Cub Man

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I’m looking to build the tail feathers on a ¼ scale cub to scale by using either dowels or aluminum tubing. Been searching for info on such a build but I’m coming up with nothing. So I’m looking for feed back from you.

cyclops2

Your choice of words gets critical when you say SCALE CUB.

Should be same shapes, # and material.

Real scale is only one way.

Scale appearing, is, anything goes on out of sight.

Most judges only look for scale appearing. TRUE scale quickly becomes a argument.

Cub Man

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I see I 'm looking for scale appearing.

BobH

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A good way to "simulate" tubing is to make a jig in the shape you desire. This can be a simple one and not complicated. Use laminated balsa to provide the curve and thickness you desire. The laminated balsa is made up of thin strips glued togather with tite bond or similar glue. These can be wetted and pinned to your jig.. The jig can be just ply cut in the desired shape. Once dry sand to a rounded shape and your all set.

badger41

cub man ,
for the tail surfaces with all the curves, the best way to go is to laminate with thin layers of bass wood or spruce. I just finished balsaUSA kit and was not happy with the way the balsa parts flexed and warped even after covering so very carefully. Had to cut out the stab and elevator the vert fin and rudder and redo them in the laminated way. I should have done it that way from the get go. But I am very happy with new parts .
I simply put wax paper over the plans measured back from the outside edge of the scale outlines about 3/8 " and put some thin nails about 3/4 ' apart to form the inside edge . Next step was to make the wood soft enough to follow these out lines. The local hobby shop had the bass wood in 1/16"x3/8" made that part easy . An old pvc pipe was closed off on one end and filled with automotive windshield washer fluid and all the wood was put inside and kept submerged ,next day all the wood acted like noodles. Very easy to shape to the inside nails . I liked the pva glues ,Titebond,Elmers carpenter etc. .
Don't cut any of the sticks till dry later,and you will find that having them full length will make the forming go much easier. Yes it looks pretty crude with all that glue all over ,but when dry and shaped you will never again go back to flat stock and and sticks.
Best of all talk about strong and round,no warps no trim changes due to fabric strech and best of all it really looks good . try it!
tom

badger41

I guess side stepping the jig and simply using the nails would be easy

Idigbo

Cub man, go for it in ali tube for the outlines, but use dowel for the elevator leading edge and the tailplane hinge spar, works a treat. At the inboard ends of the tube, where they plug into the fuselage, they need strengthening with a sleeve of tube or such like. Epoxy or CA work very well to glue aluminium to balsa and hardwoods. I had the same structure on a 1/4 Cub, 1/3 Baby Great Lakes, 1/3 Tiger Moth and an under construction 1/3 L4 Cub, which also has light gauge steel tube for the cabin area of the fuselage. Using dowel for the whole structure would be quite heavy, also hard to do with the curves of the Piper tail surfaces. The tubes can be bend round an MDF, or chipboard former, or something similar, with the former on the inside, or the tube can be easily distorted. When bending the tube around the former, always pull it round with a bit of tension, this will stop the tube from kinking, and will result in a nice smooth even curve. When covering, it may be neccessary to wrap the tube with fabric (like they do on the full size) to help the fabric adhere to the tube structure.

On smaller structures, say 1/6 scale, outlines can be made using ' basketry cane', which is strong but flexible, and can be bend round shapes (about 40mm radius) without breaking.

Hope this helps, Ian.

the-plumber

In that case don't waste perfectly good building time agonizing over an internal structure that cannot be seen once the covering is on.

I've got several hundred J-3 and L-4 photos, some store-bought and some that I took, and _none_ of those photos reveal the shape of the internal structure, and the only areas where the tube nature of the structure is evident are the leading and trailing edges of the fin, rudder, stab, and elevator. Otherwise the internal structure could be square tube (yes, we know it isn't) because with a layer of fabric, stitches, and pinking tape, the shape of the tubes is hidden and all you see is the flat surface of the covering/stitches/tape.

All the restored J-3s and the one L-4 I've laid eyeballs on use a flat plastic or wood square where the stitches are applied, and that "stitch plate" masks the round shape of the internal tubing.

