X,Y,Z

[Admin]

New addition/option. 

I asked Project Cedrus to send me the CAD for their mast attachment and I have used that to make the adaptor (will be milled aluminum) pictured.  Two of the solid 12 mm carbon rods will pass through the adaptor, it will have the two normal 8 mm screws passing straight through to the Cedrus mast from the bottom, and the carbon fuselage will now screw directly into the aluminum adaptor as well with a 6 mm screw from the back for  full X, Y, Z stabilization linking the aluminum adaptor to full carbon in all directions.

[Beasho]

It would seem there would be an incredible amount of stress here.

Only 2 bolts handling all the bending moment? 

[Admin]

Hey Beash, Good point.  Yes, I was surprised by that as well, but I do think it is what they are doing.  https://projectcedrus.com/product/fuselage-adapters/. They make note of M6 harware on their page but the specs on their data sheet which they sent me show M8, which is how I have it sketched.  As far as I can see they have two flat surfaces laying flush against each other.  Am I missing something?  I know that a lot of people ride and love these masts and that they are very light and very stiff.  They have an Axis adaptor (below) which will work in my standard well, but I would like to try this sceme as well.

[Admin]

Looking at their stock adaptor, I could probaly allow two wing rods to pass under their tunnel and still have the machine shop tap the back for me.  That may be an easy test.  This is all overkill stuff but I like the idea of it.  I am thinking that I can hit almost all masts with similar adaptors.  They are very easy to adjust if needed.  I contacted No Limitz as well as they are building a super light mast now.  Those are not adaptor based but they do have an Axis Mast made, so I am set there as well.

Mostly, I am filling time as I print out the whole four foil system for the first time with all the new tube specs and attachment points.  I am at 4 of 10 prints.

[Hdip]

Yes, that's how the Cedrus works. The two bolts handle all the stress fine. I'm pretty sure he has a blog post about it, as people seem to question that integrity often. He's apparently done the math on it, and the real world experience shows it works.

[Admin]

Great.  It looks like they are all putting some taper on the adaptors.  The actual Axis mast well has right angles.  Will have to test that first.

[PonoBill]

No problemo with the stress. I've been considering doing the same thing--I've got a Cedrus mast at the shop with no adapter. I'll probably machine my own--I haven't used my milling machine in a dog's age. I should be able to make the same part I could pay an expert to make for 50 bucks with just a few hundred bucks in failed efforts, a wastebasket full of swarf, and a few broken end mills.

Anyway, the bolts only provide clamping force. Stress is distributed along the faces of the joint. That puts the bolts in tension, which is what they are good at. There's almost no shear force. All kinds of stuff works that way.

And we're mostly managing weight. Sure, there's some drag, but it's a fraction of the weight, and that is mostly straight down--pushing the parts together.

[PonoBill]

It would be nice to run the tubes through matching holes in the adapter, and for that, you'd want something full-length, not notched out like the Cedrus adapter. Of course, you'd have to take the wing apart to get the mast out of the hole. That may or may not be an issue. If nothing else you can join the throngs of people in Hood River that drive around with a foil attached to their board. Neuve Decor.

[Admin]

It would be nice to run the tubes through matching holes in the adapter, and for that, you'd want something full-length, not notched out like the Cedrus adapter. Of course, you'd have to take the wing apart to get the mast out of the hole. That may or may not be an issue. If nothing else you can join the throngs of people in Hood River that drive around with a foil attached to their board. Neuve Decor.

I need to make some models to work out the details but this too should be ready for testing this spring .  The adaptor shape can be redesigned later to be optimized for these wings, which should allow for a reduced interface and less drag.  Ideally, this would be directly integrated into a carbon mast to also eliminate the adaptor joint. 

I can use one of the bars to dual thread the wings. I may need to use a small slot and a tool to tighten.  Still brain storming (farting) on that.