ETLB Squawk Forums — Archive

Here is my new Rib-o-mattic.  I wanted a rib jig that allowed me to clamp the gussets without having to use staples.  Also wanted to make sure the rib didn't get stuck to the jig.  I also wanted to strengthen the back of the rib where the wing meets the aileron.

to do this I made one gusset that would go from top to bottom of the back of the wing.  it also has a curved part on the back so that when I build the wing and want to enclose the back of it with 1/16 ply I will be able to glue it to the curve.

because there is a double thickness of cap strip at the back of the wing I had to make those small cap strips and the special gusset in a separate jig then use that in the Rib-o-mattic.

and here are a few more pics

great idea keep up the good work
skydragon,

Brilliant! Love it!

Peter, Kindly post this at sticky ETLB Tip of the day. Neat and extraordinary idea.
Keep up the good work!!
Regards,
Phil

you wouldn't happen to have a CAD drawing that we could take to get blown up to proportional sizes? i still have 10 ribs to go!
cheers.
Eric.

Fantastic idea. If you have a .dxf of that I could take to a cnc machine I would be very grateful. I've finished my ribs on the current build but intend to build at least 1 more max before I'm done  

Andy

Thanks for all the kind words.  Sorry but no dxf files.  I made it the old school way.  I just used the rib drawing from the plan and transferred that to a piece of 3/4 ply. then cut out the places the cap strip was supposed to be with a 5/16 bit.  Then removed the parts where I would need to clamp.  I've just made two ribs with it so far but it seems to work well.  The second rib only took 10 to 15 min.

I've been watching Peter's progress with no small amount of envy, a truly revolutionary rib jig.  Great work Peter!  Good job posting thos pics too.  

Andy you never want to switch jigs half way through your project, just keep rocking and rolling with the one you have.

I know my next plane will have the ribs built in one like Peter's

I have one small concern (or question). I know those clamps have quite a bit of clamping power in them. Aren't you worried about starving the joins of epoxy by squeezing a lot of it out?

I've been using clothespins on the back side gussets for my ribs.  They do squeeze out a little but the ribs seem very strong and I destroyed one just to be sure and the wood broke, not the glue.  

Not sure about those big spring clamps, they do exert more pressure than clothespins.

I've seen folks use those clamps on fuselage construction etc.

when i was reparing the damage to my elevator..the A&P i took it to told me to get those exact clamps. he has built a lot of planes and it currently working on a full sized spitfire made completely from wood.  so i would venture you are ok using those.

Hi Peter;
All I can say is, outstanding work! Keep posting pictures.
Bob

This looks like THE way to make ribs.

I think I might order a prebuilt rib, then use it to precisely emulate your rib o matic.

I would slap a TM logo on that thing asap before the team gets wind  

Hell I'd buy one. 10-15 minute build time sounds alright to me!

or go in cahoots with team and sell the jigs through them....might be a way to fund your max that way.

Brilliant idea!

You guys are too kind,  Seriously though If Dave wanted to make them and sell them it would be fine with me.  I would be happy to contribute something to the cause.  I do think it handles a number of issues that makes making ribs easier.  Since it is just made of 3/4 ply and could be cut on a cnc machine, I could see dave just having a bunch cut and selling them on his website or including them with kits. (I wonder if he is listening)

Oh I think he does,lol

I would buy a CNC cut rib jig like the Rib-O-Matic as soon as Team started selling them.  The ability to clamp everything in place on both sides in one pass is a huge time saver.  It is also much less messy to work with than the standard jig.

Tom

Peter, First off thanks for the permission to use the Rib-O-Matic idea. We will work on cost and labor time to see What we could sell them for or include in a rib kit , or complete kit.  We would probably make a couple minor changes. Add a logo, Change material to Acrylic.

On another note: I see you did not cut the optional triangle edge off your gussets, You save more weight in the finish build than you may realize.

Thanks again.
David Cooper
AKA: theecoop

Hey Dave,  

No Problem. Acrylic would be nice because glue doesn't stick but that is why I removed the places where glue does stick.  Also acrylic is so expensive, but I'm sure you will work all that out.  As with any new device they always need a thorough trial run.  I realized after the second rib that I had to set the distance that the sticks come out the back.  But I just wrote some notes on the jig now that issue is fixed.

I also am wondering how well just staples would hold.  Since I can get to both sides I think I'm going to try gluing up a rib with staples then just taking it out to dry.  I suppose as long as the staples hold I'd be good, then I wouldn't have to wait a day in between each rib.

Another thing I noticed is that because the jig holds the  pieces so accurately I took 24 cap strips and stacked them as a pile of 4x6 together, then put a zip tie on one end.  then I just measured and gang cut all the sticks for all the ribs at once. I think that saved a lot of time and adds to the accuracy because every part is the same for each one.

I'm sure your right about gussets. I'm going to make some rib's today.  I'll cut the extra material off the gussets for one rib and weigh them.  be interesting to see how much it is.

Peter

I like the jig made of wood.  It would be cool to brand the minimax logo in with a hot iron, wild west style.  Thanks Peter for being so selfless and contributing to the community like this.  

Dear Mr. Cooper,

Acrylic would be nice and stable and would CNC cut well.  I'm not too worried about the material, though.  CNC cut, the labor should be low enough so that you could make a really good profit and still have the price not be something that people would hesitate over.  I'd vote for selling them both separately and with the kits.  There's always going to be people who are just sure that scratch building will be cheaper, though I sure don't see it.  I'll by the kit everytime.  But I do know the Rib-O-Matic would save a LOT of time and time is the scarce resource for so many of us.  This has got to be a good thing to do.

Tom

So far I've found scratch building to be more expensive.  Hard to beat the kits in most cases.

Hello, can I buy the files to cut out the Rib-o-Matic !

Rgds Erkki

Erkki, you might be 11 years too late!

Bruce

it's never too late up until you stop trying.

Erkki, I have done something very similar to peter, without the extended gusset at the aileron connection.  I had my rib-o-matic jig CNC cut from a CAD file that I made and I will be happy to share it. It worked well for me.  Send me a PM with your email address and I'll send you the CAD file.