Twister help request.

Gents,
I wonder if anyone could trace and scan a Twister factory wing rib for me? I only need a section of it actually. From the spar forward to the leading edge. Just planning a retro-fit of "partial ribs" between the full cord ribs on my ole rebuild protect. I'd appreciate if you could also include some form of scaling device in the picture,..like a rulers edge or something. Then I can be sure to get the size correct when printed out on paper. [email protected] is the addy. Thanks.

I could copy one on a copy machine and mail it to you if that would help. On the other hand, since this is a constant cord wing with a flat tip, couldn't you just lay the outboard tip on a piece of paper, draw around it, and then mark out where the leading edge and spars go?

>Gents,
> I wonder if anyone could trace and scan a Twister factory
>wing rib for me? I only need a section of it actually.
>From the spar forward to the leading edge. Just planning a
>retro-fit of "partial ribs" between the full cord ribs on my
>ole rebuild protect. I'd appreciate if you could also
>include some form of scaling device in the picture,..like a
>rulers edge or something. Then I can be sure to get the
>size correct when printed out on paper. [email protected]
> is the addy. Thanks.
>
>
>Tony

Tony;

I have it in CAD, and can send a .pdf to you if you'd like.

LAST EDITED ON Nov-04-03 AT 11:02 AM (CST)
 
Tony,

When I built the TwistMaster I used sliced ribs for the half ribs, aka Tom Morris. If you still have the kit scrap you have the light ply from the doublers to use as a pattern. The sliced ribs weigh nothing and once the jig is made are much easier to cut than full half ribs. If you want more info I can find the jig I made and post a picture.

You can get a piece of balsa, open a diagonal half square notch on the center of one of the sides and remove materia fro, the other side untill it fits nicely between the LE and the spars.

Then you put it against one of the ribs, use a pen, and you have the airfoil

God bless you!

In Christ,

Leonard,Bob,Bob n Ion,
As Ricky Ricardo was wont to say I got some "esplain'n to do" in regards to my request. To that end I say this. The kit scraps are long since gone. I built this Twister back in 1983/84. There's no trace of the box or anything related to the build. Leonard the picture below kinda gives up info related to why your idea about tracing the wing tip shape would kinda' not worked so well. Bob R,..yup like the look of your partial cord ribs very much. I'll go that route if I can get them in there. Bob. K, thanks for the pdf file, beautiful picture you sent which should work fine. I knew someone had the stuff on file.

Thanks gents.

Bob Would you send me the pdf cad file of the twister rib.

Thanks Eric A

OK, now that I see the plane, tell me again why you need rib templates? Did something break or something? It looks like some heavy built wing tips. Larger wing area but not longer tail moment or larger tail size. Beefier nose. Oh, and with the leadout slider buried so far in, you are going to have a wear spot where the leadouts exit the tip since they will flex up and down.

Leonard,
Beefy tips, yes to look at them, but they are very light in fact. Final sanding is not complete as yet either,..they will get lighter still. Agree, L.O. slider will impart some wear and tear. I'll tape that edge as needed. Tail moment is in fact 2 inches longer. Elevator/Stab span has been increased by 2 inches over stock. (This may be what helps fool the eye?) Nose tripler has taken shape as a semi-cowl install. I think this trianglulates the nose to the LE better then a tripler install. Flap area is also over stock size. Re: Ribs. I'll be installing part ribs as Bob R.'s picture shows to help take some of the droop out between the factory ribs, at least that's the plan if I can fit them. No way will this thing be a comp flyer,..that's not the intent. Just pushing the re-contruction limits a bit. Over kill? yeah I guess so.

LAST EDITED ON Nov-04-03 AT 11:53 PM (CST)
 
Tony,

I, like Leonard, am confused. Why do you want/need partial ribs when the leading edge is sheeted? Is the sheeting so weak that you have a lot of sag in it between the existing ribs?

I am not being argumentative here, I just really don't know the answer.

OS,
Yes the sheeting is rather weak/thin in the leading edge area's. The wing is the original from the 1983/84 build which survived the crash (not wallstreet) of 1998. Everything else is new. As with most, during the rebuilding process I've run the sandpaper across the wing the odd time or two as I've progressed. The sheeting is rather wavy between the ribs but doesn't show as such on the picture. I'm sure the covering and finish will help beef up the sheet structure to some degree but perhaps not enough to give me any comfort. Hence the install of the part ribs.

I have a feeling that since you didn't use a portrait lense that the camera close up is doing strange things to the picture and giving the impression that the wing is longer than it truly is. On the leadouts, if you put some 1/64 plywood top and bottom in the slot, it will help things, but it really would be better if the slider could be mounted closer to the outside of the tip.

Leonard,
Once again I agree. Camera in telephoto mode plays with the eye's. Actual span with the new tips runs to 53 1/2 inches. It's clear by now that this re-build has gone from "rebuild as once was" to "Gee, maybe I'll install a slider? Oh how bout a weight box? Lets increase the tail volume some,..how bout those wing tips never did really like them wing tips did I". Nothing has been done in a fashion that would allow the whole to come together as a complete package as it were. Poor planning on my part, or lack of insight? None the less forward (at a snails pace) it goes. Lite ply at the L.O. exit is a good idea, "Make it so" as Capt Piccard would say.

Here is just the thing. It's called a contour gauge. Consists of a bunch of pins in a line that are trapped in a holder. You just push the pins against the part to be duplicated and you have a pattern. The pins move in and out to conform to the contour of the part to be copied. They have them at Harbor Freight, though I couldn't find it on the website. McMaster Carr cataolg shows one for 12 bucks.

For example, I recently used mine to make fuselage doublers for the Flite Streak to extend past the leading edge. If you haven't noticed, for that ARF the designers cleverly saved material by having the original doublers end at the front of the wing. A sort of designed in weak spot made more effective by making the fuselage hollow! Yes, I confess I done broke it, loop on takeoff. That's why I'm the pit crew and not the pilot.

John in the PRC

bigR,
Duh! I've got one of them in the tool box. Never even thought of that one. Thanks.

Shame on you, Tony!

BTW, I've been wndering how you built that Junar without the plans...

How did you do that?

God bless you!

In Christ,

Although I understand the desire to use half ribs on an unplanked Twister wing leading edge, it's clearly an overkill when planking is added.

The stock Twister wing construction, without half ribs or leading edge planking, is more than adequately strong, even when covered with a plastic film. It may not be gorgeous, but it is elegant in its simplicity. In addition, it is very easy to build and not difficult to keep straight, even without a jig. It is also a good airfoil.

Mike Gretz is to be commended for its design.

[photo not recovered: 3e69bb3870f12ad5.jpg]

"Let us not be too particular; it is better to have old secondhand diamonds than none at all." -Mark Twain