Author Topic: Rib Time (Read 10596 times)

Motorman · « **on:** October 11, 2016, 01:32:24 PM »

How long does it take you to cut out a set of ribs for a geodetic wing by hand? About 600 sq. in. and 40 ribs. I've got about 3 hrs in one set.

What do you need to do to get them laser cut? I'm not going to program a thing because I'm dumb on that. I can provide the ribs copied on paper or rib templates in thin cardboard or even finished ribs if I have to. Who does this and what does it cost?

The design is already out there, the Thundergazer, the problem is I make mine smaller for a 40 size engine. I contacted RSM and they are not going to help reduce their program. They say it's because the spar slot would come out too small. I just cut out 40 friggin' ribs do you think I could trim/open up a spar slot??

MM

Brett Buck · « **Reply #1 on:** October 11, 2016, 04:24:55 PM »

Quote from: Motorman on October 11, 2016, 01:32:24 PM

The design is already out there, the Thundergazer, the problem is I make mine smaller for a 40 size engine. I contacted RSM and they are not going to help reduce their program. They say it's because the spar slot would come out too small. I just cut out 40 friggin' ribs do you think I could trim open up a spar slot??

If you are using a 40, don't make it any smaller, it's already ideally sized for a 40VF or similar.

Brett

Avaiojet · « **Reply #2 on:** October 11, 2016, 06:32:06 PM »

Quote

What do you need to do to get them laser cut? I'm not going to program a thing because I'm dumb on that. I can provide the ribs copied on paper or rib templates in thin cardboard or even finished ribs if I have to. Who does this and what does it cost

MM

I do this. Costs very little.

Charles

Dan McEntee · « **Reply #3 on:** October 11, 2016, 09:03:26 PM »

If you have already cut ribs, why do you need more?
If you have the plans reduced already, you should have a file for them and that is the basis for a laser cutter.
I don't think a Thundergazer has 40 ribs if it is a geodetic wing. That is one reason why they came up with geodetic wings, to cut down on the number of ribs and cut some weight. Are you sure you counted correctly?
Just curious,
Dan McEntee

Mark Scarborough · « **Reply #4 on:** October 11, 2016, 09:49:57 PM »

THis is not a hard thing to do. It takes some time to prep the files ot cut them, and as long as you are willing to compnesate the person doing it, no big deal. You just scale the CAD file, fix the spar notch, and cut. Now if you have to draw the ribs to start with thats a project. But its just a matter of the draftsman doing the work which he should be compensated for.

Long story short, I know several people who could do it for you if you want it done, but its not free .

Motorman · « **Reply #5 on:** October 11, 2016, 10:17:02 PM »

Quote from: Dan McEntee on October 11, 2016, 09:03:26 PM

If you have already cut ribs, why do you need more?
   If you have the plans reduced already, you should have a file for them and that is the basis for a laser cutter.
   I don't think a Thundergazer has 40 ribs if it is a geodetic wing. That is one reason why they came up with geodetic wings, to cut down on the number of ribs and cut some weight. Are you sure you counted correctly?
   Just curious,
   Dan McEntee

I'm using this wing design on more than one plane and I also need a back up plane for competition plus I screwed up a little on the first wings LE. Got a better LE buck now.

The plans got reduced at the printer, I don't have a file. The (rsm) plans don't have the ribs on them. I had to trace the ribs in the kit then get a copy of that reduced then cut that out and paste it to thin cardboard and cut that out. It's actually been much easier building the 2nd plane since I have the templates.

I'm sorry it has 42 ribs, forgot the 2 center ribs are marked R0.

I made one smaller (92%) to match the electric systems I have but, I just got a couple of Brodak 40's and I have all the stuff to make that size so, seems like a good idea.

Don't need the spar notch fixed. How long does it take to scale a CAD file? I'm thinking less than a minute? Everything is smaller so it would be the same set up on the cutter right?

Charles, PM me what I need to send you. I have special balsa wood with fungus we can use.

Still looking for how long it takes to cut a set of ribs by hand. Want to know if I'm slow.

MM

Mark Scarborough · « **Reply #6 on:** October 12, 2016, 08:13:08 AM »

more to it than that, you then have to nest the ribs on the sheet so they fit to cut, but whatever, I have done this, I know people who have done this, its not hard but its not likely to be done for free. It also makes no sense to resize the file to laser cut ribs and NOT resize the spar hole, the whole point of laser cutting is accuracy, so your going to ignore that?

