Hi, Guys-

I posted this on SSWF and have gotten some interesting responses, but thought that I'd also se what some of you stationed over here think too.

I can't find any more of the cloth-hinge material I've been using and really like. Unfortunately, I'm not really sure what it really was; so I did a search on "cloth hinge materials". I found several preferences and some disagreement on durability and chemical resistance. Dacron, parachute rip-stop nylon, polyester and nylon taffeta, polyester dress lining, and rayon taffeta were suggested, with one contributor stating that polyester taffeta wears out quickly and another disagreeing. I looked up polyester fabric on the internet and found that it was susceptable to damage from some alcohols, but apparently not from methanol or ethanol. I found no data on nitromethane and didn't look up resistance to lubricants we use. A couple sites suggested polyester fabric wing coverings adhered and finished with both nitrate and butyrate dopes, but other sites said that polyesters were not very resistant to thinners. They seem OK with acetone. SO...

I went to Jo-Ann Fabrics to see what I could find. They weren't very helpful, but I brought home 3 remnants for less than $5.00, labeled as follows :

White Sport Nylon - 100% Nylon
Shan White Lining - 100% Polyester
Sign Bon Solid 118IN Voile 118 - 100% Polyester

I was not able to find the taffeta labeled. These each seem to be of useable strengths and thicknesses. Does anyone know of any problems with using any of these? 'any preferences?

Thanks much.

SK

I have used Poly-ester material from the fabric store.   Lately I have been using the SIG Coveral cut into strips and doped on to the surfaces.   Have to predope the surfaces first.   Can't remember what the old Perfect cloth material was, but used a lot of it when I could get it.  I have even tried using the scraps from my Poly-span material and do not reccoment it.

I use to use rivet covering, that I got at the airport for canvass cover planes, doped on. It had pinked edges and it must have come in 50' rolls, that's a long time ago....

Thanks, guys, for the interesting ideas. While no one actually addressed my question, I've enjoyed the responses. Now it's past time to put on some hinges; so that's on the calendar for today.

Interestingly enough, Dave and Ty, I actually looked in my closet yesterday, and tucked in with my old "Care Package" stuff from Larry Cunningham, I found a little bag of CL purchases I'd forgotten. In it were two packages of Tom Morris Dacron hinges that look like what I used last time - and like a couple of the Jo-Ann remnants I'd brought home. So I guess I'll use Tom's hinges this time. I think everything I bought is OK, and since my hinge lines are well shielded, they'll probably not be affected by chemicals. Still, if anyone wants to add anything about polyesters, I'll be listening and reading.

I've always used cloth hinges, and the present, way too l-o-o-o-o-n-n-n-g project involves just what I did the last couple times, as pictured below. Not shown is that the stab outer laminates are tapered down toward the elevator to redirect the air and meet at a point above the hinges. It seemed to work well and does shield the hinge material from sun and exhaust.

Aircraft Dacron is called "Ceconite".  Also known as Dacron "Griege", meaning it is not shrunk.  If you use it, be careful with any heat nearby.  It will shrink and bind up your controls!

Floyd

Thanks again, guys -

Charles - I know it looks like aluminum tubing (club members thought so too, even up close), but it's just dope. I always finish the hinge-line edges before hinging the two parts together, so that I don't get dope on the flexing part of the hinges, when finishing after assembly. In these cases, I used Brodak "B-25 Silver" and clear, since I was using the silver as a base finish for the model. Now that you've mentioned it and I've seen what aging eye sight did to my rounded edges this time, maybe the tubing would be a good bet. 'might try that, although continuous barrel hinges might then be a temptation.

Anyway, I did go ahead and use the Morris dacron hinges I found this time. It looks like what I did last time. They went on easily with Sig alaphetic resin glue, which sets up very fast, even after thinning and brushing on (I had pre-glued the rectangular attachment areas). You can remove and re-set for a time, but it remains anchored in place almost instantly, so that the stab and elevator remain tight. Short, early hinge deflection ensures free hinges. Process is quick. I've used Elmer's and carpenters' glues too. I think they're easier and less messy than others.

Mike - Thanks for the Aircraft Spruce link. I've used them before (materials for my KR-1 project in the 1970's) and love their catalogs, true encyclopedia's for the fabricator.

AND,... I still like cloth hinges!

SK

Charles -

If you mean the dacron hinge strips, they are 1" x 1" squares, alternated top-bottom across the span, criss-crossing each other to connect to opposite surfaces on the other side of the gap. They touch spanwise.

