MIRO 2

[CSpaced]

	Quote: Originally Posted by Rod
	Here is the seam roller. There is tons of room in this mold to get in there. Once you get used to the wet join system you will find it is the easiest lightest and strongest way to join. It also eliminates seam cracking einafter painting. The down side is not being able to vacuum bag the molding. Although the glider guys sometimes use a pressurised bag inside the mold which means you have to seal any holes in the mold.

Thanks for posting the photo, its a lot clearer to me now.

[Rod]

She almost fell out of the mold, this release system is really good. The bottom line is 840gms (29.6 oz). This is quite a bit more than the original at 655gm but I had to add strength (weight) to that one. Will carry on with this as I dont see how I could significantly lower the weight, maybe go for 25gm glass for the first layer instead of 75gm. The brown stuff is microballoons.

[brusty]

Looking very nice Rod, that dreaded weight factor never fails to rear its head does it. Just looking back at my notes, the last ExtraF3A patternship I did for John Sutherland, the undercoated Fuz including undercarriage and tailwheel blocks(I paint my moulds with a one step primer), and repairs, my moulds aren't as pristine as yours, came out at 27 ounces and that included the cowling which was to be cut out of it. I like the idea of 25 gram cloth for the first layer as you suggested, and like the Raven, wonder if you need all that carbon reinforcement in front of the firewall, there could be a couple of ounces plus of resin and cloth there ? I think I worked on about 1.2 sq meters per layer so just the lighter cloth layer and resin could save you around four ounces.

Thanks for the note about the s-glass from CST, I have ordered some today.

Carry on the good work, Regards, Barrie.

[Rod]

Yes Barrie you are quite right the 200gm carbon up front is probably over kill. I am too tight to put in the expensive 100gm carbon, shame on me. Mind you there is peace of mind with that big 4 stroke thrashing around in there. The model was designed to weigh 5kg so as long as I cear that I am OK.

[brusty]

Yes the weight thing is a worry, I'm always so knowledgable after the event Rod, and the strange thing is that I have never built anything down to destruction so there is obviously an over build every time I do a layup and make a plane !! You are also right about a four stroke bouncing around. I was only referring to the carbon used in front of the firewall, I think next time I will leave it out, especially if i follow your layup and use the 3.5 ounce S-glass, I like the sound of that.

If you can keep the finished model under 11lb you are doing well, I know what a challenge that is. As the man said, "Nothing weighs less than nothing" Cheers, B.

[my extra260]

That is great work, I am going to get another pbg extra 260 as my balsa/glass fuz hasnt had an easy life, i think it is a bit two light my whole model weighs 4.7 kgs. I didnt built my model but i wont to do a bit on the new one if i can get a new one off of mike. He said to me to keep saving so just getting my first job now should help with that :-) I love having money! Anyway i think the skins on my 260 are glued on with gorrilla glue is it a good method to use and what do you think the cheapest and easyist way is to do it, i have never done foam balsa sheeted wings.

cheers steve. Good luck with the rest of the built.

[Rod]

Hi Steve
Gorrilla glue or epoxy work well. Cheap and easy dont go together. Get yourself a vaccuum pump for skinning or use a different system (honeycomb the cores and glue the skins on with beads of gorrilla or epoxy/micro balloons) CSpaced gave a link on the last page I think. You can build a vac pump for free just search the web for a how to, it uses a fridge pump.

[my extra260]

Do i need a pump? I am only 16 and have no idea of where to start for something like that. :-)

Do i just put the balsa skins straight onto the balsa wood or it there other strength stuff to put in. i was watching pbg videos and frazer and mike used a carben spar in the middle of the wing but i am unsure if mine has that or not as it is only the 2m version.

cheers steve. thanks for the help.

[Rod]

No you dont need a pump thats just how I do it. You can use lots of weight or a press but you need to understand the different systems for success. Maybe get together with someone with experience of this stuff (Ewen Galoway is up your way). Other options are more complete kits or ARF's.

[my extra260]

so if i stick the core inbetween the cutoffs and put lotts of weight on the top will that work well? do you know of any sites on the web that will explain this/ cheers steve.

[NZ Scythe]

I built a PBG 2m Extra 260 a few years back - I was in the same boat, it was my first composite model and I had never skinned a foam core wing either. The PBG 260 does not require carbon spars as the carbon tube is quite long and there is a sub rib out at each end of the wing tube. I used 'Monkey Poo Glue' (aliphatic resin) to attach the skins, I think I applied quite a bit to get good coverage... I didn't seal the skins either. I just weighted the skins down inbetween the excess foam the wing core was cut from (like a sandwich) and loaded it up with every fat chick I could find and left it to dry for a couple of days. When I took the wings out to check they weighed a ton and I thought I had ruined them but after about a week the glue had completely dried and they ended up being extremely light (I forget the actual weight but they were less than my matrix wings)

[my extra260]

Thanks for the advice your matrix looks good on trademe I thought about it but i wont another pbg 260 first!!

My old 260 is still going well but the balsa/glass fues has problems and cracks in flight and on landings by the time i put more glass into it to stop the craking it gets hevery :-(
I have thought about useing my 260 wings on a new fuse but i think a whole new plane is the way to go and maybe sewll mine to someone just starting imac and patytern. Mike got back to me today and said 365 for all the wing cores.