ECHO Slope Wing

[thenated0g]

@Yotaman1985 discovered this technique already and it is in the pics above. Unless i did it wrong lol. Let me get some better pics of the trough setup.

## edit - they are in the pictures above.

 

[Yotaman1985]

Thanks Red, that was one of the changes I made to the latest version of the molds.

 

[Yotaman1985]

It looks right Nate for a positive plug. It will create a trough in the mold

 

[thenated0g]

Yes it has been hurting my brain trying to think of the back and forth thats happening. Printing a positive to get a negative mold to make a part

 

[thenated0g]

@jure thanks for the suggestions. Most of these we have been reading thru here and on rcgroups. We are having fun just trying stuff, seeing what happens.

 

[thenated0g]

One unique thing with using something like ultracal is that it doesnt chemically bond with epoxy, so i dont think you need pva, just wax. I know pva is one of those things that makes painting in the molds really difficult.

 

[Yotaman1985]

New top mold printed out and ready to glue together

 

[Wayne]

You have cute pink sheets.

 

[Yotaman1985]

You have cute pink sheets.

Purple to be accurate

 

[thenated0g]

 

[thenated0g]

Those look great. the mold, not the sheets

 

[Yotaman1985]

And glueing...

 

[Yotaman1985]

Visiting Family this weekend and my father in law has a wood shop so I asked him help me cut out some plywood backers for the new molds I am 3d printing. Planning to epoxy/fiberglass the plywood to the back on the molds in the recess I designed. Hoping this will help keep them more rigid and straight. I will also keep these out of the sun...

 

[Wayne]

What no bigger pictures of what looks to be a cool shop? Shame!

Turned out very nice!

 

[Yotaman1985]

What no bigger pictures of what looks to be a cool shop? Shame!

Turned out very nice!

Its a cool old shop in an old barn basically. Been around a long time with lots of dust and wood shavings. Lots of old tools and stuff too. Ill have to take some pics next time

 

[thenated0g]

Bottom ultracal molds printed out at 0.16 layers. Came out super nice. Also only took me 2x 10hr jobs to print it out since i did it at 10% infill.
Small holes are for screwing into a layer of wood for stability. Large holes are for pins to insert later while pouring concrete to leave voids.

 

[Wayne]

Excellent!

 

[thenated0g]

@Hawaii Sloper shared a link with us for a huge food sealer machine that does i think 14" wide bags. These ones easily fit in 11" bags, but nice to know we could go bigger.

 

[Hawaii Sloper]

@Hawaii Sloper shared a link with us for a huge food sealer machine that does i think 14" wide bags. These ones easily fit in 11" bags, but nice to know we could go bigger.

It's a 16" version. under $200 on amazon.

 

[Hawaii Sloper]

I took Jeremy's Onshape files and got some dimensions from them and created a version of the echo. He and Nate have been giving me a bit of help with Onshape since I just started to learn about a week and a half ago. A bit of brain bending but I've got the basics now. Here's my try at it. We are interested to see how each version comes out with the slight differences we've each made, both in construction and flight.

I didn't help in the design of the wing at all just tweaked Jeremy's design a very little bit. I made it exactly one meter wide (3cm total wider than the original with 1cm wider on each side in the center section) The last picture shows the difference in the top profiles from his to mine (line version). I was hoping to get a slight bit more loft in the center section so that maybe the wing could be capable of Peter Wick's "wag-stall".
Does anyone know of an airfoil generator in Onshape that has a PW51 airfoil? Can't seem to find one and can't edit a DXF imported into Onshape with the free version. The airfoil we are using doesn't like to be split because it has a slight camber that goes above and then below the centerline of the profile. Too many tricks needed to split it and subtract the wing shape from top and bottom mold form. Between us we did manage it different ways for each of our versions. So far this has been a fun project that Jeremy and Nate have let me be a small part of. really excited to 3D print my molds and get to the next steps. I'm going Jeremy's route with making the halves directly from the mold instead of making a positive mold like Nate.