How Do You Like to Glue Wire Joiner & Hinges?

[Kafin Noe’man]

Happy new year!

I’m now assembling my P40 ARF and I’ve reached to the point where I have to glue the hinges and wire joiner.
So, my question is how do you like to glue your flap-wing and stabilizer-elevator? Glue the hinges one side at a time? Glue the hinges on both sides together at the same time?

And when is the best time to glue the wire joiner? Is it okay if we glue the wire joiner after both of the flap/elevators are attached and its hinges are glued in to the wing/stabilizer?

Looking forward to hearing from you!


Best,
Kafin

[Ken Culbertson]

Happy new year!

I’m now assembling my P40 ARF and I’ve reached to the point where I have to glue the hinges and wire joiner.
So, my question is how do you like to glue your flap-wing and stabilizer-elevator? Glue the hinges one side at a time? Glue the hinges on both sides together at the same time?

And when is the best time to glue the wire joiner? Is it okay if we glue the wire joiner after both of the flap/elevators are attached and its hinges are glued in to the wing/stabilizer?

Looking forward to hearing from you!


Best,
Kafin

I would not be gluing them at all since I make all of my control surfaces removable.  Put the ends into brass or aluminum tubes and glue the tubes to the flap/elevator.  Then mount the joiner to the wing/stab just as if it were a horn.  What happens if you don't secure the joiner/horn to the wing in some way is all of the force of moving the controls in flight, and it is considerable, falls on the first hinge.  If you use stout wire and mount it to the wing the horn on the flap will be nearly as good as a brazed horn.  No matter what, if you do not use a brazed horn, put an extra hinge as close to the horn as you can get it.

As to how to mount hinges properly, do a search here then pop some popcorn because you will have a whole lot to read!

Ken

[Steve Dwyer]

Kafin,

If you are referring to the Dubro barrel style hinges with a fixed or removable wire, I'd consider the following method. After slotting and preinstalling all the hinges between both control surfaces, next select the glue. I prefer to use 30 min epoxy because it gives me ample time to install and position all the hinges. Many also use a white glue especially designed for hinges.  Place a dab of petroleum jelly or oil on the hinge barrel pin before applying the epoxy to the hinge, be careful not to get the jelly or oil on the surface to be glued. I also make sure the small holes in the hinge tabs are filled with epoxy, this allows for a better adhesion to the balsa once in the slot. Insert the hinges into both surfaces and align the pins parallel to the slot. I do not recommend gluing one side only as this is risky the alignment of the hinge will not be accurate when gluing the opposite hinge control surface. Lastly using a cloth with Naptha or Preclean Solvent I wipe the hinge barrel on both side and remove any epoxy that may have oozed from the slot. Check the freedom of the control surface as the epoxy sets. I don't use removable pins but once the hinges are set this would be a good time to secure the pin with a dab of epoxy.

There are several videos here describing this procedure including recessing the hinges to tighten the slot dimension. Good luck.

Steve

[jerry v]

Kafin,
I built and flown Brodak P-40 ARF. Originally it flew on OS.40 FP with 1.5 oz nose weight ( it was tail heavy). Then I put the OS.46 LA with stock muffler for better balance. I used APC 12x4 prop and landing gear have to be extended. Line length now 62 ft eye to eye.
About the flaps and elevator: make new joiner wire for flaps halfs and elevator halfs. I used piano wire diameter 3/32 inches to replace the kit weak joiners. To glue hinges - use the slowest possible epoxy and assemble everything at once. Slow epoxy will give you enough time to move flaps freely to set proper gap and position. Clean up excess glue with alcohol, acetone or else)) Monocote covering will not be damaged. After cleaning I put drop of oil on the hinges wire and move the flaps up and down. Oil protects hinges from sticking after epoxy cures.

Jerry

[Colin McRae]

Kafin, on my P40 ARF, I used Robart 1/8" pin style hinges.

My ARF kit came with CA type easy hinges which are total crap, and it is highly recommended not to use them if your ARF came with the same type of hinge. They are weak and will not last.

On my ARF, I first installed the joiner wires accurately in the flaps and elevator using 2-part 30-minute slow cure epoxy. I let it fully cure for 24 hours.

Next, I aligned and drilled all of the holes for the Robart pin hinges. I used the Robart hole centering tool. The hinges are recommended to be used with the same slow cure 30-minute epoxy. It is very important to ensure no epoxy gets into the hinge pivot joint. Before installing the hinges, I heated up a small amount of Vaseline petroleum jelly on the underside of a used soda can using a micro torch. Do not overheat it to boiling, just hot enough to liquify it to the consistency of water. When still in liquid form, I dipped the hinge pivot area into the liquid jelly and allow to cool off. This will coat the moving part area of the hinge to prevent epoxy from binding the hinge. Plus, the solidified jelly will not flow onto unwanted hinge areas. As an alternate, a drop of 3 in 1 oil on the hinge pivot area can also be used, but I prefer the heated jelly method.

