Raptortech
Foam Addict
For gluing XPS (pink insulation foam) Gorilla Glue is my favorite. It fills the gaps nicely, sands well, and is super strong!
Scale Build-Off – 140" C-47 Foamy
- Thread starter ScottyWarpNine
- Start date
I would agree here. I would be too worried that the hot glue will heat and soften in the summer sun.
JohnRambozo
Posted a thousand or more times
I'm just waiting for pics of it strapped to your Fiat. 
MikeJM
Member
Doesn't polyester resin melt foam?
ScottyWarpNine
Mostly Harmless
I have no idea, does it? If that's the case, I'm going to run into an issue when it's time to glass it...
In short, yes... it does. There are some foams that are safe for polyester resin, but not the stuff most of us use.
ScottyWarpNine
Mostly Harmless
Well that's unfortunate. I guess I'm gonna have to use epoxy resin.
My 6" inflatable wheels came in.
This is a test fitment on a failed print.
The axles are 5/32" steel rod, as are what I intend to use for all hinge pins in the mechanism. Nice and simple. As for the failure of the print, it started warping and lifting off of the build platform. I'm going to have to make a couple modifications to the design of the parts to try to prevent warping. This is probably the largest part I have ever attempted printing on my machine, so I expected to run into a few issues.
Balsa to Foam
A Jack of All Planes!!!
this is a monster build ,subscribed. Oh and what 3d printer do you have?
ScottyWarpNine
Mostly Harmless
Reprap Prusa Mendel i2. I'm running it using an Arduino Mega 2560 with a Ramps 1.2 shield.
I've had VERY good success with 30-minute epoxy thinned 50:50 with Isopropyl Alcohol. thins down to a very light syrup viscosity, wets very nice and gives plenty of working time before it thickens or gums up. wait a day and follow with WBPU + Talc (also mixed 50:50 by volume) to fill the weave. Wait a day and sand down to the epoxy and you should have a smooth surface to work from (if you hit the epoxy layer and the weave is still pronounced, run another layer of the WBPU slurry, and sand again).
Not quick, but cheap and everything but the glass cloth can be found at Lowes . . . well, even the glass if you want the really heavy stuff.
ScottyWarpNine
Mostly Harmless
Thanks for the tips. That's what I'll probably do. Does lowes sell epoxy in anything larger than those double syringes?
Well, I wanted to do a little flying today since its so beautiful on Ohio for once (still a bit cold). About a half battery in, a tree decided to rip my Tek Sumo in half
So I guess now I'm working on the... C-47! That's right, I've decided I would go the easy route and not try to replicate polished aluminum skin. This one is gonna get the olive drab Krylon treatment. Tonight I'm gonna try to get the rest of the formers in place and start thinking about the center wing section. I won't be able to get anything done this weekend and this week because I'm going to New York for spring break
Anyway, here's proof that it fits on my car:
Luckily my antenna unscrews so I can have it sitting right down the middle. Keep in mind it's gonna be a couple inches longer up front due to the nosecone, and a few more inches in back with the tail surfaces. I'll make some foam blocks for it to rest on and I'll be able to just strap it down on that. No need to buy a roof rack
Now I need to stop talking and actually work on it.
I want to be there when you arrive with that.
lol... I love it.
One thing (only because I've seen it happen once)... are you making the horizontal stab and elevator removable? If they are fixed, and if you have any AOA when the fuse is strapped to the roof you can get aerodynamic forces on the stab and put a lot of stress on the fuse. Same thing with the rudder but probably less significant.
One thing (only because I've seen it happen once)... are you making the horizontal stab and elevator removable? If they are fixed, and if you have any AOA when the fuse is strapped to the roof you can get aerodynamic forces on the stab and put a lot of stress on the fuse. Same thing with the rudder but probably less significant.
ScottyWarpNine
Mostly Harmless
Yeah that could be ugly. I plan on making the horizontal stabilizer removable. I think I'm gonna make them slide into place on a couple sections of PVC pipe, like the wing sections. The rudder is going to be permanently installed, so I'll just have to make sure I line it up as perfectly as possible. I know I mentioned taking the highway earlier, but I wouldn't take it that fast. I'm only about 30 minutes north of Malvern, so I'll take the back roads and limit myself to 45-50mph.
I didn't get as much done tonight as I would have liked, but I gotta get some sleep.
I've got 2 more formers to go, and I'm gonna shape the nose from a block of stacked foam.
I'm gonna plank the fuselage using 1/4" strips of foam. I've been cutting the strips using the setup I showed a few pages back.
Don't rush yourself. This is a pretty ambitious project and I'd certainly like to see it at FTFF.
