bracesport
Legendary member
that pink foam looks a lot denser than my green foam - I guess time will tell with the cutting!
GlassRat - Ridge Rat balsa conversion
- Thread starter thenated0g
- Start date
After cutting the side profiles i broke open the two pieces (scotch double sided tape) and used my dremel depth attachment to cut a slot from nose to tail to hold the control rod tube. I used titebond wood blue to glue in the tube and the two halves together.
I sanded off the glue that squeezed out and than applied the top profile template and cut it out. Probably would have been better if i used a rigid template, but this is v1, just to get thru the whole process so i can put up with some blemishes in the fuselage. I sanded the high spots down but will probably not worry about the low spots.
Next i need to cut out the wing saddle on the bottom. Than try and slip on the fiberglass sleeve to see if i need to remove some material for it to fit or not.
I sanded off the glue that squeezed out and than applied the top profile template and cut it out. Probably would have been better if i used a rigid template, but this is v1, just to get thru the whole process so i can put up with some blemishes in the fuselage. I sanded the high spots down but will probably not worry about the low spots.
Next i need to cut out the wing saddle on the bottom. Than try and slip on the fiberglass sleeve to see if i need to remove some material for it to fit or not.
This is a pretty cool article (gotta translate it to english, chrome does it automatically) on using 3d printed fuselages to make your "buck" for mold making. Definitely on my list when i get confident and want to make multiple copies of a fuselage.
https://thebreizmaker.wordpress.com/lainezick-un-planeur-numerique-le-master-de-fuselage/
https://thebreizmaker.wordpress.com/lainezick-un-planeur-numerique-le-master-de-fuselage/
bracesport
Legendary member
Forgot to take pictures of it but i cut out the wing saddle and than sanded the corners round. Also realized the trick to getting the sleeve on you have to stretch it open and than pull it down, so about an inch at a time i finally got it down to meet each half. So actually pretty happy with the fit. It stretched to the thick parts and shrinks down on the tip/end.
bracesport
Legendary member
I am torn whether to get some more CF braid or lay up the nose with FG! 
You will learn something either way. The braid will probably be much less finishing work, if you care about that, i'm going to go lite on the finish work on mine no matter what, just to have a functional v1.
Probably the most important tip i have found out the hard way is to get everything layed out and ready before you start vacuum bagging something. Once you get gloves on and the epoxy starts getting on stuff, its just a big mess. Trying to tear off masking tape with latex gloves? Stupid.
First step was wetting out the fiberglass with my thin laminating epoxy. I used a small paint brush to get it on and a roller to spread it out. Afterwards i layed some 3k carbon tow to add some rigidity. Nose to tail on the top and bottom and than some on the sides to give more strength to the wing saddle area as this area of the nose is a common breakpoint i have seen around other planes on crashes.
I than wrapped the fiberglass in some cheap drop cloth plastic
Next the entire thing was wrapped in paper towels as a breather cloth. I wasn't sure how much epoxy would seep out and didn't want to ruin my actual drop cloth material.
And finally into the vacuum bag overnight. It was probably 80f and i set it to 20-17 inches of mercury for about 9.5 hrs.
This morning i took it out and it had set. There are a lot of places where the material bunched up and left seem lines and excess. But its a strong fuselage. I will take a day maybe and sand it and do some minor work on it, but it should be strong enough to fly either way.
First step was wetting out the fiberglass with my thin laminating epoxy. I used a small paint brush to get it on and a roller to spread it out. Afterwards i layed some 3k carbon tow to add some rigidity. Nose to tail on the top and bottom and than some on the sides to give more strength to the wing saddle area as this area of the nose is a common breakpoint i have seen around other planes on crashes.
I than wrapped the fiberglass in some cheap drop cloth plastic
Next the entire thing was wrapped in paper towels as a breather cloth. I wasn't sure how much epoxy would seep out and didn't want to ruin my actual drop cloth material.
And finally into the vacuum bag overnight. It was probably 80f and i set it to 20-17 inches of mercury for about 9.5 hrs.
This morning i took it out and it had set. There are a lot of places where the material bunched up and left seem lines and excess. But its a strong fuselage. I will take a day maybe and sand it and do some minor work on it, but it should be strong enough to fly either way.
Decided to skip any finishing work on the fuse besides some sanding. Will just use some filler primer and paint later on it.
bracesport
Legendary member
@thenated0g - I have a busy couple of weeks ahead so you will get ahead of me - I was thinking to make my wings separate and plug them into the sides of the fuse - have you got any tips on what system I could use?