They're quite easy to put in place. After measuring (not necessary for most modelers, it seems) and marking their positions, I brush some diluted glue on the rectangular areas where the strips will be and let that dry. Then re-applying in each successive location and pressing each strip in place is easy. After all the hinges were on the stab, I glued their other ends to the elevator in just a few minutes. The attachment process itself is quick and easy, the least of building challenges.

I've been thinking about doing what Eric Rule (RSM) does in his kits, as in Mikes pictures on his P-40 thread, which I think is similar to what you suggest. I'm not at this point too concerned with hiding the hinges, but they come close to disappearing in the process of covering the elevator, sanding level, and finishing. Labor saving is good though!

Someone here or maybe at SSW had a method I want to try. Cut the stab and elevator pieces each out of half thickness balsa and sandwich a continuous fabric strip between them. The result is there's nothing to hide on the surface, and a completely sealed hing line. Plus, I would think the laminated parts make a stronger control surface. I think I'll try that on my current build. If I don't botch it, I'll post pictures.

Rusty

Rusty the new RSM Electric P40 Pofile uses a ribbon for a continuous hing between the elevators and the stab and the flaps and wing.  I have not completed the wing yet so I do not have pictures on the building thread yet so you cannot see how this works on the flaps but I will be glad to take the time and explain it.

The stab is two pieces of 3/16" balsa.  Each elevator (left and right) are two pieces of 3/16" balsa also .  Here is how you build the stab.

NOTE:  THIS IS EXTREMELY IMPORTANT.  MAKE SURE YOU BEVEL THE LEADING EDGES OF THE ELEVATORS BEFORE YOU PUT THE RIBBON BETWEEN THEM.  ALSO MAKE SURE YOU LEAVE ABOUT 1/32 OF A SPACE BETWEEN THE LEADING EDGES OF THE ELEVATORS AND THE TRAILING EDGE OF THE STAB SO YOU WILL HAVE ADEQUATE TRAVEL OF THE ELEVATORS.

Lay the bottom stab pieces on the plan and mark where your wire joiner legs go into the elevators.  This plane uses a wire joiner for the elevators and flaps but the horns are nylon and surface mount to the elevator and flaps.  The music wire pieces that come with the kit are 3/32" but I cut in 1/8" grooves and fill with epoxy.  The way I do this from this point forward is that I cut in grooves on the top and bottom pieces where the wire horn will go into the elevators.  I have a round 1/8" file that I use to cut a groove in all four of the pieces (top and Bottom).  Once this is done, I pin the bottom left and the bottom right pieces of the elevator on a piece of sheetrock or whatever you have that will work, against a straight edge and put the wire horn legs in place in the groove.  I fill the horn channels with 30 minute epoxy and lay the horn in place.  I then cut two small squares of 1/2oz fiberglass cloth and lay over the horns and brush over them with some epoxy.  Whe the leading edges of the elevators are flush with my straight edge, I cut a piece of Parchment paper or wax paper and lay over the horn legs and weight down the horns and let them dry usually over night.

When this has cured, cut a couple of pieces of 1" white satin ribbon the length of each elevator and lay on your table. Using a straight edge ruler, take a crayon and draw a line right down the center of the ribbon.  This is important because it keeps the glue from wicking into the ribbon and making the hinge stiff.   Repin you bottom half fo the elevators again and using ZPOXY finishing resin, brush the resin over the surface of the two bottom pieces of the elevator being careful not to drip resin over the leading edge of the elevators.  Once you have brushed on your resin, take a old credit card or playing card and squeege off the resin.

Now take to two pieces of ribbon you have cut and place a little less than 1/2 of the width of the ribbon on the leading edges of the elevators making sure you have enough hanging out to go between the stab pieces when you get to that part of construction.  Work the resin into the ribbon so it will adhere to the balsa well.

Now grab the two top elevator pieces and making sure the grooves in the top pieces are directly over the horns, pin or weight down the elevators making sure your ribbon pieces are sandwiched inbetween and you have enough sticking out to go between the stab pieces.

When this assembly is dry, put the bottom 3/16" piece of the stab underneath the ribbon that protrudes out of the elevators and apply resin on the ribbon and complete surface of the bottom piece of stab.  Now lay the top 3/16' piece of the stab on tope and weight down making sure you have left as least 1/32 of an inch between the stab and elevators.  Once this is dry you are finished with the stab and elevator unit.

The wing flaps are built exactly the same way but application of the flaps to the wing is a little different.  Go ahead and build your flap unit using the same procedure as you used for the elevators.

