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.

Friday, April 01, 2022

JT’s miscellaneous updates #5 - Passenger's Handle

Getting in, and especially out of a LongEZ’s back seat can be a bit tricky. 

With the nose down (grazing position) the passenger steps over the fuselage with the left foot onto the pilot’s seat, then swings the right leg over the strake and into the rear compartment (preferably not on the seat cushion).

As one does this, there is a strong need to grab something to steady oneself and not fall backward onto the Tarmac. Lack of directions in this procedure might cause an inexperienced passenger to fall off the plane, bringing with him parts of the structure he shouldn’t have touched, let alone grabbed.

There is only one structure between the seats that is sturdy enough to withstand any force, the headrest. Unfortunately, that is not evident when standing tall between compartments.

Terry and me at Rough River 2016

A metal rollover structure would be an ideal place to grab, but JT doesn’t have one, so I decided on the next best thing… a dedicated passenger handle attached to the headrest.

I designed it in CAD, then cut the basic parts on the plasma cutter for later bending and welding.

CAD helps get idea out of one's head

Not having a bending brake handy, I had to rig something up in the press so that I could make the same bend on both sides.

Using thickness gauges to repeatably position the bending extrusion onto the part

The setup was a bit ghetto, but it worked flawlessly producing two identical parts.

Not great for a large production run, but good enough to bend two parts.

You can see how the extrusion created the large radius bend

Another look at it

Symmetry is what I was after

Next, I jigged all the pieces up on the table, and did a pretty ugly but sturdy welding job on them. This was only my second time welding aluminum, and it showed. However, after a bit of grinding it looked passable.

Best chance to make a part as designed is to make sure nothing is able to move.

Well, it's not pretty, but it's strong and doesn't wobble.

Definitely overbuilt, even after grinding the welds.

Looking good enough to be pressed into service

After a coat of primer I installed it on the headrest using backing plates on the inside.

I think it'll work

I'm liking the fit so far

Backing plates add a ton of sturdiness to this design

It is hard to believe how sturdy this handle turned out to be, one can literally pull himself up from the back seat without trouble. Every passenger seems to appreciate this unexpected secondary use of it.

Doesn't impede passenger's forward vision that much

Wow, this thing is sturdy as hell! I can even pick my not-so-light self up from here.

Getting in and out meanwhile has been easier than ever.

Perfect place to grab and steady oneself

The biggest drawback is that it’s a bit hard to spot in the gray color. 

Very inconspicuous (perhaps too much), but oh so helpful.

I shall add some color to make it stand out soon.



Tuesday, March 29, 2022

JT’s miscellaneous updates #4 - Relief tubes

As an aside, most of the future updates on this blog were done nearly two years ago, during the first wave of the 2020 pandemic, and have already been test flown successfully many times, up until issues with the Ellison TBI forced me to ground JT, and upgrade to a bonafide fuel injection system (still in progress as of this writing).

But let’s look at this so important mod in the making (stay until the end for a video on the finished system).

Luckily for me, JT’s birth father (Terry) had already done most of the difficult plumbing for this, from the cockpit and backseat down both gear legs, so all I had to come up with were the very beginning and termination points.

Starting up top, I used two funnels sold by Aircraft Spruce, and a soft rubber hose to connect to JT’s existing plumbing. I also designed , and 3D printed a clip to hold the funnel in place during flight. The clip fits right over an existing cable tie anchor mount.

3D printed ABS funnel holder and cable tie anchor

How it's supposed to fit

Cable tie anchor mounts on nose wheel cover

Funnel holder in place

After a bit of testing inside the cockpit, I chose to attach the clip to the nose wheel fairing because it is easily accessible by the pilot in flight by feel alone, it keeps the funnel and hose out of sight, and this area was previously going unused.

Funnel held in the stored position

Keeping the hose out of sight was important as not to make the entry and exit out of the cockpit any more difficult than it already is. To that extent, I decided to cut the hose, and use a couple of 90º elbows to conform to the existing structure without kinking the soft hose.

Can you even see the relief hose?

