Hi. I'm working on an old PILOT 1/4 scale Decathlon. The fuse is all framed-up and covered w/ Sig Coverall. I'm at the point of setting up the door and side window hinges. Never having done operable doors, I was wondering if you guys have any suggestons as to the appropriate hinges to use. I would rather hinge from the inside in order have the hinges hidden from sight. Any pics would be greatly appreciated.

Thanks.

Find the smallest pin-type control hinges that you can and slot the doorframe like you were going to mount an aileron or rudder. If you mount the hinge inside the door, it has to have enough offset so that the thickness of the door doesn't bind it when you open the door.

khodges, thanks for the suggestion. At the door and window locations, the fuse is a lamination of 1/8" balsa and plywood, tricky to get a flat, pinned-style hinge in there.

If the ply is inside and the balsa outside, try to slit at the seam between them with a #11 blade, go slow and make the slot longer than you need by a couple mm, enough to get a small piece of razor saw into it to "clean "it out. You can trim the hinge, and in some cases, just cut it in half. This isn't my idea as much as SIG's, this is how they show to mount the drop-down door and lift-up window on their Cub kit. Instead of gluing it in, if you get a fit that is tight enough, you might want to pin the hinges, will allow you to remove the door if you ever need to without worry of tearing up the doorframe. DuBro makes some really small (thin) hinges designed for 1/2A and .20 size planes that would work well for door hinges on a plane the size of yours, after all they don't have to take aerodynamic loads.

khodges, thanks for the explanation, but if I understand you correctly, then I am to insert the hinge in the door frame in the middle of the fuse side between the 1/8" balsa and 1/8" ply lamination, right? Now, if I then attach the hinge to the door on the inside (the door is 1/8" plywood, won't it still bind??

I used very small Klett hinges on my Cub. Just used two, mounted as close to the outside surface of the door and fuse as possible. An X-Acto saw blade works well to dig out a 1/16 slot. The door and fuse skin may bulge slighty, but a little filler smooths the area out.

You'd have to slit the door also, like the door frame, and also slightly bevel the hinged surface so it will clear somewhat as the door opens. It is only going to allow about 30-40 degrees of swing from the closed position before it starts to bind. Does this door have to open all the way for access to the cabin, or is this a cosmetic detail? The other way would be to get some very small brass hinges like those used in music box lids or very fine dollhouses, they hinge like the doors in a house and would permit greater opening. You'd have to trim them to fit and probably pin them instead of gluing. Homepylon's method looks like mine, and works well for the cub doors, but you may not have the thickness to work with.

Why not hinge it like the full scale? It has external hinges with a long pin that goes between the two hinges. the pin had a cable attached with a handle on the inside to pull and release the door. Have a couple hundred hours in a Decathalon so I'm describing this from memory but I'm sure you could find a picture of this area pretty easy. Would be easy to do with some aluminium or brass sheet. Don

Sounds like a good way to go. Having never seen a full size Super D, I was thinking concealed hinges, but looks like Citabria, or whoever builds the Decathalon now, made it easy. This way would not bind the door at all; pinned style hinges would still work, trim them to make them smaller, paint them to match cover.

Yup, looks like external hinges are the way to go. Homepylon, that's a beautifull looking Cub you got there. I too build a Sig kit, the clipped wing version. Here are a couple of pictures. The Pilot Decathlon is shaping up very nicely - it seems to have a very scale outline, but I must say that the almost non-existent instructions proved to be a challenge.

Homepylon-- I had to look twice at your finished plane picture- until I saw the OS cylinder head, I thought it was the full-size plane that maybe you used for reference--that is one fine looking aircraft.

LuvBipes, your Cub is just as awesome, I love the Hazel Sig paint scheme. What size Saito is that? Here's my humble attempt, second plane I ever built:

Khodges, humble attempt?? Holy cow, that's one heck of a nice plane. I bet adding all that glass area took a bit of time. I'm a hack compared to you guys.
My 1/4 scale Cub has a Saito 150 in the nose which allows it to perform some very unscale like maneuvers (I fly a lot of IMAC stuff), like hovering and knife-edge circles. It's 3 years old now and has given me 100+ trouble-free flights, The darn thing still puts a smile on my face every time I fly it. Here's a rear view shot.

Oh, btw, just got back from the LHS and picked-up these Robart hinges which I'm gonna' try. They're Part # 350 Door Hinge 1/5 & 1/4 Scale, and here's a link to the web page (you mustr scroll down a ways). I'll report back as to how they work.
http://www.robart.com/Hinge.aspx

thanks again guys.

OK, the Robart hinges are nice, but waaaay too big for a 1/4 scale plane. IMO they would look OK on 40% plane. Anyway, I decided to hinge externally with some Sonictronics hinges I had lying around. Hopefully they'll hold up OK.

The attached photo is of hinges that my mate, Ken Spears made for his 33% Decathlon.
I also make similar for mine but don't have photos of them. I'm sure Ken won't mind me uploading his.

These hinges are quite easy to make out of brass profile and a brass pipe.

Dunno how applicable it might be to the Decathlon, but the Piper Cub/L-4 prototype hinges should be pretty simple to fabricate (I hope, 'cuz I ain't made mine yet). Here's a photo of a 1:1 L-4 lower door :