I like the Boobys
- Thread starter thenated0g
- Start date
jpot1
Elite member
Funny you ask. Just flew this again this past weekend - super fun flying. CG very close to forward tips and you will be good to go!
Decided to start working on my booby's. I have two sets of cores cut out of blue foam. I had to slightly adjust the plans to fit within the restrictions of the cnc machine, ie the towers only go so far in each direction, but its pretty close to the original plans i had wanted. It actually worked in the favor of cg, as i have more room now to add ballast. Before the cg was in front of the center section.
I am using this booby project as my first fully vacuum bagged fiberglass plane. It will be 5 different sections that i will glue together later with epoxy and fiberglass strips. There are several reasons to make them in 5 sections. One i need to get the wire holes in each section and run the wires and you don't want to do this before bagging. Secondly the mylars will not go over the compound curves where the sections meet. I have two full sets so i can make mistakes on the first one and do better on the second. To begin with i am going to vacuum bag the center section by itself and see how it works. If i am happy with how it turns out i will try doing 2 or more sections at a time to speed up the process.
I will be using 3oz fiberglass on this first one. It will have a 1-2 inch strip of 6oz glass on the leading edges for some landing protection. A couple strips of carbon tow for stiffness around cg, and possibly some kevlar for live hinges, but still working on that, i may just do goop hinges.
For color i got some chiffon cloth in black and red. This will be directly underneath the fiberglass.
So the layers in the vacuum bag will be:
Mylar, 3oz fiberglass, chiffon red cloth reinforcements (carbon tow/kevlar), Foam core, reinforcements, chiffon black, fiberglass, mylar
The mylar is what gives the fiberglass the "glass" finish.
The other ways you can add color is by painting the mylars, dying the epoxy, painting the wings when done, using various translucent paper products under the fiberglass like rice paper and tracing paper, and there are some companies that do full color prints directly to fiberglass. Using chiffon seemed like a pretty easy way to get a nice color.
Im just waiting on my chiffon fabric to get the center section going.
bracesport
Legendary member
@thenated0g - I found the booby's - man you make some interesting ships - loved the video at post1
forgot to restock my foam rollers i use for epoxy so while i wait for those to get here from amazon i started cutting out all the fiberglass and balsa for the vertical stabilizers. Going with an exact copy of a surfboard fin i liked on google images. One piece of balsa, layer of 6 oz s-glass on each side and than 3 oz on top of that for a nicer finish (smaller weave). I am going to try Plexiglas this time instead of Mylar to get the glossy finish on the fiberglass.
center section and vertical stab's under the bag
bracesport
Legendary member
looks great - with a bit of luck, I will suck and glue a trial wing tomorrow! 
Opened the bag this morning to mostly success. Vertical Stabs came out great in the plexiglass. Very easy to break open. Only issues is i'm not sure how hard it will be to clean up the plexi, ie can the epoxy be removed from it and plexi reused or is this a one time use.
They are very lite and i think strong enough to not snap in half on hard ladings.
The center wing core came out very strong with just a few minor issues i need to fix. The bottom came out great but the top had a few spots on the leading area that didn't get enough epoxy. The chiffon cloth i added under the fiberglass made it difficult to tell how wet it was. I guess i need to add more on the next parts. Overall though this is super strong. Will just need some sanding on the leading edges and some trimming around the other edges to clean up. I will pinstripe the leading edges black .
They are very lite and i think strong enough to not snap in half on hard ladings.
The center wing core came out very strong with just a few minor issues i need to fix. The bottom came out great but the top had a few spots on the leading area that didn't get enough epoxy. The chiffon cloth i added under the fiberglass made it difficult to tell how wet it was. I guess i need to add more on the next parts. Overall though this is super strong. Will just need some sanding on the leading edges and some trimming around the other edges to clean up. I will pinstripe the leading edges black .
bracesport
Legendary member
I would call that a success!
Got all the mylar cutout for the other 4 cores and started tracing the fiberglass to cut em out.