As a suggestion, I would recommend using the foam nose as a plug for fiberglass. This will allow you to make it removable and place the batteries as far forward as possible in a tray you could fabricate for the nose.
SnowRocker88
Amateur pilot and builder
Yeah that could be ugly. I plan on making the horizontal stabilizer removable. I think I'm gonna make them slide into place on a couple sections of PVC pipe, like the wing sections. The rudder is going to be permanently installed, so I'll just have to make sure I line it up as perfectly as possible. I know I mentioned taking the highway earlier, but I wouldn't take it that fast. I'm only about 30 minutes north of Malvern, so I'll take the back roads and limit myself to 45-50mph.
I didn't get as much done tonight as I would have liked, but I gotta get some sleep.
I've got 2 more formers to go, and I'm gonna shape the nose from a block of stacked foam.
I'm gonna plank the fuselage using 1/4" strips of foam. I've been cutting the strips using the setup I showed a few pages back.
You could just strap it up top on its back so the horizontal stabilizer is down in the wake of the car...much less air pressure and much less velocity. Essentially in a trapped pocket of turbulence.
ScottyWarpNine
Mostly Harmless
Well I'm finally back in town. Things are going slow, but at least it is moving again.
I got the rest of the formers done, now I need to decide what to do next.I think I'm going to wait to plank the fuselage because having access to the insides will be vital for mounting servos, routing wires, linkages, etc.
My next step will probably be the vertical stabilizer. It will consist of three layers of my 1/2" foam, with two carbon fiber arrow shafts running through the center layer for strength. I will then sand and shape the laminated layers by hand till I'm happy or die of pink foam inhalation.
The wing will be tricky, but I think I will be able to use the same construction technique as with the fuse. Like I said earlier, I'm going to use PVC pipe to make a sliding tube wing mounting system. Center section will likely be permanently mounted to fuselage. Blah blah blah, all talk for now.
I've been more thinking than doing unfortunately, here is a weight budget I've compiled with rough estimates that I've pulled out of nowhere, and hobbyking's website.
Batteries: Two Multistar 10,000mAh 6S batteries, about 6lbs total.
Servos: Seven HK15328A extra large ball bearing metal gear servos, about 1lb total.
Misc electronics & linkages: about 2kbs maybe.
Fuse total weight: 8lbs total (almost 2lbs as it sits)
Wing total weight: 8lbs maybe (I really have no idea)
Motors and ESCs and Props Total: about 4lbs.
Retracts and wheels: about 3lbs
Estimated Total weight: 32lbs
I was aiming for 30 dead, but we'll see. I rounded up on all figures. That's not bad considering the actual kit can be as much as 50lbs.
I estimate I will pull about 75-80A at full throttle. That gives me about 3,330-3,552W, so over 110W/pound. This thing should boogie.
Anyway, that's all I have for now, I just felt like I had to post something. Hopefully next update will be more impressive.
I got the rest of the formers done, now I need to decide what to do next.I think I'm going to wait to plank the fuselage because having access to the insides will be vital for mounting servos, routing wires, linkages, etc.
My next step will probably be the vertical stabilizer. It will consist of three layers of my 1/2" foam, with two carbon fiber arrow shafts running through the center layer for strength. I will then sand and shape the laminated layers by hand till I'm happy or die of pink foam inhalation.
The wing will be tricky, but I think I will be able to use the same construction technique as with the fuse. Like I said earlier, I'm going to use PVC pipe to make a sliding tube wing mounting system. Center section will likely be permanently mounted to fuselage. Blah blah blah, all talk for now.
I've been more thinking than doing unfortunately, here is a weight budget I've compiled with rough estimates that I've pulled out of nowhere, and hobbyking's website.
Batteries: Two Multistar 10,000mAh 6S batteries, about 6lbs total.
Servos: Seven HK15328A extra large ball bearing metal gear servos, about 1lb total.
Misc electronics & linkages: about 2kbs maybe.
Fuse total weight: 8lbs total (almost 2lbs as it sits)
Wing total weight: 8lbs maybe (I really have no idea)
Motors and ESCs and Props Total: about 4lbs.
Retracts and wheels: about 3lbs
Estimated Total weight: 32lbs
I was aiming for 30 dead, but we'll see. I rounded up on all figures. That's not bad considering the actual kit can be as much as 50lbs.
I estimate I will pull about 75-80A at full throttle. That gives me about 3,330-3,552W, so over 110W/pound. This thing should boogie.
Anyway, that's all I have for now, I just felt like I had to post something. Hopefully next update will be more impressive.
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