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#composite

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TomKrajci 🇺🇦 🏳️‍🌈 🏳️‍⚧️

How to remove/demold a part from a fragile part. (Hint: You can create shear in more than one way, and it may be better than creating a peeling action with hammer and chisel.)

The blue Styrofoam that served as the form will be destroyed as it's removed from the fiberglass wingtip weel, but it's a one-off form/mold that lacked any taper.

(This is a follow up to universeodon.com/@KrajciTom/11 )

#avgeek #aviation #ElectricAircraft #ExperimentalAviation #homebuilt
#Glider #DIY #Wing #Epoxy #Fiberglass #Composite #Shear #Peel

No! You risk damaging the wing's surface this way. (OK, you could use a plastic/rubber wedge, but let's try a finesse method first...)
The long clamp squeezes on both ends of the fiberglass part...never touching the wing. This squeeze causes the base of the fiberglass part to bow outwards...shearing along the surface of the wing.
Only light force was applied to tighten the clamp...and the part easily popped off.
Public
TomKrajci 🇺🇦 🏳️‍🌈 🏳️‍⚧️

Making a custom wingtip wheel for my glider's right wing.

The bottom of the wingtip was covered with clear packing tape, then lightly waxed.

Hot glue temporarily attached the blue Styrofoam mold/form, which also contains the 60mm diameter roller blade wheel.

The part is made from seven plies of 7725 weave fiberglass that will be cut into a triangular shape after wetting with epoxy.

No vacuum bag, so this is a hand lay up. I had to use some small pieces of metal to coax the fiberglass to stay in the correct place.

The garage will be heated overnight so that the part cures, then some tugging and a rubber mallet should separate the part.

#avgeek #aviation #ElectricAircraft #ExperimentalAviation #homebuilt
#Glider #DIY #Wing #Epoxy #Fiberglass #Composite

The underside of the wing tip has been covered in clear packing tape, then waxed.
This is one ply of dry fiberglass, colored white, laying over a piece of green plastic sheet. Faintly visible through the fiberglass is a triangular pattern. After wetting seven plies, I will cut the fabric to that triangular shape. That shape will drape over the form and make the part in one step. The two edges of the open triangle will join and overlap along the trailing edge of the part, aft of the wheel.
Wetted fiberglass has a green tint. Scrap metal helps hold the fabric in the correct location. Strips of light brown fabric are Teflon coated fiberglass, which serves as peel ply. I'm using it to also help coax the fiberglass into the desired shape.
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TomKrajci 🇺🇦 🏳️‍🌈 🏳️‍⚧️

Making a fiberglass wingtip wheel for the glider wing.

1st photo - making the mold/form out of foam, with a 60mm diameter inline skate wheel in place. Note that the underside of the wing is covered with clear tape to protect it from epoxy when I lay up 7 plies of glass.

2nd photo - making the fabric template. A single piece of glass fabric (weave 7725 because it drapes so well over various curves and corners) will make the final part, but there will be an overlap along the trailing edge. I draped a piece of plastic over the foam form after it was hot-glued to the wing and then traced out the pattern, with some reference marks such as a center line.

3rd - Demolding the cured part by squeezing it so that it flexes/distorts a bit...and the epoxy at the base easily shears off from the waxed clear tape. (No need for hammer and wedges.)

4th - rough sanded final part.

#avgeek #aviation #ElectricAircraft #ExperimentalAviation #homebuilt
#Glider #DIY #Wing #Fiberglass #Epoxy #Composite

Blue Styrofoam is attached to the underside of the glider wingtip. The foam is easy to sand and shape to the desired contour. Unfortunately, such a mold is single-use becuase I did not add any taper to the part, so I had to tear the foam out with pliers after the fiberglass cured. No worries, I have paper templates in order to quickly make a second form for the other wing.
A template for the fiberglass fabric. This wingtip wheel is a single-layup operation. Note that while the leading edge will be a continuous piece of fabric, but the trailing edge will have the two ends overlap.
Demolding a part *should* be an easy matter...if you set things up correctly...good geometry in the mold, proper use of release wax, etc.
Final part after rough sanding to remove the outer weave pattern. It will get a proper trimming job later, then painted white.
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TomKrajci 🇺🇦 🏳️‍🌈 🏳️‍⚧️

Final shaping of the leading edge of the horizontal stabilizer airfoil.

