing cone/cage/roller/seal assembly slideds over the axle. (shown in the second image) The cup portion of the bearing pressed into the hub. The seal is pressed onto the cone, and does not rotate. The seal has a flexible outer portion that lightly rides against the hub the inside of the hub. When you tighten the axle nut, it captures both bearing seals, and prevents them from rotating. The wheels ride entirely on the two bearings. I'll post a couple more photos when it is all together, it will make a little more sense.

[lsa140]

The tail spring arrived from Mark this weekend. I had to do a quick test fit, but haven't drilled any of the bolt holes.

[lsa140]

[lsa140]

I sure enjoy this little Wezu 6" square. It get's used constantly on the airplane project. The machined, wide surfaces come in very handy. They have a 4" as well that would work well.

More welding...

[Bdflies]

Hey LSA! It's been a couple of weeks, with no updates. I, for one, look forward to seeing your progress and innovations.
Throw me something, mister!

Bill

[lsa140]

Thanks Bill, the busy summer work season has kicked off... I'll be out of town through fall. It is tough to be away from the project, but it is time to pay the bills. I'm living vicariously through all of you guys posting your progress on the forum!

[lsa140]

Cut out the fuselage engine mount bushings. I left them a little long for welding, though after checking the fit, I won't leave extra length inside the fuselage for TIG welding. It is much easier to weld close to the edge of something with TIG, and it will be easier to get the torch in there without more bushing length. The bushing were chucked in a drill to debur and face. I used some emery cloth to remove the tool marks, and debur the edge. A countersink was used to debur the inside.

I am using 1/2 x 095 4130 tubing for the bushings. The factory engine mount will be used to align the bushing on the fuselage. Once they are fully welded, a 5/16 piloted chucking reamer will be used to bring the hole to the final dimensions.

I had a chance to try out one of the reamers I ordered from Pan American Tool. http://www.panamericantool.com/high-...g-reamers.html I was impressed with how well it worked. I ordered the (1/4") 44-310, (5/16") 44-510, and (3/8") 33-630. Shipping was quick and cheap.

[BTAZ]

One lesson from my build.

I didn't leave the bushing quite long enough on the inside and therefore didn't have enough clearance on the edge of the nut to the surrounding tubing.

Required some rework when I went to build the mount and learned this.

So make sure your bushing protrudes far enough inside and is positioned to provide enough clearance for the head of the bolt bolt/nut plus socket/wrench.

[lsa140]

Thanks BTAZ, I'll bolt the bushings up to the mount for alignment, and check the nut clearance before tacking/welding. I left them 3/8" longer than plans call for.

[lsa140]

Worked on fitting the factory Continental mount to the fuselage. I cut out a piece of flat melamine, cross marked center of crankshaft, and drilled the 3/8" holes for the C-85 bolt pattern. When I bolted the melamine to the engine mount I noticed the two upper bushings had the washer/flange surface welded on crooked. The lower ones looked good.

I used a cross line laser shooting directly down the fuselage C/L and a digital level to check mount alignment. Everything looked spot on until I checked the alignment when viewing the airframe vertically down. The melamine bolted in place of the engine was angle to the right around 3/4 deg. I double checked the firewall, and verified that it was 90 deg to C/L. Then I checked the mount itself and found that it was out of aligment. The melamine bolted in place of the engine was out of parallel with the where the mount bolts to the fuselage. (see photo) If I leave it as it is the back of the engine case will be on C/L and the tip of the spinner will be kicked to the right over 3/8".

Encountering this jogged my memory back to assembling the tubing kit. When I pulled the longerons together at the tail post location, one was longer than the other. Both on the top and bottom fuselage sections. Each time I checked the aligmnet of my marks and blocking, and everything was spot on. Then I put a flexible tape on the longerons themselves lengthwise and found that it wasn't aligment that was the issue, the actual longerons where different lengths. I had three choices: shift the tail post off the center line, kick the firewall alignment out of square, or trim the long longeron back. I ended up trimming the longerons equal length, and moving forward with the correct aligment. I'm wondering now if I left the longerons alone, kicked the firware over slightly if the factory engine mount would line up.

The tubing kit is cut out by hand, not CNC. There are small varitions from the plans. It was a challenge deciding whether to assemble the tubing how it fit best, or how it aligned to plan dimensions.

I plan on trimming a small amount off the two right mount bushings, and extending out the fuselage bushings on the left slightly to bring the engine mounting surface into alignment.

[lsa140]

After some tweaking, I'm happy with the engine mount fit and alignment. Previously I had the engine mount surface bolted tight to the melamine, and the bushings clamped tightly in the corners of the firewall tubing. It was causing several minor differences between the airframe and engine mount to stack up into a larger than acceptable misaligment. The upper mount washers that had been welded on crooked were also warping the mount as I tightened them against the melamine.

I loosened all of the mount/melamine bolts, and removed the two top bolts. Then I started slightly adjusting each bushing (that gets welded in the corners of the firewall), while keeping them within 1/16" of the corner. When everything was within satisfactory tolerances, the bushings were tacked in place.

The plans call for 1-1/2" long fuselage bushings. I cut mine 1-7/8". 3/16" of that extra length sticks out past the firewall, the other 3/16" extends a little further into the fuselage for bolt clearance. This is will make for a little easier welding, and I'll likely trim the bushing flush to the firewall after welding.

I continue to be very happy with the little Miller Diversion 165 TIG. It allows for quick, clean, easy to weld over tacks in hard to reach spaces.