I second the motion to laminate the curved parts of the tail feathers. Ever so much easier than bending tubing or dowel. Use balsa top and bottom, lite ply core. Use Titebond and cushioned clamps; finished product is seriously strong and light. That's the way the BUSA 1/3 J-3 (my L-4) is built.

badger41

Cub Man,

while laying out the out line for the nails also layout that portion of the stab that can plug into the fuse. This is so much easier when the wood is in the wet/noodle condition. After sanding just slip the tube [ alum or brass]over the laminated stab ends.
The 1/3 has an adjustable stab option where the 1/4 does not and you have to make that yourself.
tom

abufletcher

I have to disagree here. I found the process of laminating (in my case balsa) to be a major pain that gave less than satisfying results. I've seen other people do a great job (including master builder "Donnie" who explained the technique to me) but it sure didn't work for me the first couple of times I tried. In contrast, bending aluminum tubing was really simple (I wanted to say "a snap" but that seemed wrong) and incredibly fast and I think the results are far better and far more scale.

The whole trick with the tubing is to rub on some soap and then heat is until the soap turns black. Then just bend the aluminum by hand around a suitably sized cylindrical object. No jib was needed, just bent the tubing directly over the plans.

feep

Another way to go is to use tubing and bend it with sand inside. Join your tubing with dowels on a staight section. I only throw this out there because the best way to go is the way that works for you. This technique may come in handy in another situation. In the case for your Cub you need to prioritize. Strenghth, weight, appearence, building technique, ( not neccessarily in this order).

abufletcher

Interestng factoid here about the reason the famous Pfalz rudder is the shape it is. Seems that on the prototype the were using a more squarish shape like on the Nieuport but to make the tight bends that required the tubing needed to be filled with a hard to come by (during wartime) type of wax that then had to be melted back out -- slowing down the production lines.

So by altering the shape to the now classic curved shape (while still maintaing the same rudder surface area) they were able to avoid the need to fill the tubing thus streamlining production.

cyclops2

Tapeing 1 end of the tube and filling/ tapping it vertically till it is filled will let you bend it very tightly. Pulling on it as you bend is a big help. --Try a few tests to get the hang of it.

Think of a repair method if you want to. Aluminum is tough to repair. Wood is easy.

vogel605

I've been using 1/16 by 3/8 spruce or basswood soaked (as mentioned) and laminated. For straight runs I use carbon fiber arrow shafts avail. at sporting good stores. Balsa will not laminate well. Carbon fiber and hardwood laminations accept glue well, and are super easy to repair if needed. They do produce a super strong structure.

feep

I like the idea of arrow shafts. I'm thinking of doing a 1/4 scale Fokker Eindecker and The idea of carbon fiber for the fuselage seems feasible. The real thing was welded steel tubing. Weght is a big factor in WW1 aircraft, especially in the rear so I will certainly be investigating strong and light building technique for the stab and rudder.

The PIPE

Dear Cub Man:

The PIPE here again...and if you can access the AMA Digital Archive, and look for the RC Giant Scale Bristol Scout D building articles in the March and April 1981 AMA magazine, you'll find my old buddy HANK ILTZSCH used aluminum tubing...1/8 inch OD...for HIS Bristol Scout D's tail outlines !

I picked up on this from Hank, to do the tail outlines of my 1/6th scale Fleet Finch and Bücker Jungmeister bipes way back in the very early 1980s, with the K&S hobby shop round aluminum tubing, which DOES come in one YARD lengths in addition to the usual "one foot" lengths..it's available right down to their 1/16th inch OD smallest standard size on those one yard long lengths!

And there's NO chance of distorting the aluminum tubing with ANY sort of heat shrinkable model aircraft covering while shrinking it...this CAN happen with the outline pieces that are fabricated with laminated strips of thin wood (either balsa OR plywood), but NOT with aluminum tubing on there in the laminated strips' place..believe me, I've tried both, and the laminated outline pieces always distorted, and got somewhat "swaybacked", during the heat shrrinking process...the aluminum tubing simply will NOT do that...so I'll NEVER go back to laminating thin wood strips for tail outlines EVER AGAIN...!

A REALLY well stocked hobby shop should have the one yard length pieces of the K&S aluminum tubing for your needs...hope you've got one in your area...or have one that can order it for you!