Motorman · « **Reply #7 on:** October 12, 2016, 08:58:26 AM »

RSM is already doing this on the full size plane so the ribs are already nested maybe? Just scale the file cut me a set and if I have to trim the spare slot that's allot easier than cutting out the whole 42 rib set. They said they won't do it. I don't know, I guess there's more to it than I think.

Rib rant off,
MM

Mark Scarborough · « **Reply #8 on:** October 12, 2016, 09:04:42 AM »

Thats what I am trying to splain to ya, its not as simple as you visualize,, well it is simple,but it takes time..I do this, have done this, and will do it again,, there are people that will do it for you but you will pay for their time.

Motorman · « **Reply #9 on:** October 12, 2016, 12:27:58 PM »

I don't know how you got onto this thing where you think I want it done for free but, that's not the case.

MM

Avaiojet · « **Reply #10 on:** October 12, 2016, 04:42:59 PM »

MM,

I PM'ed you. Guess I'm on your ignore list and you forgot.

Dan McEntee · « **Reply #11 on:** October 12, 2016, 06:55:42 PM »

Quote from: Motorman on October 12, 2016, 08:58:26 AM

RSM is already doing this on the full size plane so the ribs are already nested maybe? Just scale the file cut me a set and if I have to trim the spare slot that's allot easier than cutting out the whole 42 rib set. They said they won't do it. I don't know, I guess there's more to it than I think.

Rib rant off,
MM

Anyone that does this is going to look at it as what possibility is there that anyone else would want to buy the ribs sets also to make it worth their time. So far, you seem to be the only one. Most people value their spare time at 30 to 50 bucks an hour. If they are doing the scaling "on the clock" it may be more to figure in overhead and the cost of software. Just reducing a plan on a copy machine doesn't mean that everything aerodynamically will work also. If you reduced a Thundergazer to a size for a Brodak .40, you probably should have relofted the ribs and maybe you could have done away with a bunch of them As far as the time needed to cut ribs, if you already have the templates and are set up. I would think about an hour to an hour and a half while you are watching a rerun of Flying Leathernecks of some other aviation related movie would do it. Potty breaks included..
Did you really NOT know that balsa can have a fungus in it? You must be pretty new to model airplanes. You should be reading old model airplane magazines. There is so much that you have missed.

Type at you later,
Dan McEntee

Motorman · « **Reply #12 on:** October 12, 2016, 08:39:17 PM »

Quote from: Avaiojet on October 12, 2016, 04:42:59 PM

MM,

I PM'ed you. Guess I'm on your ignore list and you forgot.

You're not on my ignore list and you've got mail.

MM

Steve Helmick · « **Reply #13 on:** October 13, 2016, 04:41:00 PM »

I would re-draw for straight ribs and stack cut them, like I did in the olde days. I don't think the torsional rigidity is likely to be significantly different. The extra couple of ribs won't weigh much more, especially with your moldy balsa.

Steve

Motorman · « **Reply #14 on:** October 14, 2016, 04:50:13 PM »

That would be interesting as the airfoil shape is different from root to tip and it tapers in thickness.

MM

Dan McEntee · « **Reply #15 on:** October 14, 2016, 05:58:47 PM »

Quote from: Motorman on October 14, 2016, 04:50:13 PM

That would be interesting as the airfoil shape is different from root to tip and it tapers in thickness.

MM

And why would that present a problem? Stack sanding ribs has been around since the Dead Sea was sick. Lots and lots of articles in the old magazines only showed a root and tip rib for stack sanding. It's been described here on the list several times in great detail.
Type at you later,
Dan McEntee

Brent Williams · « **Reply #16 on:** October 15, 2016, 03:49:44 PM »

You could probably have John Miller set this up for you in compufoil to adjust the spar size, sheeting thickness and trailing edge dimensions.

Tim Wescott · « **Reply #17 on:** October 15, 2016, 04:17:40 PM »

Quote from: Motorman on October 14, 2016, 04:50:13 PM

That would be interesting as the airfoil shape is different from root to tip and it tapers in thickness.

MM

The nice thing about stack-cutting is that it automatically takes care of that for you. Each rib ends up being tapered, so before you start sheeting and cap-stripping you need to (carefully) run over the whole wing with your longest sanding board, then you're good to go.