Then I installed all the hinges with epoxy on the flaps and wing sections. First all hinges on the flaps, then attach the flap assembly to the wing. You don't need much epoxy in each hole. You have to work reasonably fast because the epoxy starts to set and thicken. Once installed and having the parts snug up against each other with minimal gap, I rotated the flaps up and down several times to align the hinges, ensure free movement, and no binding. I also used some rubbing alcohol to wipe off and remove any excess epoxy. Once done, I let it fully cure for 24 hours.

Then I repeated the entire process for the stabilizer/elevator.

Also, before any gluing of the hinges, pre-fit the wing/flaps and stabilizer/elevator together with hinges to ensure all the holes are the correct depth so the finished control surfaces will have zero or minimal gap, and the surfaces move freely.

There are also lots of YouTube videos available on hinge installation. I did my fair share of hinge install video watching before I did the real thing. I even also practiced a control surface hinge install on some scrap balsa surfaces to make sure I was comfortable with the above-mentioned Robart hinge install method. Highly recommended to do a practice run as you don't want to make a mistake on the model.

[Steve Dwyer]

How many here remember the old brass Perfect hinges that were popular in the 50s and 60s that used a long interconnecting wire as a pin?  Two hinges were installed next to each other instead of like today's interlocking fingered barrel style. I still have one model I built at 13 that has these, they worked ok and were a step up in appearance from cloth hinges.

PS Jerry V. how the heck are you? Haven't seen you since we were drenched flying at the Ringmaster Fly Athon last fall.

Steve

[jerry v]

PS Jerry V. how the heck are you? Haven't seen you since we were drenched flying at the Ringmaster Fly Athon last fall.

Steve
[/quote]

Steve,
It was a year ago!)) I’m fine!

Kafin,
I used Du-Bro nylon hinges. They are more “forgiving “ during installation than Robart hinges. Throw away CA hinges, they won’t survive CL stunt.

Jerry

[Kafin Noe’man]

glue hinges - use the slowest possible epoxy and assemble everything at once.

Does it include gluing the wire joiner at once?

[jerry v]

Does it include gluing the wire joiner at once?

Kafin,
After dry fit of all components get ready for glue. P-40 wing with flaps installed slides into fuselage, and don’t forget to slide a “wedge” together to plug the opening for flaps. You can call it a fairing. Make sure the groove for joining wire in the fairing is big enough for flaps free movement. Now back to the glue. I used 30 min epoxy. Insert the joining wire with the glue into both flaps, put clear scotch tape over the glued area on the each flap, overlapping the wire and flap to keep wire in place. Put the assembly on the wax paper cowered flat surface to have alignment on the “vee” hinge line. Mix epoxy again and install the hinges with the glue into both flaps. Tape over the joining wire will help to hold everything together. It’s easier to hold flaps vertically during this process. Mix more glue and install all the hinges with flaps into the wing. Wipe extra glue from the hinges, set the correct gap with the card stock and move the flaps back and forth until you feel the free unbinded movement. Pull the card stock out and check the actual flap angle deflection. You need up to 40 degrees of the free movement. More gap - bigger angle. Any gap in the hinge line will be sealed with clear tape later. Now is a good time to wipe all your epoxy fingerprints from Monocote  from all surfaces with the acetone. I usually waste a lot of nitrile gloves for hinges installation. 30 min epoxy gets tacky within 10-15 minutes. Every new epoxy mix is thinner than one mix for all. And 2 hours cure time is enough to position all components in place. All process may take you 30 minutes to one hour, epoxy is still manageable. Clean all hinges with rag, acetone or rubbing alcohol and continue moving flaps . Put oil on the clean hinges and continue to move flaps. I use the oil for  the bronze brushing on the speed 400 can electric motors. Oil pipette has a very thin needle. At this time it’s a good idea to put proper shims in the hinge line gap ( and gap is not consistent in the ARF) And hold the wing on the leading edge vertically with flaps on top vertically. Epoxy still not cured and flaps with hinges will “sink” into the wing. That’s why you need to put shims to keep the correct gap. This is what I called install all together. Stabilizer and elevator hinges are installed in the same way.
Kafin, you can make a custom control horn brazed to the joining wire and make better ball joint linkage. Original kit hardware requires to bend the pushrod to clear the flap movement (I did this) Or you can install the offset control horn on the flap to be closer to the edge. Or make custom steel control horn brazed to the joining wire.

Jerry