Had to be creative with the routing

A couple of 90º elbows helped a bunch

You can see the tan hose going into a white elbow, then the blue adapter hose into JT's drain tube.

Keeping a down slope on the hose at all time is of paramount importance for proper drainage of course. The faster the drainage, the less the chances of the stuff freezing in the hoses, and creating backup problems. If you know what I mean?


Even though only a tiny portion of the front hose is visible, I painted it black to make it even more difficult to see.

Testing hose and paint

Relief hose new color scheme

Hose is even harder to notice now

Out back, the original hose ended abruptly above the disk brakes. Here too I tried a variety of possible solutions, like going straight down using a quick-connect coupling and a straight length of hose, but I thought the heat from the brakes might end up causing problems.

One of the many relief hose ending iterations

Perhaps a little too close to the tire as well

In the end, I opted for a further aft exit out of the rear wheel pant. The plastic tube was cut at a 45º bias facing backward to elicit a slight vacuum, and assist gravity in flight.

Home Depot or Lowes find

Hose bending jig

This hose is pretty darn stiff

Note the 45º cut at the end

A little heat calmed the hose down in a hurry

Cold compressed air stiffened it back up in the new shape

The jig allowed for two identical hoses

A 3D printed doughnut was glassed over the exit hole (not shown here)

Left wheel pant after the mod

Right wheel pant

Offset from the tire in order to be in clean airstream

45º cut to create a slight draw

Both wheel pants in the hangar, ready to go fly.

The inflight portion of the testing consisted of Chris Cleaver flying in close formation while I poured water from a bottle in the funnel, and verifying the ChemTrail.

Funny thing is now that I can go anytime I want, I hardly have any trouble holding it. Power of the subconscious I suppose.

I did however have to use it on a flight, and boy did that feel good! Ask me sometime about the many close calls of the past, a few of which are pretty hilarious. For those without this mod, let’s just say that sometimes what comes out of a bottle might one day be less than what one tries to put back in it! Forewarned is forearmed.

Best of all, it’s out of sight and out of mind when not needed.

This mod definitely earns “Marco’s two thumbs up” award.

Saturday, March 19, 2022

"Tooling up" - CNC plasma cutter update #5

Adding 12” of Y travel, a motorized Z axis, and so much more. 

The main question is… WHY?

Why another foot of travel? Why spend time and money on a third axis for a 2D plasma cutter? Why not get on with it and finish JT’s latest mods? Why, why, why???

I suppose if I am to get off topic again, you all deserve an explanation, or two, to include… What the heck have I done in the past 12 months?

Chris and myself visiting BizMan after he started flying Scooter

I will say that the amount of blog posts I’ll have to publish to catch you all up will take forever to get through, but I plan on slowly releasing updates and eventually bring you back up to speed with all that has been, and still is going on in the shop and with JT. 

Flying on BizMan's wing

Spoiler alert… after quite a bit of fun and flying, JT ended up in the shop again for the past year for major modifications. 

No… not something I did. 

All the mods you have seen, and a bunch more I haven’t even told you about yet, worked great, but the Ellison Throttle Body Fuel Injector started to show its age and give problems, precipitating the latest round of upgrades. But I shall tell you more about those in an upcoming post. 

Today I’d just like to discuss the plasma table upgrades.

Basic Langmuir table (no water tray)

I’m in need to cut a new firewall for JT (long story for another post), but anyone I asked either couldn’t handle it, or wanted too much money for it. Now, I would like it to look good and ideally be made of one piece of titanium or stainless, to that end I have painstakingly reproduced JT’s back end in CAD in order to mechanize the cutting of its firewall, which apparently I will have to do.

Unfortunately, while the firewall lays within the water table outline, the plasma torch itself cannot reach the far edge of the table, thus the firewall crown remains just outside of my plasma cutter's envelope (Y axis).

It’s always something!

Luckily for me, Langmuir (maker of my plasma cutting table kit) has come up with a few upgrades, one of which extends the Y rail about a foot, allowing the plasma torch to reach all the way to the far edge of the water table, bringing the top of the firewall back within cutting reach.