I agree with Mark that it's valid that RSM may view doing a smaller-than-normal set just for you is more work than it's worth. First, even if they just took what they had and shrunk it, and accepted that there'd be a lot of wasted balsa around the edges and wrong-sized spar notches, it would be a lot of machine set-up time for just one set of ribs. I strongly suspect that RSM normally cuts kits in larger batches than that. Second, doing special one-offs like this can end up biting a manufacturer in the ass -- projects don't always get finished, and when you do a special-order like this it can get forgotten that it was, indeed, special order -- but no one ever forgets who it came from. This happened to my dad's company often enough that he wouldn't do a custom job on production parts unless he had confidence in the people it was going to, and he never, ever, let factory seconds out of his hands.

For next time, consider getting a set of Legacy 40 wing ribs from Brodak -- they're all cut & ready to go, they're the right size, and now you know how to make the leading edge sheeting.

Motorman · « **Reply #18 on:** October 15, 2016, 09:40:51 PM »

I've been looking at that legacy 40, is that geodetic?

MM

Tim Wescott · « **Reply #19 on:** October 15, 2016, 10:43:56 PM »

Quote from: Motorman on October 15, 2016, 09:40:51 PM

I've been looking at that legacy 40, is that geodetic?

Nope. Plain old straight ribs.

If you're just bound and determined to do geodetic, then you probably need to keep going the way you're going. Or apply to Bob Hunt for a lost-foam set with geodetic ribs.

Steve Helmick · « **Reply #20 on:** October 16, 2016, 09:42:50 PM »

Quote from: Dan McEntee on October 14, 2016, 05:58:47 PM

And why would that present a problem? Stack sanding ribs has been around since the Dead Sea was sick. Lots and lots of articles in the old magazines only showed a root and tip rib for stack sanding. It's been described here on the list several times in great detail.
Type at you later,
Dan McEntee

Yeah! Much like a foam wing, in fact. Only slice the foam core into 1/16" or 3/32" thick sheets every couple of inches or so, and there you have it. Add spars and stuff and you have a wing.
Except foam ribs suck.

Steve

Motorman · « **Reply #21 on:** October 17, 2016, 07:35:14 AM »

Stack sanding ribs wouldn't make the job any easier. You still have to cut them all out.

MM

Fredvon4 · « **Reply #22 on:** October 17, 2016, 09:31:56 AM »

This seems a good thread to ask an ignorant question...

But first:

I copied a LOT of ribs in my life...none for geo wings.

However many for swept, tapered, thinner....and obviously a constant chord set is very easy doing stack sanding inside of two templates

I have never traced and CUT any set of "one at a time" rib sets and the truth is--- today I would pay anything for a good set of perfect laser cut ribs....and in fact have bought a few rib sets

Any Way... for years now I read these "how to do it" CAD or other discussion on ribs, cutting or design....

The question....what is meant by the term "Lofting"?

Trostle · « **Reply #23 on:** October 17, 2016, 09:34:47 AM »

Quote from: Motorman on October 17, 2016, 07:35:14 AM

Stack sanding ribs wouldn't make the job any easier. You still have to cut them all out.

MM

Huh? The reason for "stack sanding" ribs is that the process ends up with a set of ribs where each rib is properly tapered and shaped without the need to cut out individually shaped ribs with the inherit inaccuracies involved. Yes, it is necessary to sand the beveled edges but that is no worse than the need to sand the laser burn marks from laser cut ribs.

Just saying.

Tim Wescott · « **Reply #24 on:** October 17, 2016, 09:40:03 AM »

Quote from: Motorman on October 17, 2016, 07:35:14 AM

Stack sanding ribs wouldn't make the job any easier. You still have to cut them all out.

You haven't stack-cut ribs, I see.

Make tip and root templates
Cut a bunch of blanks
Bolt the blanks together in between the templates
Carve the stack to the shape of the blanks (finishing by sanding)
Build a wing

It's only a bit more tedious than cutting out a bunch of same-sized ribs with a good template. The only challenging part, if you're going to jig-build the wing, is getting the second jig hole accurately drilled in all the blanks, and even that's quite doable if you've got a good drill press and the skills to go with it.

I'm sure that there's directions somewhere here on this site, if your search skills are good. Being a compulsive Googler, I did that: this page may not be the best description, but it's certainly describing what I do.

