The XPB Stage 1 underway.

[bexrbetter]

Each rib could have a small notch cnc'd into its leading edge which using a taut fishing line

Just a thought for you but I have a sneaking suspicion that you probably already have this potential (minor) issue resolved.

Each rib has a shoulder cnc'd into it that keys it to the spars, I do like the fishing line idea as a secondary check though, thanks.

 

 

 

If not, a potential solution could be to have a separate rib and flange with each flange being bent to 90 degrees and pre-drilled only on the rib face but not on the spar face. The spar face could be back-drilled through the spar mounting holes after clamping the flange to the spar in its required location.

As Fonzie would say, "Correcto mondo".

 

It was always the plan and had already been executed on previous wing examples, probably shown in this thread somewhere. I'd go look for it myself, but it would be depressing to see how much time has passed since ...

 

 

[geoffreywh]

So the ribs are assembled onto the spar. Along comes the leading edge sheet (predrilled) clecoed onto the spar and ribs (keeping them in position) .And with straps and help it gets folded around and becomes the LE....... is there no internal support for the LE?. It looks very vunerable.

 

But I'm not familar with fuill size practice.

 

 

[Marty_d]

So the ribs are assembled onto the spar. Along comes the leading edge sheet (predrilled) clecoed onto the spar and ribs (keeping them in position) .And with straps and help it gets folded around and becomes the LE....... is there no internal support for the LE?. It looks very vunerable.But I'm not familar with fuill size practice.

That's how Zenith do it. Nose ribs form the shape of the LE and the front skin is just curved over, ratcheted tight and clecoed to the spars at top and bottom. The curve of the aluminium supported every 600mm or so by the ribs forms a strong LE.

 

 

[Guernsey]

Stone the crows, things are getting very exciting , the speed at which you are updating and improving means that the Mark 10 will be the first to fly..

 

Alan.

 

 

[bexrbetter]

is there no internal support for the LE?. It looks very vunerable.

It's not a problem at all, the radius makes it well and truly strong enough.

 

The curve of the aluminium supported every 600mm or so by the ribs forms a strong LE.

Because I'm a cantilever wing, my spacing is a lot tighter than that, and because I'm me, there's even an extra one thrown in. We'll see what happens after the wing load test, I am looking for 8 geez.

 

 

[Marty_d]

I am looking for 8 geez.

Geez!!

 

(There's one.)

 

 

[bexrbetter]

So the Farmer says to his sheepdog; "How many in the pen?".

 

 

 

Dog answers; "40"

 

 

 

Farmer surprised asks; "How can that be, we have only ever had 38 sheep?"

 

 

 

Dog says" "Yeah, I rounded them up".

 

One of my idiosyncrasies when designing is to round everything off, why should something be 594 mm when it can be 600, why should something be 3.9 degrees when it can be 4? etc. All through anything I build you find all these plain numbers, sans fractions.

 

So when I just measured my first nose rib for skin sizes, how delighted am I to find it's 1 meter exactly! - small things for small minds!

 

 

 

[Deskpilot]

Ah, my un-asked question is answered...........SketchUp.

 

 

[bexrbetter]

Ah, my un-asked question is answered...........SketchUp.

Sketchup 3D and Librecad 2D.

 

I need Librecad because Sketchup doesn't do true circles.

 

 

[bexrbetter]

.. and now 2 full sets of ribs.

 

 

 

[bexrbetter]

and this one ..

 

 

 

[Marty_d]

Fantastic work Bex.

 

I'm very intrigued by that method of making ribs. How would the weight compare to an equivalent with non-riveted flanges?

 

From an engineering viewpoint view would your solution be any weaker than a bent flange?

 

One of the things I like about your concept is that the exact rib size can just be CNC'd out, which makes it very easy for tapered wings. To make my ribs I had to first make wooden forms with provision for relief valleys, clamp and bash the hell out of it to bend the flange over, then fiddle about with each one for ages afterward to take out any warps. And that was just for ribs the same size as the wing is constant chord. Can't imagine fabricating several different size moulds for tapered wing, much less the elliptical shape if I ever end up doing a Spitfire.

 

Your method on the other hand takes out the work and also doesn't warp.

 

You mentioned in a previous reply to Kasper that you'd done flanges at non-square angle to account for wing taper - how'd that work? Just a gentle curve in those flange strips?

 

 

[bexrbetter]

I'm very intrigued by that method of making ribs. How would the weight compare to an equivalent with non-riveted flanges?

The same eventually when I optimise it later, plus the rivets. Weight is weight, sure, but the rivet weight is miniscule.

 

I don't spend a lot of time on optimisation currently in case I change the part designs so I expect this actual craft's result to be about 10%~15% heavier than what it could be.

 

From an engineering viewpoint view would your solution be any weaker than a bent flange?

It's stronger - but also irrelevant, ever heard of, or anyone ever mention a fear of rib failure?

 

Doesn't happen.

