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Building Tips and technical articles. => Building techniques => Topic started by: Randy Powell on February 20, 2008, 10:17:58 PM

Title: Rib Cutter for Mark Scarborough
Post by: Randy Powell on February 20, 2008, 10:17:58 PM
Mark,

Here are some pics that make the rib strip cutter pretty clear. If you have any questions, just ask. As you can see by the second from the bottom pic, this base has been used before. More than once. For a new rib template, I just take the pins and plywood off. Sand it and make new locations. Works fine overall, though as I said, I wish I would have used a standardized template size overall so I didn't have to always modify the base. But, it works.
Title: Re: Rib Cutter for Mark Scarborough
Post by: Mike Lauerman on February 21, 2008, 10:42:52 PM
Hi, Randy.
When you talk, I listen. 'Scuse me, Mark...can I just squeeze in here for a second? Sorry...
Now, Randy...when you make the first cut, do you move the material up 1/4", or the template down? (is the template pinned?) Thanks.
Excuse me, Mark...just let me back out of here...thanks...
Title: Re: Rib Cutter for Mark Scarborough
Post by: Randy Powell on February 22, 2008, 09:04:58 AM
Hi Mike,

I make the first cut on the blank before putting it in the jig. Square up the template on the blank and cut the rib shape. Then put the blank in the jig, push it up against the top stop. That will leave about a 1/4" of material between the top stop and the template. Cut along the template and you have a 1/4" strip rib. Pull the rib out and slide the blank up against the top stop and repeat.

Usually when the blank becomes small enough that it is entirely behind the template, I use a piece of scrap wood or another blank to maintain the pressure on the cutting blank. Remember, it takes two strip ribs to make on full rib, so you end up cutting a lot of strips. Boring, but easy
Title: Re: Rib Cutter for Mark Scarborough
Post by: Mark Scarborough on February 22, 2008, 09:47:46 AM
Thanks Randy
I think I finally got the picture. sorry it took awhile, I have been spening time with my Son who is on leave from Iraq. Hes here for a few days and we are really having a good visit. Last night he kicked my booty playing Medal Of honor on the PS2, well um yeah hes pretty good, or I suck! fun was had. Hopefully when he gets back stateside I can corrupt him into building some models. Hes artistic and loves to do hand type work so maybe?
anyhow, I like the jig, you mention that you wished you had started out "standardizing" it?  What are your thoughts there, heck why make your mistakes , I can make myown, so I may as well start off right.
Title: Re: Rib Cutter for Mark Scarborough
Post by: Tom Niebuhr on February 22, 2008, 09:55:27 AM
I use the same type of jig. It is detailed very well one the Hunt/Werwage video on building I-beamers
Title: Re: Rib Cutter for Mark Scarborough
Post by: Randy Powell on February 22, 2008, 01:31:38 PM
Tom,

Man, I may have to get said video. I've heard enough about it.   ;D

Mark,

Just that I wish I had made all my templates so that the front and rear pins were in the same place. Would have cut down on the 6 or 8 bases I've had to make to accomodate various templates. Not a big deal, but a minor niggle.
Title: Re: Rib Cutter for Mark Scarborough
Post by: john e. holliday on February 23, 2008, 08:41:18 AM
Randy, I notice the flat on the leading edge of the rib.  Is that what the notch on the jig is for?  Also do you make that cut before moving the blank up in the jig?  I am going to steal your idea as the jig I make usually has the rib deeper at one end than the other no matter how much sanding/filing I do on it.  DOC Holliday
Title: Re: Rib Cutter for Mark Scarborough
Post by: Randy Powell on February 23, 2008, 02:14:09 PM
Doc,

This was just a specific application. The slot on the template is because the ribs are attaching to the leading edge horizontally instead of vertically as is more normal. And yes, I do the little horizontal cut first then move the blank up and make the airfoil cut. As with a lot of my wings, it's a tedious process.

One of the things I've discovered (probably more about myself than the actual building process) is that I can't build one of these wings in one or even 5 or 6 sessions. I build on the wing a bit, then work on something else. Go back and do some more on the wing and jump to something else. While this sort of wing isn't very complicated, it is just tedious as heck. Have to do it in small bursts.
Title: Re: Rib Cutter for Mark Scarborough
Post by: john e. holliday on February 26, 2008, 08:35:54 PM
Makes for great looking construction.  Too bad it has to  be covered up.  I know when I flew combat and some stunt planes I would use the transparent covering(silk) to cover the planes.  DOC Holliday
Title: Re: Rib Cutter for Mark Scarborough
Post by: Randy Powell on February 27, 2008, 09:00:14 AM
Hi Doc,

Yea, one of these day, I'll take the time to insure the interior construction is clean (no nicks in wood or bits of wood from band sawing hanging around) and the good, clean looking joints, then I may try a transparent sort of finish. Build up clear with no filler coat then shoot tinted dope. That always looks kinda cool.

One of these days.
Title: Re: Rib Cutter for Mark Scarborough
Post by: Bill Little on February 27, 2008, 11:40:56 AM
Hi Randy,

I threaten myself with doing another transparent/translucent finish!  But, so far, I have only done it on small planes and OTS/Classic builds.

I always loved the look of Jim Lee's Sunflyer! (sp??)  (then again, I love a lot of planes Jim has built over the years! LOL!!)