I have done that twice. First was my 200% guinea pig and i used aluminum spars glued into each wing and than smaller ones that went across inside. On my 8ft zagi wing i have carbon fiber tubes glued into the wings and an aluminum spar inside. I just use packing tape on the spot to keep the wings together. Little piece on nose and trailing edge. If you have a 3d printer you can find little things you glue in place that use a rubber band to keep the wings together.
Glued cores together on the main wing, trimmed the ends to the 48" length and started marking out parts locations and cuts. Went with 20% thickness on ailerons and decided to make it easy and go full span out to the wingtips. Now i can figure out where i want the servos and sink some servo wires into the foam before bagging. I need to write these down as i will be using some colored pigment this time and wont be able to see these marks.
wing joiner thingys: https://www.thingiverse.com/thing:2193811
just find an appropriately sized rubber gasket or rubber band
edit: i would think with a dremel or chisels you could make the same type of thing out of hard wood or even mdf with some CA glue to harden it up.
just find an appropriately sized rubber gasket or rubber band
edit: i would think with a dremel or chisels you could make the same type of thing out of hard wood or even mdf with some CA glue to harden it up.
bracesport
Legendary member
@thenated0g - thanks for the tips - I will update my design to include this kind of wing joiners!
what some guys do is a 3 piece wing instead of 2. They permanently glue in a center section of wing into the fuselage with an inch or two sticking out. So that essentially becomes part of the fuselage and you can make the center (where most of the load is going to be) stronger as well. never tried it myself. But than you would only need a way to keep the wings together and not ALSO how to make it stick to the fuselage.@thenated0g - thanks for the tips - I will update my design to include this kind of wing joiners!
bracesport
Legendary member
@thenated0g - what kind of filler do you use on the sanded fuse?
I have some epoxy filler, heres the description:
Phenolic Microballoons
(BJO-0930)
These red/purple color phenolic spheres when mixed with epoxy resins will create a low density paste compound which will sand easily and improve strength/flexibility of the cured resin. Better for large gap filling.
http://www.uscomposites.com/fillers.html
But i see lots of guys using bondo filler too.
Phenolic Microballoons
(BJO-0930)
These red/purple color phenolic spheres when mixed with epoxy resins will create a low density paste compound which will sand easily and improve strength/flexibility of the cured resin. Better for large gap filling.
http://www.uscomposites.com/fillers.html
But i see lots of guys using bondo filler too.
I did mark out the mylar's for the vacuum bagging of the wing, and got the aileron servo wires submerged in the foam, but mostly i have been researching mold making on rcgroups and getting a list of supplies. Thats mainly why i am rushing this v1. I am not interested in nice looking plane but something that works good enough to make a really nice version.
Assuming everything goes well with v1 i will then make another copy of the fuselage out of mdf. A perfect plug/buck to create a 2 piece mold. To start off i am going to be using some ultracal 30 which is a professional version i guess you could call it of plaster of paris. Compared to epoxy or polyester mold making supplies, it is super cheap. Like a 25lb bag shipped to me for $45.
Ill continue to post mold making stuff as i'm making my final choices on how to do it and then ill start a new thread specifically on mold making once i get going on my first one.
https://plaster.com/product/usg-ultracal-30/
I have heard that on its own these are good for a few good copies of fuselages, but if you want it to last a long time you can coast the inside of the mold with epoxy before using.
Basically you would make a 2 part mold of your part. Than do fiberglass, carbon, epoxy on the inside of those molds and than connect the two halves, of which there a various ways to do that, as the parts are wet or after they set.
Pretty exciting, as this, after vacuum bagging, has been something i have been afraid of trying (ie lacked confidence to even attempt) but now that i have looked at it and gotten parts listed out i feel like its something doable.
Assuming everything goes well with v1 i will then make another copy of the fuselage out of mdf. A perfect plug/buck to create a 2 piece mold. To start off i am going to be using some ultracal 30 which is a professional version i guess you could call it of plaster of paris. Compared to epoxy or polyester mold making supplies, it is super cheap. Like a 25lb bag shipped to me for $45.
Ill continue to post mold making stuff as i'm making my final choices on how to do it and then ill start a new thread specifically on mold making once i get going on my first one.
https://plaster.com/product/usg-ultracal-30/
I have heard that on its own these are good for a few good copies of fuselages, but if you want it to last a long time you can coast the inside of the mold with epoxy before using.
Basically you would make a 2 part mold of your part. Than do fiberglass, carbon, epoxy on the inside of those molds and than connect the two halves, of which there a various ways to do that, as the parts are wet or after they set.
Pretty exciting, as this, after vacuum bagging, has been something i have been afraid of trying (ie lacked confidence to even attempt) but now that i have looked at it and gotten parts listed out i feel like its something doable.
bracesport
Legendary member
@thenated0g - I am looking forward to this - you have wet my appetite for epoxy!