2 next wing sections out of the bag. Last minute i decided to see what regular office paper looked like under fiberglass. Pretty happy with the textured look. Im sure the color behind the paper (black) has something to do with how it looks. Probably need to test other colors behind it in the future. Also i am noting that light pencil marks really show up (L and R). Oh well now i know. next one i will not mark the fiberglass.
Got one of the outer wing cores bagged last night. One thing i have come to realize is that vacuum bagging is like 95% preparation and 5% of your time is the actually bagging and laminating portion. So the more prep time you spend getting everything ready, the better the outcome. This is the 6th time i have gone thru this whole process and it just gets way less stressful each time and i can focus on the different steps now more fully. IE the more i do this the happier i am with this process and i can see why guys online were telling me just to go to vacuum bagged fiberglass as its all they do now. Also all the prep work can be done at almost anytime before, you don't have to bag immediately, so that's been helpful to spend an evening getting everything out and ready. Mylars waxed and polished, masking tape cut down to usable chunks on the side of my workbench, paper towers seperated and ready, etc.
I have a couple pictures here showing the 6 oz s-glass i am putting on the leading edge with just some super 77 to keep it in place until it gets wetted out. So when done only about 3-4mm in the nose is left uncovered by the top and bottom cloth. And again S-glass is 30% stronger and 15% stiffer than normal E-glass fiberglass, so its crazy rigid up there.
And this is a note for me to look at in the future, but currently my environment for bagging is my shop and since its june/july in norcal that means its been around 78-87f in my shop (depending on if i bag overnight or during the day) for the epoxy setting temp. I have been leaving it under vacuum for about 11-12 hrs at 19 inches of mercury at the top. It drops to probably 16 inches over a minute or so and than it pumps back to 19 over about 4 seconds. After the 11-12 hrs i usually turn the pump off but leave the bagging system alone overnight or 9 hrs while i am away at work. I had read that you should let the mylars sit against the epoxy to get a better finish so that's why i have been doing.
I have a couple pictures here showing the 6 oz s-glass i am putting on the leading edge with just some super 77 to keep it in place until it gets wetted out. So when done only about 3-4mm in the nose is left uncovered by the top and bottom cloth. And again S-glass is 30% stronger and 15% stiffer than normal E-glass fiberglass, so its crazy rigid up there.
And this is a note for me to look at in the future, but currently my environment for bagging is my shop and since its june/july in norcal that means its been around 78-87f in my shop (depending on if i bag overnight or during the day) for the epoxy setting temp. I have been leaving it under vacuum for about 11-12 hrs at 19 inches of mercury at the top. It drops to probably 16 inches over a minute or so and than it pumps back to 19 over about 4 seconds. After the 11-12 hrs i usually turn the pump off but leave the bagging system alone overnight or 9 hrs while i am away at work. I had read that you should let the mylars sit against the epoxy to get a better finish so that's why i have been doing.
bracesport
Legendary member
@thenated0g - this is all great info - my domestic vac unit is a toy and did not do much other than keeping things clean while glueing - I will think about whether I can improve the pump!
yeah i have been pretty impressed with this little $20 12v pump. Only issue is that its so small it can take a minute to evacuate a lot of air.
https://www.amazon.com/gp/product/B0192KPBCK/?tag=lstir-20
https://www.amazon.com/gp/product/B0192KPBCK/?tag=lstir-20
Had several requests on Instagram and youtube to do a full length video on the entire process so on the final piece, the right side version of the last post, i will do a lightly edited longer video and try and explain all the steps im current doing for vacuum bagging. In getting ready, getting all the parts out, i realized that i didn't want any external stickers and i still needed to put my FAA stuff on it so i decided to try the office paper thing again. I also wanted a distinctive stripe to help with orientation. And someone had suggested that instead of that upc scan bar saying "california" it should be my FAA numbers so i printed this out to stick on during the layup. The smart tag takes you to my instagram account, just cause i had the room.