 

One of the things I like about your concept is that the exact rib size can just be CNC'd out, which makes it very easy for tapered wings. To make my ribs I had to first make wooden forms with provision for relief valleys, clamp and bash the hell out of it to bend the flange over, then fiddle about with each one for ages afterward to take out any warps. And that was just for ribs the same size as the wing is constant chord. Can't imagine fabricating several different size moulds for tapered wing, much less the elliptical shape if I ever end up doing a Spitfire.

Your method on the other hand takes out the work and also doesn't warp.

Geez, You summed it up near perfect.

 

1 hour for the laser (including travel), then about 4 hours to clean then rivet both wing sets, including me hand drilling and de'bur all the holes.

 

Or if you like, a long day or weekend to have a full set of tapered wing ribs done (this is just the D box ribs, remember the other side of the spar needs doing as well).

 

QUOTE="Marty_d, post: 604806, member: 7951"]

 

You mentioned in a previous reply to Kasper that you'd done flanges at non-square angle to account for wing taper - how'd that work? Just a gentle curve in those flange strips?

 

Yes, about 93+ degrees, mileage might vary. There's more trickery to it though, need to be careful to understand that the inner radius of the flange is that, a radius, and that the squared edge of the rib doesn't like to match up, all cured by a simple little trick when assembling them that actually kills 3 birds with one stone.

 

I'm uncertain if to match hole them or not, as it's so simple to do and impresses the powers to be for the 51% rule of actual fabrication work undertaken and learnt skillz for your Repairman's Certificate.

 

.......

 

You should build your Spit through me, I'd do it at material cost + short labour, and then you would have a dirt cheap plane and I would have a marketable item with development costs partially paid for by you.

 

 

[geoffreywh]

oh please match hole

 

 

[bexrbetter]

oh please match hole

Even Vans match hole isn't match hole in reality, you have to do some work to claim it as your own build, so I should allocate some of the fabrication to the easiest and most fool proof processes.

 

Of course then a bigger fool will come along ...

 

 

[Nobody]

Even Vans match hole isn't match hole in reality, you have to do some work to claim it as your own build, so I should allocate some of the fabrication to the easiest and most fool proof processes.Of course then a bigger fool will come along ...

Make the user do the fabrication on the easiest bit to ship. I screwed up an alieron spar. $20 part, shipping...... 10 times that had I not had another box coming later....

 

 

[bexrbetter]

Mapping out the Elevator lever and links etc.

 

Please note that this is a mock up only made from scrap laying around and is not indicative of the final part design or materials used. Sad I have to explain it but you wouldn't believe some of the responses I've had to obvious "mock up" pictures over the years.

 

 

 

[Bruce Tuncks]

Yep the Van's matched hole is really only a pilot hole but if they save jigging then they are worth lots.

 

Bex, are you planning flush rivets? I reckon the Vans flush rivets make most of the work compared to raised rivets but of course they are lower drag.

 

I know it's too early to ask, but what sort of performance are you looking for? I am interested in doing a matched-hole kit one day..

 

 

[Nobody]

Yep the Van's matched hole is really only a pilot hole but if they save jigging then they are worth lots.

For the newer Vans kits (RV-12 and RV-14)the holes are punched to the final size.

 

 

[bexrbetter]

I know it's too early to ask, but what sort of performance are you looking for?

Of boring, safe, reliable Toyota Camry standard.

 

I am interested in doing a matched-hole kit one day..

Raises some interesting points, there are matched hole kits out there that take obscene amounts of hours to complete, Vans probably the worst.

 

I'm trying to put together a non-complicated kit that's fast to build and I will use the appropriate methods, materials and systems to achieve that.

 

I think "matched hole" ingrains in some people's minds that build speeds will be fast, Vans and some others prove that not be true.

 

Let me mention that Vans is one of, if not the best kit plane in the World, and highly desirable, I'm just stating facts here.

 

The problem and time loss of drilling your own holes is in the measuring, scribing, center punching and pilot hole'ing (and the inaccuracies that come with that) - and I have eliminated all those processes.

 

For the newer Vans kits (RV-12 and RV-14)the holes are punched to the final size.

And I know builders of them who are needing to clean a lot of holes. All sheets either have stress in them already, or get stressed, or relieve the stress during the punching process. Smug to say I have a little trick so mine really do line up first time, eat my shorts Vans!

 

 

[Birdseye]

Of boring, safe, reliable Toyota Camry standard.

Surely no aeroplane can be *that* boring......

 

 

[bexrbetter]

Surely no aeroplane can be *that* boring......

That's just an analogy of course, but from my point of view IF I make it to market eventually, then I hope to be at a price point to attract new people to flying and that will require a docile, forgiving machine.

 

There are plenty of BMW and Ferrari's out there, and at that premium price too.

 

 

[Marty_d]

That's just an analogy of course, but from my point of view IF I make it to market eventually, then I hope to be at a price point to attract new people to flying and that will require a docile, forgiving machine.There are plenty of BMW and Ferrari's out there, and at that premium price too.

You could save weight and cost on the interior by going for the WW2 look... paint it plain green...

 

 

[bexrbetter]

You could save weight and cost on the interior by going for the WW2 look... paint it plain green...

.. and here's today's latest build picture ..

 

 

 

[Marty_d]

You wish! (I wish... probably all of us wish...)