1st photo. I have sanded the leading edge to be flush with blue painters tape, and removed the tape so that I can continue sanding to blend/feather the micro to match the surface of the horizontal stabilizer.

Most of the tape has been removed. It's about 0.004 inch (0.1 millimeter) thick and in this closeup that 0.004in step/mismatch is easy to see.

2nd photo. I have blended/feathered the step into the horizontal stabilizer with 220 grit sandpaper. (Later I will use 400 grit sandpaper to get an acceptably smooth surface before I use the spray gun.)

3rd photo. Comparing the leading edge profile to a template.

I am where I want to be...the very nose is a bit pointy. Careful removal of micro at the very nose will make it less pointy and match the overall shape of the template.

#avgeek #aviation #ElectricAircraft #ExperimentalAviation #homebuilt
#Glider #DIY
#Fiberglass #CarbonFiber #Composite
#Aerodynamics

I have sanded the leading edge to be flush with blue painters tape, and removed the tape so that I can continue sanding to blend/feather the micro to match the surface of the horizontal stabilizer. Most of the tape has been removed. It's about 0.004 inch (0.1 millimeter) thick and in this closeup that 0.004in step/mismatch is easy to see.
I have blended/feathered the step into the horizontal stabilizer with 220 grit sandpaper. (Later I will use 400 grit sandpaper to get an acceptably smooth surface before I use the spray gun.)
Comparing the leading edge profile to a template. I am where I want to be...the very nose is a bit pointy. Careful removal of micro at the very nose will make it less pointy and match the overall shape of the template.
Public
TomKrajci 🇺🇦 🏳️‍🌈 🏳️‍⚧️

I have added a retaining rail for the top half of the seat pan.

The retaining rail keeps the top of the seat pan from pivoting forward when you first sit in the cockpit before you strap in.

It is assumed that you will remain snugly strapped in for the entire flight.

I have not built any capability to pivot the top of the seat pan forward as part of the seat adjustment capabilities...I'm very tall and I need every quarter inch of room I can find in the cockpit.

The seat pan can still be easily removed by moving the lower part of the seat pan beyond its normal adjustment range. At those extremes the upper seat pan retaining pins are outside of the retaining tracks.

This is only one way to skin the cat. Your mileage may vary.

First comment to this toot will be an overview photo of the seat pan in the cockpit.

#avgeek #aviation #ElectricAircraft #ExperimentalAviation #homebuilt
#Glider #DIY
#Fiberglass #CarbonFiber #Composite

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Bits&Terminal Jeff

I would like to thank the local non-chain hardware store for still having RCA cables - there's multiple years worth of dust on the packaging, but I don't care, I'm happy 😊

Testing composite video on the Apple IIe tonight!

Note: I love what's written at the bottom of the packaging - "Suffering is caused by endless desire, the desire that creates bad Karma". Probably means cable gnomes will return the missing cables.

Trisonic-branded RCA audio-video cable bundle. At the bottom of the packaging "Suffering is caused by endless desire, the desire that creates bad Karma".
#appleII#retroComputing#RCA
Public
OptimusPrimeBot

This composite image of seventeen images shows the progression of a total solar eclipse at the NASA's Glenn Research Center in Cleveland, Ohio on Monday, April 8, 2024. A total solar eclipse swept across a narrow portion of the North American continent fr ☀️🌑

#Cleveland #Composite #Eclipse #Eclipse2024 #Moon #NASA/GRC/JordanSalkin #NASAGlennResearchCenter #Sun

▶️ 1 new picture from NASA (Image Library) commons.wikimedia.org/wiki/Fil

This_composite_image_of_seventeen_images_shows_the_progression_of_a_total_solar_eclipse_at_the_NASA's_Glenn_Research_Center_in_Cleveland,_Ohio_on_Monday,_April_8,_2024_A_total_solar_eclipse_swept_across_a_narrow_po_(GRC-2024-C-02657).jpg
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