Mark Scarborough · « **Reply #25 on:** October 17, 2016, 09:41:18 AM »

Lofting is pretty much a mathematical process to generate the curved line of the rib,
you will get a table of values of which there will be two( or three if its asymmetrical), the first is the distance along the datum line from the origin, the second is the distance off that datum line. It plots a point, there will be multiple points plotted which then you use standard drafting techniques to join the dots and create the profile

so point one might be .10 .23 this means you move down the catum line .1 inches and then offset above the line .23 ( its a positive number so its above, if its negative its below)
there will be a whole batch of these coordinates. If you want a rib that is different than 10 inches ( kind of the defacto baseline length) then you multiply all coordinates by a variable to arrive at the length you want.
For example if you want a rib that is 20 inches long, you multiply all the numbers by "2"

If you want a rib that is 20 inches long but only half as thick, you multiply the first number by two and the second you use as is for half the height,,

Its a lot simpler than it sounds, but it does involve math. You can plot points i CAD then connect them with a spline.. or you can plot them manualy and connect them using proper drafting techniques and a french curve set

Motorman · « **Reply #26 on:** October 17, 2016, 10:44:14 AM »

Now I think of it stack sanding is a little more work if you have to sand the angle off each one. It's academic anyway since this wing is geodetic. You just cut them out and sand down to the ink line. Still allot more work than a laser cut set.

MM

Fredvon4 · « **Reply #27 on:** October 17, 2016, 12:07:45 PM »

Mark

seriously sir, I sincerely appreciate the time it took to craft the response

I think some should understand I am NOT a math wiz, nor an aero engineer, or in any way considering experimenting with airfoil shapes

So I have to ask...considering the hundreds of proven designs, aspect ratios, moments, relative distance and empennage size ratios, designed engine, power, and moment, gyroscopic precession, etc etf

So other that designing some new airplane why is any of this necessary other than as a mental exercise?

OK I re-read this before posting and have to admit...many things are worth the mental and curiosity exercise...

Does it count that I found the Dick Mathis or Howard Rush airfoil real good and used it to make my own bastard aircraft?

Tim Wescott · « **Reply #28 on:** October 17, 2016, 12:13:26 PM »

Quote from: Motorman on October 17, 2016, 10:44:14 AM

Now I think of it stack sanding is a little more work if you have to sand the angle off each one. It's academic anyway since this wing is geodetic. You just cut them out and sand down to the ink line. Still allot more work than a laser cut set.

Perhaps more work than getting a laser cut set from someone else -- but if it was less work in all, you'd have sent your .dxf files off to the laser cutter by now and wouldn't be asking questions here.

Mark Scarborough · « **Reply #29 on:** October 17, 2016, 12:49:48 PM »

Quote from: Fredvon4 on October 17, 2016, 12:07:45 PM

Mark

seriously sir, I sincerely appreciate the time it took to craft the response

I think some should understand I am NOT a math wiz, nor an aero engineer, or in any way considering experimenting with airfoil shapes

So I have to ask...considering the hundreds of proven designs, aspect ratios, moments, relative distance and empennage size ratios, designed engine, power, and moment, gyroscopic precession, etc etf

So other that designing some new airplane why is any of this necessary other than as a mental exercise?

OK I re-read this before posting and have to admit...many things are worth the mental and curiosity exercise...

Does it count that I found the Dick Mathis or Howard Rush airfoil real good and used it to make my own bastard aircraft?

well, there are many articles from the past that reference using the side of a shoe to draft the airfoil.
that said, if you know how to do this, then you can accuratly translate my 700 square inch airfoil to your 500 square inch airfoil and get the proper plot.
is that what you always want? not as a strict rule, there are a lot of other factors.

My simple answer, meant respectfully , if you do not know how to perform this, than the airfoil data associated with accuratly lofting ribs is probably wasted on you and you would be better to take someones design, copy ALL the relevant datum points, and change the shape of the rudder, wing tips, and elevator/stab tip shapes but leave everythign else the same.

a stunt airplane is a SYSTEM of *hopefully* carefully selected parameters, and changing one parameter can have unanticipated affects on the outcome.
I use an Impact as my basis of design, I change the turtledeck shape, the rudder/vertical shape, wing tips and stab tips, alter the nose length slightly because I tend to build and finish a bit tail heavy, so I lengthen the nose ever so slightly and poof there is my "design"

Fredvon4 · « **Reply #30 on:** October 18, 2016, 07:56:11 AM »

Mark that was an excellent reply and I appreciate it

I had not considered the rescaling aspect or for that matter applying the technique to the task as you described in the last part of you post

Thanks for taking the time to educate me

Motorman · « **Reply #31 on:** October 18, 2016, 09:53:04 AM »

The way I reduced the airfoil was to pick the wing area I want (575) then calculate the basic root, tip and span that gets me there with the same aspect ratio ect as the full size plane. Once I have the root chord, I trace out all the ribs from the (630) plane on paper and go to the copier. You get the copy reduced and measure the ribs to confirm. Sometimes you have to make a few trys before you get the size just right but you can make any size wing you want. In my case it was "Set the copier at 92% please".