Hope this helps...

Yours Sincerely,

The PIPE!

Bud Faulkner

My Feedback: (1)

You can also use aluminum welding rod available in lengths 1/16",3/32",1/8",5/32",3/16" and 1/4"
I have an article on this for model aviation. If anyone wants me to send it mail me and I will do so when I get home from work this evening (late).


Bud

Cub Man

My Feedback: (50)

My current plane as I type this is as follow. I have taken the balsa planes and have changed them a little to make it fit closer to the true outline of a cub. Balsa USA has the tail as a 3 layer laminate with lit ply in the middle. I’m taking this lit ply section and precutting it to fit the new outline. Next I will take some 1/16 strips of bass wood and put a laminate around the outside of the lit ply keeping the lit ply in the center of the laminate. I will use carbon fiber tubes for the straight sections. Thoughts on this setup????

The PIPE

With LAMINATED WOOD in there, you COULD get those "swaybacked" problems I mentioned...!

Dear Cub Man:

The PIPE here once more...believe me, Hank Iltzsch DID convert me "for keeps" to using ALUMINUM TUBE for tail surface outlines...and when compared to the laminated wood outline pieces I HAD tried using in the past, the aluminum tubing has the older laminated wood curved pieces beat in every respect...ESPECIALLY when a heat shrink fabric covering gets used!

For some of the SAM-type Old Timer models, where the original style of construction HAS to be used for it to be accepted as a "true Old Timer", the designs that DO call for laminated wood strips for curved outlines might still have to be replicated with that same exact method...but for a Scale model, where the full size aircraft could very likely use some sort of metal tubing for the tail outline, like a Cub does, it's STILL a better idea to follow "the full scale way of things"...

...and give that aluminum tubing, like K&S's yard-long lengths (where the curved part WILL be longer than one foot in total length) the firm nod for use on the tail surface outlines!

Not meaning to dissuade you from using the laminated wood, but IF that laminated wood outline piece "swaybacks" between the ribs, when a heat shrink fabric covering gets applied to the tail, maybe that idea of Hank's, mine, and others to try using the aluminum tubing idea MIGHT not sound "terribly out-of-place"...

I'm just hoping you DO end up with nicely contoured tail surfaces after the heat shrink fabric covering IS shrunk tight, no matter how you choose to build the tail outlines!

Yours Sincerely,

The PIPE....!

badger41

I have seen the Cub that was a kit with all alum tubing back in the 80's and I have seen many flat stock [balsa] bend ,flex ,bow. I have seen the warping so bad its a wonder it flew. But I have never seen a laminated part once built ever move, flex, warp or push and pulled by the fabric and paint finish. I once thought that it was difficult to make ie. paterns , but thats why the nails evolved. Keep it simple is the answer. Do it once and you will never go back, for these kind of parts.
tom

Cub Man

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well I'm an AutoCAD Drafter during the day so I keep a folder on my PC with all my drawings on it. I have the wood on order just waiting

frank99

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i think you are the guy i need do you have a cub webb site in ky? and here is a picture of a bearing on my 1/3 cub, BOB N. plans, a cable runs on the bearing for the ailerons, is this on the real cub, do you know where to get one, the plane has a few lost parts,i can make some parts, but to many arfs, need practice, but this might be hard to find thanks frank

Bud Faulkner

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frank,
Where did you get your brass pulleys?

Bud

frank99

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bud got a hand full here, one of the pulleys is (missing), got this plane on rcu and it is nice but this is a bob nelitz plans 1/3 cub (scale), it is framed up 95% but like i say a few things are missing. wood ez but metal? i have built four sig 1/4 cubs but this one is scale and i would like it to look like your planes, nice and right, any ideals on locating the pulley would be nice thanks frank
oh thanks for all the tips on dave patrick p-18 got a few parts for that plane (muffler os 1.6) but i guess i would have a better chance at winning the lotto(365mil) than getting this plane, frank, to many planes on the work bench[&:] semelka

frank99

My Feedback: (29)

bud here are a few pics of this beautful aircraft, had to take two pics, to big with both wings on, got to get this beaut in the AIR, power os 320 4/c this will be a head turner when finished thanks frank