The glider's oxygen cylinder 'tank farm' is now secure.

The steel frame is bolted to the concrete floor. It's also bolted to the studs in the wall.

Each cylinder is independently held/constrained and can be individually removed and replaced.

There should be no opportunity for all four cylinders to tumble in an avalanche. (One cylinder tumbling is bad enough.)

Note that the transfill fittings and hoses are not yet installed because these cylinders are still empty. I'll get them filled when I'm far enough into flight testing that I will be soaring to higher altitudes.

Sailplane Grand Prix - day 4 of competition.

Video is cued up to a pre-start discussion of the turnpoints on the course (which are a cylinder around a GPS point), and why they are larger than normal today. (The sailplane only has to briefly enter the cylinder to 'round the mark', not fly all the way to the central GPS point.)

https://youtu.be/Twb58nx-11Q?t=1034

The Sailplane Grand Prix started today with its first day of racing out of Saint Auban in southern France in Provence-Alpes-Côte d'Azur.

Live tracking allows us to see the progress of the race over the Alps. The video is cued to just before the mass start.

https://youtu.be/uwCAblPCsVs?t=1122

The first glider to reach the finish line...was given a penalty: "Crossing below the finish altitude" (as defined by GPS)...so the winner of the day was the 2nd pilot across the line.

https://sgp.aero/final2025-results

My glider wings need mylar to cover over the control surface gaps, but what width?

When the flaperons are moved to fully expose the pintle pockets, I can still use a 30mm wide strip of mylar.

https://en.wikipedia.org/wiki/Pintle

https://en.wikipedia.org/wiki/Gudgeon

All control surfaces will get mylar covering to reduce drag.

Glider registration has arrived!

https://registry.faa.gov/aircraftinquiry/search/nnumberinquiry

I have a few more items to do in this build project, then weight and balance.

Next paperwork drill is to schedule an inspection in order to receive the airworthiness certificate...which opens the door to flight testing.

"This one's for real
I already bought the keys."

Steely Dan - Deacon Blues

https://www.youtube.com/watch?v=ICK6e9WK2A8

Two black Sharpie lines will show my progress of gentle hand sanding of the glider wing's leading edge. This will be to remove the orange peel texture.

The underside of the glider's right wing is ready for sanding to remove orange peel from the final coat of paint.

(Now I know how long of a line a Sharpie can draw before it runs out of ink)

The three oval areas are inspection/access ports to the inner moving parts of the flight control system...flaperons, and spoilers.

The grid of black lines will help me monitor the progress of sanding.

Delivery day for the oxygen cylinders!

I got help loading them in the truck when I picked them up at the delivery point in Alamogordo.

Back home, I'm alone and the unloading was slower and deliberate. Fortunately, I only had to lower the cylinders off the bed. Raising them would have required a ramp or other equipment.

I got them into the garage before the next monsoon rainstorm.

I need to make a wall rack to hold them upright, safely, securely. I think I need to get a 20-foot stick of 1-inch square steel tubing from the world famous Basin Pipe and Metal.

Can I make an air liquefaction plant?
https://en.wikipedia.org/wiki/Liquefaction_of_gases

Successful test of the right wing tip light assembly.

The electrical power was provided from the wing root, 25 ft away.

The first comments to this post will include some photos.

Because glider wings and winglets are removable, I had to make the wiring connections work despite repeated disassembly. I am using automotive door jamb connectors that are spring-loaded knobs or bullets of brass.

The glider turtle deck and cockpit get a few more items.

The oxygen tank is now mounted under the turtle deck. A retaining cable runs back to the rear steel carrythrough tube, and will only be used once...in the event of a crash. (Wooden 2x4's are mockups for the wing spars to ensure I am installing items with acceptable clearance.)

A two-litre water bladder hangs behind the seat pan, and the drinking tube is at a convenient location.

I still have to install another fiberglass antenna bracket under the aft end of the turtle deck.

Glider progress on closing out open spaces in the fuselage.

First photo shows the new fiberglass closeout panels I made this weekend. The new panels have bits of blue tape on them.

Second photo shows a fiberglass GPS antenna bracket near the top of the turtle deck.

What you don't see in the second photo are the wing spars, which will run across this space.

I am considering also making fiberglass shields to cover the autoconnect funnels, which are gray and located aft of the wing spar cutouts.

I need to install some anchor plates into the glider, around a blind corner (a bulkhead flange) in cramped quarters.

https://www.aircraftspruce.com/catalog/hapages/anchornutsk1000.php

It's easy to drop these small parts, and Murphys Law dictates that they fall into an inaccessible place.

Fortunately, you can run string through the mounting lugs to serve as a lanyard.

If you install an anchor nut on metal, you use rivets. On composite panels you often embed them in epoxy.

If you work in a wood shop, you probably use tee nuts:
https://www.aircraftspruce.com/catalog/pnpages/04-02058.php

Making glider composite parts requires time, and timing because epoxy must first cure.

Before I went to bed last night, I layed up fiberglass on simple molds to make various closeout panels.

The epoxy cured while I slept, at least enough to de-mold.

Now the parts are sitting on the glider trailer and getting warmed by the sun. In a couple hours they will be fully cured.

Gliders need help to get airborne.

Here's an update I pulled from an SSA (Soaring Society of America) newsletter:

"The SSA awarded several grants for projects and Bill Daniels of the White Sands Soaring Association provided an update on how grant money is advancing their winch project."

"Our thinking is shifting to power electronics, data capture and temperature management. The big battery pack which can power 40 to 50 launches on a charge is also sitting on the shop floor. The inverters are in hand. The load pins (a kind of load cell) serve as axles for the upper pulleys while measuring forces on them. They are being made on the other side of the world and should arrive in a few weeks. Various connectors and other bits arrive daily. Since everything is liquid cooled and we operate in a hot climate, we will need robust temperature management systems which are still being designed."

https://www.ssa.org/

It's time to install the turtle deck on the glider fuselage.

The octagon steel frame was useful for sanding and painting...rotating the fuselage to allow work on the underside. The octagon gets in the way of installing the turtle deck.

Previously I could grab the empty hole at the nose of the fuselage and raise/lower onto various support stands. Not anymore. The motor/spinner have filled that hole and they can't handle significant side loads. So, I need help to raise and lower the fuselage, especially now that it holds all the equipment.

The red steel frame jack is merely a large lever with a sling to support the fuselage. It's big but has lots of mechanical advantage so I don't have to exert much force.

The shark fin antenna is now only a couple inches above the floor.

Now I can install the oxygen system and add some closure panels.

I need to cover exposed high-voltage, high current terminals in the glider fuselage.

My index finger and pinky are pointing to the terminals. They will be at +115VDC with respect to ground when the battery pack is connected. The safety fuse is rated at 325 amps. A 'mere' short to ground at 250 amps will keep on smoking, and smoke in the cockpit is scary bad. This is a good reason to fly with a parachute.

The second photo shows a potential solution, which was molded on a discarded paint mixing cup of the right size.

Hmmmm, what do high-voltage high-current terminals look like in an EV auto/truck? Do they have fancy thick boots for insulation?

Successful high power test of the glider's electric motor with the spinner and propeller installed.

I had it at full power: 4600 RPM and 150 amps at 115 volts DC. I conducted this test three times. No problems with vibrations, excessive temperature of the motor or any other components, or rapid draining of the batteries.

This is a major milestone for the electric motor system.

The glider battery is nearing the end of its charging cycle.

The battery management system has told the charger to reduce charging current while the 14 cells are being balanced to the same voltage. In this photo some cells are properly balanced, but not all. Once all the LED's go out, then all cells are properly balanced and the charging is complete.