Chronicling my Long EZ construction (and a few other things).
Disclaimer
This blog is for entertainment purposes only, and is not meant to teach you how to build anything. The author is not responsible for any accident, injury, or loss that occurs as a result of reading this blog. Read this blog at your own risk.
When my talented friend Phil talks to me about his ideas, I listen carefully, and when he told me about a microscope LED light on eBay that might work as a spindle light, I easily parted with $20.
LED microscope light
The light turned out to be very bright, and that’s a great thing since I’ve often been forced to hold on to a flashlight while milling. It might be because of the mill's location, or perhaps the partition I erected to keep swarf at bay, but my setup has not been the best as far as ability to see what's going on.
Until now… that is if I could figure out a way to attach it to the mill. See, the root of the word "spindle" is… spin(duh!), and since it does spin, this makes it impossible to attach a light directly to the spindle itself.
After spending a little time looking up to the mill’s head from below, I had the idea of replacing one of its plastic cover with an aluminum piece that would be be concentric with the spindle, serve as a mount for the light, and not interfere with the spindle rotation.
Plastic cover
Plastic cover original position
Mill's head with the plastic cover removed
After reverse engineering the plastic cover, as well as the microscope light, I came up with a drawing of the proposed mount made with Fusion 360.
Approximate dimensions for the MicroMark mini-mill
This is what I will be trying to make
Now, these dimensions are the best I could come up with while working upside down with a caliper, but should be close enough to make it work.
During a lull in my fiberglassing activity, I got on with the latest mill improvement.
Machining the spindle light mount
Unfortunately, I did have some issue with the mill. Because I still haven’t wired the limit switches, I might have accidentally over-traveled the X axis just before this job, and possibly dropped a few ball bearings from the ball-nut, as a result my milling of circles was off by as much as 0.040” (1 mm). Crap!
Luckily for me, this piece will never be seen again after today, and with the the location of the holes being the only critical part of the design, I quickly ran it by the lathe to make the mount round again.
Not pretty but it fits, and that's all it matters.
The spindle is unaffected by the mount
The light fit snugly on the mount. Thumb screws were not necessary except to prevent possible sliding movement due to vibrations.
Nearly a press fit, the light easily stays on without screws.
Light on the mount, but off the mill.
Back side
So, I ended up radially drilling (#40) and tapping (3-0.5 metric) three holes into the aluminum mount to match the thumb screw locations.
As I said, this is just a light mount, let's not get overly complicated here.
Smallest metric tap I have
Three holes drilled and tapped
Assembly side view
Obviously, one would not want the screws to protrude through the mount and end up rubbing the spindle, so I made sure to stop when I saw the end of the tapered tap reach the inner diameter of the mount. This ensured the screws would be confined to the mount itself at all times.
Thumb screws unable to protrude into the spindle space
Tool changes are still as easy to do as they were prior to the modification.
Spindle light is up and out of the way
Overall I am very pleased with the results of this upgrade.
I might need sunglasses now
Though I was concerned that the tool would cast a shadow right over the part to be cut, this turned out not to be the case. The whole cutting area is now flooded with so much bright light that I can even see what I’m doing now!
No tool shadows present within the work envelope
UPDATE: It turned out that the lack of precision was due to a bolt that loosened up due to the vibrations that occurred when I took full depth of cut passes. The bolt in question snugs the Y ball-nut to the table, and after tightening it the problem disappeared entirely. Here are the latest backlash numbers...
One pretty common complaint heard in Long EZ circles is that of cold legs. A couple of reasons for this are the inability of the typical heat exchanger to send warm air from the rear mounted engine all the way up to the nose of the plane, and the air leak prone nose compartment.
Over the years builders have come up with all kind of creative solutions for this common issue. My approach would be to seal up as many holes as possible first, then worry about possible heating options.
Looking at the upside down nose of my Long EZ, one obvious source of unwanted high pressure air is the nose gear hinge area. The gaping holes left there look capable of delivering cold air right on the pilot’s legs.
"Dang, you can almost see the back-seater from here! "
My friend Beasley had a very interesting approach to sealing this area, by using a small forward-hinged spring-activated door in front of the hole.
The forward hinged door is able to slide on the strut cover as the gear leg moves
His approach was made possible by the omission of the foam wedge that went right in front of the nose gear hinge.
This foam piece is a faint attempt at closing one of the gaps
Since I had already installed it, I had no real good place for a hinge, and had to think of a different solution. One thing I couldn’t understand was the reason for the hole to begin with, so I thought about sealing it shut from the inside.
Grabbing some ever present scraps of foam around the EZ shop, I whittled them until they fit.
Getting the foam scraps to the right shape
Foam scraps closing the hinge hole
One other advantage of this modification, was the boxing on the fifth side of the forward space between NG30s, leaving a small enclosed space that could be handy to store a few tools, or a spare tube.
Foam scraps as seen from inside the nose compartment
I removed the foam pieces, glassed them on both sides, and tested them again.
Proceeding with the modification
After more fitting and sanding
I'm starting to like where this mod is going
At this point I reinstalled the nose gear, and finding no interferences anywhere, I went on to the installation phase.
Behind the microscope LED light, the Dremel is removing foam and micro for a flox corner joint.
Given the small confines, the Dremel was used extensively in this area.
Foam and micro were also removed on all four sides of the horizontal piece
Three sides were filled with flox, then the piece was inserted carefully in place
Same piece curing, as seen from inside the nose compartment.
The next day I added BID tapes just to secure this first piece, and make sure there would be no gaps for air to get through.
Small BID tapes
Sealing the horizontal piece
Same thing one day later
After flipping the fuselage right side up, I started working between the NG-30s.
Getting ready for a flox corner
Flox sandwich
To be cleaned up
Tying things together
Peel-ply over BID
In the morning, after a little cleanup.
No air is coming through here
My feet would have rested right next to the drafty hole
So, one might ask... What's the point of sealing the holes by the hinge when you can clearly see another gaping hole right behind it?
"Yeah... what about that hole!"
You would be talking about the hole through which the nose gear actuator operates. Well, you've got to have that hole. The good news is that the flange I added to the front of the entire nose strut will completely seal this area in flight when the nose gear is retracted. I might get a little indirect air for a couple of minutes on takeoffs and landings, but I can live with that. I have more ideas on how to seal the remaining space between NG-30s in a way that will not impact the actuator mechanism and still be removable for maintenance, but we'll leave that for later down the road.
Nose gear hinge "box"
It's a tight squeeze in there now
Looking toward the right NG-8
I'm very happy how this mod turned out
The struts operates just fine, and the cold air shall remains outside.