The other more expensive update has to do with adding a third axis. This will allow the torch head to move up and down to maintain the proper constant distance from the material to be cut, even when this material is a little warped and won’t lay flat. This is pretty common with thin, large sheets of metal as in a firewall 🤔, especially with the introduction of heat during cutting.

Without Torch Height Control (THC), the best case scenario in a warped sheet situation would be the torch being too high or too low at times, and the cut too shallow, or too hot melting desired features of the part. Worst case, the torch would end up way too low, crash into the sheet, and move it about the table.

None of these option is acceptable when the material cost gets high enough that one do-over would negate the savings of doing things oneself, but since the price of these mods would be about the same as getting someone else to do it for me... well, you know me by now 😁.

The loot arrives

2 axes v/s 3 axes Controller box
Z axis and Torch Height Control (THC) hardware

So, I embarked in another side project. Personally, I like to think of these projects as domino pieces that one has to carefully stack in order to achieve the end goal. To others they might look as a distraction… until their final purpose is revealed, that is.

I still remember people telling me to stop wasting time on my mill and lathe CNC conversions, but now the same folks tell me that I have it easy because I have a CNC mill and lathe. 

Ha ha! 

As I said… Domino pieces, ducks in a row, you know!?

Back to the matter at hand! Since the Z axis kit got here first, let’s mount that on the cantilevered X axis first.

The Z axis required adding a Z Driver, and a THC electronic module. The new Controller enclosure had plenty of room for it all, so that part went pretty fast.

Controller box as it came from Langmuir
Z axis Driver installed in Controller box

THC electronic module
Controller main board

Main board with THC module installed

Adding the Z motor/axis took a little bit longer, but was still easy to do.

The original manual Z height setter
The original Manual height setter gets reused on the new Z axis assembly

Wiring the Hypertherm CNC port through the Voltage Input Module to the Controller box was explained fairly easily in the instructions, but with 220V and 50A on tap it is not something you wanna screw up.

Voltage input module wiring

With the electronic addition completed, I moved on to other creature comfort items I long wanted to update. 

Having a water table is a great help in keeping fumes down and parts from warping too much, and getting the water into the water tray is pretty simple, just borrow Gina’s gardening hose, and in a few minutes it’s done. 

Getting the dirty water out of the tray however, is usually a mess. I usually just flip the table on its side say 60º or so, and dump it all onto my driveway, submerged metal trimmings included. Then it’s back to the gardening hose again to clean up the driveway, then pick up trash metal off the concrete, use a floor squeegee and a mop to cleanup the spill on the garage floor (now as slippery as an ice skating rink), then reinstall the little wheels that fell off during the tilting process… you see where this is going.

I decided to replace the tiny wheels with 4” tall ones, add a water drain with a hose leading to a tank. 

Original wheels were too small, and liked to fall out often.
McMaster-Carr item #60945K31 (½"-13 thread)

New wheels installed. Fit was perfect.

Ideally the tank would remain with the table at all times, so I added a bottom tray to hold the tank and the plasma cutter to my list of upgrades.

Lower tray design in CAD

As for the the leg braces that would support the tray, I started with a design Lyle shared on the Langmuir FireShare website, and lengthened it by about 2”, then cut it out of a mild steel sheet, bent it, and welded it across the bending slot for strength.

Bending the plate at the slot
Our EAA Chapter's bender
All plates bent at the slot
TIG welding the slots shut
The setup for welding
Outer corner weld
Inner corner autogenous weld
All plates welded up
Another look at the plates
Buying hardware to join the plates
Priming the plates
Painting the plates
The final product
Support plate mounted on a leg
Back side of the assembly
All four support plates mounted

The tray itself was made from scratch out of 2x2 and 2x1 steel beams. I started out by cutting, drilling, and adding threaded inserts onto the two main X direction beams.

