ECHO Slope Wing

[Yotaman1985]

Since Sunset @thenated0g and I have been making progress on what has turned into a new slope wing design. We had originally planned to continue with the Mini Buzz project but after designing the wing in CAD and making some modifications, the decision was made that it had changed enough to warrant a new name.

We decided to name it ECHO and it will be a molded wing instead of foam core. It has a 38" span using an MH45 airfoil and will be hollow molded using 3d printed molds. In keeping with the idea we had for the Mini Buzz, we have designed this wing and molds to fit inside food vacuum bags.

It has been super fun designing this with Nate and we are each trying some different ideas to see what works best. Ill let him chime in with his thoughts and plan but I have 3d printed internal ribs with a carbon spar that will be epoxied inside the two mold halves. I have always wanted to 3d print molds for a plane so Im super excited to finally be doing it.

We'll post updates on the molding process and hopefully have a functional wing in the near future.

 

[Wayne]

So both of you have printed mold sets?

Oh yeah, I want to be the first to ask:

Are you done yet?

 

[Yotaman1985]

Hey Wayne,

Yea, Nate has printed a set of molds as well. He'll post with his pics and progress here too.

I convinced both Nate and Kelly to get Bambu printers... Lol

 

[thenated0g]

This is I think primarily fun project for us to learn like modern 3D printing use for mold making with the echo kind of being something we can use around that. So it's half us figuring out mold making with 3D printers and half kind of getting this plane to work in a way that we like. But we are each going on our own little tangents I guess like he's gonna do a bunch of internal sparring like he showed in the pictures whereas I wanna try and get the least amount maybe like one spar and reinforce with layers to make it a little bit heavier.

One of the main design restraints that I wanted for this project was that it had to fit inside of food sealer bags because eventually we would like to put this out there for other people to try making and not have to buy a bunch of vacuum equipment.

If any of you saw my little yellow mini buzz at sunset here is it on top of the echo I think it actually has a very similar or close wing area just a different silhouette you know it's a stretched wing.





One difference on mine as I went with 20% infill on the 3D print I think Jeremy went 15% and it just feels incredibly solid like even squeezing it as hard as I can I can't move it so it should survive the vacuum pretty well. Jeremy did vacuum bag one of his parts and left it overnight and it didn't damage it at all so my 20% should be just fine.



I had Jeremy "cut" me out what an internal spar would be if it went wing tip to wing tip so I can cut this out of plywood on my laser and that's what I'm going to try for my first build. I'm still working on what layers of fiberglass and carbon I want to do. For my first layup I'm going to do just some layers of fiberglass as a test before I get to using any carbon later because it's more expensive.

 

[thenated0g]

We have some self leveling epoxy molding resin coming and this will be what we finish the original mold with

XCR Clear Epoxy Coating Resin - Easy Composites

Highly UV stable, fast curing, clear epoxy resin for hard-wearing, glossy coatings on furniture, boat decks and more. Buy online, expert support, fast shipping across the USA.

www.easycomposites.us

 

[thenated0g]

 

[Wayne]

Love it!

 

[Wayne]

We will have to send you some brushed motors for it.

 

[thenated0g]

I was telling Jeremy that i have tried to start this project several times over the past 10 years. Even learning every 3d design program out there to try and make it work. So he was finally able to get thru the design hurdles that always stopped me.

 

[OribaSJ88]

That's a very cool project! It's great for a personal/low volume molded projects. It will lead to a far better product than 3D printing alone. There was a thread on RCG that covered one user's builds in some detail. Checkout the posts by TPEHAK in the thread if you haven't seen it. He covers his efforts to make 3D-printed molds for both fuselages and flying surfaces. He got some truly beautiful results.

RCG: 3D-Printed Molds

 

[Yotaman1985]

That's a very cool project! It's great for a personal/low volume molded projects. It will lead to a far better product than 3D printing alone. There was a thread on RCG that covered one user's builds in some detail. Checkout the posts by TPEHAK in the thread if you haven't seen it. He covers his efforts to make 3D-printed molds for both fuselages and flying surfaces. He got some truly beautiful results.

RCG: 3D-Printed Molds

Awesome, thanks! Ill definitely take a look at that

 

[thenated0g]

Yeah we have been looking at everything we can on rcgroups and YouTube. Thanks.

 

[Doc James Hammond]

It looks like a good design.

Everything is the right size and in the right places. No silly wingtip fins.

Well done!

Doc.

 

[Wayne]

I think Bracesport on this forum posted up some good stuff a few years ago..

 

[thenated0g]

I am pretty happy with using expanding gorilla glue for joining the mold parts. I had sanded them pretty well before clamping up. I found that it really doesn't like to stick to unsanded pla so it is very easy to remove the stuff that squeezes out. Scrapes off or even just pull off cleanly.

I have lots of other things i want to try with 3d printing mold making.

I would like to do a similar print but a positive instead of a negative so that i can do a more "traditional" mold with gelcoat and fiberglass. Even try pouring Ultracal 30 to make a solid concrete mold.

I want to try and see how hard it would be to cut out matching foam parts to put inside the before gluing the 2 halves together for internal support.

I want to play around with different things like Rx and battery holders/servo holders inside before gluing together.



One thing im playing around with is a servo holder, a "universal servo holder" ring, and a "marking ring".
The "marking ring" would be glued to the inside of the mold before layup. It would become part of the mold. The point is both create a perfect circle imprint and low spot where you could easily drop a razer blade in to cut a hole later, but after vacuum forming it would show an obvious "bump" that you than would glue the universal servo holder over. And than you could make a servo hold that would fit in that ring for whatever servo you want to use. Still super work in progress, just messing around. Yes i have seen how other people do it lol

 

[Wayne]

I like the creative thinking! I'm not fully following what you are explaining, but that is ok, you keep going! If you do not try it, you will never know.

 

[zeo0nie1]

Very inspiring thread

You've probably thought of this but it'd be a shame to put all the effort into it only to have PLA ribs and other internals deform on hot days.

 

[Yotaman1985]

Very inspiring thread

You've probably thought of this but it'd be a shame to put all the effort into it only to have PLA ribs and other internals deform on hot days.

Thanks for the thought. I printed them with 100% infill and they will be epoxied in on top and bottom so I dont think it will warp but definitely something Ill keep an eye out for.

 

[Wayne]

I'd for sure use something other than PLA for anything that will be outside. For me PLA is disposable things, or indoor stuff. If you are looking for the PLA to offer any strength and the plane has any dark colors, I don't think it will help you much unless you make it pretty thick, at the point weight is going through the roof. PETG prints nearly as nice and is cheap while tolerating more heat. PETG CF is even nicer for some applications. Next steps up are Nylon, ABS, ASA, etc. They can be more expensive and more trouble to work with but strength and heat capability goes way up. After that you pretty much jump into the high temp stuff, they require printers capable of the high temps and have a learning curve.

We use a mix of most of these, but pretty much swarn off ASA and never did much ABS. ASA smells like concentrated cancer. It's a pretty neat material, but we have decided to avoid it, something that smells that bad can't be good to be around.

We are using the high temp stuff a bit these days and am planning to use it on a number of new projects. It is not cheap though!

 

[Hawaii Sloper]

Thanks for the thought. I printed them with 100% infill and they will be epoxied in on top and bottom so I dont think it will warp but definitely something Ill keep an eye out for.

You could easily laser cut some balsa spars.