If you have some kind of digital file of the ribs you can effect it that way, I don't. I do have a full sized set of laser cut ribs. Is there anybody who can digitize them, reduce the size and then laser cut a smaller set? Seems like a good business opportunity to make all different size planes of famous designs.

MM

Mark Scarborough · « **Reply #32 on:** October 18, 2016, 10:11:48 AM »

Quote from: Motorman on October 18, 2016, 09:53:04 AM

The way I reduced the airfoil was to pick the wing area I want (575) then calculate the basic root, tip and span that gets me there with the same aspect ratio ect as the full size plane. Once I have the root chord, I trace out all the ribs from the (630) plane on paper and go to the copier. You get the copy reduced and measure the ribs to confirm. Sometimes you have to make a few trys before you get the size just right but you can make any size wing you want. In my case it was "Set the copier at 92% please".

If you have some kind of digital file of the ribs you can effect it that way, I don't. I do have a full sized set of laser cut ribs. Is there anybody who can digitize them, reduce the size and then laser cut a smaller set? Seems like a good business opportunity to make all different size planes of famous designs.

MM

It gets back to the same thing again, return on investment, if a competent draftsman did this you can expect a few hours to resize it, make the spar notches correct, rework the plan sheet appropriately and all of this on someone else s design. That is assuming you can get a copy of the original CAD file to start with otherwise you are talking MANY hours to redraw it ( moral issues here for infringing on artistic copyrights) and he could expect to sell how may rib sets per size?
To be a business opportunity there needs to be potential profit, I just cant see there being enough demand for a re-scaled impact to justify the labor to redraw it, UNLESS the customer was willing to cover the cost. My time sitting at CAD desk is worth at the least 45 or 50 bucks an hour, so if it takes three hours, thats 150 bucks. How many rib sets will I have to sell to recoup any of my labor? thats the problem,,
There are guys who do it purely for the love of doing it, I used to, but now I need every scrap of time to build my own airplanes and to take away from that I either need to get paid/compensated, or owe someone for something. Not to be discouraging, just realistic

Brent Williams · « **Reply #33 on:** October 18, 2016, 10:49:03 AM »

If you are hoping to reduce the Thunder Gazer from its 630 sq in to 575 sq in, then you haven't finished the entire math formula if you stopped at 92%.

You need to take the square root of 92% to get the actual percentage to scale down the the entire aircraft.

In your case, 575/630 = 0.91269

Now take the square root of 0.91269 √0.91269 = 0.95535

So, if your desired wing area for your plane is 575", then you would need to reduce the Thunder Gazer plans by 95%, not 92%

A 92% reduction from 630" is actually 535 square inches.

535/630 = 0.84920
√0.84920 = 0.92152
Thus 92% = 535 sq in.

Motorman · « **Reply #34 on:** October 18, 2016, 11:58:42 AM »

All I know is a 92% copy of the ribs at Sir Speedy makes a 575 sq. in. wing. Check how the flap hinges are right where the ribs come together at the TE. Love geodetic.

Quote from: Mark Scarborough on October 18, 2016, 10:11:48 AM

There are guys who do it purely for the love of doing it, I used to, but now I need every scrap of time to build my own airplanes

I know how that is, I helped allot of people for many years. I recently stopped doing favors and jobs where I make $5 an hour. It's funny how many friends you loose after that.

MM

Avaiojet · « **Reply #35 on:** October 18, 2016, 12:04:59 PM »

Quote from: Brent Williams on October 18, 2016, 10:49:03 AM

If you are hoping to reduce the Thunder Gazer from its 630 sq in to 575 sq in, then you haven't finished the entire math formula if you stopped at 92%.

You need to take the square root of 92% to get the actual percentage to scale down the the entire aircraft.

In your case, 575/630 = 0.91269

Now take the square root of 0.91269 √0.91269 = 0.95535

So, if your desired wing area for your plane is 575", then you would need to reduce the Thunder Gazer plans by 95%, not 92%

A 92% reduction from 630" is actually 535 square inches.