Here is how you apply the flaps to the trailing edge of the wing.  You have two pieces of 3/16 x 3/8 balsa sticks in the kit and the ribbon is glued or sandwiched inbetween these two pieces which are glued to the trailing edge of the wing.  Take one piece of the 3/16 x 3/8 stick and glue it to the bottom half of the trailing edge of the wing.  This will give you a Shelf to which you can glue the protruding pieces of ribbon sticking out of the flaps to.  Scoot the flaps into position and glue down the ribbon to the applied piece of 3/16 x 3/8.  Then glue the other piece of 3/16 x 3/8 over the ribbon on both the inboard and outboard wing leaving at least 1/32" gap in between the trailing edge of the wing and the leading edge of the flaps.

I hope this helps

Mike

Not yet Joe.  I am in the process of building the wing and will take some pictures as I do this. 

Mike

Charles-

OK...I'm up for air after wrestling with the club newsletter and playin a gig. I'm not quite sure what all your question implied, but perhaps the answer is somewhere in these photos of what I described. These are the hinges I just installed, but except for the earlier shots, I have no illustrations of sheeting the stab. This is the new one. BTW, the truss work only took a couple hours on a sunday morning, less time than arriving at a reasonably tapered elevator, after repairing errors; so the truss work is well worth the minor effort in achieving a torque resistant stabilizer.

1) Brushed-on, thinned "Sig-Bond" aliphatic resin glue in rectangles at hinge locations.

2) Parts aligned as a check.

3) Beginning attachment of hinges to stab. I chose to do the stab attachments first, because I like to draw a line for allignment, and that line will be under sheeting that won't allow ink to bleed through any dope finish. I may or may not sand the marks on the elevator away, since I plan of using West Systems epoxy. If I use just silkspan and dope though, I'll need to remove the ink.

4) All hinges anchored to stab. I just brushed on the thinned aliphatic resin glue in over the same areas, one at a time, to attach individual hinges. The amount was just enough to rise into the weave, but (usually) not to puddle. I pressed each hinge against the wood with fingers and removed excess.  I then flexed the hinges to go to correct alternate sides of elevator when mated, as shown.

5-6) All hinges glued to elevator. The glue sets fast, and I did hinges in adjacent pairs to align the surfaces vertically, since the elevator had gotten thinned a bit too much (that's age related incompetence!). I first attached a pair of hinges near one tip, then at the center, and finally at the other tip. The elevator gets deflected after gluing each pair to ensure free movement, but this glue has set enough after each operation to be able to work over a sheet of waxed paper without making a mess or getting excess onto the bare wood.

7) Close-up of center, "warts and all." You can see the patch I had to put on elevator, when I sanded wrong in tapering - too good a piece of straight C-grain to waste. I had used the varying-diameter piano wire method to taper and still screwed it up. This was particularly annoying, in that experience is supposed to make one better at his! What doesn't show is that this is the second elevator made, the first one having been too light and flexible/unstable. The rectangular pieces where the horn attaches are pads to distribute attachment compression forces. Another thing not shown is that I had to laminate CF veil over the pad on the bottom in order level it, where I'd inset it too deep - another dubious first on this project. Two steps forward and one back. The horn-bolt holes are through dowels inserted vertically between the pads. Oh, heck, I'll show that too...

8 ) Earlier step, recess for pad, showing dowels epoxied in.

9) ...and trial horn attachment.

10) Another close-up. What I ment about finishing the elevator is that these hinges and other imperfections will be covered with either CF veil, .56-oz FG, or silkspan. With any choice, sanding should remove the covering above each hinge, pretty much leveling the whole surface. For this plane, whether the hinges show is inconsequential. But I can't see a problem for top contest level stunters to have that area completely filled in and smooth with cloth hinges.

11) Finally, this is the end cross section as it appears after the hinging, but before sheeting of the stab and contouring the section. I don't know why the elevator t.e. appears warped; it isn't. I've completed three this way, and this is the worst...

SK

Serge.  I like your idea of extending the stab sheeting to partially hide the hinge gap.  I'm going to use your idea on my next plane.

I personally like to glue my cloth hinges with Ambroid.  Doesn't require any pre-glueing, and sticks down with first application.

Floyd

Floyd-

I doubt that the pre-gluing was absolutely necessary, but it seemed like a reasonable precaution. At normal thickness, this glue should suffice with a single application. I always pre-glued using Ambroid too.

Charles-

I don't get many planes finished; so this is just the third tail done this particular way. I've been around - on this Earth - for quite a while now, but mostly I'm just very careful (obviously not enough!) and pay attention to detail. So I'm just an above-average quality builder who has never really tried yet to do a full contest type finish. I would never compare my efforts and results to what we see so often on these forums.

SK