Time to get this bottom shelf started!
Drilling clearance holes for threaded inserts
Threaded insert before installation
Permanent installation of the insert
What a threaded insert installation looks like
Testing the insert with a AN3-4 bolt
X direction beam installed
Bottom shelf securing strategy

Then I fitted three crossbeams, and tack-welded them together in place before moving the whole assembly to the welding table.

Test fitting the bottom tray's crossmembers
Removing the tray for further welding
Tray's temporary welds
Getting ready to weld the main structure of the tray

I mostly used the TIG welder on this project, up until I got to welding the 1x4s, and by that time I had ran out of Argon gas, so I switched to my brand new MIG welder for the first time.

Tig weld
More TIG welds
Main structure welded
1x4 stringers
Cutting the stringers
Setting the stringers up for welding
MIG welds came out better than I anticipated
Main bottom shelf structure welded
Expanded steel support welded to the shelf skeleton

I was going to leave the tray be, but with water right over the top I figured it would turn to rust in no time, so I primed it, and painted it. I am glad I did, because I really like the way it came out.

Temporary paint booth
Shelf primed twice
Top of shelf painted a Titanium silver
Same color on the bottom
Bottom shelf finished and installed at last
Another look at the installed tray before wiring the table

Next item on the upgrade list was to recess and create a new drain.

I 3D printed a dimple die design Mrak shared on FireShare, and used it to dimple the waterbed.

Dimple die made out of Polycarbonate ABS. Good enough for a few squeezes.
Central drain visible with slats removed
Future drain hole before dimpling
Bottom die in place
Top die before squeezing
Top die pulled tight to dimple the water bed
Clearly visible dimple in the water bed

The new dimple in the bed allowed the original brass fitting to fit flush in order to better evacuate the water.

Brass plug reinstalled (with silicone paste) minus the original rubber seal

I removed the zinc plug and threaded a ¼” NPT fitting to a faucet, and then to a spare bucket, I mean… tank, I had in the shop.

Tray survived the water buffalo test 😂
A 5 gal bucket holds all the water, and it's easy to dump it back on the tray.

When the Y axis extension showed up, I quickly installed it, and was ecstatic to see that now every inch of the water table is within reach of the plasma torch.

Y axis extension delivered about a month later
Y axis extension items

First I had to remove the existing shorter Y axis and support beam.

2x2 beams removed
About 1 foot difference in length

With the longer ones installed you can see how much space was gained with this upgrade.

Y axis shuttle able to move (to the left in this photo) much further now

Last but not least, I decided to make a new mount for the laptop. I did this because the normal mounting is 90º off of the table, and I always end up jogging the Y instead of the X axis, and running into things because of that.

I reused a piece of the short Y axis support I had just removed to create a new place to mount the laptop stand.

Repurposing the 2x2 beam removed from the table
The beauty of this piece is that some holes already lined up
However, they needed to be slightly enlarged.
The fit is tight, and I noticed a little rubbing between components
Adding a relief hole made it all better
The new down-tube will offer a better mounting option for the laptop, and pathway for wires.
Laptop stand mounted. The hollow down-tube will house some of the wiring.

This plasma table finally started to look like it meant business, so I decided to tuck the wiring out of sight as much as possible, and prevent the mess of cables I used to trip over in the past.

This wiring mess was one of the problems I was trying to solve with the tray mod.
I think the wiring is much much better now
The use of cable raceways cleaned up the wiring immensely 
A 110v cable, one 220v cable, and an air hose are now the only table's tethers. 
Wire management in action
Air and electrical tethers
The plasma table is now a self contained unit able to be moved about and used as needed without further setup

While I should have been content with what I had achieved thus far, there was one more improvement I wanted to make in order to make lining up of the torch on a point more precise.

I designed and 3D printed a holder having the same outer diameter as the plasma torch, and the inner diameter to fit a 9mm laser. Substituting the laser device for the torch, when accurate alignment is needed, will allow to jog the table much more precisely than how I’ve done it thus far… eyeballing it.

This laser fits 9mm handguns
The laser will be used to align the plasma torch to a starting point when higher precision is needed
Old firewall on plasma table
Example of using the laser for accurate plasma torch alignment with a feature