Why not just take the wingspan of the model and decide on the span of the model you want? Then do the math.

I reduce the size of models all the time just changing the wingspan. Shrink or expand, every measurement goes along with it.

Motorman · « **Reply #36 on:** October 18, 2016, 12:21:02 PM »

He's figuring area off of percentage and coming up with a conversion factor. I get it but, I just take a couple of guesses until I get the size I want. Not as brainy but it still works.

MM

Brent Williams · « **Reply #37 on:** October 18, 2016, 12:29:49 PM »

A square root is a math function. (we're not talking about the root airfoil shape here )

2 squared is 4
The square root of 4 is 2.

Because your are wanting a reduction in specific Square inches, You must take the square root of your simple ratio reduction to get the actual reduction percentage.

I hope this hasn't come off as overly snarky, as I do quite like your concept of a reduced sized Thunder Gazer. Just understand that you haven't built a 575" plane....you have built a 535" plane at your 92% reduction rate.

Mark Scarborough · « **Reply #38 on:** October 18, 2016, 12:32:46 PM »

Quote from: Avaiojet on October 18, 2016, 12:04:59 PM

Why not just take the wingspan of the model and decide on the span of the model you want? Then do the math.

I reduce the size of models all the time just changing the wingspan. Shrink or expand, every measurement goes along with it.

no it does not actually, if you care about square inches or any volumetric function you MUST take all factors into account, IOW wingspan, and MAC to get area. Note that area = width times length, it does NOT equal length

Bob Hunt · « **Reply #39 on:** October 19, 2016, 06:55:26 AM »

Well, first you are not talking about geodetic ribbing; you are talking about Warren Truss ribbing. In a geodetic wing the ribs intersect at least once. Think of an egg crate. The Warren Truss ribs are indeed angled, but they do not intersect.

Secondly, an easy way to produce perfect ribs for a Warren Truss wing (or for a geodetic wing) is by the use of the Lost-Foam process. The name is a misnomer; the foam is not actually lost. In this system the foam wing blanks are marked for desired rib positions for a built-up wing, prior to being cut into a wing shape. Once the core is cut, the rib positions can be marked accurately onto it and labeled, and they can also be marked and labeled in the lower cradle section, which is just as accurate a negative representation of the wing’s lower airfoil as the core is a positive.

The core can then be cut up into extremely accurate rib stations to be used as templates for generating equally accurate balsa ribs. An absolutely perfect built-up representation of the original foam core shape can then be assembled in the lower cradle half, which becomes a form-fitting building fixture.

Note that not only does this system produce ribs that have perfectly accurate side view shapes, but also ones that are accurately shaped when viewed from above (taper at the leading edge to fit the molded shell that will be added during construction), and from the front (thickness taper). Not even laser cutting can achieve that! At least not the type of laser cutting that we are used too…

We have made hundreds of these wings, and at least two of the models built with them have won World and Nats Championships. David Fitzgerald’s Thunder Gazer wing and Bill Werwage’s P-47 wings were built using this system. And, it can be easily adapted to make fully-sheeted built-up wings.

The accompanying photos should tell the story. If you’d like more info with lots more photos, please email me or call me.

Later - Bob Hunt

Bob Hunt · « **Reply #40 on:** October 19, 2016, 06:59:46 AM »

Here are a couple more photos of the Lost-Foam process. One shows the sanded rib on the foam template better than the one in the above post.

Later - Bob

Bob Hunt · « **Reply #41 on:** October 19, 2016, 07:06:51 AM »

Here are a few photos of Warren Truss wings that were built using the Lost-Foam process. Easy peasey.

Bob

Tim Wescott · « **Reply #42 on:** October 19, 2016, 11:19:09 AM »

Quote from: Bob Hunt on October 19, 2016, 06:55:26 AM

Note that not only does this system produce ribs that have perfectly accurate side view shapes, but also ones that are accurately shaped when viewed from above (taper at the leading edge to fit the molded shell that will be added during construction), and from the front (thickness taper). Not even laser cutting can achieve that! At least not the type of laser cutting that we are used too…

Surely by now someone has made a 4-axis laser cutter that'll tilt the laser head to achieve this. Then we can have "lost digit" wings that go together as nicely as yours.

Randy Powell · « **Reply #43 on:** October 19, 2016, 01:56:50 PM »

Yea, get on that, Tim.