Hey guys, progress report......

Ok I have redesigned just a few aspects of the fuse and rudder. More to come yet tho....
I will begin on the wing spars next week and try to finish the fuse. The elevator spar is not pictured nor is the new engine. CUYUNA 430! Man I love eBay. I got the block with tuned exhaust, a redrive and carb for 350! Next up is trying to get an engine mount fabricated.("I swear its for a go cart!") Prop is three blade ivoprop from j-bird but wont be ordered until needed. I decided to attach the longerons straight then curve them to shape. Also pictured are the templates for the foam cutting. Stay tuned for the controls setup......

Originally Posted by radioinred

Ok I have redesigned just a few aspects of the fuse and rudder. More to come yet tho....
I will begin on the wing spars next week and try to finish the fuse. The elevator spar is not pictured nor is the new engine. CUYUNA 430! Man I love eBay. I got the block with tuned exhaust, a redrive and carb for 350! Next up is trying to get an engine mount fabricated.("I swear its for a go cart!") Prop is three blade ivoprop from j-bird but wont be ordered until needed. I decided to attach the longerons straight then curve them to shape. Also pictured are the templates for the foam cutting. Stay tuned for the controls setup......

Really looks good.

What adhesive are you using to bond foam to the wood?

Ron

Hi,
Agree with Ron - looking very nice indeed. Keep it up.

Duncan

Thanks very much for the nice words. The glue used to bond the foam to the wood is gorilla glue. The bond line is incredibly strong though the glue is a bit heavier than other choices. clamping foam is tricky. I got creative and used cloth padded tie down straps and that worked just fine. Gorilla glue makes a huge mess if you are not careful and it turns your fingers black for a couple days.

Originally Posted by radioinred

Thanks very much for the nice words. The glue used to bond the foam to the wood is gorilla glue. The bond line is incredibly strong though the glue is a bit heavier than other choices. clamping foam is tricky. I got creative and used cloth padded tie down straps and that worked just fine. Gorilla glue makes a huge mess if you are not careful and it turns your fingers black for a couple days.

That is what it looked like, just wanted to be sure. Have you or anyone, worked with it covering large areas? I am thinking of a deck cover on my tool trailer, three 4X8 sheets 1/2" with a layer of aluminum screen wire between each for extra strength. I am not sure how much swell might take place, don't want too much thickness between the sheets.

Any ideas out there ?

Ron

Just curious... is your wing spar going to be a wood-foam-wood sandwich too?

bmcj, yes but not quite like the rudder stem is. the wing spars will have spruce top and bottom caps with two inch dow extruded foam for the webbing. The webbing itself will be laminated with three pieces of foam: two 3/4 inch pieces glued and pressed to either side of a 2 inch solid piece. Ill post a quick example soon.

RonL, I dont know if the aluminum screen wire would give you any extra strength. In fact it might be a weakpoint in the point in the bond line. The magic of gorilla glue when it comes to wood is in the moistening of the wood and the clamping. Gorilla glue certainly does expand while curing... Perhaps if you omitted the screen and used the gorilla glue sparingly you could have a nice sturdy cover. The only potential problems I see (from my experience) are achieving clamping pressure over the entire surface of the lamination. The glue follows the moisture into the grain of the wood in essence welding the sheets together. The screen could potentially interrupt this. I don't actually know though... tell me what happens.

Next up is trying to get an engine mount fabricated.("I swear its for a go cart!")

"three wheeled off-road vehicle"


Looking good!

Someone should point out (again) how scary this whole thing is: We've discussed Gorilla Glue here before. In short, it's a simple Polyurethane product that cures brittle, with a friable surface. Even relatively small vibrations can introduce many points of damage, all of which will lead to a fairly quick and catastrophic failure. Gorilla Glue is fine for simple furniture and non-structural architectural uses but hardly sufficient for flight structures, even the lightest ones. There's a very good reason why the light plane industry has pretty much standardized on epoxy based products.

I'd like to ask an even more basic question: Where do you sit? I see what appears to be a cockpit area in the appropriate part of the fuselage, but man, I don't see any place for legs to go through the bulkheads, excepting two very small square holes. Have you actually sat down in the cockpit yet? For any serious length of time?

Q2: If that's what those square holes are, why is there another pair farther forwards? Your photos are titled as "Phil's Ultralight", but it looks like there are two seats? I'm confused. Did I miss something earlier?

Glancing at the spar structure for a tail surface I don't see any spar cap. That is what would resist the bending moments as a beam. The webs (shown) would only resist shear loads. The spar caps and webs also have to be connected together to transfer all related stresses. Etc.

Gad. Just read through the "She is Born" thread.

radioinred - Did you actually sit in the fuselage and see if you fit?

Originally Posted by BDD

Glancing at the spar structure for a tail surface I don't see any spar cap. That is what would resist the bending moments as a beam. The webs (shown) would only resist shear loads. The spar caps and webs also have to be connected together to transfer all related stresses. Etc.

That was my concern when I asked about building the wing spars with the same method. The foam works good for stabilizing and spacing, but provides very little to the ability to transfer loads.

Bruce

Originally Posted by Topaz

Gad. Just read through the "She is Born" thread.

Yeah, ya think???

Bruce

P.S. - Good observation on the seating area. Looks too tight, unless the views are deceiving.